Proceedings of the

3rd Biennial Spooner Dairy Sheep Day

Saturday, August 25, 2007 Spooner Agricultural Research Station

College of Agricultural and Life Sciences University of Wisconsin-Madison

Spooner, Wisconsin

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Spooner Sheep Day was held annually at the Spooner Agricultural Research Station for 50 years – from 1953 through 2002. We believe that it is the longest running agricultural field day of the several organized each year on the various Agricultural Research Stations of the College of Agricultural and Life Sciences, University of Wisconsin-Madison. After the 2002 Spooner Sheep Day, the decision was made to hold the traditional Spooner Sheep Day every-other year on even-numbered years. This decision was made so that a Spooner Dairy Sheep Day could be held on odd-numbered years with a program that could be better tailored to the focused issues of the dairy sheep industry. Therefore, there is still a sheep field day at the Spooner Agricultural Research Station every year, and even though the 2007 field day is only the 3rd Spooner Dairy Sheep Day, it is the 55th consecutive annual sheep field day held at the station, and we hope to host many more.

David L. Thomas, Proceedings Editor Department of Animal Sciences University of Wisconsin-Madison and Cooperative Extension University of Wisconsin-Extension 1675 Observatory Drive Madison, WI 53706 dlthomas@wisc.edu 2007

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TABLE OF CONTENTS

PROGRAM …………………………………………………………………………………… 1 EFFECT OF SUPPLEMENTATION ON MILK PRODUCTION OF DAIRY EWES – C. M. Mikolayunas, D. L. Thomas, Y. M. Berger, K. A. Albrecht, D. K. Combs, and S. R. Eckerman ………………………………………………………………………………………. 2

THE EAST FRIESIAN BREED OF SHEEP IN NORTH AMERICA – Yves M. Berger ………………………………………………………………………. ……….. 10

RAISING LAMBS THE RIVER RIDGE WAY - Larry and Emily Meisegeier and Ruth Grinnell ………………..…………………………………………………………………. 17 30-DAY WEANING SYSTEM - Kim Cassano and Rich Toebe ………………………..…… 21 MIX WEANING AT DREAM VALLEY FARM - Tom and Laurel Kieffer ………………. 22 EFFECT OF PREPARTUM PHOTOPERIOD ON MILK PRODUCTION OF DAIRY EWES - C. M. Mikolayunas, D. L. Thomas, Y. M. Berger, T. F. Gressley, and G. E. Dahl …. 25 PROGRESS REPORT: EFFECTS OF PREPUBERTAL GROWTH RATE OF EWE LAMBS ON THEIR SUBSEQUENT LAMB AND MILK PRODUCTION - David L. Thomas and Yves M. Berger…………………………………………………………………… 32 SHEEP PASTURE MANAGEMENT FOR 2007 - Phil Holman …………………………… 40 KATAHDIN HAIR SHEEP AT THE SPOONER AGRICULTURAL RESEARCH STATION - David L. Thomas and Yves M. Berger ………………………………………….. 42 2006-2007 PERFORMANCE OF THE SPOONER AGRICULTURAL RESEARCH STATION FLOCK - Yves M. Berger…………………………………………………............ 43

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PROGRAM

3rd BIENNIAL SPOONER DAIRY SHEEP DAY (Focusing on research and issues of the dairy sheep industry.)

Spooner Agricultural Research Station of the University of Wisconsin-Madison Spooner, Wisconsin

Saturday, August 25, 2007

8:30 a.m. Registration - Station Headquarters

9:00 Welcome and Station Update – Heidi Zoerb, Academic Planner in the Office of the

Dean; Dick Straub, Director of Agricultural Programs and Agricultural Research

Stations; Dan Schaefer, Chair of the Department of Animal Sciences; and Yves

Berger, Superintendent of the Spooner Agricultural Research Station; College of

Agricultural and Life Sciences, University of Wisconsin-Madison

9:15 Supplementation of Lactating Dairy Ewes – Claire Mikolayunas, Graduate

Research Assistant, Department of Animal Sciences, UW-Madison

10:00 Assessment of the East Friesian Gene Pool in North America – Yves Berger

10:30 Break

10:45 The Lamb Weaning and Milking System that Works in Our Operation –

Day–1 Weaning and Milking – Larry and Emily Meisegeier, Dairy Sheep

Producers, Bruce, WI

Later Weaning and Milking – Rich Toebe and Kim Cassano, Dairy Sheep

Producers, Catawba, WI

Later Weaning and Day-1 Milking (MIX System) – Tom and Laurel Kieffer, Dairy

Sheep Producers, Strum, WI

Noon Lunch - Purchase tickets at the time of registration

1:15 p.m. Photoperiod Effects on Milk Production of Dairy Ewes – Claire Mikolayunas

1:45 Effect of Level of Nutrition of Ewe Lambs on Their Milk Production – Dave

Thomas, Professor of Animal Sciences, UW-Madison

2:15 Move to Sheep Pastures and Barn

2:30 View Sheep Pastures and Discussion of Pasture Issues and Research – Phil

Holman, Assistant Superintendent, Spooner Agricultural Research Station 3:15 Dairy Sheep, Katahdin Hair Sheep, Sheep Barn, and Milking Parlor Open for

Self-Guided Tour with Staff Available to Answer Questions

4:00 Adjourn

Attendance at the educational sessions of the Spooner Dairy Sheep Day is free. There is a charge for the lamb barbecue lunch.

For more information, contact Lorraine Toman at the Spooner Agricultural Research Station (phone: 715/635-3735, email: lltoman@wisc.edu).

Spooner Dairy Sheep Day is sponsored by the College of Agricultural and Life Sciences, University of Wisconsin-Madison and Cooperative Extension, University of Wisconsin-

Extension.

Make Plans Now to Attend the 2008 53rd Biennial Spooner Sheep Day on Saturday, August 23, 2008.

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EFFECT OF SUPPLEMENTATION ON MILK PRODUCTION OF DAIRY EWES

C. M. Mikolayunas1, D. L. Thomas1, Y. M. Berger2, K. A. Albrecht3, D. K. Combs4, and S. R. Eckerman1

1Department of Animal Sciences, 2 Spooner Agricultural Research Station, 3Department of Agronomy, and 4Department of Dairy Science

University of Wisconsin-Madison

Introduction Dairy sheep production throughout the world is generally pasture-based, with ewes receiving

supplement in the milking parlor. No studies have reported the effect of supplementation under dairy sheep production conditions in the United States - genetics based on Lacaune and East Friesian breeds and grazing of improved, temperate pastures. Two grazing trials were conducted at the Spooner Agricultural Research Station to determine the effect of supplementation of ewes at different stages of lactation and the effect of different levels of supplement. Nutrient Requirements Can a dairy ewe consume enough pasture dry matter?

Previous authors have suggested that dairy ewes can consume 4 to 6 % of their body weight (BW) in dry matter (DM) per day. However, these estimates are based on ewes of different breeds with lower production levels. Avondo and Lutri (2004) presented data of various breeds with weights of 93 to 165 lb. and milk production levels of 2.4 to 4.4 lb./d. Dairy ewes at the Spooner Station can weigh over 220 lb. and produce up to 6.5 lb./d. A recent confinement feeding trial at the Spooner Station found intake levels between 3.2 and 3.9 % of BW for ewes producing 5.3 to 5.7 lb./d. Large ewes may eat less DM as a percent of their BW due to the increased size of their rumen, which can hold feed longer and extract more nutrients per lb./DM than smaller ruminants.

Based on an average level of intake of 3.7% BW, a “typical” dairy ewe from the Spooner

Station in mid-lactation weighing 198 lb. may consume 6.3 lb. DM/d. Based on this level of intake, she would need to consume 49 lb. of fresh pasture (at 15% DM), 14.6 lb. silage (at 50 % DM) or 8.3 lb. dry hay (at 88% DM). Due to the high water content of pasture and the size of a ewe’s rumen, she may have a hard time eating such a quantity of pasture. However, previous reports of DM intake levels of lactating ewes on pasture indicated levels of intake ranging from 3.4 to 5.8% BW (Pulina et al., 2005; Molle et al., 2003). Therefore, if pasture availability is high, this “typical” ewe may be able to consume enough forage DM.

According to the Small Ruminant Nutrition System (2006), a ewe of this size, with a milk

production level of 5.68 lb./d (5.5% fat and 4.8 % protein), has an energy requirement of about 2 times maintenance or 3.5 Mcal/d net energy for maintenance and 3.7 Mcal/d net energy for lactation. In addition, the ewe has a protein requirement of 0.75 lb./d of metabolizable protein. Can pasture provide enough energy and protein to meet this ewe’s maintenance and milk production requirements?

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Can pasture provide enough dietary energy? Energy for ruminants comes primarily from two types of carbohydrates, fibrous

carbohydrates (measured as neutral detergent fiber, NDF) and non-fiber carbohydrates (NFC). Both sources are fermented in the rumen primarily to produce energy for microbial growth. In the process, fermentation by-products are released, including methane, carbon dioxide, heat and acids. The volatile fatty acids (VFA) released include acetate, butyrate and propionate, which are absorbed across the rumen wall and used by the ruminant for muscle growth, adipose tissue formation, and lactation. Fibrous carbohydrates contain cellulose and hemicellulose and are bound to lignin in plant cell walls. The fiber particles contribute to rumen health by stimulating chewing action and saliva production by the ruminant. Saliva contains sodium bicarbonate, which helps to maintain a neutral rumen pH for rumen microbes. The slow fermentation of fibrous carbohydrates stimulates the production of acetic acid, a precursor of milk fat. A reduction in dietary fiber is associated with a decrease in rumen health and a depression in milk fat. If dietary NDF levels are too high, it can have a negative impact on dry matter intake and milk yield.

Non-fiber carbohydrates, including simple sugars and starch, ferment quickly in the rumen.

These sugars provide an energy source for microbial growth. Since their fermentation is nearly complete, NFC yields more VFA than NDF carbohydrates. The fermentation of dietary NFC promotes the production of propionic acid, an important precursor of milk lactose. Since lactose is the main osmole in milk, the amount of lactose produced is closely related to the amount of milk produced. In dairy ewes, lactose levels average 4.8%. If NFC levels are too low, then DM intake, fiber digestion, and milk yield may be limited. If NFC levels are too high, the large increase in VFA will contribute to rumen acidosis and decreased intake and milk production. In addition, high NFC may contribute to body fat deposition in late lactation ewes due to hormonal regulation and energy partitioning (Cannas, 2002).

The type and level of carbohydrates affect the growth of rumen microbes, which are the main

sources of protein for ruminants and the production of VFA, which are utilized directly by the host ruminant. Therefore, the levels of these two energy sources must be closely monitored to avoid health problems and limits to production. Cannas’ (2002) dietary guidelines for ewes at high production levels (3.7 to 4.6 lb. of 6.5 % fat corrected milk/d) recommend NDF levels of 33 % DM and NFC levels of 38% DM. Based on NRC tables for pasture combinations, Table 1 indicates that while NDF levels may be adequate, forages alone cannot provide adequate NFC to meet the needs of high producing dairy ewes. Grain supplements such as corn and soybean meal can provide supplemental NFC to a forage-based diet.

Table 1. Composition of feeds.

Pasture Grass

Pasture Mix

Pasture Legume

Corn Barley Soybean Meal

NDF 50 44 38 9.5 18.1 14.9

NFC 17.5 17.5 22.5 76.4 64 28

RDP 14.7 17 19.7 5 10.6 32.6

RUP 5.3 5 4.3 4.4 2.6 17.3

(Complied from Combs,1999 and NRC, 2007)

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Can pasture provide enough protein? Amino acids are essential for tissue and wool growth, milk production, and gluconeogenesis.

Ruminant requirements for amino acids may be supplied either by dietary protein which escapes rumen degradation (RUP) or by microbial protein synthesized from rumen degraded dietary protein (RDP) or non-protein nitrogen. Microbial protein can account for 60% of the protein reaching the small intestine and is abundant in essential amino acids (Wattiaux, 1999). Achieving a mixture of microbial and dietary protein sources is ideal for lactating ruminants.

The majority of protein in pasture is RDP (Table 1), which is converted to ammonia or

branched chain fatty acids and utilized by rumen microbes for growth. Non-protein nitrogen compounds, such as urea in feed or saliva, may also be converted to ammonia and utilized by rumen microbes or absorbed directly. The extent of microbial growth from the ammonia pool also depends on energy available from dietary carbohydrates. If rumen ammonia levels are too low to meet microbial growth requirements, there will be a shortage of rumen bacteria and a reduction in feed digestibility. If rumen ammonia levels exceed microbial capacity or energy availability, the excess ammonia will be absorbed across the rumen wall. Once in the bloodstream, the liver converts ammonia to a detoxified form, urea, which can be recycled to the rumen through the blood or excreted in urine or milk (Van Soest, 1994). As dietary nitrogen increases beyond the blood’s holding capacity, excess urea is expelled in urine or milk. Milk urea nitrogen (MUN) levels are closely related to blood urea nitrogen levels in sheep and can be used as an indicator of protein utilization (Cannas, 2002). Recommended levels for sheep range from 14 to 22 mg/dl (Cannas, 2002).

Rumen undegradable protein (RUP) is absorbed directly in the small intestine, providing

amino acids of high biological value. While microbial protein can provide most of the absorbed protein required by ruminants, dietary RUP may provide amino acids which compliment microbial protein, such as methionine and lysine. Supplementation of RUP sources have been shown to increase milk yield in dairy cattle, though results are mixed (Santos et al., 1998). Variations are often due to the source and quality of the RUP sources.

In lactating blackfaced ewes, supplementation with rumen protected (or rumen undegradable)

methionine (Lynch et al., 1991) increased growth of their lambs, indicating that low levels of methionine may limit milk production in ewes. Sheep have a high requirement for sulphur-containing amino acids (methionine and cystine) to support wool growth, and high levels of milk production may increase this requirement. Therefore, RUP sources may be important to maintain milk production in lactating ewes. When feedstuffs high in RUP were supplemented to low producing dairy ewes, there was a numerical, though not significant, increase in milk yield (Ubertalle et al., 1998). The response to RUP may have been limited by the production potential of this breed of dairy ewe. Results from two different supplementation trials conducted in 2005 and 2006 at the Spooner Agricultural Research Station suggest that RUP may have contributed to the differences in milk yield response between the trials.

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2005 Trial In 2005, 56 3-yr-old ewes were arranged in a 2 x 2 factorial treatment design; in early (21 ±

10 DIM) or late lactation (136 ± 9 DIM) at the start of the trial and receiving 0 or 1.8 lb. DM/d (2 lb./d as-fed) of a corn and soybean meal supplement during the grazing period. On May 25, 2005, ewes began grazing and supplementation treatments were started. Ewes were machine milked twice per day and provided pasture for approximately 20 hr/d. Ewes were rotationally grazed through 20 acres of pasture, ranging in composition from 40% to 95 % orchardgrass and 60% to 5% kura clover and/or various other grass species. Milk production testing was conducted weekly, bi-weekly milk samples were analyzed for milk fat, milk protein, and a sample was compiled for milk urea nitrogen analysis.

Results There was no significant interaction between stage of lactation and supplementation

treatments. All results presented are the main effect of supplementation on milk production, regardless of stage of lactation. Supplemented ewes produced an average of 0.50 lb./d more milk than unsupplemented ewes (3.50 vs. 3.00 lb./d, respectively; Figure 1).

Figure 1. Milk yield of ewes receiving 0 or 2 lb. corn and soybean meal supplement.

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/d)

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Figure 2. Milk composition of ewes receiving 0 or 2 lb. corn and soybean meal supplement.

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Supplemented ewes had lower (P < 0.05) milk fat percentage than unsupplemented ewes (5.75 vs. 6.00 %, respectively). Milk fat percentage is inversely related to fiber content of the diet. Therefore, ewes consuming a low-fiber supplement may have lower total NDF intake, possibly leading to a milk fat depression (Bencini and Pulina, 1997). Low milk fat percentage has also been documented in grazing dairy cows receiving grain supplementation (Reis and Combs, 2000). Supplemented ewes also had lower (P < 0.05) milk protein percentage than unsupplemented ewes (4.84 vs. 5.04%, respectively).

During the 82 d trial, supplemented ewes produced 43.5 lb. more milk than unsupplemented

ewes (278 vs. 235 lb., respectively). Based on the reported average sheep milk price in Wisconsin of $ 0.55/lb. (WASS, 2006), supplementation increased gross return by $23.93/ewe. Based on the level of supplement provided (1.8 lb. DM/d or 2.0 lb. as fed/d), supplemented ewes received a total of 164 lb. of as-fed grain. Therefore, the breakeven cost for supplementation in this study was $0.145/lb of supplement or $290/ton.

Trial milk urea nitrogen (MUN) levels ranged from 18.0 to 33.6 mg/dl and were higher than

recommended levels for sheep (14 to 22 mg/dl; Cannas, 2002) at most sampling periods. These results indicate ineffective utilization of dietary nitrogen, either due to excess nitrogen intake and/or insufficient energy intake. Pasture protein levels remained high throughout the grazing season, averaging 24.2 % CP and ranging from 16.6 to 30.6 %. Supplemented ewes were consuming both highly degradable pasture protein and supplemental soybean meal, while unsupplemented ewes may not have had enough NFC to optimally utilize the pasture protein. 2006 Trial

Based on the 2005 trial results, the Spooner Agricultural Research Station began supplementation with whole corn in 2006. The next trial was conducted to determine if milk production and protein utilization is affected by level of corn supplementation. Ninety-six 3-, 4-, and 5-yr-old ewes, averaging 112 ± 21 days in milk at the start of the trial, were randomly assigned to four treatments: 0, 1, 2, or 3 lb. as-fed whole corn/d. Supplementation treatments began on May 25, 2006 when ewes went to pasture and continued for 88 days. Similar to the 2005 trial, ewes grazed mixed grass-legume pastures for approximately 20 h/d. Ewes were machine milked twice/d. Milk production was tested every week, bi-weekly milk samples were analyzed for milk fat, milk protein, and a sample was compiled for milk urea nitrogen analysis. Results

Daily milk yield of supplementation treatments is presented in Figure 3. Results presented in Table 3 indicate a linear increase (P < 0.0001) in milk production in response to increasing levels of corn supplementation. Supplemented ewes (1, 2, and 3 lb. corn) produced more (P < 0.01) milk than unsupplemented (0 lb. corn) ewes, and high levels of supplementation (2 and 3 lb. corn) resulted in more milk production (P < 0.0001) than low levels of supplementation (0 and 1 lb. corn).

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Figure 3. Milk production of grazing dairy ewes fed varying levels of corn (lb./d as-fed).

Table 3. Milk production and composition of grazing ewes fed varying levels of corn supplement.

Level of supplementation (lb./d) Contrasts (P =)

0 1 2 3 Trt (P =) Linear 0 vs.

Suppl. Low vs. High *

Milk, lb./d 2.87a 2.91a 3.11b 3.17b 0.0001 0.0001 0.0019 0.0001 Fat, % 6.26b 6.40b 6.09b 5.89a 0.0001 0.0001 0.1462 0.0001 Fat, lb./d 0.179 0.186 0.189 0.187 0.1331 0.1251 0.2395 0.0350 Protein, % 5.29 5.41 5.37 5.39 0.0740 0.0942 0.0120 0.3807 Protein, lb./d 0.151a 0.153a 0.168b 0.168b 0.0002 0.0001 0.0043 0.0001 MUN, mg/dl 18.93a 17.11b 13.58c 13.62c 0.0001 0.0001 0.0001 0.0001

* Low = 0 and 1 lb./d, High = 2 and 3 lb./d

Milk fat percentage generally decreased with increasing level of supplement. Low

supplement treatments had significantly higher milk fat percentage than high supplement levels. This supports results from the 2005 trial. Low fiber levels in the supplement, which would constitute an increasing percent of total dry matter intake, may contribute to milk fat depression. Milk protein percentage was slightly higher in supplemented ewes (1, 2, 3 lb/d) compared to unsupplemented ewes. This contributed to the significant linear increase in milk protein yield.

Milk protein yield and milk urea nitrogen values indicate that corn supplementation increases

the utilization of dietary protein in ewes grazing high quality pastures. Protein levels of pastures during the 2006 season averaged 20.6 %CP and ranged from 11.5 to 25.7 %. The combination of a supplement low in protein (corn) and lower protein pastures resulted in MUN values closer to the recommended range for dairy ewes (Figure 4) compared to 2005. In both years, pasture protein levels and MUN values were closely correlated, and supplemented ewes had lower MUN level than unsupplemented ewes, regardless of type of supplementation.

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Figure 4. Relationship between trial milk urea nitrogen values and pasture crude protein percent.

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The economic benefit of level of corn supplementation is presented in Table 4. Based on the

current price of corn, supplementation is only profitable at a level of 2 lb./d even though all three supplement levels resulted in increased milk production.

Table 4. Economic evaluation of varying levels of corn supplement.

Level of Supplementation (lb./d)

1 2 3

Additional milk yield (lb./d) 0.04 0.24 0.30

Total additional milk (lb./88 d) 3.52 21.12 26.4

Increased income/ewe ($0.55 / lb. milk) $1.94 $11.62 $14.52

Grain fed (lb.) 88 176 264

Total grain cost* $5.02 $10.03 $15.05

Net per ewe at current corn price - $3.08 + $1.59 - $0.53 Breakeven corn cost ($/lb.) $0.022 $0.066 $0.055

($/ton) $44 $132 $110

* Price of $3.19/bu in Chicago (56 lb./bu) = $ 0.057 per pound or $114 per ton

Summary and Conclusions

Supplementation of grazing dairy ewes had a positive effect on milk yield regardless of type of supplementation. At a level of supplementation of 2 lb./d, the greater increase in milk yield observed with supplemental soybean meal and corn in the 2005 trial compared to corn alone in the 2006 trial may be due to the positive effect of increased RUP in the soybean meal. While some studies support the positive effect of dietary RUP on milk yield, results have not been consistent, and further trials are needed to confirm this effect in high producing dairy ewes.

Supplementation increased milk yield, but it may also buffer dietary intake against variations

in pasture quality. In addition, it should be possible to adjust the type and amount of supplement

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to compliment pasture quality as forage energy and protein levels change due to seasonal and pasture management effects. Literature Cited Avondo, M. and L. Lutri. 2004. Feed intake. 65-77 in Dairy Sheep Feeding and Nutrition. G.

Pulina ed. Avenue Media, Bologna, Italy. Bencini, R. and G. Pulina. 1997. The quality of sheep milk: A review. Aust. J. Exp. Agric.

37:485-504. Cannas, A. 2002. Feeding of lactating ewes. 123-166 in Dairy Sheep Feeding and Nutrition. G.

Pulina ed. Avenue Media, Bologna, Italy. Combs, D. 1999. Dairy updates: Grain supplementation to grazing herds. Feeding No. 501 of

The Babcock Institute for International Dairy Research, Madison, WI. Lynch, G. P., T. H. Elsasser C. J. Jackson, T. S. Rumsey, and M. J. Camp. 1991. Nitrogen

metabolism of lactating ewes fed rumen protected methionine and lysine. J. Dairy Sci. 66:2268.

Molle, G., M. Decandia, N. Fois, S. Ligios, A. Cabiddu, and M. Sitzia. 2003. The performance of Mediterranian dairy sheep given access to sulla (Hedysarum coronarium L.) and annual ryegrass (Lolium rigidum Gaudin) pastures in different time proportions. Small Rumin. Res. 49:319.

National Research Council. 2007. Nutrient Requirements of Small Ruminants: sheep, goats, cervids and New World camelids. Natl. Acad. Sci., Washington, D.C.

Pulina, G., A. Cannas, and M. Avondo. 2005. How to graze dairy sheep and supplement their diets in order to improve production. Page 89 in Proc. 11th Annual Great Lakes Dairy Sheep Symposium, Burlington, VT.

Reis, R. B. and D. K. Combs. 2000. Effects of increasing levels of grain supplementation on rumen environment and lactation performance of dairy cows grazing grass-legume pasture. J. Dairy Sci. 83:2888-2898.

Santos, F. A. P., J. E. P. Santos, C. B. Theurer, and J. T. Huber. 1998. Effects of rumen-undegradable protein on dairy cow performance: A 12-year literature review. J Dairy Sci. 81: 3182-3213.

Small Ruminant Nutrition System. V. 1.6.0. 2006. Department of Animal Sciences, Texas A&M University, and Cornell University.

Ubertalle, A., R. Fortina, L. M. Battaglini, A. Mimosi, and M. Profiti. 1998. Effect of protein degradability on urea nitrogen in sheep milk. Science e Tecnica Lattiero-Casearia. 49:67.

Van Soest, P. J. 1994. Nutritional Ecology of the Ruminant. Cornell University Press, Ithaca, NY.

Wattiaux, M. 1999. Protein metabolism in dairy cows. 17-20 in Dairy Essentials. The Babcock Institute for International Dairy Research, Madison, WI.

Wisconsin Agricultural Statistics Service. 2006. Wisconsin Dairy Sheep Industry Overview. http://www.nass.usda.gov/Statistics_by_State/Wisconsin/Publications/Dairy/dairysheep.pdf. Accessed Dec. 20, 2006.

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THE EAST FRIESIAN BREED OF SHEEP IN NORTH AMERICA

Yves M. Berger Spooner Ag. Research Station

University of Wisconsin-Madison

Introduction When sheep dairying started in the late 1980’s in the United States, a country in which the

milking of sheep was unheard of, pioneer dairy sheep producers had only the existing domestic breeds to bring into the milking parlor. Although breeds such as the Dorset or Polypay are considered by sheep persons as “milky”, new dairy sheep producers quickly realized that the commercial milk production of those breeds was not sufficient to provide a decent return and a sustainable enterprise. They were soon looking for ways to increase the milk production, and it was logical that they would turn to specialized dairy breeds. The East Friesian is the most famous of those breeds but was not present in North America. Moreover, at this time, the importation in the United States of a new breed of sheep from Europe, either as live animals, embryos or even frozen semen, was near impossible because of encephalopathy diseases (ovine and bovine) that started to create some worldwide concerns. American dairy sheep producers were left with no possibilities of introducing a dairy breed until events started to develop in Canada in 1990. The East Friesian breed

The East Friesian is considered to be the world’s best milk producing dairy sheep. Litter size in the East Friesian is reported as averaging 2.25 lambs with milk yield of 500 to 700 kg per lactation of 240 to 260 days testing 6 to 7% milk fat, the highest average dairy milk yield recorded for any breed of sheep.

The origin of the Friesian sheep breed is the region of Friesland extending along the North

Sea coast westward from the Weser River in northeast Germany along the north coast of the Netherlands and south to the Schelde (Scheldt) River at the border of the Netherlands and Belgium. Offshore is a fringe of islands including the West "Frisian" Islands belonging to the Netherlands, the "East Frisian" Islands belonging to Germany, and, to the north, the North "Frisian" Islands divided between Germany and Denmark.

The German East Friesian Milk Sheep (Ostfriesisches Milchschaf) is the best known and

most important of the Friesian breeds and is the breed known in the scientific literature as the "East Friesian". It was found in small numbers in many parts of the country as a household milk producer.

They are highly specialized animals and do poorly under extensive and large flock husbandry

conditions. It is perhaps no mere coincidence that the region of Friesland is also the origin of the Friesian cattle breed, including the Holstein, which has the highest milk yield of any breed of livestock. Friesian cattle and East Friesian sheep are alike in other important regards. Neither fares well in harsh, hot environments, but both have produced excellent crossbreds with adapted local breeds. An example of the dramatic effect the East Friesian milk sheep can have on breeds

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adapted to environments too severe for the purebred East Friesian is from the development of the composite Assaf breed in Israel from crossing East Friesian with the Awassi, a breed adapted to the arid Middle East. Lamb and milk production among yearling Assaf is double that of the Awassi. The Spooner Agricultural Research Station, University of Wisconsin-Madison in the mid 1990’s also demonstrated the ability of the East Friesian breed to greatly improve the milk production of domestic breeds by mere crossbreeding.

Other Dutch breeds may be derivatives of the Friesians, i.e. old style Texel. Near the Belgian

border is the Vlaams Schaap or Flemish Sheep also called the Vlaams Melkschaap/Flemish Milk Sheep. The origin of the Flemish Milk Sheep is vague but it is doubtless also related to the Friesian breeds with litter size recorded as of the order of 2.5 lambs per litter. The first importation of East Friesian in North America/Canada

In 1966, Agriculture Canada at the Agriculture Research Center Ottawa imported the East Friesian breed from Europe with the intent of creating a synthetic breed (in crossbreeding with other breeds) that would have a high fertility, high lambing rate and good milking ability. By 1972, the flock was closed to all new importation, and the imported animals were destroyed. The remaining flock constituted the base for the three Arcott breeds: Outaouais, Canadian and Rideau. Although developed for research purposes, the 8-month production cycle of the Rideau Arcott as well as its propensity for having triplets, quickly caught the eye of Canadian sheep farmers. Between 1982 and 1986, Agriculture Canada continued the minimum of selection necessary to maintain the genetic base for the new composite breeds. In 1986, the Canadian Sheep Breeders Association recognized the Rideau Arcott commercially. The Rideau is now one of the most popular breeds in Canada with 15% of its composition being East Friesian.

Second importation of East Friesian in Canada

The dairy sheep fever was not limited to the United States but was spreading to Canada. In 1990, a young entrepreneur-farmer immigrant from Switzerland established a farm in Chase, British Columbia, Canada. He quickly purchased a flock of Rideau Arcott and obtained the authorization to import frozen semen of the East Friesian breed from the Swiss Federal Center for Artificial Insemination. In 1993, the first East Friesian F1 crosses were born. The producer kept upgrading his flock and had ¾ East Friesian in 1994, 7/8 East Friesian in 1995 and higher percentage East Friesian blood in the following years (by continuing this grading-up system one can finally have animals considered as “purebreds”).

In 1994, another Canadian immigrant, this time from Germany, established in Markdale,

Ontario and imported 64 East Friesian embryos from the Harper Adams Agricultural College, Newport, Shropshire in Great Britain. 31 lambs were born from those embryos at an average cost of $2000 Canadian dollars (embryos were purchased for $Can 800 each). This was followed by another importation in 1995 of embryos and frozen semen from Great Britain, the Netherlands, and Germany.

At about the same time in 1994, another immigrant from Germany established in Spruce

View, Alberta imported frozen semen from the same source and frozen embryos the following year.

12

In 1995 the pace of importation of East Friesian in Canada accelerated with Canadian companies (Ova Genetics – Rosebud Breeding Center - Eurosheep) in Alberta also importing semen and embryos from the same source. The same year, a Canadian producer at Ste Helene-de-Chester, Quebec imported frozen embryos from Sweden.

In 1996, another immigrant from Germany, located in Finch, Ontario, imported EF semen

and EF embryos from 9 different lines from the Swiss Federal Center for Artificial Insemination as well as embryos from the French dairy breed of Lacaune.

No more importation of dairy sheep seems to have occurred in Canada after 1996.

Importation of East Friesian in the US

The importation of East Friesian germplasm into the U.S. is, of course, very much linked to the importation into Canada.

In 1993, the Spooner Agricultural Research Station of the University of Wisconsin-Madison

along with 2 other Wisconsin producers imported the first ½ East Friesian rams from British Columbia in the United States. Those rams served as the base for the University milking flock. The following year the Research Station imported a ¾ EF ram from the same source, and then a 7/8 EF ram. Some New England producers also imported crossbred East Friesian rams from British Columbia.

In 1995, a major dairy sheep producer in New York imported EF frozen semen from New

Zealand. New Zealand (Silverstream Ltd) had imported East Friesian embryos from Sweden (same lines as the producer in Quebec).

1996 was the boom of importation of East Friesian germplasm through various channels with

the number of live East Friesian becoming more abundant in Canada due to the birth of embryos imported in 1995. The Spooner Agricultural Research Station imported EF frozen semen from England and New Zealand as well as live pure EF rams from Canada. At the same time, Canadian entrepreneurs formed alliances or partnership with American producers in order to sell high priced breeding stock throughout the country. Canadian entrepreneurs also sold breeding stock directly to American producers, who in turn set up shop to sell stock such as A-1 Sheep Imports in Oregon or Crane Creek East Friesians in Iowa, as examples. The list of American buyers of East Friesian stock is impossible to compile because without some sort of tracking systems one cannot be aware of all transactions. Also in 1996, for a very short period, the importation of live animals directly from Europe was authorized. Ag-Innovations, a small company located in Vermont, imported live East Friesians from Belgium and the Netherlands. In fact, most of the East Friesian animals imported by Ag-Innovations were originally from the Netherlands. Those animals were later put in quarantine by the State of Vermont in 1998 and destroyed in March 2001. Ag-Innovations also imported live East Friesian animals (ewes and rams) from Silverstream in New Zealand, the same company from which Old Chatham in New York and The Spooner Research Station imported germplasm from in 1995 and 1996, respectively.

Between 1993 and 2002, many live East Friesians were purchased in Canada where the breed

13

is still raised as a recognized purebred with a registry held by the Canadian Sheep Breeders’ Association. With the discovery of the first case of BSE in a Canadian cow, the border between the U.S. and Canada closed to all live animal exportations from Canada to the U.S. in 2002. Impact of the East Friesian Breed in the U.S.

It is estimated that there are between 65 to 75 dairy sheep operations in North America milking approximately 10 to 11,000 ewes. Most of those ewes are East Friesian crossbred with domestic breeds (mostly Rideau Arcott in Canada and Dorset or Polypay in the U.S.). There is no doubt that the introduction of the East Friesian breed in North America was necessary to increase the commercial milk production and to make the dairy sheep sector viable. It is possible nowadays to have a flock of sheep with a production average of 700 to 800 pounds of milk during a lactation of 220 days, which is remarkable.

The East Friesian breed, however, did not quite live up to its reputation and hype. The huge

milk yields shown in catalogs never really happened. It is my personal opinion, however, that without the East Friesian, there would be no dairy sheep producers in North America. The introduction of the Lacaune in 1998 gave producers other crossbreeding options. Many milking ewes are now Lacaune x EF x Domestic crosses. The reasons for producers not milking pure East Friesians ewes are multiple:

- Not enough East Friesians animals in North America. - Not enough different blood lines of East Friesian to establish a population. Most of the

imported East Friesians can be traced back to the same origin (see Table 1). Constant breeding of the animals with the same blood lines (father-daughter, father-grand daughter…) results in increasing the coefficient of inbreeding. Although not always detrimental, inbreeding is generally avoided because of high risk of weakness and malformation in animals.

- Limited financial capacity of dairy sheep producers, keeping them from purchasing high priced breeding stock. The purchase was mostly limited to rams.

- Research showing that crossbred EF ewes can have a high milk production output without going to purebreds.

- Research showing that pure East Friesian lambs have a higher mortality rate than lambs of other breeds because of a greater susceptibility to respiratory diseases.

Conclusion

Practically all East Friesian animals present in North America have the same origin as shown in the Table 1. A fairly high degree of inbreeding must be expected in the pure East Friesian. It is interesting to go to the Canadian Sheep Breeder Association web site (http://www.clrc.ca/cgi-bin/query.cgi?_association=30) and look up at the East Friesian registry. Practically all pure East Friesian animals come from Wooldrift, Rosebud and Eurosheep (Shepherd Gourmet). They started as imported embryos from the same few Dutch ewes (N409, P912, L901, 0166-022 to name a few) and from the same rams (Vos 137, Berksmar 18, Porte, T 708, S542) the rams being already related to the donor ewes (N409 is the dam of S542 and 0166-022 is the dam of Vos 137). Some embryos from Great Britain (originally from Switzerland), Sweden (originally from Switzerland), and Switzerland complete the very narrow East Friesian gene pool present in North America.

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In 2005, Casellas and Thomas, calculated the breeding values of all EF rams used at the Spooner Research Station (Table 2) including the breeding values of the sires of some of the rams when sufficient data could be used. It appears that Dutch rams have a better estimated breeding value for milk yield than rams of Swiss origin, with the exception of Odo who proved to be very valuable. New Zealand rams, with genetic origins in Sweden and Switzerland, have an average breeding value. Sources

- Alastaire Mckenzie, Ste-Helene-de Chester, Quebec, personal communication - Axel Meister, Markdale, Ontario, personal communication. - Berger Y.M. and D.L. Thomas. 1997. Early experimental results for growth of East

Friesian crossbred lambs and reproduction and milk production of East Friesian crossbred ewes. In Proceedings of Great Lakes Dairy Sheep Symposium, Madison, Wisconsin, April 4th, 1997.

- Casellas and Thomas. 2005. Personal communication - Diane Kauffman, Colfax, Wisconsin - Hani Gasser, Chase, British Columbia, personal communication - Josef Regli, Finch, Ontario, personal communication - Josef Regli, Finch, Ontario, personal communication - Principles of Sheep Dairying in North America. Yves Berger Editor. Published by

UWEX Press (http://learningstore.uwex.edu/Sheep-C26.aspx). - Thomas D.L., Y.M. Berger and B.C. McKusick. 1999. East Friesian germplasm: Effects

on milk production, lamb growth, and lamb survival. J. Anim. Sci. 77(Suppl. 1): 126 - Thomas, D.L., Y.M.Berger, Brett C. McKusick, Randy G. Gottfredson, and Rob Zelinski.

2001. Comparison of East Friesian and Lacaune breeding for dairy sheep production systems. 7th Great Lakes Dairy Sheep Symposium. Proceedings. Eau Claire, Wisconsin, Nov 1-3, 2001

- Thomas, D.L. 2004. Overview of the dairy sheep sector in Canada and the United States. 10th Great Lakes dairy Sheep symposium. Proceedings. Hudson, Wisconsin, November 4-6, 2004

- Stephanie Mitcham, Summer, Iowa - http://www.ansi.okstate.edu/breeds/sheep/friesianmilk/index.htm - http://www.rideausheep.org/sheets.php - http://www.clrc.ca/cgi-bin/query.cgi?_association=30

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Table 1. Origin of East Friesian Animals in North America.

Importer Imported from Item Lines Hani Gasser (BC) Switzerland semen Odo, Orf, Garfield

Holland Embryos-semen N409, P912, L901, 0166-0022 (the most famous)

Wooldrift (ONT)

Great Britain Embryos-semen Ancellor lines Vos 137, Berksmar 18,

Porte

Holland Embryos-semen Same as Wooldrift

Great Britain Embryos-semen originally from

Holland

Vos 137- Berksmar 18, Porte, S542

Switzerland Semen Odo, Orf, Garfield sold through the USA by Jarvis

Eurosheep (ALB)

Germany Semen Othello, black EF ram sold through the USA by Jarvis

Holland Embryos-semen Same as Eurosheep, many sold in the USA through

Kaufmann- Hagen

Rosebud (ALB)

Great Britain Embryos-semen Same as Eurosheep

Lucille Giroux (QUEBEC)

Sweden Embryos Originally from Switzerland related to Regli (?)

Josef Regli (ONT) Switzerland Embryos-semen New lines from Switzerland

New Zealand Semen New Zealand related to Giroux, Quebec

Old Chatham (NY)

Ag Innovation Live Grand sons of S542 and N409

Canada

Live Regli, Wooldrift, Rosebud

Great Britain Semen Vos 137, Berksmar 18, Topaz

Spooner UW-Madison (WI)

New Zealand Semen B40, B21, B26, B87, B49 related to Giroux , Quebec

and Old Chatham (??)

Canada Embryos-live Wooldrift – Rosebud Crane Creek EF (IW)

New Zealand Semen Same

A1 Sheep Import (OR)

Canada Embryos-semen ?

Holland Live All daughters of S542 and grand daughters of N409

Belgium Live

Ag. Innovation (VT)

New Zealand Live Same as others

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Table 2. Breeding values of EF rams used at Spooner (Casellas and Thomas, 2005)

Milk yield (kg) Rams Description BV Rank

0137VOS Semen from England, son of ewe 0166-022 Dutch origin 103.8 1

1605 Sire 287F, Dam 6J, Dutch origin, Purchased from Larry

Meisegeier, River Ridge Stock Farm 81.2 2

ODO310 Semen from Switzerland through Hani Gasser 62.2 3

287F Sire S542 (son of ewe N409), Dam 0166-022 (dam of Vos 137),

Dutch origin 60.3 4

B87 Semen from New Zealand, Silverstream 58.9 5

AXM316K Has for grand parents: ewe L901, ewe 0166-022, ram vos 137, ram

S542 all Dutch origin 50.3 6 0018 Berksmar Dutch origin, not much information 45.2 7

AXM213H Has for grand sires Vos 0137 and S542, Dutch origin 44.9 8

78K Son of ram Nerton 12F, Switzerland, purchased from Regli 44.8 9

C2 ½ East Friesian ram from Odo310. Purchased from Hani Gasser 42.2 10

B49 Semen from New Zealand ram, Silverstream 41.2 11

283F Son of super elite ewe P912, Dutch origin 29.2 12

B26 Semen from New Zealand ram, Silverstream 24.6 13

B40 Semen from New Zealand ram, Silverstream 21.6 14

B21 Semen from New Zealand ram, Silverstream 20.9 15

TOPAZ Dutch origin, semen purchased in England, not much info 20.2 16

Nerton12F Sire of many of Regli’s animals, Swiss origin 18.5 17

GAR5074 Semen from Switzerland through Hani Gasser 16.3 18

998 Ram from New Zealand, Purchased from Old Chatham -14.9 19

62K Son of ram Nerton 12F, Switzerland, Purchased from Regli -18.3 20

2D ¾ East Friesian ram from Gar5074, Purchased from Hani Gasser -47.1 21

C27 ½ East Friesian ram from Odo310, Purchased from Hani Gasser -67.3 22

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RAISING LAMBS THE RIVER RIDGE WAY

Larry and Emily Meisegeier and Ruth Grinnell River Ridge Stock Farm

Bruce, Wisconsin

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30-DAY WEANING SYSTEM

Kim Cassano and Rich Toebe Jump River Shepherds’ Dairy

Catawba, Wisconsin

What is it? Mothers raise their lambs until the lambs are 30 days old, weigh 30 lbs, and are eating

enough concentrate to make it without milk. When lambs reach their “30’s”, they are weaned, and their mothers enter the milk line. We fudge a bit in the beginning to get a sizable group of mothers to milk. How does it work?

Basically our farm looks like a commercial lamb operation until we start milking in April except that we keep a careful eye on the udders. We shed lamb in March. New families spend time together in jugs and mixing pens until ready to join a larger group. Families are grouped according to the ewes’ nutritional needs, i.e., singles, twins, multiples. Lambs have access to grain through creep gates. What about triplets, quadruplets, etc?

Lambs who aren’t getting enough milk from mom are moved to an orphan pen and raised on bucket bottles. They also are weaned at 30 days and 30 lbs. What about singles?

Newborn singles generally don’t drink enough of a dairy ewe’s production. We check the ewes’ udders and hand milk when necessary during the first few days until thirst and production balance out. Is it labor intensive?

We spend time milking ewes with too full or uneven udders, and making sure triplets and quadruplets are getting enough to drink. We save time by not having to train lambs to drink or to clean their “bottles”. Isn’t weaning late more stressful?

Lambs and mothers do get upset about being separated, but this tends to last just 2 to 3 days. Shepherds can minimize this with low stress weaning techniques. We like to take the lambs when the ewes aren’t looking and then call them away to a feeder full of grain. And keep them out of earshot. Why bother?

Because we like it. We like that lambs get to stay with their mothers instead of being separated so early in life. We like that lambs have time to learn all the useful things a mother can teach. We like that lambs get to drink real milk. We like not spending time cleaning buckets and teaching lambs to suck off them. It works for us.

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MIX WEANING AT DREAM VALLEY FARM

Tom and Laurel Kieffer Dream Valley Farm Strum, Wisconsin

Our History with the MIX System of Weaning What is MIX weaning?

At 10 to15 days after lambing, ewes and lambs are separated for approximately 15 hours of each day, overnight, after which time the ewes are milked in the morning before being rejoined with their lambs. Lambs receive creep feed, but no milk replacer.

Where did the idea originate?

We became aware of this method in 1999 when UW-Madison researchers Brett McKusick, Yves Berger, and Dave Thomas presented the results of a study they had done comparing milk production and lamb growth for three weaning systems; DY1 (lambs weaned at 24 hours and raised entirely on milk replacer and creep feed), MIX, and DY30 (lambs stay with their dams for 30 days, then are weaned onto creep feed). The report is found in the proceedings of the 47th Spooner Sheep Day and the 5th Great Lakes Dairy Sheep Symposium – both in 1999.

Why did we try it?

We liked the idea of raising the lambs on ewes’ milk rather than on milk replacer. We did not feel we had the extra time or facilities to attempt DY1 weaning. The research results indicated that the MIX system had the greatest potential financial yield per ewe.

What are the weaknesses of this system?

Ewes on MIX will put about 85% of their total production in the bulk tank – the rest feeds their lambs. While on MIX, these ewes will withhold butterfat during machine milking to the point where their milk will be 3 to 4% butterfat. The process requires daily separation of the lambs and dams, potentially adding extra stress.

Why do we still do it?

It’s easiest to keep doing something you are set up for, know how to do, and know what results to expect. We have good success in lamb health and growth, as well as milk production. We do not have adequate facilities to switch completely to DY1 lamb rearing, nor sufficient cash flow to make the needed modifications. When possible, we still prefer to operate natural processes (we generally like the idea of lambs raised by their dams).

Our Current Weaning System

In 2007 we used a combination of all three systems of weaning. The first approximately 30 ewes lambing go to the MIX weaning system. Those lambs will

be 10 to 20 days old at the time of MIX startup. The reason for doing this is to collect a large enough group of ewes to justify milking startup.

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The next approximately 50 to 70 ewes will be DY1, with the lambs trained to bottle and machine feeding. This places additional fresh ewes on 2x day milking very soon after the MIX ewes start, giving a short time window of low-butterfat milk. By this point, our currently available lamb rearing facility is nearly full.

Actually our DY1 is more like DY2 to 4, so the lambs get a good feeding of colostrum, and

we don’t need to separate this milk in the parlor. During this time, we also make use of any frozen milk left from the previous year by feeding

it in nipple pails. Until the earliest born lambs are fully weaned and moved out of the rearing area, all singles

are weaned DY1, with the remainder on MIX, and an occasional DY30. As lambs reach full weaning and are moved out of the rearing area, new DY1 lambs can be added. This is a limitation placed on us by our current facilities.

Our Current MIX Weaning Process Facility

As with any lamb rearing system, the lambs need a light, clean, dry comfortable shelter with fresh water and creep feed. The daily separation process requires a pen with creep gate into the lambs’ space. We use the holding area leading to our parlor. As the ewes enter the pen, a closed gate stops them from proceeding all the way to the parlor entrance, and a back gate allows us to enclose and work with a group of about 30 ewes with lambs (not necessarily their own). On the side wall of this enclosed area is the creep gate into the lamb area.

Method

The separation is done just before each evening milking. The front gate is closed, and the ewes with lambs are moved in to the holding area. The gate behind is closed. The lambs then are coaxed through the creep gate. A second person or one-way panel just inside the creep area will be needed for the first few days, as the lambs will want to come back out to the ewes. Also during the first few days this will be a very noisy time. When this group of lambs is all in their area, the cut gate is opened, allowing the ewes to proceed forward to the parlor entrance. With two people separating a group of 50 ewes with lambs, this process takes 15 to 20 minutes to begin with.

After the first few days, when the ewes have realized they are heading for the parlor – which

means grain – the front gate can be used as a cut gate and opened slightly toward the ewes as the group enters the holding area. Some of them will pass right through, leaving the lambs behind to be chased through the creep gate. In a few more days, many of the lambs will enter their area also as the group comes in, and the process is almost automatic, taking one person perhaps 5 to 10 minutes to complete.

The ewes are milked in the morning. After milking the lambs and ewes are rejoined. If the

total milking flock numbers less than about 150 during MIX time, the entire flock is kept together. The ewes with fully weaned lambs simply pass right by the cut gate.

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General Thoughts And Plans

2007 was our first year attempting DY1 on a larger scale, with less than hoped for success – too many lambs were lost and general health was lower than we want to see (I am hoping to learn some things at Sheep Day that will help us out in 2008). The automatic machines worked well, but we had a lot of moisture build up on the floor, causing excessive ammonia build up – some from the machines (nipple drippage), and some from barn leakage. It is very important to keep these machines clean. Also, it seemed the milk replacer we had this year was rather sticky – it did not readily fall to the bottom of the machine’s hopper, which required constant attention to avoid the lambs running out of milk. We want to have a significantly better facility for 2008, if we can swing the $. The MIX system has always worked well for us, and can be done with less labor and a more basic facility. We will continue to use this system for some of our weaning. In our situation, we feel that DY30 is suited best to unusual cases such as large litter sizes or ewes with problems that require them to be treated and held out of the milking flock. In reality, DY30 has also happened because we got ‘behind the 8 ball’ during the heavy lambing time.

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EFFECT OF PREPARTUM PHOTOPERIOD ON MILK PRODUCTION OF DAIRY EWES

C. M. Mikolayunas1, D. L. Thomas1, Y. M. Berger2, T. F. Gressley3, and G. E. Dahl4

1Department of Animal Sciences, 2 Spooner Agricultural Research Station, University of Wisconsin-Madison, Madison, Wisconsin, USA

3 Department of Animal and Food Sciences, University of Delaware, Newark

4Department of Dairy Science, University of Florida, Gainesville

Background

Seasonal changes in day length regulate many aspects of mammalian physiology, including reproduction (Ortavant et al., 1988), fattening (Forbes, 1982), and wool growth (Lincoln and Baker, 1995). Milk production is also affected by day length; long days during established lactation increase milk yield in dairy cattle (Peters et al., 1978) and dairy sheep (Bocquier et al., 1997). Lactating ewes exposed to long day photoperiods (16 h light; LDPP) for the first 5 months of lactation produced 25% more total milk than ewes exposed to short day photoperiods (8 h light; SDPP). At the end of the light treatments, when all ewes were switched to equilibrated day lengths (12 h light), the LDPP ewes experienced a 37% decrease in milk production over the next six weeks while SDPP ewes only experienced an 8% decrease in milk production (Bocquier et al., 1997). A similar effect of LDPP on established lactation has been observed in dairy cows over a range of production levels and stages of lactation (reviewed by Dahl et al., 2000). The proposed mechanism of action for this response is the release of melatonin from the pineal gland. In darkness, melatonin is secreted and levels are elevated. Exposure to light inhibits an enzyme necessary for melatonin synthesis, resulting in depressed levels during daylight hours. Thus, melatonin levels fluctuate daily and the perception of daylength depends on the duration of high melatonin levels, or length of darkness. The pattern of melatonin secretion influences the levels of insulin-like growth factor I (IGF-I), which has been identified as the hormone responsible for the positive effect of extended day length in lactating ruminants.

In contrast to the positive effects of long days during lactation on milk production, recent

work in dairy cattle suggests that long days during the prepartum period has a negative effect on subsequent milk production. Dairy cows exposed to short days (8 h light:16 h dark; SDPP) for either 60 d (Auchtung et al., 2005) or 42 d (Velasco et al., 2006) prepartum, had higher milk yields during the first 16 weeks of lactation than cows experiencing long days (16 h light: 8 h dark; LDPP). The proposed mechanism of action is the effect of photoperiod on circulating prolactin and prolactin receptors in the mammary gland. Auchtung et al. (2005) found an inverse relationship between daylength and circulating prolactin levels; cows in SDPP treatments for 60 d prepartum had lower levels of circulating prolactin than those in LDPP at both 33 and 5 days before calving. Prolactin levels were inversely related to the expression of prolactin receptor mRNA; cows experiencing SDPP had increased expression of prolactin receptor mRNA in mammary tissue (Auchtung et al., 2005). Thus, SDPP ewes may be more sensitive to the natural periparturient prolactin surge, possibly experiencing enhanced proliferation and survival of mammary cells (Auchtung et al., 2005; Wall et al., 2005) due to the role of prolactin in mammary gland development. Since dairy ewes respond to postpartum photoperiod treatment,

26

this study was conducted to determine the effect of prepartum photoperiod on milk production, milk composition and circulating prolactin levels of dairy ewes. Prepartum Photoperiod Trial

Twenty-two multiparous, 4-yr-old dairy ewes were randomly assigned to one of two photoperiod treatments: LDPP (16 h light; 8 h dark; n=11) or SDPP (8 h light; 16 h dark; n=11). Ewes were housed in a climate controlled environment (17° C and 30 to 70 % relative humidity). Photoperiod treatments began approximately 6 wk before lambing, on December 20, 2005. Light exposure, averaging 365 lux at sheep-eye level (0.76 m above the floor), was provided by fluorescent lights and controlled by an automatic timer.

Lambs were removed within 12 h of parturition and ewes were moved from photoperiod

treatment rooms to the milking room, where all ewes were managed together and experienced a photoperiod of 12 h light. Ewes were milked twice per day, at 0700 h and 1700 h. Pre- and post-lambing feeding consisted of ad libitum alfalfa silage (17.5 % crude protein, 47.97 % neutral detergent fiber, 22.8 % non-fiber carbohydrates) and 2 lb./d of whole corn. Ewes had free access to minerals and water. On April 10, all ewes returned to the Spooner Agricultural Research Station and were integrated into the resident milking flock. During this post-trial period, all ewes received the same amount of silage and corn supplement. All ewes were moved to pasture on May 16 and continued to receive corn in the milking parlor. Silage feeding was discontinued while ewes were on pasture, but due to a summer drought, silage feeding was resumed in mid-summer.

During the trial period on campus, daily milk production for individual ewes was measured

twice weekly and milk composition was analyzed weekly. Once ewes returned to the Spooner Agricultural Research Station, milk production and milk composition was measured monthly. Milk samples from the morning milking were analyzed for percentage fat and percentage protein (AgSource Milk Labs, Stratford, WI). Due to variations in lambing date, trial days in milk (DIM) ranged from 34 to 63 d and averaged 53 d. Long term production data included data from an average of 180 DIM. Blood samples (20 ml/ewe) were collected from each ewe between 0800 h and 1000 h via the jugular vein twice weekly starting 6 weeks before lambing. Results and Discussion Milk Production and Composition

Dairy ewes experiencing SDPP for six weeks prepartum produced 0.31 lb./d more milk (P < 0.1) than LDPP ewes during the first eight weeks of lactation (Table 1, Figure 1). Average daily milk fat percentage was higher (P < 0.001) in SDPP ewes than LDPP ewes (6.04 vs. 5.51 %, respectively), but there was no difference in milk protein percentage between the groups during the first 6 weeks of lactation (Table 1, Figure 2).

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4.2

4.7

5.2

5.7

6.2

5 9 12 16 19 23 26 30 34 37 41 44 47 53

Average days in milk

Mil

k (lb

)

SDPP

LDPP

Figure 1: Mean test day milk production of SDPP and LDPP treatments during the trial period. * Least squares means within a test day are different (P < 0.1). Number of ewes in each

treatment for each test:

DIM 5 9 12 16 19 23 26 30 33 37 40 44 47 51 54 58

SDPP 11 11 11 11 11 11 11 11 11 11 11 11 10 8 7 4

LDPP 11 11 11 11 11 11 11 11 10 10 9 9 9 8 8 5

Table 1: Average test day milk production and milk composition of prepartum light treatment groups during trial period (average 53 DIM) and trial plus post-trial period (average 180 DIM).

Trial Period Trial and Post-Trial Period

SDPP LDPP P = SDPP LDPP P =

Milk, lb/d 5.36 5.05 0.0534 3.88 3.53 0.0309

Fat, % 6.04 5.51 0.0003 6.28 6.48 0.2162

Protein, % 4.61 4.54 0.4485 5.23 5.12 0.2408

During the trial period plus the post-trial period (approximately 180 DIM), SDPP produced an average of 0.35 lb/d more milk (P < 0.05) than LDPP ewes (3.88 vs. 3.53 lb/d, respectively). Over approximately 180 DIM, there were no differences in milk fat or milk protein percentages (Table 1).

*

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4.5

5

5.5

6

6.5

7

1 2 3 4 5 6 7 8

Fa

t (%

)

SDPP LDPP

Figure 2: Mean test day fat and protein percentage of SDPP and LDPP treatments during the trial period. * Least squares means within a test day are different (P < 0.05).

The milk production results of this study support previous work in which cows exposed to SDPP for 42 (Velasco et al., 2006) or 60 d (Auchtung et al., 2005) prepartum produced more milk during the first 16 wk of lactation than animals exposed to LDPP. In our study, however, milk fat percentage was different between treatment groups; this has not been observed in previous prepartum photoperiod trials with dairy cattle. The difference in fat yield is important to sheep milk producers, whose milk is primarily made into cheese. Prolactin

Circulating prolactin levels were lower (P < 0.05) for SDPP ewes than for LDPP ewes from 1 wk before to 0.5 wk after lambing (Figure 3). These results support findings in dairy cattle, in which cows in SDPP treatments for 60 d prepartum had lower levels of circulating prolactin than those in LDPP at both 33 and 5 d before calving (Auchtung et al., 2005). In both studies, prolactin levels reached similar levels shortly after parturition.

* *

*

4

4.5

5

5.5

6

1 2 3 4 5 6 7 8

Week of lactation

Pro

tein

(%

)

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Figure 3: Mean concentration of plasma prolactin in SDPP and LDPP ewes. * Least squares means within a test day are different (P < 0.05). ** Least squares means within a test day are

different (P < 0.001).

0

40

80

120

160

200

-6 -5 -4 -3 -2 -1 0 1

Week relative to lambing

Pla

sma p

rola

ctin

(n

g/m

l)

LDPP

SDPP

These results support the theory that the effect of prepartum photoperiod is mediated by

circulating prolactin levels, which influence the number or sensitivity of prolactin receptors on mammary secretory epithelial cells. There is an inverse relationship between circulating prolactin levels and the expression of prolactin receptor mRNA in the liver, lymphocytes and mammary tissue of steers (Auchtung et al., 2003) and cows (Auchtung et al., 2005). Cows experiencing SDPP had increased expression of prolactin receptor mRNA, possibly increasing sensitivity of the mammary gland to the natural periparturient prolactin surge and enhancing proliferation and survival of mammary cells (Auchtung et al., 2005; Wall et al., 2005).

Work by Akers et al. (1981) demonstrated that “prolactin plays a critical role in mammary

differentiation for key biochemical steps involved in the synthesis of milk, especially those associated with lactose“. Therefore, a possible cascade of events to describe the effect of prepartum photoperiod on milk production may be: 1) short photoperiod in prepartum ruminants results in decreased circulating prolactin levels, 2) decreased prolactin levels stimulate the increased expression of mRNA for prolactin receptors, resulting in a greater number of prolactin receptors on mammary secretory epithelial cells, 3) the natural increase in circulating prolactin at parturition stimulates complete differentiation and commitment of mammary secretory epithelial cells to produce lactose, increasing milk production. Summary and Conclusions

Dairy ewes exposed to SDPP for approximately six weeks prepartum produced more milk with a higher milk fat percentage during the first eight weeks of lactation and more milk over the entire lactation period than ewes exposed to LDPP. Short days prepartum resulted in a decrease in circulating prolactin levels, which may have contributed to increased sensitivity of the mammary gland to the parturient prolactin surge and an increase in milk production in the subsequent lactation.

** **

**

*

30

The effect of prepartum photoperiod on milk production reported in this study may have contributed to the increase in annual milk production of dairy ewes at the Spooner Agricultural Research Station from 1996 to 2004 (Berger, 2005). In an analysis of factors contributing to this progress, Berger noted effects of dairy genetics, breed composition and weaning system, findings supported by previous authors (Bencini and Pulina, 1997; McKusick et al., 2001). Some of the increase in milk production was attributed to a change in the breeding and lambing seasons. Lambing has gradually moved from March and April to late January or early February. Ewes milking during the increasing daylength of spring and summer are likely responding to the positive effects of increasing photoperiod on milk production (Bocquier et al., 1997). In addition, winter lambing ewes are experiencing shortened prepartum photoperiods, which may be an additional factor in increasing milk yield. Therefore, management for decreased prepartum photoperiod may be a strategy to increase milk production in dairy ewes. Literature Cited Akers, R. M., D. E. Bauman, A. V. Capuco, G. T. Goodman, and H. A. Tucker. 1981. Prolactin

regulation of milk secretion and biochemical differentiation of mammary epithelial-cells in periparturient cows. Endocrinology. 109:23-30.

Auchtung, T. L., P. E. Kendall, J. L. Salak-Johnson, T. B. McFadden, and G. E. Dahl. 2003. Photoperiod and bromacriptine treatment effects on expression of prolactin receptor mRNA in bovine liver, mammary gland and peripheral blood lymphocytes. J. Endocrinol. 179:347-356.

Auchtung, T. L., A. G. Rius, P. E. Kendall, T. B. McFadden, and G. E. Dahl. 2005. Effects of photoperiod during the dry period on prolactin, prolactin receptor, and milk production of dairy cows. J. Dairy Sci. 88:121-127.

Bencini, R., and G. Pulina. 1997. The quality of sheep milk: A review. Austr. J. Exp. Agric. 37:485-504.

Berger, Y. M. 2005. Evolution of milk production at the Spooner Agricultural Research Station between 1996 and 2004. Pages 6-13 in Proc. 11th Annual Great Lakes Dairy Sheep Symp., Ithaca, NY.

Bocquier, F., S. Ligios, G. Molle, and S. Casu. 1997. Effet de la photopériode sur la production, la composition du lait et sur les consommations volontaires chez la brebis laitière. Ann. Zootech. (Paris). 46:427-438.

Dahl, G. E., B. A. Buchanan, and H. A. Tucker. 2000. Photoperiodic effects on dairy cattle: A review. J. Dairy Sci. 83:885-893.

Forbes, J. M. 1982. Effects of lighting pattern on growth, lactation and food intake of sheep, cattle and deer. Livest. Prod. Sci. 9:361-374.

Lincoln, G. A., and B. I. Baker. 1995. Seasonal and photoperiod-induced changes in the secretion of alpha-melanocyte-stimulating hormone in Soay sheep – temporal relationships with changes in beta-endorphin, prolactin, follicle-stimulating- hormone, activity of the gonads and growth of wool and horns. J. Endocrinol. 144:471-481.

McKusick, B. C., D. L. Thomas, and Y. M. Berger. 2001. Effect of weaning system on commercial milk production and lamb growth of East Friesian dairy sheep. J. Dairy Sci. 84:1660-1668.

Miller, A. R. E., E. P. Stanisiewski, R. A. Erdman, L. W. Douglas, and G. E. Dahl. 1999. Effects of long daily photoperiod and bovine somatotropin (Trobest ®) on milk yield in cows. J. Dairy Sci. 82:1716-1722.

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Ortavant, R., F. Bocquier, J. Pelletier, J. P. Ravault, J. Thimonier, and P. Volland-Nail. 1988. Seasonality of reproduction in sheep and its control by photoperiod. Aust. J. Biol. Sci. 41:69-85.

Peters, R. R., L. T. Chapin, K. B. Leining, and H. A. Tucker. 1978. Supplemental lighting stimulates growth and lactation in cattle. Science. 199:911-912.

SAS. 1999. SAS/STAT. User’s Guide, Version 8.2 SAS Institute Inc., Cary, NC. Velasco, J. M., E. D. Reid, K. E. Karvetski, T. F. Gressley, R. L. Wallace, and G. E. Dahl. 2006.

Short day photoperiod increases milk yield in cows with a reduced dry period length. J. Anim. Sci. 84(Suppl. 1):147. (Abstr.)

Wall, E. H., T. L. Auchtung, G. E. Dahl, S. E. Ellis, and T. B. McFadden. 2005. Exposure to short day photoperiod during the dry period enhances mammary growth in dairy cows. J. Dairy Sci. 88: 1994-2003.

32

PROGRESS REPORT: EFFECTS OF PREPUBERTAL GROWTH RATE OF EWE LAMBS ON THEIR

SUBSEQUENT LAMB AND MILK PRODUCTION

David L. Thomas1 and Yves M. Berger2 1Department of Animal Sciences and 2Spooner Agricultural Research Station

University of Wisconsin-Madison Introduction

In many sheep production operations in the Midwestern and Eastern U.S., lambs are managed for maximum body weight gain and fed high-energy diets continuously from shortly after birth until they are marketed as slaughter lambs. Since lambs in a flock are often managed together, potential replacement ewe lambs are fed high-energy diets along with lambs in the flock destined for slaughter.

However, the practice of feeding replacement ewe lambs for maximum body weight gain

may have detrimental effects on their milk production as ewes. While relatively little research has been conducted with sheep to address this issue, much has been conducted with cattle. The majority of well-designed studies have shown that high feeding levels for dairy heifers during the prepubertal period is detrimental to milk production as cows (reviews by Sejrsen and Purup, 1997 and Sejrsen et al., 2000 and the book by Akers, 2002). Increased feeding levels for beef heifers during their prepubertal period also has been shown to result in decreased milk production or decreased weaning weights of their calves (Holloway et al., 1973; Martin et al., 1981; Johnnson and Obst, 1984; Buskirk et al., 1996).

Studies evaluating the effects of prepubertal feeding level in ewe lambs on udder

development or subsequent milk production or lamb weaning weights are fewer in number and are less conclusive than the studies in cattle. Umberger et al. (1985), McCann et al. (1989), Johnsson and Hart (1985), and Johnsson et al. (1986) found slightly greater amounts of udder parenchyma (milk production tissue) in meat-type ewe lambs that had been fed at lower levels in the prepubertal period compared to ewe lambs that had been fed at higher levels, but the differences were not statistically significant. In contrast, McFadden et al. (1990) reported a non-significant increase in parenchymal udder tissue in full-fed compared to restricted-fed meat-type ewe lambs. In the studies of Umberger et al. (1985) and McCann et al. (1989), ewe lambs fed at lower levels had increased milk production in five out of six trials (differences were not always significant). Milk production in the latter two studies was estimated one or three times during the lactation period using the weigh-suckle-weigh technique (weighing lambs before and after suckling to estimate milk production) or by using oxytocin to remove milk. In a study with dairy sheep, milk production at first lactation was not different between levels of prepubertal feeding for Lacaune ewe lambs, but Manchega ewe lambs fed at the lower level produced 41% more (P < 0.05) milk than Manchega ewe lambs fed at the higher level (Ayadi et al., 2002). Each of the above sheep studies was conducted with a relatively small number of animals, and only one study measured milk production over the entire lactation period.

In their review of the cattle and sheep literature on the effects of prepubertal nutrition on milk

production for application to the U.S. dairy sheep industry, Tolman and McKusick (2001)

33

concluded that U.S. dairy ewe lambs should be restricted in their feed intake to about 65 to 75% of their ad libitum intake from 4 to 6 weeks of age through 20 weeks of age in order to increase the rate of mammary growth and to increase the total amount of epithelial tissue that will later develop into milk-secreting tissue.

The objective of this study was to estimate the effects of growth rate of dairy ewe lambs on

their lamb and milk production as adult ewes. The study would involve larger numbers of ewes than in previous sheep studies, measure milk production over the entire lactation in a commercial-like dairy sheep setting, and, hopefully, provide conclusive results.

Materials and Methods

The study is in progress at the Spooner Agricultural Research Station of the University of Wisconsin-Madison. Two hundred fifty two ewe lambs born in the late winter and early spring of 2004 (n = 104), 2005 (n = 85), and 2006 (n = 62) have been utilized in the study. The ewe lambs were of high percentage East Friesian (EF) or Lacaune (LA) breeding or various crosses of these two dairy breeds, with the exception of 18 ewe lambs born in 2004 that were sired by Dorset rams with less than ½ of their genetic composition from the EF and/or LA breeds.

Ewe lambs were removed from their dams at 1 to 2 days of age and raised on milk replacer

and a high concentrate (22 % crude protein) ad libitum diet until approximately 30 days of age. They continued on the high concentrate ad libitum diet for an additional 2 to 3 weeks after weaning from the milk replacer and then were randomly assigned to one of two growth treatments – full feed (FULL) or restricted feed (REST). Both treatment groups were fed a 13 % crude protein grain mix of whole shelled corn and a high protein pellet in straw-bedded pens (2 pens of lambs on each treatment each year). A small amount of alfalfa hay was also provided – less than 0.50 lb. per head per day.

Ewe lambs in the FULL group received as much of the grain mix as they could consume, and

average per head feed consumption was calculated daily. Each ewe lamb in the REST group received approximately 70 % of the average per head intake of the FULL group from the day before. The goal was to have REST lambs gain at 70 % the rate of FULL lambs. Lambs were weighted weekly. If the REST lambs were gaining markedly faster or slower than 70 % of the growth rate of FULL lambs, the proportion of the FULL intake that was fed to them was decreased or increased.

Ewe lambs remained on the nutrition treatments for approximately 100 days until they were

approximately 5 months of age. After the end of the treatments, all ewes were managed together. They were fed alfalfa hay ad libitum and 2 lb. of corn/head/day. The corn was decreased to 1 lb./head/day about 2 weeks before the start of mating. Ewe lambs were first mated in October-November at slightly over 7 months of age and lambed in March and April. Yearling and 2-year-old ewes were bred approximately a month earlier to lamb in February and March. The vast majority of lambs were removed from these ewes at 1 to 2 days of age and raised on milk replacer, and the ewes were then placed on twice per day milking in the parlor. In 2005, 17 of the 2004-born ewes were allowed to raise their lambs for approximately 30 days before the lambs were weaned and the ewes placed in milking. Ewes were pastured on kura clover-orchard grass

34

pastures during the grazing season, fed haylage at other times, and fed 2 lb. of concentrate per head per day in the milking parlor.

Results

Average per head feed consumption of the 12 pens of lambs over the years of 2004, 2005, and 2006 is presented in Table 1. As designed in the experiment, the REST group ate less (P < 0.05) of the grain mix than the FULL group (1.94 vs. 2.67 lb./head/day). Grain mix and total feed consumption of the REST group was 73 and 75 %, respectively, the consumption of the FULL group.

Table 1. Feed consumption least squares means for full- or restricted-fed dairy ewe lambs.

Treatment No. pens Grain/hd/d, lb. Hay/hd/d, lb. Total feed/hd/d, lb.

Full feed 6 2.67a .45 3.12a Restricted 6 1.94b .41 2.35b Restricted/Full .73 .91 .75 a,b Means within a column and within a treatment group with no superscripts in common are statistically different (P < 0.05).

Figure 1 illustrates that the nutritional treatments were successful in creating weight differences between the FULL and REST ewe lambs with the REST lambs lighter than the FULL lambs at the end of the trial. By chance, the ewe lambs on the REST treatment were 1.8 lb. heavier (P < 0.10) than the ewe lambs on the FULL treatment at the start of the trial (Table 2). However, by the end of the trial period, REST ewe lambs were 14.3 lb. lighter (P < 0.05) than the FULL ewe lambs. The average daily gain of the REST ewe lambs was 75 % that of the FULL ewe lambs; somewhat greater than the 70 % sought in the study but still within the range recommended by Tolman and McKusick (2001).

Also presented in Table 2 are the effects of breed of ewe lamb. The ewe lambs were divided

into two groups: a majority of East Friesian (EF) or Lacaune (LA) breeding. The 18 Dorset-sired ewe lambs in the study were from dairy cross ewes and were assigned to the dairy breed representing the greatest proportion of their genetic composition. Ewe lambs of a majority of EF breeding had greater (P < 0.05) end weights and slightly greater (P < 0.10) average daily gains than ewe lambs of a majority of LA breeding.

35

Figure 1. Body weights of ewe lambs during the treatment

period.

0

20

40

60

80

100

120

49 63 77 91 105 119 132 148

Age, days

We

igh

t, lb

.Full Restricted

Table 2. Age, weight, and average daily gain least squares means for East Friesian or Lacaune and full- or restricted-fed dairy ewe lambs.

Start End

Treatment No. ewe lambs Age, d Weight, lb. Age, d Weight, lb.

Average daily

gain, lb.

Breed: > 50% EF 126 49.9 38.9 147.4 101.6c .64a > 50% LA 126 50.3 37.5 148.0 98.3d .62b Nutrition: Full feed 129 50.8 37.3a 147.6 107.1c .72c Restricted 123 49.4 39.1b 147.8 92.8d .54d Restricted/Full .75 a,b Means within a column and within a treatment group with no superscripts in common are statistically different (P < 0.10). c,d Means within a column and within a treatment group with no superscripts in common are statistically different (P < 0.05).

An important finding from this study was that the lower weights of the REST ewe lambs at the end of the trial period did not have a long-term effect on their body weights. The REST ewe lambs had greater (P < 0.05) average daily gains from the end of the trial to their first mating approximately 2 months later and from their first mating to their first lambing at slightly over 1 year of age (Table 3). While the FULL ewes were still heavier (P < 0.05) than the REST ewes at first mating, the REST ewes more than compensated in the following 5-plus months and were slightly heavier (P < 0.10) than FULL ewes at first lambing (Table 3). Therefore, restricting feed

36

intake to 70 to 75 % of ad libitum intake in ewe lambs should not have an effect on adult ewe body weight.

By first lambing, the EF and LA ewes were of similar weights (Table 3).

Table 3. Least squares means for ewe lamb mating and lambing weights of East Friesian or

Lacaune and full- or restricted-fed ewe lambs.

Treatment No. ewe

lambs mated Mating wt.,

lb. ADG end of trial to first mating, lb.

Lambing wt., lb

ADG mating to first lambing, lb.

Breed: > 50% EF 121 135.5a .43c 163.6 .17 > 50% LA 124 131.5b .41d 163.1 .18 Nutrition: Full feed 127 135.5a .35b 161.0d .15b Restricted 118 131.5b .48a 165.7c .20a a,b Means within a column and within a treatment group with no superscripts in common are statistically different (P < 0.05). c,d Means within a column and within a treatment group with no superscripts in common are statistically different (P < 0.10).

Reproductive performance was available on the 2004-born ewes when lambing at 1, 2, and 3 years of age, the 2005-born ewes when lambing at 1 and 2 years of age, and the 2006-born ewes when lambing at 1 year of age.

Ewe lamb nutrition treatments had no effect on ewe fertility (percentage of ewes lambing of

ewes exposed and available at lambing time) or prolificacy (number of lambs born per ewe lambing, litter size) with 93 % of all ewes lambing and 1.75 lambs born per ewe lambing (Table 4). LA ewes gave birth to 12 fewer (P < 0.05) lambs per 100 ewes lambing than EF ewes (Table 4). The lower prolificacy of LA ewes compared to EF ewes has been documented in this flock earlier (Thomas et al. 2005). Table 4. Least squares means for reproductive traits at 1, 2, and 3 years of age of ewes

of East Friesian or Lacaune breeding and full- or restricted-fed as ewe lambs.

Treatment No. ewes No. exposures Fertility, % Prolificacy, no.

Breed: > 50% EF 120 224 92.5 1.81a > 50% LA 124 217 92.7 1.69b Nutrition: Full feed 126 224 91.9 1.74 Restricted 118 217 93.3 1.76 a,b Means within a column and within a treatment group with no superscripts in common are statistically different (P < 0.05).

37

Lactation performance was available on the 2004-born ewes when lambing at 1 and 2 years

of age and on the 2005-born ewes when lambing at 1 year of age. The 2004-, 2005-, and 2006-born ewes are currently completing their 3rd, 2nd, and 1st lactations, respectively.

Lactation length and yield of milk, fat, and protein were not affected by ewe lamb nutrition,

but FULL ewes had slightly greater (P < 0.10) percentages of milk fat and milk protein than did REST ewes (Table 5). The results of this study, to date, contradict the majority of the cattle data and the limited amount of sheep data that show increased milk production resulting from slower compared to higher prepubertal growth rates.

EF ewes had 47.5 lb. greater (P < 0.10) milk yield than LA ewes, but Lacaune ewes had

greater (P < 0.05) percentages of milk fat and milk protein than EF ewes resulting in similar amounts of fat and protein yield for the two breeds (Table 5). Table 5. Least squares means for lactation traits at 1 and 2 years of age of ewes of East Friesian

or Lacaune breeding and full- or restricted-fed as ewe lambs.

Treatment No.

ewes No.

lactations Lactation length, d

Milk yield, lb.

Fat, %

Fat yield, lb.

Protein, %

Protein yield, lb.

Breed: > 50% EF 60 88 187.3 521.2a 5.42d 28.4 4.46d 23.5 > 50% LA 61 90 184.3 473.7b 5.94c 28.7 4.79c 23.1 Nutrition: Full feed 60 88 187.9 504.5 5.77a 29.2 4.68a 23.7 Restricted 61 90 183.6 490.4 5.59b 27.9 4.57b 22.8 a,bMeans within a column and within a treatment group with no superscripts in common are statistically different (P < 0.10). c,d Means within a column and within a treatment group with no superscripts in common are statistically different (P < 0.05).

However, Table 5 does not tell the complete story. There were statistically significant interactions between breed and nutritional treatment for yields of milk, fat, and protein. This indicates that the nutrition effect was dependent upon the breed for these traits. Ewes of a majority of EF breeding had higher (P < 0.05) yields if from the FULL treatment than from the REST treatment, and the differences were quite large: +77.6 lb. for milk yield, +5.2 lb. for fat yield, and +3.9 lb. for protein yield (Table 6). In contrast, differences between REST and FULL treatments were not significantly different in ewes of a majority of LA breeding, although the REST ewes had slightly higher yields than the FULL ewes (Table 6).

Breed differences in response to prepubertal nutritional treatments have been reported. In

Danish dairy cattle, Hohenboken et al. (1995) found the greatest milk yield in each of three breeds in the group that had the slowest average daily gain as heifers, but the response was less in the highest milk yield breed (Friesian) than in the two lower milk yield breeds (Danish Red and Jersey). In dairy sheep in Spain, milk yield was not different between levels of prepubertal

38

feeding for the high milk yield breed (Lacaune), but the low milk yield breed (Manchega) produced 41% more (P < 0.05) milk when fed to gain slower than to gain faster (Ayadi et al., 2002).

Table 6. Least squares means for lactation yield traits by breed and nutritional treatment combinations.

Treatment No.

ewes No.

lactations Milk

yield, lb. Fat

yield, lb. Protein

yield, lb.

Breed-Nut. EF-Full 27 39 560.0a 31.0a 25.4a EF-Rest. 33 49 482.4b 25.8b 21.5b LA-Full 33 49 448.9b 27.4a,b 22.0a,b LA-Rest. 28 41 498.5a,b 29.9a,b 24.1a,b a,bMeans within a column with no superscripts in common are statistically different (P < 0.05). However, no studies have shown the large positive effects on milk yield of ad libitum feeding during the prepubertal period observed in the EF ewes in this study. It remains to be seen if this breed x ewe lamb nutrition interaction for lactation yield traits persists as these ewes accumulate more lactations and as the lactation records of the 2006-born ewes are added to the data set. We are still dealing with a relatively small number of observations at this point in time in this study. Stay tuned as more data is collected on these ewes. Literature Cited Akers, R. M. 2002. Pages 242-250 in Lactation and the Mammary Gland. Iowa State Press,

Ames, IA. Ayadi, M., G. Caja, X. Such, and J. Ghirardi. 2002. Effect of the level of feeding before puberty

on fertility and milk production during first lactation in Lacaune and Manchega ewes. Proc. XXVII Symp. Spanish Soc. Sheep and Goat Prod., Valencia, Spain.

Buskirk, D. D., D. B. Faulkner, W. L. Hurley, D. J. Kesler, F. A. Ireland, T. G. Nash, J. C. Castree, and J. L. Vicini. 1996. Growth, reproductive performance, mammary development, and milk production of beef heifers as influenced by prepubertal dietary energy and administration of bovine somatotropin. J. Anim. Sci. 74:2649-2662.

Hohenboken, W. D., J. Foldager, J. Jensen, P. Madsen, and B. B. Andersen. 1995. Breed and nutritional effects and interactions on energy intake, production and efficiency of nutrient utilization in young bulls, heifers and lactating cows. Acta Agric. Scan. Sect. A Anim. Sci. 45:92-98.

Holloway, J. W. and R. Totusek. 1973. Relationship between preweaning nutritional management and subsequent performance of Angus and Hereford females through three calf crops. J. Anim. Sci. 37:807-812.

Johnsson, I. D. and I. C. Hart. 1985. Pre-pubertal mammogenesis in the sheep. 1. The effects of level of nutrition on growth and mammary development in female lambs. Anim. Prod. 41:323-332.

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Johnsson, I. D., I. C. Hart, and A. Turvey. 1986. Pre-pubertal mammogenesis in the sheep. 3. The effects of restricted feeding or daily administration of bovine growth hormone and bromocriptine on mammary growth and morphology. Anim. Prod. 42:53-63.

Johnsson, I. D. and J. M. Obst. 1984. The effects of level of nutrition before and after 8 months of age on subsequent milk and calf production of beef heifers over three lactations. Anim. Prod. 38:57-68.

Martin, T. G., R. P. Lemenager, G. Srinivasan, and R. Alenda. 1981. Creep feed as a factor influencing performance of cows and calves. J. Anim. Sci. 53:33-39.

McCann, M. A., L. Goode, R. W. Harvey, E. V. Caruolo, and D. L. Mann. 1989. Effects of rapid weight gain to puberty on reproduction, mammary development and lactation in ewe lambs. Theriogenology 32:55-68.

McFadden, T. B., T. E. Daniel, and R. M. Akers. 1990. Effects of plane of nutrition, growth hormone and unsaturated fat on mammary growth in prepubertal lambs. J. Anim. Sci. 68:3171-3179.

Sejrsen, K. and S. Purup. 1997. Influence of prepubertal feeding level on milk yield potential of dairy heifers: A review. J. Anim. Sci. 75:828-835.

Sejrsen, K., S. Purup, M. Vestergaard, and J. Foldager. 2000. High body weight gain and reduced bovine mammary growth: physiological basis and implications for milk production. Domestic Anim. Endo. 19:93-104.

Thomas, D. L., Y. M. Berger, R. G. Gottfredson, and T. A. Taylor. 2005. Comparison of East Friesian and Lacaune sheep breeds for dairy production. J. Anim. Sci. 83(Suppl. 1) and J. Dairy Sci. 88(Suppl. 1):342.

Tolman, B. and B. C. McKusick. 2001. The effect of growth rate on mammary gland development in ewe lambs: A review. Proc. 7th Great lakes Dairy Sheep Symp., Eau Claire, Wisconsin. University of Wisconsin-Madison, Dept. of Anim. Sci. pp. 143-155.

Umberger, S. H., L. Goode, E. V. Caruolo, R. W. Harvey, J. H. Britt, and A. C. Linnerud. 1985. Effects of accelerated growth during rearing on reproduction and lactation in ewes lambing at 13 to 15 months of age. Theriogenology 23:555-564.

40

SHEEP PASTURE MANAGEMENT FOR 2007

Phil Holman Spooner Agricultural Research Station

University of Wisconsin-Madison

Through July 2007, the University of Wisconsin-Madison, Spooner Agricultural Research Station has again experienced very dry conditions. Rainfall totals are over 5.5” below normal so far. Pasture forage production has been greatly limited where precipitation has been lacking. To our advantage, we have irrigation available on some of our pastures. Irrigation has maintained our ability to rotationally graze the ewes this summer.

Pasture Trials and Demonstrations

1. Fescue, white clover, and chicory variety preference trial 2. Kura clover - orchardgrass seeding in year 2 3. Fall pasture of late planted spring grains

Fescue, White Clover, and Chicory Variety Grazing Preference Trial

This trial is being conducted with Dr. Paul Peterson, University of Minnesota Extension Forage Agronomist. It consists of 18 varieties of tall fescue, 1 prairie grass, 10 varieties of white clover, 1 kura clover, 2 hybrid clovers, and 3 varieties of chicory.

The trial was established in the spring of 2006 with each entry planted in an area 6’x 20’ and

replicated 4 times. Each variety/species is evaluated for stand density and plant height prior to grazing. After grazing has occurred, plots are visually rated as to the percentage grazed.

The biggest preference differences are between species. The sheep prefer clovers and the

prairie grass entry, then sheep will eat the chicory, and lastly, they will eat the fescue. Fescue leaves are coarse and rough so the sheep prefer other species. The fescue leaf characteristics are most prevalent in the first spring grazing. With subsequent grazings, the sheep are consuming more of the fescue. There are some variety preference differences as well in the fescues and white clovers, but data collection is ongoing and results are not available at this time. Kura Clover and Orchardgrass Seeding Year 2

A pasture was renovated in the fall of 2005/spring of 2006. First the existing bluegrass/quackgrass pasture was killed with glyphosate. In the spring of 2006, the pasture was fertilized, limed, and tilled (plow and disc) to have a good seedbed. On April 27, 2006, the pasture was seeded with 8 lbs./A of Endura III kura clover and 7 lbs./A of Albert ochardgrass. Endura III is a newer variety of kura clover which will be released under a different name (still unknown) and Albert ochardgrass was selected for its winter hardiness.

In 2007, the pasture is developing into a nice kura clover/orchardgrass mix. It contains

approximately 30% kura clover which is good for the second year. Kura clover is known for slow establishment in the first and second years of growth. It will be interesting to see if the kura clover continues to improve. Already this pasture area is producing more forage than the previous bluegrass/quackgrass pasture.

41

Fall Pasturing of Late Planted Spring Grains

On August 18, 2006, oats were seeded into fields that had been in winter rye. These fields were grazed in October after we were done with the milking season. The oats had grown to 12-15” tall and provided adequate forage quality for non-lactating ewes.

A major benefit of late planting oats for grazing was that it allowed us to extend our grazing

season and let our normal pasture acres have a rest period in October. Due to lack of soil moisture, we are uncertain whether or not we will be planting any late

spring grains this year.

42

KATAHDIN HAIR SHEEP AT THE SPOONER AGRICULTURAL RESEARCH STATION

David L. Thomas1 and Yves M. Berger2

1Department of Animal Sciences and 2Spooner Agricultural Research Station University of Wisconsin-Madison

The Katahdin is a breed of hair sheep developed in the U.S. Two hair ewes and a ram were

imported from the island of St. Croix, U.S. Virgin Islands in 1957 by Michael Piel of Maine. After experimenting with several crosses, he developed the Katahdin breed primarily from crosses of Suffolk, Wiltshire Horn, and the hair sheep from St. Croix. His goal was to develop a meat sheep that did not require shearing.

Coat color is often white, but tan, brown, red or roan coat colors in solid, spotted, blackbelly,

or reverse blackbelly patterns are also common. Most animals are polled. Katahdin sheep are small to moderate in body size.

Katahdin sheep have become very popular in recent years as an easy care sheep that does not

require shearing. The Katahdin breed ranked sixth among all purebred breeds of sheep in number of animals registered in 2006, and the breed has more flocks enrolled in the National Sheep Improvement Program, the national genetic improvement program for sheep, than any other breed.

On August 9, 2007, 9 yearling ewes, 3 ewe lambs, and 2 adult rams were selected from the

Katahdin flock of Bob and Amanda Nusbaum at Potosi, Wisconsin. The Nusbaum flock numbers over 100 Katahdin ewes and is probably the largest flock of Katahdin sheep in Wisconsin. These ewes and rams were transported to the Spooner Agricultural Research Station on August 10, 2007 to be used in the station’s sheep research program.

The Katahdin sheep initially will be crossed with some of the dairy sheep at the station that

carry the least amount of wool; most likely dairy sheep with a high percentage of Lacaune breeding. The goal is to determine if a high producing dairy sheep can be developed with a hair coat. A dairy sheep with a hair coat eliminates the cost and labor associated with shearing, and sanitation in the milking parlor may be improved. However, commercial market lamb value may decrease due to decreased pelt values.

Results from this new study will be available at future field days.

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2006-2007 PERFORMANCE OF THE SPOONER AGRICULTURAL RESEARCH STATION FLOCK

Yves Berger

Spooner Agricultural Research Station University of Wisconsin-Madison

Table 1. 2007 Reproductive performance of mature ewes ( milking). All ewes bred

naturally by Hampshire starting August 16 while ewes were still at milking. Lambing started January 10. All lambs raised on milk replacer.

Breed* 1/2E,C 3/4E,C >3/4E,C 1/2L,C 3/4L,C >3/4L,C E x L

or L x E

TOTAL

No. of ewes at breeding

7 15 25 9 13 12 184 265

No. of ewes at lambing

7 14 25 9 13 11 177 257

No. of ewes aborted

1 0 0 0 0 0 1 2

No. of ewes open

0 0 3 0 0 1 4 8

No. of ewes lambed

6 15 22 9 13 10 172 247

No. of lambs born

14 36 54 21 29 16 374 544

No. of lambs weaned at 30 days

11 31 44 19 27 10 302 444

Fertility 100% 100 88% 100% 100% 92% 98% 96% Litter size 2.0 2.4 2.45 2.33 2.23 1.6 2.17 2.2 Survival to weaning

79% 86% 81% 90% 93% 63% 81% 82%

Birth wt 11.8 12.5 11.1 12.2 10.8 11.2 12.3 Wean age 32 27 28 27 28 29 27 Wean wt 34.5 32.8 30.1 33.5 31.5 32 31.7

E = East Friesian L = Lacaune C = ½ Dorset, ¼ Romanov (or Finn), ¼ Targhee

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Table 2. 2007 Reproductive performance of 1 year old dairy ewes. EF and Lacaune ewes were artificially inseminated. All other were naturally bred with dairy breed rams. Natural breeding on October 1 and artificial insemination on October 15. All lambs were raised on

milk replacer.

Breeds* EF L EF x L No. of ewes at breeding

8 1 55

No. of ewes at lambing

8 1 54

No. of ewes aborted 0 0 0 No. of ewes open 0 0 2 No. of ewes lambed 8 1 52 No. of lambs born 12 1 82 No. of lambs weaneds

9 1 71

Fertility 100% 100% 96% Litter size 1.5 1.0 1.58 Survival to weaning 75% 100% 87% Birth weight Weaning weight 100 d weight

* EF = East Friesian L = Lacaune EF x L = various percentages of Lacaune or East Friesian

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Table 3. 2006 milk production by lactation and genotypes

Number of

ewes1

Weaning systems2

Average production (pounds)

%BF Average days at milking

1rst lactation

½ EF 0

½ Lacaune 0

¾ EF 2 DY1 569 5.88 209

¾ Lacaune 0

7/8 EF and EF 4 DY1 397 5.20 161

7/8 Lacaune and Lacaune

3 DY1 472 6.55 207

Lacaune x EF 22 DY1 447 6.2 196

EF x Lacaune 19 DY1 554 5.39 200

Total ewe lambs 50 490 5.8 196

2nd, 3rd, 4th lactation

½ EF 11 DY1 658 6.36 226

½ Lacaune 11 DY1 697 7.08 225

¾ EF 14 DY1 750 5.98 218

¾ Lacaune 15 DY1 722 6.87 227

7/8 EF and higher EF

16 DY1 727 5.78 212

7/8 Lacaune and higher Lacaune

2 DY1 540 6.74 201

Lacaune x EF 68 DY1 773 6.37 221

EF x Lacaune 68 DY1 841 6.10 222

Dorset x E or L or EL

10 DY1 711 6.32 215

Total adults 215 DY1 771 6.29 221

All ewes 265 DY1 718 6.20 216 1Number of ewes: including all ewes having been milked at least 20 days 2Weaning systems: DY1 = Ewes put at milking 24 hours after lambing

Photoperiod’s trial

Short photoperiod Long photoperiod

N ewes pounds % fat Days milked pounds % fat Days milked

11 730 6.47 226

11 698 6.43 226