1/25/2011

1

Benefits of a short calving season

Rick FunstonReproductive Physiologist

UNL – Beef Research and Extension

GSLBBR

ARDC

NERECPHREC

WCRECLincoln

KCWL

NCTA

Dalbey

Where does it begin?

Recent NAHMS Survey

55% of operations (34% of cows) no defined breeding season

61% of operations and 62% of cows 105 d or less

26% of operations and 23% of cows 64 d or less

Why have a limited breeding season?

Nutritional management Observation at calving Uniformity of calf crop Facilitation of management Identify reproductive problems

1/25/2011

2

Heifer Selection and Development

1. Cull daughters of “bad mark” cows2. 3. 4. 5. 6.

Replacement Heifer Selection

Jim Gosey, 2005

1. Cows that need help calving2. Cows that calve late (+42 days)3. Cows that fail to wean a calf4. Cows that have big teats/need help5. Cows that wean a light wt. calf6. Cows that have “attitude” problems

* assume opens are culled

What are“Bad Mark”Cows* ?

Jim Gosey, 2005

1. Cull daughters of “bad mark” cows2. Cull light wts., big birth wt & 6 frame3. Cull youngest (born +45 d. calving )4. Select daughters of oldest cows5. Optimum (not maximum) preg. rate6. Pigmented eyes & udder7. Form = depth rib, chest width, guts

Replacement Heifer Selection

Jim Gosey, 2005

Extensive heifer development systems

Lower Development Costs $70 +Selling open heifers was profitableDetermine adaptability early?o Short breeding seasono Lighter breeding weightso Lighter mature weights?Must continue to grow through

calving

Synchronization of Estrus in Cyclic Cows/heifers

$ 1.70

0 10Day

PGF2a

5

Synchronized heats

Turn in Bulls

Used with 32-day breeding season at Fort Keogh with the Season of Calving herds over the past 3 years and has consistently yielded pregnancy rates > 85%.

1/25/2011

3

Increased Calf Weaning Age and Weight

with Estrous Synchronization

Schafer et al., 1990 CSU Beef Report. p. 115

13 days

41 lbs

Wea

ning

Age

/ W

eigh

t

Pregnancy Rate

No synchronizationSynchronized

60 day breeding season

45 day breeding season

2075 521

Calf Production

Length of breeding season

60 days 45 daysNo Synch Synch

Calved in 1st 21 d, % 61 73Calf birth date, Julian day

86 85

Calf birth BW, lb 84 81Calf weaning BW, lb 483 503Calf value, $/calf 507 528

Time of Calving Affects Feedlot Performance

Period of calving, 21 day periods

Steer calves (n = 661) 1st 2nd 3rd

Weaning weight, lb 515 483 435

Feedlot ADG, lb/day 3.61 3.62 3.63

Carcass weight, lb 816 800 771

Marbling score 574 554 527

Yield grade 3.0 2.8 2.6

Choice, % 84 83 73

≥ Average choice, % 30 17 12

Carcass value $1102 $1079 $1025

Actual Profit Differences are Large

•It takes the profit from two early-calving cows to cover the loss from one late-calver.• A cow that calves in the first 21-day calving interval her entire 8 or 9-year life, will produce the weaning weight equivalent of 1 ½ to 2 ADDITIONAL calves in her lifetime compared to one that starts late and stays late.

Effect of Calving Date on the Number of Cows

Calving the Following Year

(Patterson et al., 1992)

1/25/2011

4

Reproduction is the single most important factor for profitable

beef production.

Effect of Location on Pregnancy Rates

Can you cull a cow based on one year’sprogeny carcass data when you don’tknow who the sire is?

Sire Selection

Determines more than 85% of the total improvement made in a herd

Selection for Reproductive Traits

Trait Heritability % Calving interval 10 % Calf Crop 10 Days between calving/1st breeding 5 Days open 3 Inseminations/conception/cow 3 Age @ Puberty 40 Scrotal Circumference 50 Body Condition Score 40

Reproductive Traits

1.Puberty/ Resume cycling

2.Fertile ovulation

3.Conception (Cow and Bull)

4.Maintenance of Pregnancy

5.Give birth to live calf

These interdependent traits

culminate in a qualitative response,

measured 1 time every year.

1/25/2011

5

Calving Ease

16 % advantage in conception rate to cows not having dystocia (2000 head; Laster 1973)

Short duration of labor; 10% more in estrus at beginning of breeding season; 14% higher fall pregnancy % (Doornbos 1984)

Calving Assistance

Item Late EarlyCalf Vigor 1.1 1.2PPI 51 49% in heat 82 91*Services/conception 1.24 1.15Fall Pregnancy 78 92* Calf ADG 1.63 1.74*Calf WW 387 422*

Stage II

Scrotal Circumference

21 day reduced age at first estrus; 1.6cm increase in scrotal circumference in progeny from 141 sires selected for scrotal circumference (Morris, 1993)

Daughters of bulls with a high SC EPD reached puberty 62 days earlier than a low SC EPD line (Hough, 1991)

Has Age of Puberty Changed?

Milk Production

Balance between productivity and resource availability and cost

Selection for increased milk will not be profitable in all systems

Mature Size

Increased feed requirements per cow. Related positively to other growth

traits.

Most desirable = cows that excel in early growth, but mature at moderate weight.

Kolstad, 1993; MacNeil et al., 1994; Koots and Gibson, 1998

1/25/2011

6

Angus Genetic Trend for YW, MW, and Milk

Which Direction to Go?

GrowthReproduction

MarblingEfficiency

Milk ProductionLean Yield Marbling

Growth

Advantage of Crossbred Cows

Trait Maternal HeterosisLongevity 1.2 yrs (44%)Calf Weight/Cow Exposed 74 lb (25%)Net Profit/Cow Exposed $100

Body condition at calving and prepartum nutrition

Prepartum nutrition more important than postpartum nutrition in determining length of postpartum anestrus

Inadequate dietary energy during late pregnancy lowers reproduction even when energy is sufficient postpartum

Animals should be BCS 5-6 at calving

Requirements for Protein and TDN

Animal Protein TDN

TDN:CP Ratio

800 lb heifer,

not pregnant7 54 7.7

Pregnant heifer,

1.25 lb/d gain8 55 6.9

Lactating cow,

15 lb milk/d11 62 5.6

Moore and Kunkle, 2000

1/25/2011

7

If protein content falls below requirements,

then energy intake can be reduced

Forage Protein Content, %

Mathis, 2000

Reduced Intake

Less than 10% of today’s beef producers know the nutrient content of their forage.

Forage Analysis

Forage # %CP Range Alfalfa 759 16.1 6.3-23.5 Prairie 536 9.6 2.6-16.8 Meadow 40 8.1 5.0-11.0

SupplementationType CostTimingFrequency

Top 5

5 Places to Save Cut hay waste Feed more crop residue Weigh and sort cows Body condition scoring Supplementation

strategies

5 Places to Spend Forage analysis Preg testing Implants and

ionophores Mineral Suppl. Herd biosecurity

Excess Protein Heifers fed excess DIP had elevated PUN,

and lower first service conception rates (82 vs 61%).

Beef heifers grazed pastures either N fertilized or not, and supplemented SBP or not.

Elevated systemic ammonia and urea. Embryo survival was 68 and 74 % for high

and low N, and 65 and 76 % for non supplemented and supplemented.

1/25/2011

8

Alfalfa Pivots

Excess nitrogen?Phytoestrogens?

Excess UIP

Negative effects on several hormones that positively influence reproduction when fed at high level (.71, .55, .25 lb/d; Kane et al., 2000).

Heifers fed additional UIP during development reached puberty at a later age and heavier weight, fewer serviced in 1st 21 d (.55 lb/d; Lalman et al., 1993).

Dried Distillers Grains (DDG) An opportunity for producers

Available – supply increasing Affordable (per unit of energy or

protein)

Complementary to many forages High Fiber Energy: > 120% corn Crude protein: 30%

UIP: approximately 50% of CP Fat: 10-12% High P

Supplement CompositionDM Basis

Supplement Intake

0.73 % BW 0.57 % BW

CON DDG

DDG 99.76

DCGF 73.00

Whole Corn Germ

24.48

Urea 2.33

Trace Mineral .16 .20

Vitamin ADE .03 .04

1/25/2011

9

Results

b

a,b P < 0.003

a

A.I. Conception Rate

A.I. Pregnancy Rate

Final Pregnancy Rate

a b

Fat Supplementation

Most benefit has been shown in prepartumsupplementation

Postpartum diet appears to be important Birth weight may increase if fed before

calving May have benefit on cold tolerance in

newborns Concerns feeding high linoleate postpartum Economics?

Effect of Rumensin on Puberty and Conception Rates

Group No. heifers % Cycling % Bred

Rumensin 24 92 55

Control 26 58 47

Treatment Age @ Puberty % PregnantHigh Roughage 383 83Rumensin +90% HR 369 96Rumensin +100% HR 369 96

BALANCED NUTRITION:

KEY TO OPTIMIZING

PRODUCTION

Protein Energy Minerals Vitamins Water

Effect of Time of Gain From

Weaning to Breeding on Heifer

Performance

No difference in ageat puberty, conceptionrate, or calf performancethe next year.Clanton et al., 1983

EVENGAIN vs LATEGAIN,Age and Weight at Puberty, no effect, 12% less feed w/LATEGAIN. Smith et al., 1995

Timing of Gain and Reproductive Performance

Item Even Gain Late Gain

FSCR 56.4 71.1

Overall 87.5 87.5

1/25/2011

10

Longevity and Heifer Development System

Freetley, USMARC, unpublished

Winter Grazing

Crude protein in cattle diets on Sandhills range

0

2

4

6

8

10

12

14

Pro

tein

, %

OM

APR MAY JUN JUL AUG SEP OCT NOV DEC JAN FEB

Month

Net Energy (NE) Requirement for a 1200 Lb March Calving Cow With 23 Lbs/day Peak Milk Production

0

5

10

15

20

Calve 3 5 Wean 9 11

Months After Calving

NE (M

cal/d

ay)

NRC (1996)

Effect of Weaning Date on Cow Body Condition Score

P<.0001

Pregnancy

95.1%

94.2%

Effect of Protein Supplementation on Cow BCS

P<.0001

Pregnancy 93.8%

95.5%

Restriction Re-feeding

BCS 7

BCS 5

BCS 3

BCS 6

BCS 5

Effect of sire on pregnancy rates

Sire TAI Pregnancy

A 70B 43C 65D 60

1/25/2011

11

Technician EffectsTech Preg

Rates

1 672 443 61

Transportation after AI

Stress and AI?

+ Bucket Load of Estrogen +

+Pushed Around by Friends for

12 Hours

Off Feed24 Hours +

Pack Her OwnWeight 30 Times

in 12 Hours +

Cowboy’s Armin Rectum + .5 cm Rod in

Vagina/Cervix = Stress is Maximized

Handling Cattle after AI

1 - 4 8 - 12 29 - 33 Synchronized Pregnancy Rate 74% 62% 65%

Breeding Season Pregnancy Rate 95% 94% 94%

Mean Day of Conception 9.6 13.4 13.6

Day Transported after AI

Factors that Affect Estrous Response & Conception

Rates Body Condition Scores

Age

Postpartum Intervals

Percent Cycling in Herd

Nutrition

Weather

Correct Application of Protocols

2011 Beef Cow Protocols

1/25/2011

12

2011 Beef Cow Protocols 2011 Beef Cow Protocols

2011 Beef Heifer Protocols 2011 Beef Heifer Protocols

2011 Beef Heifer ProtocolsFeatures Recommended systems for

cows & heifers Select systems by type

Heat detect & AI systems Heat detect & cleanup AI

systems Fixed-Timed AI Systems

List of daily activities Generates Barn Calendar Cost per AI pregnancy Support materials

1/25/2011

13

Questions?

beefrepro.infoResources

Past and Upcoming ARSBC Events westcentral.unl.eduAg Managers Tool BoxFeed cost calculator and other decision

support tools beef.unl.edu rfunston2@unl.edu