Breeding program

8/12/2019 Breeding program

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SECTION 5

Planning the Breeding ProgramDarrh Bullock

e qua ity o catt e pro uce y the ee in ustry is eterminey the cattles genetic makeup and the management system to

which they are su jecte . Genetic ma eup is un er tota contro oree ers, oth pure re an commercia , an this responsi i ityhould not be taken lightly. Research has shown that different typesf cattle perform differently under varied management conditions.

is means that ee pro ucers cannot just se ect or the maximumn traits of economic importance but that they must match their

genetics to their resources and environment.e se ection o u s an hei ers, an the ree ing system use ,

ictate the genetic quality of the calf crop. e purebred producerses selection for genetic management, while the commercialro ucer uses oth se ection an mating systems, especia yrossbreeding.

Because most sires are purchased from them, purebred breed-rs exert a great in uence on the irection o the ee in ustry.ommercia pro ucers are insisting that the pure re see stocroducer keep records and make these records available. It is im-ortant that oth pure re an commercia pro ucers un erstann use the princip es an too s o genetic improvement.

Goa s an TargetsHaving goa s that you inten to meet is important or many

reas o ee pro uction ut may e most critica or the ree ingrogram. ese goals may include reproduction, calf performance,

ncome, cost containment, or a number of others. Breedingmanagement ecisions wi impact each o these goa s to varying

egrees. e breeding management practice that has the greatestmpact on reproduction would be crossbreeding, whereas selections the est management practice or improving carcass qua ity. Set

goals for your beef herd that are important to your familys qual-ty of life and then determine which management and breedingractice wi est he p you to attain those goa s. Remem er, most

management decisions can be changed in an instant, but changesto your herds genetics generally take time.

e ee catt e in ustry is very segmente , with many ca veshaving three or more owners e ore arriving at the grocer orestaurant. is type of system has its drawbacks for the industrys a who e, ut it oes a ow some opportunities. When consi er-ng your ree ing program, you must consi er when you p an to

market your cattle (weaning, preconditioned, yearling, finished)nd what kind of end product you are trying to produce.

e most common opportunities to mar et catt e inten e ormeat production are:1. Calves sold at auction at weaning. Buyer has no knowledge of

a ves other than what is seen in the esh.

2. Ca ves so o the arm at weaning. Buyer has irect contact withthe producer and is more aware of performance information tovarying egrees, ree type, an management in ormation.

3. Ca ves so either at auction or o the arm a ter precon i-tioning at least 45 days postweaning. is marketing systemis only profitable if the buyer is aware of the preconditioning;there ore, i ca ves are so at auction, it shou e a speciapreconditioned sale (CPH-45 in Kentucky).

4. Yearlings sold after backgrounding either at auction or off thearm. Buyer genera y has itt e now e ge o the catt e, ut

older cattle tend to have better health as feeders compared tocalves.

5. Retaine ownership through ee yar to nish. Once the catt ehave reached their finished condition, there are additional op-tions:A. Se ive as commo ity catt e. is asica y means you

a e the average price o catt e purchase that wee .B. Sell on the rail (in the meat).Once again additional options

re now avai a e ( or more in ormation see Section 9, Keyeef Cattle Marketing Concepts):

1. Sell on a grade and yield basis. Carcasses are valuedccording to how well they do from a Quality and Yieldra e asis.

. Sell on a grid or formula. is is a more precise systemthat pays premiums for certain types of cattle. Some grids

re etter suite or high-qua ity gra e catt e, an othersre better suited for better yield grading cattle.

When an how you p an to mar et your catt e p ay importantroles in your breeding decisions.

ere is not a right or wrong answer to when and how to marketcatt e. Depen ing on your resources, one option may e etter thananother, ut certain situations may cause you to consi er one o theother options. Some examples of situations that may cause you tore-eva uate how you mar et your catt e wou e rought or otherrestrictions to grazing management, mar et an /or utures prices,alternative feed availability, or others. Although it is important toset goa s an have targets, it is a so important to e exi e i op-portunities or a versities eve op.

Her Assessmentnce your goals have been established and you have a target that

you are shooting or, it is important to etermine the per ormanceand potential of your current herd. When going through this pro-cess, it is very important to be honest with yourself and examineyour operation with a critica eye. You may n that your her is


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SECTION 5PLANNING THE BREEDING PROGRAM

er orming at the appropriate eve or the eve o managementthat you have, or you may n that you nee to ma e some rasticgenetic changes in order to meet your goals.

e first step in the herd assessment process, for a commercialro ucer, is to etermine the ree ma eup o the her . is wi

tell you whether you have been doing a good job of crossbreeding.

If you have cows in the herd that are greater than 75% of one breed,you shou ma e some changes to your ree ing program. is wibe discussed in greater detail in the crossbreeding section below.

e next step is to determine the production level of your herd.You must eep goo recor s. With goo recor s, you wi e a eto assess the reproductive performance (including calving distri-bution), sickness, growth performance, cow condition at weaning,

n any other characteristics that you eep recor s on. Having thisn ormation wi he p you etermine i changes are nee e an

help you determine how best to make those changes. If you donot current y eep goo recor s, see Section 11, Recor Keep-ng, an start a recor - eeping program imme iate y. Withoutecords, you can still assess your herd for other factors, but you

wi e rastica y imite . e ast step in this process is etermining the size o your

ows, both from a weight and frame standpoint. Frame scores areffi cially determined by a calculation that includes the age and

hip height o the ca . e rame size then pre icts the expectemature size or finished weight of that calf as shown in Table 5-1.It is important to understand that the predicted mature weights

re assuming a con ition score o 5, an the nishe weights aressuming a backfat thickness of 0.4 inches. Knowing the frame sizef the cow herd will have an impact on two areas: cow maintenancen carcass weights.

Frames Effect on Cow MaintenanceFor most commercial cattle producers, cow maintenance costswi have the greatest economic impact. Larger- rame catt e weighmore at maturity an there ore have higher maintenance nee s.ypically, these cattle will also have additional growth geneticsesu ting in increase income to o set the increase costs. isost/return a ance is what is important or you to eterminender your management scheme. If your goal is to have larger

feeder calves, realize that this may result in larger mature cows thatwi cost more to maintain, or they wi have re uce repro uctive

erformance if not properly maintained.

Frames Effect on FeedlotPerformance and Carcass Weight

e growth and development relationship between large- andsma - rame catt e can e o serve in Figure 5-1. e growth pat-tern of the different types of cattle is similar, and the X illustrates

the optimal finish point for the cattle. is is the point where itecomes ess e cient to continue to ee the catt e. At this point,the catt e are starting to accumu ate more at an ess musc e.Since it requires more feed to put on a pound of fat than a poundo musc e, the catt e ecome ess e cient.

As a genera ru e, arger- rame catt e ten to grow at a asterrate; however, they reach their optimal finish point later and atheavier weights. e implications are that larger-framed cattle re-quire more ee to nish an have greater expenses ue to a ongerperiod in the feedyard; however, they are heavier at finish and willgenerate more income. As long as cattle do not fall into the lightor heavy carcass category, the tra e-o is pro a y equa . e reaproblem occurs when cattle of varying frames are fed together to

a constant endpoint. e average of the group will meet industrynee s, ut there may e a arge num er o over- an un er- nishecattle in the group. Grouping cattle according to type going intothe feedyard or sorting the cattle out as they finish is essential inpro ucing a uni orm, accepta e pro uct.

Ta e 5-1.Frame re ation to mature size an carcass weig t.

FrameYear ng H p

Height

ExpecteMature

eight

ExpecteHarvest

eight

Expectearcasseight

43 1,025 50 00

4 45 1,100 ,050 60

5 47 1,175 ,150 725

6 49 1,245 ,250 785

7 51 1,320 ,350 50

8 53 1,395 ,450 15

1,465 ,550 75

Small Growth Curve

GrowthU

nits

Time Units

X

Large Growth Curve

GrowthU

nits

Time Units

X

F gure 5-1.Growt curve comparison o sma - vs. arge- rame catt e.

Examp e o Ca ves rom a Large-Frame Bu an aModerate-Framed Bull with the Same EPDs for Growth

If two bulls have the same genetics for growth but differ inrame, we wou expect the arger- rame u s ca ves to e ta er

at weaning and as yearlings, the finished calves to be heavier and

take longer to feed to optimal finish, and the females to be larger asmature cows. However, ecause the u s have the same ExpecteProgeny Differences (EPDs) for growth, we would expect the calvesto weigh the same at weaning and as yearlings. If large- and moder-ate- rame ca ves weigh the same, the arger- rame ca ves i e yhave ess musc ing an /or ess o y capacity. To put this into per-spective, compare a 6-foot 8-inch person who weighs 250 pounds,with a 5- oot 8-inch person who weighs 250 poun s.


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Management AssessmentManagement is another component o your operations that

hould be assessed. In order to properly determine the genetictype of cattle that you need, it is important to know what will be

rovi e an how that impacts the per ormance o your her .When assessing management, the primary areas of concern arelabor and nutrition availability.

LaborLabor availability is an important component when determin-

ng your breeding program. Even on farms that are completelyami y owne an operate , a or is a consi eration. It muste etermine how c ose y the catt e wi e care or. In other

words, are you a full-time farmer who spends a great deal of timewith the catt e an can provi e assistance when nee e , or areyou a part-time armer who gets the opportunity to see the catt e

nly on occasion and whose cattle are required to be more selfuffi cient? Knowing this information can assist in developing a

ree ing program. As an examp e, a u -time armer who o servesthe cattle multiple times in a day may not have to pay as much

ttention to getting a calving-ease bull as the part-time farmerwho rare y sees his catt e. A itiona y, a u -time armer usua yhas more opportunity to provide additional nutrition to the cattlewhen they are in need and can probably manage high-producing

att e etter than a part-time armer who cannot a ways ee theattle on a timely basis.

utr t on e avai a i ity an qua ity o nutrition are extreme y important

when etermining your ree ing program. Di erent types o catt e

erform differently depending on the nutrition that they receive.esearch has shown that un er nutritiona y stress u situations,

ma er, ess-pro uctive catt e are more e cient at turning theesources available into pounds of salable product. eir calves aretill smaller on average, but they tend to have higher reproductionates that o set the e ciency in weight. Un er i ea nutrition,

there were very little effi ciency differences between high-perform-ng cattle and moderately performing cattle. In an environment

that provi es more nutrition than the catt e nee , the arger, high-erforming cattle were the most effi cient at producing poundsf salable product or weaned calves. Based on this information,

management operations that provi e exceptiona nutrition shouonsider more productive types of cattle; however, operations withoor nutrition, either in availability or quality, should consider less-ro uctive catt e (sma er an /or ess mi ing a i ity .

Nutrition assessment should include forage base (infectedfescue with sparse legumes, high-quality grass/legume mix, cool-/warm-season grass mix, etc. , the nutritiona qua ity o storefeeds (silage, hay harvested and stored correctly, hay harvested

fter optimum maturity and stored outside on the ground, etc.),n economica avai a i ity o purchase ee stu s. Quantity anua ity o ee resources wi e a actor in many managementecisions, including breeding management.

Genetic Principleso u y un erstan ree ing management, it is important to

know some basic genetic principles. Knowing the role geneticsplays in each economically important trait of beef cattle can assistin ma ing wise se ection ecisions. It is necessary to now whichtraits can be altered through breeding management (selectionand/or crossbreeding) and which traits should be altered by othermanagement techniques.

Most traits of economic importance (calving ease, weaningweight, etc.) in beef cattle are controlled by two factors: the envi-ronment in which the anima ives an the anima s genetic ma eup(genotype). e environment consists of not only the weather buthow the cattle are managed. Creep feed, forage quality and quantity,an hea th programs are examp es o environmenta e ects. Envi-ronmenta e ects on economica y important traits are contro ethrough management techniques, such as nutrition and healthprograms, which are discussed in other sections of this manual.

e two types o genetic e ects on economica y important

traits of beef cattle are additive and nonadditive. When a bull andcow are mated, each contributes 50% of its genetics to their calf. Ifthat ca is then a owe to repro uce, it passes 50% o its genetics toeach of its calves; however, each calf gets a different sample of genesfrom its parents (that is why brothers and sisters are different). esamp e o genetics that o spring receive rom their parents an u ti-mately pass on to their progeny is referred to as the additive geneticeffects. ese are the genetic effects passed on from generation togeneration; there ore, they are the asis o se ection.

Herita i ity, the percentage o each trait contro e y the a i-tive genetic effects, is an important factor when making selection

ecisions. To visua ize this etter, o spring have more o the samecharacteristics as their parents or high y herita e traits. In other

words, the genetics that caused the parents to perform in a certainmanner wou e passe on to the ca ves an they wou per ormsimi ar y. High y herita e traits respon more rapi y to se ection,while lowly heritable traits respond more rapidly to managementpractices (environment) and heterosis (crossbreeding). Table 5-2i ustrates the re ative herita i ity an heterosis o severa economi-cally important traits.

Another genetic effect that is important when making selectionecisions is genetic corre ations. A genetic corre ation occurs when

you select for one trait and another trait is affected. e effect of onetrait on the other can be either complementary or disadvantageous.Here is an examp e o a comp ementary genetic corre ation: as se-

Ta e 5-2.T e re ative erita i ity an eterosis e -fects of several economically important traits in beef.

Tra t Her ta ty Heteros s

Birt weig t mo erate- ig mo erate

Weaning weight moderate moderate

Year ing weig t mo erate mo erate

Mi ing a i ity mo erate mo erate

Carcass traits high low

Repro uction ow ig

Longevity ow ig


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ections are ma e or increase weaning weight, year ing weight isso increase . Here is an examp e o a isa vantageous corre ation:

s selections are made for increased weaning weight, birth weightlso increases. Genetic correlations work the same regardless of

which trait is eing se ecte or. In other wor s, as se ections aremade to decrease birth weights, weaning and yearling weights are

sually decreased, too. e implications of genetic correlations formany traits or which expecte progeny i erences are ca cu atere discussed below and in Table 5-5.

Nonadditive genetic effects refer to how the genetics from thetwo parents com ine an how they interact with the environment.

e best example of nonadditive genetic effects are the benefitsealized from crossbreeding. ese benefits are known as heterosis.

Heterosis is e ne as the increase in pro uctivity in cross respring over the average o ree s that are crosse . Heterosis

s highest for lowly heritable traits (such as reproduction) andowest or high y herita e traits (such as carcass traits (see Ta e

5-2 for the impact of heterosis on several traits). Crossbreedingmight result in relatively small amounts of heterosis for each trait,

ut these e ects ten to accumu ate to pro uce arge increases invera pro uctivity. In some instances, a portion o this a vantages passed on to future generations, but to optimize the benefits, arossbreeding program should be implemented.

For most traits that we ea with in catt e, the genetic contri u-tion is provided by many gene pairs, and the environment con-tributes significantly to how the cattle perform. Two exceptionsto this are the traits o coat co or an po e /horne . To nowhow color and horns occur, it is important to understand a few

oncepts. Color and horns are determined by one pair of genesach. In other wor s, the com ination o two genes etermines

what color the calf will be (the exceptions are breeds with dilutergenes such as Charolais), and the combination of two other

genes etermines whether it wi have horns or not. In theseom inations, ac is ominant to re , an po e is ominant

to horns. If an animal has two black genes, we call it homozygousac (resu ting in a ac ca ; i it has two re genes, it is ca e

homozygous red (resulting in a red calf); if it has one of each,t is called heterozygous (resulting in a black calf because the

black gene is dominant). e same is true with horned/polled:an anima has two po e genes, we ca it homozygous po e

(resulting in a polled calf ); if it has two horned genes, it is calledhomozygous horned (resulting in a horned calf ); if it has one of

ach, it is ca e heterozygous (resu ting in a po e ca ecausethe polled gene is dominant). erefore, just because a bull is black

nd polled does not necessarily mean that he will produce black,o e ca ves. Figures 5-2 an 5-3 i ustrate some samp e matings.

Visual determination of color and polled/horned is impossiblexcept in the case of a homozygous recessive calf, which we know

has two recessive genes.Investigating the trait in a ca s pe igree can e e ective in

dentifying homozygous dominant cattle, but it is not conclusive.e on y conc usive way to etermine i an anima is homozy-

gous ominant or heterozygous is to have a tissue samp e testesing molecular technology (described in more detail later in

this section).

Cross ree ing or t eCommercial Producer

rossbreeding is the mating of cattle of different breeds orbreed composition. It can be an effective method of improving

ee pro uction. e two primary reasons to use cross ree ingare (1) heterosis (hybrid vigor) and (2) breed complementarity(breeds have characteristics that complement each other and fit

the environment . When crosses are ma e, one ree s strength cancomp ement the others wea nesses. Since no one ree is superiorin all traits, a planned crossbreeding program can significantlyincrease her pro uctivity.

e two greatest economica impacts on pro ta i ity rom het-erosis is the increase in production and longevity of the cows. Whenproduction is measured as weaning weight per cow exposedwhichta es into account repro uctive rate, surviva , mi ing a i ity, angrowththe increase is between 20 and 25% when compared to astraightbred operation. at means that by maximizing crossbreeding,the e ects o heterosis a one wou a 20 to 25% more income. ebenefit of increased longevity should not be underestimated either.Crossbred cows will stay productive in the herd longer. Cows are the

most pro uctive when they are etween ve an 10 years o age. Froman economical standpoint, it is best to have as high of a percentageof the cow herd in that five- to 10-year age group and minimize thenum er o rep acement hei ers that are retaine each year. is goais achieve through cross ree ing. Even i cross ree ing cannot emaximized, utilizing a system that does not include cows with greaterthan 75% o any one ree wi ma e the e ort worthwhi e.

ree comp ementarity has more to o with the ree s thatyou choose to go into your cross. Beef breeds in the United Stateshave different characteristics for performance traits. However, forgenera purposes, the ree s can e categorize into groups ase

75% chance of the calves being black, and 25% chance of the calves being red.

Cow

(Black) Genes B

B BB (Black)

b Bb (Black)

b

Bb (Black)

bb (Red)

Bull (Black)

Figure 5-2.The possible offspring of mating heterozygous blackcows to a eterozygous ac u .

F gure 5-3.T e possi e o spring o mating omozygous omi-nant black cows to a homozygous recessive red bull.

100% chance of calves being black, but they will be carriers of the red gene.

C

ow(

Black) Genes b

B Bb (Black)

B Bb (Black)

b

Bb (Black)

Bb (Black)

Bull (Red)


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n simi ar per ormance eve s. Ta e 5-3 shows which ree typemany o the common ree s t into. Bree s in the same ree type

an be used in similar ways. Finding a combination of breeds thatwill perform optimally in your environment (management) is criticaln eve oping a success u ree ing program. Pro ucers with high

management, particularly in nutrition quantity and quality, can uti-

lize high-producing breeds more effi ciently than producers who caner more imite nutritiona avai a i ity. Most Kentuc y operationswould probably be considered moderate in their ability to provide

dequate nutrition to their cattle. Under normal conditions, the cattleo very we an maintain an a equate eve o con ition. However,nder adverse conditions, such as drought or harsh winters, the nu-

trition level is not adequate to maintain condition, and reproductiveer ormance su ers. In genera , mo erate pro uction eve s in theow herd are what most Kentucky operations can sustain.

To achieve the level of production that is desired, a combina-tion o ree se ection an u se ection within the ree can e

ti ize . Se ection can e ase on herita e traits, such as growth,while crossbreeding enhances traits such as reproduction. Figure 5-4

hows the re ative importance o oth se ection an cross ree ingn an improvement program. Superior pure re s are the ac onef a crossbreeding program. Do not be fooled into thinking that if

you use crossbreeding, you no longer need to buy good bulls. Con-verse y, o not thin that uying goo u s wi o set the ene ts

f crossbreeding. Crossbreeding and selection are complementarynd should be used in tandem in commercial herds (see Figure 5-4).

Crossbreeding SystemsCrossbreeding systems must be planned for each operation,

epending on herd size, potential market, level of management, andaci ities. A ong-term p an is necessary to gain maximum ene ts

from crossbreeding. e advantages and disadvantages of variousrossbreeding systems are listed below.

Two-Breed Terminal Cross is system uses straight re cows an a u o another ree .

It is a terminal cross if stopped at this point. An example would beAngus cows re to Charo ais u s. In this system, rep acementsmust be bought from another source, or part of the herd (perhapsheifers and young cows) would have to be bred to Angus bullsto generate rep acement hei ers. is is not a esira e system

ecause it oes not rea ize any heterosis in the cow since she is atraightbred.

ree-Breed Terminal Cross is system uses a two- ree cross (F1 cow an a u o a

third breed. It produces maximum hybrid vigor in the cow andalf. is is an excellent system because hybrid vigor is realizedor oth growth rate an materna a i ity. Rep acement ema es

for this system must be purchased or raised from another source.is is a good system for any size herd if high-quality replacement

ema es are avai a e.

Table 5-3.Grouping of some cattle breeds by functional type.

SmallerBeef

mallerDual Purpose

SmallerDairy

Angus merifax AyrshireBee a o e vie GuernseyBelted Galloway Milking Shorthorn JerseyDevon Norman e

Dexter PinzguaerGalloway Red PollHere or a ersLong orn aren a seMurray Grey elsh Black Po e Here orRed AngusScotc Hig anS ort ornSussexW ite Par

Zebu ebu Crosses

Bra man Barzona C ar rayGyr Bee master Ge rayIndu-Brazil Braford PinzbrahNe ore Bra maine Re BrangusSahiwal Brahmanstein Santa GertrudisZe u Bra mousin Senepo

Bra ers Sim raBrangus

LargerBee

LargerDua Purpose

LargerDa ry

B on e DAquitaine Bee Friesian Brown SwissCharolais har-Swiss HolsteinC ianina Maine AnjouLimousin immentalMarchigiana

F gure 5-4.Ro e o se ection an cross ree ing in etermininglevel of performance.

LevelofPerformance

Time

Withb

othSel

ection

andC

rossbr

eeding

WithS

electio

n,witho

utCros

sbreed

ing

Without Selection, with Crossbreeding

Without either Selection or Crossbreeding

Two-Bree Rotation or Crisscross is is a simple crossbreeding system involving two breeds

an two ree ing pastures. A two- ree rotation is starte ybreeding cows of breed A to bulls of breed B. In each succeedinggeneration, replacement heifers are bred to bulls of the breed thatis the opposite o their sire (see Figure 5-5 . Two ree s o u s


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re require a ter the rst two years o matings. e two ree shosen shou e compara e in irth weight, mature size, an

milk production. is minimizes calving diffi culty in first-calfheifers and simplifies management.

ree-Breed Rotationis system follows the same pattern as the two-breed rotation,

but a third breed is added (see Figure 5-5). e three-breed rotationmaintains a higher eve o hy ri vigor than the two- ree system.Mating plans can be confusing, but individual cows are not movedfrom one breeding group to another. ree distinct groups of cows

re eventua y create , an they are mate to the sire ree to whichthey are least related. is scheme continues for the life of the cow.

Rotational-Terminal Sire Combination is system invo ves the use o rotationa mating o materna

breeds (breeds A and B) in a portion of the herd to provide re-lacement females for the entire herd (see Figure 5-5). e older

ross re cows are then mate to the termina sire ree ( ree). All of the terminal cross offspring are marketed.

is system maintains a high level of production but also re-uires a high eve o management. It a most oes away with hei ere ection since near y a hei er ca ves pro uce y the rotationa

mating must be kept to maintain herd numbers.

Heifers out of Heifers is is a speci c examp e o a rotationa -termina sire com ination.

ere is no foundation to the argument that you should not keep aheifer out of a heifer. In contrast, this system is one of the best availableto maximize e ciency. In her s that have more than one u or where

AI is a possibility, this is a productive crossbreeding system. Breed allheifers and enough younger females to total about two-and-a-halftimes the num er o rep acement ema es you p an to eep the nextyear to an easy-calving, good maternal bull. For example, if 10 replace-ment females are desired the following year, breed 25 heifers and youngema es to the u . Se ect a rep acement hei ers out o this group oalves. Breed the rest of the herd (older cows) to a growthy, heavy-

muscled terminal bull, and market all of the calves (refer to three-breedtermina cross . is system a ows the pro ucer to get easy ca ving inthe rst-ca hei ers an goo materna characteristics in the rep ace-ment heifers and to maximize growth and muscling in the majority ofthe feeder calves. e only drawback is the nonconforming steers out

the hei ers an young cows, ut the ene ts are worth it.

AI Roto-TerminaThis system usually uses a very strict synchronization pro-

gram, an a cows an hei ers are mate to a materna -type/heifer-acceptable bull, using artificial insemination (AI). All

ows (excluding virgin heifers) are then exposed to a terminaltype u . Virgin hei ers that o not conceive y the irst mating

an be inseminated a second time, or a larger number of replace-ments will need to be retained through pregnancy testing eachyear. Hei ers are on y retaine rom the AI matings.

Mo i e Cross ree ing In many h er s , the a ci i ties a n eve o management

required to use intricate crossbreeding systems are not avail-able. However, with some modification, you can use some ofthe asic cross ree ing princip es. Heres how to simp i y thetra itiona systems:

urchase crossbred females.is is the simplest and fastestmetho o o taining maximum hy ri vigor. Purchase two-

ree cross ema es can e re to a termina sire o a i erentbreed; this maximizes both individual and maternal hybrid vigor.

e pro ucer nee s an avai a e supp y o high-qua ity, isease-ree ema es.

se bull-breed rotation.This involves using a bull of onebreed for a set number of years (recommendation of four years),then rotating to a i erent ree o u . I a a ance etweengood feeder calves and good replacement heifers is desired,

switching between breed types is also desired. In other words,use a British ree u or our years, then switch to a Continen-tal breed for four years, then switch back to the original breed.Try to save a larger number of replacement heifers in yearsthat a materna -type u is use . On y one ree ing pastureis required, and replacement heifers are generated within theherd. This system sacrifices some hybrid vigor when comparedto a two- ree rotation, ut it is simp e enough to e practicaor more pro ucers.

Se ectionSe ection re ers to the ree ers ecision to use some anima s

as parents an to cu others. For se ection to e most e ective,breeders must be able to identify superior animals. is is doney p acing emphasis on economica y important traits that are

heritable (see the Genetic Principles segment of this section).National Cattle Evaluations, which furnish genetic information(Expected Progeny Differences) on various traits, are availablerom most ree associations an are use u in ma ing se ection

decisions. By using AI, the average producer can select a bull ofproven breeding value from the national herd rather than usingone o esser qua ity.

Figure 5-5.Two-breed rotational system (criss-cross).

Crossbred Heifers

BreedA

Breed B

Crossbred Heifers


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Bull SelectionBull selection is one of the most important decisions you will make

s a cow-calf producer. e bull (or bulls) is generally thought of asha the her ecause he contri utes ha the genetic ma eup to eacha crop. However, in her s where rep acement hei ers are retaine ,pproximately 87.5% of the genetic makeup of each calf comes from

the ast three u s use . ere ore, the importance o se ecting u sgenetica y suite to your operation cannot e overemphasize .

e first decision to make when selecting a bull is which breedr breed type to use. Producers always have strong feelings about

the merits o their avorite ree s o catt e. However, no one reexcels in all traits. It is important to know the relative strengths and

weaknesses of various breeds so you can plan mating systems inwhich ree s comp ement each other an t your environment.

Knowledge of some general characteristics of breed types is help-ful in planning. British breeds (those that originated in the BritishIses, such as Angus an Here or genera y have goo erti ity, goo

isposition, moderate birth weights and mature size, and finishingt medium weights. Continental breeds (European breeds, such as

Simmenta an Charo ais are arger, have aster growth rates, anhave eaner carcasses un ess e to heavier weights. American ree s(primarily of Brahman origin) are moderate in growth traits and have

etter heat to erance an ongevity than other ree types.Se ect a ree or com ination o ree s to use in your ee

rogram based on the following: goals of your operation mar eta i ity in your area cost and availability of good seedstock climate how ree s in a cross ree ing program comp ement each

other

how breeds in a crossbreeding program fit your environment persona pre erence.

Table 5-3 groups breeds according to size and type (beef, dairy,ual purpose, and zebu influence). Table 5-4 indicates the level ofro uction o some ree crosses, ase on growth rate an matureize, lean-to-fat ratio, age at puberty, and milk production.

A sire breed in a crossbreeding program might have the follow-ng characteristics: rapi growth rate, mo erate to thic musc ing,nd adequate calving ease. A dam breed might have these charac-

teristics: high fertility, good milking ability, and small to mediummature size. Since no ree possesses a o these characteristics,ome compromises must be made when selecting breeds for a

rossbreeding program.Once you have chosen a ree , it is time to se ect a u withinthat ree . Use our asic criteria when se ecting a u : physicaoundness, reproductive soundness, performance information,n visua appraisa .

Physical SoundnessStructural soundness is important if bulls are to travel distances

to keep up with cows and be able to mount them (especially if theyre expecte to ree a arge num er o cows in a short time .eware of the following problems: rear legs that are too straight

(post legs), rear legs too close at the hocks with too much angle (cowhocked), corns, and abnormal hoof growth (evidence of founder).Structura soun ness shou e emphasize to the point o theanimal being functional. A minor flaw that will not affect a bullsperformance should not be grounds for overlooking the bull. Ifthe u is going to e use in a strict y termina system (no hei ersretained), less emphasis can be placed on physical soundness, butit cannot be ignored.

Reproductive Soundnessepro uctive e ciency is est measure at this stage y a ree -

ing soundness evaluation (BSE). (For a complete discussion, seeSection 4, Managing Reproduction). A bull should have passedhis BSE, or the se er shou e wi ing to guarantee that he wibefore you proceed with the selection process.

Performance InformationWhen purchasing a her u , emphasize the genetics that ani-

mal will pass on to its offspring, not on how that animal performed.ere are three methods for evaluating bulls based on performance:

actua measurements, contemporary group ratios, an ExpecteProgeny Differences (EPD).

Actua Measurements e easiest metho o per ormance eva uation is simp y com-

paring animals actual measurements. Unfortunately, this is a poormetho o per ormance eva uation ecause the environment con-tri utes arge y to the anima s actua measurement. Raw or evenadjusted figures on most economically important traits are not veryvaluable in bull selection. For example, if you are considering a bullan a you now is that he ha a weaning weight o 600 poun s,

Table 5-4.Some breed crosses grouped into production types.

Bree Group1

Growth Ratend Mature

ze

Lean-to-Fat

Rat oAge at

Pu ertyMilk

Pro uct on

Jersey-X 2 + +++++

Hereford-Angus-X ++ + +++ ++

Re Po -X ++ + ++ +++

South Devon-X +++ ++ ++ +++

Tarentaise-X +++ ++ ++ +++

Pinzguaer-X +++ ++ ++ +++

Sahiwal-X ++ ++ +++++ +++

Brahman-X ++++ ++ +++++ +++

Brown Swiss-X ++++ +++ ++ ++++

Ge vie -X ++++ +++ ++ ++++

Simmental-X +++++ +++ +++ ++++

Maine Anjou-X +++++ +++ +++ +++

Limousin-X +++ ++++ ++++ +

Charolais-X +++++ ++++ ++++ +

C ianina-X +++++ ++++ ++++ +

X = Here or -Angus on am si e, sire ree is iste rst.

+ = low, +++++ = highSource:Crossbreeding Beef Cattle for Western Range Environments. 1988.University o Neva a-Reno an USDA. TB-88-1.


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you o not have much to go on. He cou have een raise y ahei er on rought-stric en pasture an have superior preweaninggrowth genetics, or he could have been raised by a mature cow

n lush pasture with plenty of creep feed and actually have poorgenetics or preweaning gain. Environmenta con itions p ay a arge

art in a calfs actual measurements but have no effect on their

future offspring. Selecting cattle based on actual measurementshou e the ast a ternative, an in ormation on environmentaonditions should not be ignored.

ontemporary Group RatiosA contemporary group ratio is calculated by dividing a calfs

measurement (adjusted for age of dam, age of calf, etc.) by the averagejuste measurement o the group o same-sex ca ves with which

t was raise an mu tip ying y 100. is means an average ca inthe group would have a contemporary group ratio of 100, calveswith arger than average measurements wou have va ues greaterthan 100, an ca ves with sma er measurements wou have va uesless than 100. A weaning weight contemporary group ratio of 113

n icates the ca is 13% heavier than the average o the group withwhich it was raise . However, a contemporary group ratio o 113 on

ne farm may be entirely different from a contemporary group ratiof 113 on another. erefore, contemporary group ratios should note use to compare catt e rom i erent ocations or catt e raisender different conditions on the same farm. Contemporary groupatios are the best alternative when EPDs are unavailable but shouldn y e use in those circumstances.

xpected Progeny Differences e est way to etermine ree ing va ues or economica y im-

ortant traits is by using Expected Progeny Differences (EPDs). EPDsre computed using the bulls actual measurement along with measure-

ments rom any re atives. A itiona y, EPDs account or i erencesn environmental (management) conditions. erefore, EPDs are aredictor of the genetics that a bull will pass on to his offspring, which

s what we are intereste in when we are uying a u . e i erencen EPDs o two anima s o the same ree in icates the expecte i -

ferences in the average performance of the offspring of those animals.For example, if bull A has a weaning weight EPD of +20 pounds, and

u B has a weaning weight EPD o +5 poun s, an they are mate to alarge number of comparable cows, under similar environmental condi-tions, a 15-pound difference between the average weaning weights oftheir caves wou e expecte (20 poun s - 5 poun s = 15 poun s .In other words, calves sired by bull A would weigh 15 pounds more

t weaning on average than calves sired by bull B, due to genetics forncrease growth to weaning. It is i e y some ca ves sire y u B

would weigh more than some calves sired by bull A, but on average,alves sired by bull A would have a weight advantage. EPDs can beither positive or negative or the measurement in question. ey areasi y use to ma e comparisons among catt e ut can on y e use

to compare animals of the same breed.An a itiona use o EPDs is to get an in ication o how a u

an s within his ree . Charts are avai a e rom each ree thathow how a bull ranks within the breed based on his EPDs. Hav-ng knowledge of how a breed performs on average and knowing

how a u s ca ves wi per orm can assist in matching a u to

your management an resources. In genera , EPDs are a ris -management too an are not a per ect science. I you use EPDsfor selection purposes, you will purchase bulls that do not performas expected, but this will happen far fewer times than if you useother means o se ection or per ormance. It is important to useEPDs alone and not in conjunction with actual measurements or

ratios. By using EPDs in combination with other measurements,you actua y re uce your a i ity to manage ris .raits available for comparison vary from breed to breed. ey

usually include some of the following: birth weight, weaning weight,mi ing a i ity (expresse as poun s o weane ca , an year ingweight. Other traits for which EPDs are offered on some breeds areyearling hip height, mature hip height, mature weight, carcass traits(hot carcass weight, at thic ness, ri eye area, an mar ing score ,scrotal circumference, stayability (measure of longevity), calvingease, and others. e following are descriptions and implicationso se ection o some common y use EPDs (not a ree s provi eall the EPDs listed).

Birth Weight EPDi erences in this EPD re ect i erences in the average irth

weight of the two animals offspring. is is an extremely importantEPD, particularly when selecting a bull to breed to replacementhei ers. Birth weight is the argest contri utor to ca ving i cu tyand should be controlled. As cows mature, their ability to havelarger calves without complication increases, and restrictions on

irth weight EPDs can e re axe to some egree.Imp ications:Birth weight is genetically correlated to growth in

cattle. When birth weights are decreased, you can expect a decreasein weaning an year ing weights. ere ore, it is not a visa e tosimply buy the bull with the lowest birth weight EPD (this is particu-larly true when breeding cows that are not first-calf heifers). Instead,

within the esire ree , etermine a irth weight EPD you arecom orta e with, an o not uy a u a ove this eve . I a ca ving-ease EPD is available, it is likely a better indicator of potential calving

i cu ty an shou e use instea o the irth weight EPD.

Weaning Weight (Direct or Growth) EPD is EPD measures the genetic contribution of the parent to

weaning weight with no consi eration to mi . In other wor s,differences in weaning weight direct EPDs indicate the averagegenetic potential differences of the calves to grow to 205 days,assuming mi ing a i ity o the ams is the same.

Imp ications:Weaning weight direct is genetically correlatedwith birth weight and milking ability. As weaning weight directgoes up, irth weight usua y goes up, an mi ing a i ity usua ygoes down. However, yearling weight is usually increased.

Milk (Weaning Milk or Maternal Milk) EPD e termino ogy or this trait is i erent among the ree s ut

refers to the expected milking ability of a parents daughters in poundso weane ca . A u with a 10-poun a vantage in weaning weightmi EPD shou pro uce aughters that raise ca ves that average 10pounds heavier due to the increased milking ability of their daugh-ters. Bulls with higher weaning weight milk EPDs sire daughters withan a vantage in mi ing a i ity an /or materna a i ity.


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Imp ications:Mi ing a i ity is genetica y corre ate with growthtraits. As mi ing a i ity goes up, the genetic potentia or growth o tengoes down. Avoid extremes in this trait, particularly in breeds knownfor superior milking ability. It is easy to produce too much milk for the

nvironment the catt e are in. I this happens, cows ose con ition,which results in increased feeding or loss of reproductive perfor-

mance, either of which decreases the economic potential for the herd.

Weaning Weight MaternalCombined or Total Maternal) EPD

is EPD is simp y ha the weaning weight irect EPD p us theweaning weight milk EPD. is measures the daughters ability toaise a calf to weaning (205 days), regardless of whether the growthomes rom genetics or growth or mi .

Imp ications: Most producers know whether they need toncrease the milking ability or the growth potential of their herdn shou ocus on the point o nee .

Yearling Weight

is EPD measures genetic i erences in weight at 365 ays.is EPD ecomes more important than the weaning weight EPD

when the marketing endpoint is postweaning.Implications: Yearling weight is unfavorably correlated

with irth weight an mi ing a i ity. Year ing weight is a sohighly correlated with mature weight. The mature size of your

ow herd will increase and milking ability will likely decreaseyou se ect or increase year ing weight an retain rep ace-

ment heifers.

alving-Ease or Calving-Ease Direct EPDDifferent breed associations measure calving ease differently.e difference in two same-breed animals calving-ease EPDs

n icates the average percentage i erence in ca ving i cu tyn the cows or hei ers re . In a ree s, arger num ers in icate

greater calving ease.Imp ications: is is the est EPD to use in trying to re uce

a ving i cu ty. It is not recommen e to use this EPD in con-junction with birth weight EPDs or actual measurements becausethose factors have already been taken into consideration when

a cu ating this EPD.

alving-Ease Maternal or Calving-Ease Daughter EPD is EPD measures the ca ving-ease a i ity o an anima s augh-

ters. Larger values indicate a greater likelihood that an animalsaughters will have less calving diffi culty.

Imp ications:High ca ving-ease materna EPDs on a u oesnot indicate that he is an easy-calving (heifer-acceptable) bull; itmeans his daughters should be easy-calvers. To determine an easy-

a ving u , use either the ca ving ease irect or irth weight EPD,not ca ving-ease materna .

Fat Thickness EPD is is a carcass trait EPD that in icates eanness. Lower va ues

ndicate less external fat cover, which reflects a more desirableyield grade.

Imp ications:Use extreme caution i you use this EPD when re-p acement hei ers wi e retaine . A re uction in at thic ness, whi ebeneficial to carcass value, can cause a reduction in fleshing abilityand a loss of reproductive performance in replacement heifers.

Ribeye Area EPD

is is the best easily measured indicator of muscling. Ribeyearea is a actor in ca cu ating yie gra es, with arger ri eyes con-tributing to a more desirable grade.

Implications:Extremes should be avoided in this trait. Eventhough arger ri eyes pro uce more esira e ( ower yie gra es,todays consumer is concerned with portion size, and extremelyheavily muscled carcasses are diffi cult to market. Because cattle can

e varia e in musc e expression, this EPD shou e use in com-ination with visua appraisa or musc ing through the quarters.

Marbling Score EPD is trait has the argest ro e in etermining the qua ity gra e o

carcasses. Larger values indicate more marbling (flecks of fat within

the ean o the ri eye , which resu ts in higher USDA Qua ity gra es(USDA Prime and Choice; see Section 8, e End Product). Eachwhole number difference reflects one marbling score difference.erefore, an advantage of 0.5 marbling score EPD indicates prog-eny y that u shou gra e 50 egrees etter on average.

Imp ications: When marketing calves on the rail, this traitcan be important because quality grade is a large factor in carcasspricing. I a pro ucer is not receiving a premium or high-qua itycarcasses, this trait should not be overemphasized.

Percent Intra-Muscular Fat (IMF) EPD is measurement is similar to the marbling score EPD; how-

ever, it is determined using ultrasound data. is EPD should be

use in the same manner as the mar ing score EPD, with higherva ues in icating anima s that shou pro uce progeny that wihave better USDA Quality grades.

Imp ications:Same as mar ing score EPD.

Mature Weight and Height EPDs is is an indicator of mature size of an animals daughters.

Mature weight is a juste to a con ition score 6 asis. In otherwords, differences in this EPD reflect the mature (five to 11 years)weight differences of daughters with a condition score of 6. emature height EPD re ects the i erences in inches o the anima sdaughters at maturity.

Implications:Larger cows are typically less effi cient in produc-ing poun s o ca per acre than sma er, more mo erate cows. isEPD allows producers to have direct control over the mature size oftheir cow herd. If these EPDs are not available, the best alternativeis to se ect or mo eration in year ing weight EPD ecause maturesize an year ing weight are c ose y corre ate .

Scrotal Circumference EPDi erences in scrota circum erence are re ecte in the average

scrotal circumference of an animals bull calf crop.Implications: Breeders of purebreds can use this EPD to

increase scrota circum erence o u s they p an to mar et


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ince scrota circum erence is an in icator o sperm pro uction(volume). For practical purposes, this EPD should be ignored by

ommercial producers, and greater emphasis should be placedn the bulls actual scrotal measurement. is is because an actual

measurement o scrota circum erence is an in icator o that u serving capacity, and his scrotal circumference EPD is an indicator

f how large his bull calves scrotal circumference will be. In com-mercia operations, we are concerne with how many cows a uan breed, but the bull calves will be castrated.

Heifer Pregnancy Rate EPDHeifer pregnancy EPDs estimate differences in daughters

bility to conceive to calve as a two year old. Just like the stay-i ity EPD, hei er pregnancy EPDs are expresse in terms o a

ercentage i erence. For examp e, two hei er pregnancy EPDs5 and 10, differ by 5%. Daughters of the bull with the EPD of 10re 5% more i e y to conceive than aughters o the other u ,ssuming oth sets o aughters are raise an manage in theame environment.

Imp ications:Se ecting u s with higher hei er pregnancy EPDshou resu t in etter pregnancy rates in the her over time. How-ver, because reproductive traits are lowly heritable, there is very

little variation or spread between bulls for this EPD, and progresstowar a noticea e change wi ta e severa years o se ection.

tayability EPD ese EPDs are the pre iction o the genetic i erences e-

tween daughters probability of staying in the herd to at least thege of six years.

Imp ications:Se ecting u s or higher staya i ity va ues shouncrease the longevity of his daughters that are selected as replace-

ments. In other words, a bull with a higher value for stayability EPD

hou have a higher percentage o his aughters remaining in theher to at east age six.

Accuracy ValuesAn accuracy va ue (ACC is given or each EPD ca cu ate an

s a measure o the re ia i ity o that EPD. EPDs are never per ect,nd as more information is obtained on an animal, the EPD value

may change, either up or down. Accuracy values indicate the likelymaximum amount an EPD may change with new in ormation, anthey indicate how much confidence can be placed on whether

the EPD is the true genetic va ue or that trait. EPDs, regar ess otheir accuracy va ues, are the est avai a e estimate o an anima sgenetic merit.

Accuracy values range from 0.00 to 1.00 and can be classified intothree basic categories: low (0.00 to 0.50), moderate (0.51 to 0.70), andhigh (0.71 to 1.00). As accuracy increases, the amount of possible

change in an EPD related to added information becomes smaller.ese ranges o possi e change are oth trait- an ree -speci c. Fora correct range of possible changes in EPDs, obtain a sire summary forthe breed in which you are interested.

Un ess arti cia insemination is an option, accuracy va ues areusually of little concern to commercial producers. Young bulls (whichalways have low accuracy) are usually purchased, and any offspringpro uce are cross re or nonregistera e ca ves. ere ore, thebulls accuracy will likely remain low. Low-accuracy bulls are a factof life for most commercial producers, but their EPDs are still the

est avai a e in icator o their progenys potentia per ormance.ertain management practices he p e iminate pro ems asso-

ciated with low-accuracy bulls. Since the bulls EPD might not be

comp ete y accurate, a young u shou e mate with a imitenum er o ema es. I his EPDs are inaccurate, it wi not have amajor effect on the herd.

Expected progeny differences are useful to both purebred andcommercia pro ucers. Bee ree ers can use recor s to mate thebest to the best, or, perhaps more important, cattle producers canuse this information to select the right bull to use on a particularcow or set o cows ase on their wea nesses or strengths. For ex-ample, a commercial producer selecting a bull to breed to first-calfheifers can use either birth weight or calving-ease EPDs to choosea u that wi minimize ca ving pro ems, whi e maintaining anacceptable level of growth and milk. EPDs allow you to make ge-netic change or maintain current production that is appropriate

or your pro uction goa s an environmentIt is a so o extreme importance to un erstan how each eco-

nomically important trait responds to selection based on perfor-mance in ormation (EPDs . Ta e 5-5 summarizes these corre ations.

a e 5-6 gives in ormation on three u s with i erent per or-mance data. Assuming all bulls are structurally and reproductivelysound and visually acceptable, which bulls would you select? If youron y priority is to maximize growth, se ect u C. I your priorityis calving ease (breeding heifers) and improving milk, select bullB. If your priority is improving growth and improving milk whilemaintaining re ative ca ving ease, se ect u A. Bu se ection is anindividual decision based on the producers needs. e best bullfor one producer may not be the best bull for another.

Table 5-5.Selection based on EPDs.B rteight

Wean ngWeight

Year ngeight

M ngAbility

Ca v ngEase

MatureS ze

BW EPD + 0 - +

WW EPD + - - +

YW EPD + - - +

Mi EPD 0 * -* 0

= as EPD goes up, t is trait a so ten s to increase.

= as EPD goes up, this trait tends to decrease.

= no relationship.

Increase mi EPDs resut in ecrease growt rate or t e rsteneration. Due to a e mi pro uction, o spring o rst-generation

females have increased WW and YW.

Table 5-6.Example of performance information on various bulls.

Ca v ngEase

B rtWeight

Wean ngWeight

Year ngWeight

MaternaMilk

IRE EPD ACC EPD ACC EPD ACC EPD ACC EPD ACC

A . + . . . . .

B 105 0.70 -2.5 0.75 - 2 0.90 7 0.85 25 0.80

C 87 0.70 12.0 0.72 40 0.80 62 0.75 - 5 0.70


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Economically Relevant TraitsRecent emphasis in genetic eva uations has een to etermine

conomically relevant traits (ERT) for analysis. e purpose of thisort is to provi e pro ucers with EPDs that more c ose y re ect

conomic impact on their her . A goo examp e is the irth weightnd calving-ease direct EPDs. e birth weight EPD in itself has no

conomic impact to a pro ucer ecause ca ves are not so y theoun at irth. Instea , it is use as an in icator or ca ving ease,

which has a major economic impact. erefore, many breeds haveeveloped EPDs for calving-ease direct so that the actual trait ofconomic importance is eing se ecte or. is oes not mean thateedstock producers should stop collecting birth weights or other

traits that do not have direct economic impact because these traitsontri ute in ormation or computing the ERTs. A itiona ERTs

will be developed in the future, which in many cases will involveonsolidating several other EPDs. ese should result in fewer

EPDs that have a more irect economic impact.

Selection IndicesSelection indices have been available for beef producers forevera eca es ut have not een wi e y use . In genera , se ec-

tion in ices a ow pro ucers to ma e se ection ecisions or sev-ral traits simultaneously based on their economic relevance. Inther wor s, an equation is eve ope , an each trait is weighteccor ing to its economic impact. A u s EPDs can e enterento the equation, and a single number is generated based on that

bulls ability to pass on profitability to his offspring. For example,the o owing in ex might e use (this is on y a samp e in ex anhould not be used in practice):

I = 0.5*CE + 0.2*CW + 3*MARB - 1*FAT

Tra ts Bull A Bull B Bull C

E 5.0 1.3 -2.5

CW

MARB 0.5 0.4 0

FAT 0.7 -0.3 -0.5

I = in ex va ueE = Calving-Ease Direct EPDW = Carcass Weight EPD

MARB = Mar ing EPDFAT = Fat T ic ness EPD

For Bull A, the index value would be:Bu A (I) = 0.5*(5.0) + 0.2*(15) + 3*(.5) - 1*(0.7) = 6.30

Bu B (I) = 0.5*(1.3) + 0.2*(10) + 3*(1.0) - 1*(-0.3) = 5.95Bull C (I) = 0.5*(-2.5) + 0.2*(15) + 3*(0) - 1*(-0.5) = 6.75

With this examp e, Bu C wou e the u o choice ecausehe was the highest indexing. is would indicate that Bull Cwould produce the most profitable calves based on this index.

ne important thing to remem er is that a in ices o not tll producers. In this example, the calves would be used in aetained ownership program, and the bull would probably note re to hei ers. For a pro ucer who was ree ing hei ers an

the calves were marketed at weaning, this index would have novalue and could actually be detrimental. e other important

aspect o in ices is that the va ues shou e weighte accor ingto economic va ue, not hunches or guesses.

e problem with selection indices is that they are typically toogeneral and do not perfectly fit an individuals operation. When ase ection in ex is eve ope , certain assumptions have to e ma ethat may or may not be correct for an individual operation. Ad-

ditionally, when indicator traits are used rather than ERTs, thereis more opportunity or error.urrently there is not a good system available in the United

States for developing indices that are custom made for individualpro ucers. is is in the eve opmenta stages, an it is hopethat it will be available in the near future. is system would likelyrequire producers to fill out a questionnaire about their operationan mar eting scheme. is in ormation wou then e use tocompute a customize se ection in ex or that pro ucer ase onthe economic outlook of cattle and feed prices. e system shoulda so a ow pro ucers to a ter expecte economic scenarios.

Just as EPDs are not a per ect science, se ection in ices are notexact, and the opportunity for breeding mistakes will still exist.

However, they wi a ow ee pro ucers to se ect u s ase ontheir tota economic impact, not just short term or or one trait.When this technology develops further, more information willbecome available. Selection indices will likely become more userrien y an common as the techno ogy a vances.

Visua AppraisaMany traits of importance, including body capacity, thickness,

etc., are not measure y EPDs. A so, visua inspection is necessaryto determine the structural soundness of a bull. Even with all theadvanced technologies, visual appraisal is a necessary step of bullse ection. e o owing traits are some that may e consi ere

for visual appraisal.

Temperament e excita i ity o catt e is o great concern to many pro ucers.

I having ca m catt e that are easi y han e is a se ection priorityof yours, then spend time locating a bull with a good disposition.Temperament is herita e, so parents with a goo isposition usu-a y have ca ves with a goo isposition.

ere are two types of disposition problems that should beeva uate : catt e that try very har to avoi human contact ancatt e that try to ma e irect human contact. When eva uatingbulls, you should move around the cattle, on foot, at a safe distance

and in close proximity to shelter if needed. Cattle that try to avoidhuman contact are genera y on the ar si e o the group with theirhead held very high. As you move around, they will always keepthemselves positioned on the opposite side of the herd. ey alsoappear nervous an ma e quic , excite movements. Aggressivebulls are usually easily identified as the bull on the front side of thegroup that is very excited; he always faces you and may challengeyou when approache .

emperament can cause problems because of increased healthrisk to humans and other livestock and can adversely affect carcassqua ity. Both types o isposition pro ems are very angerous, an

u s exhi iting this ehavior shou not e se ecte .


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e iminate rom urther consi eration, regar ess o price. Fa s inthe catt e in ustry are usua y short- ive , an argain u s areoften economic disasters in the long run.

Sire selection continues after you purchase the bull. Observethe u c ose y uring the rst ew wee s o the ree ing seasonto see if he is willing and able to mate with the cows. Bulls with a

high libido (sex drive) and high fertility sire the early calves. Also,o serve cows or return to heat a ter mating to see i they conceive.Your final step is to annually evaluate each bulls progeny. If thebulls calves are acceptable and the bull continues to pass a BSE,retain him. I the u s ca ves are unaccepta e, i the u ai s hisBSE (a second chance may be in order first), or if a breed changeis necessary to maintain heterosis, replace him.

Heifer SelectionHeifer selection is also important for commercial producers, but

heifer selection is an easy task if proper sire selection is practiced.When rep acement hei ers are to e retaine , u se ection can-

not e overemphasize . Se ection shou inc u e materna a i ity,mature size moderation (particularly frame size), and calving-easematerna , i avai a e. From the resu ting hei ers, se ection shou

e ase on physica structure, o y capacity, an i e ihoo oreaching puberty by the next breeding season (older heifers that arec oser to their target weight are more i e y to e rea y to ree .Pe vic areas can a so e use u to cu un ersize or misshapepelvises. If purchasing replacement heifers, knowledge of their sireor the reputation of the breeder is desirable.

Cow Cullingow culling plays a small role in the genetics of your herd and

should be based solely on economic considerations. e followingare i e y reasons to cu cows: open, consistent y poor ca ves orunderperforming calves based on production records (young cat-tletwo- and three-year-oldsshould not be expected to performat the eve o o er cows , structura e ects, or isease. Unusuasituations in the market can alter normal culling procedures, butfavorite cows that do not perform should not be kept.

Molecular Technologiesiotechnologies have made many advances in recent years, and

they are starting to have an impact on beef production. Most peopleare ami iar with mo ecu ar io ogy use in crimina investigations

that in hair, oo , or semen samp es at a crime scene with a sus-pect. e basic principle is that every cell in an individual has thesame genetic co e as every other ce in that in ivi ua , an no twoindividuals have the exact same genetic code (with the exception ofidentical twins and clones). In order to determine the genetic code,the stran s o DNA are cut at speci c ocations, which eaves stran so i erent engths, epen ing on the in ivi ua . By comparing thelengths of DNA strands from a sample and the individual, it can bedetermined if there is an identical match. e closer the relationship

etween two in ivi ua s, the c oser their genetic co e wi resem e.e same principles are used in technologies that are currently avail-able and others that are being developed for use in beef cattle.

Body CapacitySince catt e are oragers an usua y e iver a 70- to 100-poun

alf, adequate body capacity is needed for the animals to consumenough nutrients or maintenance an growth. Bo y capacity isetermine y the ength an epth o o y an spring o ri .

usc ing e u shou e we musc e , which is p ain y evi ent in a

arge, u ging orearm an thic ness in the roun . Care u eva ua-tion should be made to determine whether thickness is due to truemuscling or fat deposits. Bulls with a wide base or stance that areoun e over the top- ine an thic through the ower hin quarter

(stifle region) are typically well conditioned and heavy muscled.arrow-based bulls that are flat over the top-line yet show good

thic ness through the hin quarter are typica y at an may evenbe light muscled. Location of muscling can be important. It is bestf the bull has most of his muscling along the top-line and in theoun . Since the most expensive cuts are towar the rear, heavy-

fronted feeder calves are not desired.

ConditionBu s shou have a equate con ition ut shou not e over at.ey shou have a compara e o y con ition score o a 5 or 6.

oneBone su stance can a so e eva uate on u s. Typica y the est

n icator o heavy one is hoo size. Bu s that have arge hooves(circumference, not length) and good bone diameter in the cannonbone are indicating heavier bone.

Testicular DevelopmentTesticles should be measured and be of acceptable size (see

Section 4, Managing Reproduction, for more information oncrota circum erence . A itiona y, they shou e o serve toetermine if they are developed properly and if they are of similarize and have proper suspension. ere will be slight variation in

the size o the testic es o a u , ut arge i erences shou evoided.

Frame SizeI per ormance in ormation is not avai a e or rame size (or

hip height), evaluate this trait visually.

SummaryI you are purchasing a u in a sa e, eci e which u s you i e

n how much you are wi ing to pay e ore the i ing starts. Donot sit back and see how they are going to sell while the best bulls

re selling. Do not do the entire selection process in the time itta es an auctioneer to se a u . Stu y the per ormance in orma-tion ahead of time, and arrive at the sale site early enough to allow

dequate time to evaluate the bulls. Any bull that does not appearon paper to e o potentia ene t to your cow her shou e


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Genomics and Proteomicsesting or homozygosity is a orm o genomics, ut there is even

greater potential for economic benefit to producers. is is thetechno ogy o n ing speci c genes that a ect traits o economicimportance. Traits such as co or an horne /po are contro eby one gene pair, and the environment has little influence. is

ma es them re ative y easy to i enti y. However, pro uction traitsare contro e or in uence y mu tip e gene pairs to varyingdegrees, and the environment plays a large role in how the traitsare expressed. Genomics is the process of trying to identify whichgenes contri ute to certain pro uction traits an to what egreethey influence that trait. Knowing this information will be usefulin combination with current genetic evaluation techniques toincrease the accuracy o genetic va ues (EPDs .

Proteomics uses many of the same techniques as genomics butis different in its approach. Instead of trying to find out which geneis pro ucing a certain enzyme (protein , it is more concerne withwhat enzymes (proteins) are affecting a certain trait, in what quantitythey are being produced, and if they are altered. For example, thepro uction o certain enzymes y an anima can resu t in higher

egrees o mar ing. I enti y which anima s pro uce this enzymeto a higher degree and, if that expression is inherited by its offspring,wou ea to etter se ection too s or improving mar ing. ere-ore, this in ormation wou a so e use in concert with genomics

information and statistical modeling to improve genetic evaluations.In most cases, producers may not know that genomics or proteomicsare eing use ; however, they may notice that the EPDs they re y onare more accurate, causing them to make fewer selection mistakes.

Another potential use of genomic/proteomic information in theuture may e to sort catt e into i erent management groups. One

possible scenario would be to collect blood from the calf crop at a

young age and, based on their molecular genetics, sort them intomanagement groups. One group may nee to e ac groun eafter weaning and then sent to the feedyard, another may need togo directly to the feedyard after weaning, and yet another may haveno possi i ity o reaching an accepta e qua ity gra e an cou eorage e or the groun ee mar et. is wou great y improve

the effi ciency and profitability of beef production.

SummaryIn summary, there are two important practices that commercia

producers should apply to their beef breeding program: crossbreed-ing and selection. Breeds should be selected based on their ability

to achieve your pro uction/economic goa s an their a i ity to tyour production environment (management). ese breeds shouldbe used in a planned crossbreeding program that maintains a higheve o heterosis. Once the ree s are etermine , in ivi ua u s

should be selected based on the level of performance you desirefor each trait of economic importance. Overall performance of the

ree or these traits shou e consi ere in etermining this eve .Bulls should also be appraised visually and be sound breeders.

If these steps are followed, you can customize your cow herd tomeet your goa s within your pro uction environment.

Blood TypingB oo typing is a means o etermining i an anima is rom a

pecific mating or by a specific sire. For genetic evaluations to beorrect, it is important that parentage is exact. In one- u units,

this is typica y not a pro em un ess a u jumps a ence. However,n range breeding conditions, there are often multiple bulls in a

asture-mating situation. I correct parentage is not etermine ,the ca crop is exc u e rom the genetic eva uation, or the EPDs

omputed will be less precise. is technology typically is not ofmportance to commercial producers but can have some usage foree stoc pro ucers.

Homozygosity Testinge genetics for color and horned/polled are very important

or many ee pro ucers. Knowing i a u is homozygous orheterozygous for either of these traits can have economical valueto a producer.

Most ree s, even those that are tra itiona y re , o er a

black version. This was accomplished very simply through arocess called grading-up. For beef cattle, this generally oc-urre y ree ing an Angus to the ase ree , which wi resu tn ac ca ves, ut they are ha Angus. In turn, those ca ves

were mated back to the base breed, which results in half of thatgeneration eing ac ; these ca ves are sti 25% Angus. The

ac ca ves rom that mating were then mate ac to the asebreed, and the black calves retained. This process is continued

ntil the offspring are considered purebred for the base breed.At that point, the ac u s an cows are mate to each otherto generate some black (about three-fourths of the first mating)

nd some red offspring. Of these black calves, and in subsequentgenerations, some wi e homozygous or the ac gene, anome will be heterozygous. A homozygous bull has two black

genes and will always produce black calves. A heterozygous bullhas one ac an one re gene so, epen ing on the catt e he ismated to, he can produce either black or red calves. The sames true for breeds that have the horn gene; polled bulls may bearriers an pro uce horne ca ves.

Tests are now avai a e that can etermine i a u is a re genearrier. Using the technologies described above, companies canetermine rom a oo or hair samp e i a u is a carrier. Eachree has speci c gui e ines or etermining co or genotypes,nd producers should contact their respective breed association

for specific details.

Be ore incurring the cost o homozygosity testing, use com-mon sense. If you examine the pedigree of an animal and eitherarent is homozygous recessive for that trait, you know the animal

s a carrier (heterozygote . Remem er that a ca gets one co orgene from each parent, so if one parent has two red genes, one

f those red genes is passed to that calf. If both parents are blackn the ca is ac , there is no way o etermining homozy-

gosity/heterozygosity other than testing. e same is true forolled/horned cattle.

Breeding program

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