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Selection of Selection of Breeding ProgramBreeding Program
An S 426 An S 426 Fall 2007Fall 2007
Selection of Breeding Selection of Breeding ProgramProgram
Setting of goals is of major importance Setting of goals is of major importance and includes goals for:and includes goals for:
1. Reproduction1. Reproduction2. Calf performance2. Calf performance3. Income3. Income4. Etc.4. Etc.
Breeding management will impact each of Breeding management will impact each of above in varying degrees:above in varying degrees:
1. Breeding management practice with 1. Breeding management practice with greatestgreatest
impact on reproduction is crossbreedingimpact on reproduction is crossbreeding2. Selection is best management practice for2. Selection is best management practice for
improving carcass quality improving carcass quality
Selection of Breeding Selection of Breeding ProgramProgram
Once goals established, herd assessmentOnce goals established, herd assessmentis needed – where is herd atis needed – where is herd at
1.1. Determine breed makeupDetermine breed makeup2.2. Determine production level – need accurate Determine production level – need accurate recordsrecords3.3. Determine average weight and frame size Determine average weight and frame size of cowof cow
herdherd
Larger frame cows have higher Larger frame cows have higher maintenancemaintenance
costscosts
Table 1. Frame relationship to mature size and carcass Table 1. Frame relationship to mature size and carcass weightweight
Yearling Hip Height (in)Yearling Hip Height (in) Expected Expected Weight (lbs)Weight (lbs)
Frame Frame Bulls Bulls HeifersHeifers Mature Mature Steer Steer Steer SteerScore Score CowsCows HarvestHarvestCarcassCarcass 33 45 45 43 43 10251025 950 950 600600 44 47 47 45 45 11001100 10501050 660660 55 49 49 47 47 11751175 11501150 725725 66 51 51 49 49 12451245 12501250 785785 77 53 53 51 51 13201320 13501350 850850 88 55 55 53 53 13951395 14501450 915915 99 57 57 55 55 14651465 15501550 975 975
Figure 1. Comparison of growth curves of small and large Figure 1. Comparison of growth curves of small and large framed cattle.framed cattle.
Selection of Breeding Selection of Breeding ProgramProgram
Larger frame feedlot cattleLarger frame feedlot cattle1. Grow at faster rate1. Grow at faster rate
2. Require greater amounts of feed and in 2. Require greater amounts of feed and in feedyardfeedyard
longer, thus greater expenseslonger, thus greater expenses
3. Heavier finish weights generate more income3. Heavier finish weights generate more income
4. Real problem if variation in frame sizes in 4. Real problem if variation in frame sizes in samesame
feedyard, may need to sort for:feedyard, may need to sort for:a.a.b.b.
Selection of Breeding Selection of Breeding ProgramProgram
Genetic changeGenetic change1. Genetic change may not result in improved 1. Genetic change may not result in improved animalsanimals2. Genetic improvement means superior animals 2. Genetic improvement means superior animals withwith
greater profitabilitygreater profitability
Brought about in two ways:Brought about in two ways:1.1.2.2.
Selection of Breeding Selection of Breeding ProgramProgram
Selection – factors affecting:Selection – factors affecting:1. Variation –1. Variation –2. Heritability –2. Heritability –3. Selection differential –3. Selection differential –4. Generation interval –4. Generation interval –
Predicting genetic change =Predicting genetic change =Genetic change per year =Genetic change per year =
Progress through selection dependent uponProgress through selection dependent uponnumber of traits selectednumber of traits selected
where n = number of traits where n = number of traits selectedselected
Selection of Breeding Selection of Breeding ProgramProgram
Single-vs. multiple-trait selectionSingle-vs. multiple-trait selection
Single-trait selection produces rapid genetic change, Single-trait selection produces rapid genetic change, butbut
unfortunately likely results in undesirable changes inunfortunately likely results in undesirable changes incorrelated traitscorrelated traits
Increasing frame size resulted in increased:Increasing frame size resulted in increased:1.1.2.2.3.3.4.4.
Selection of Breeding Selection of Breeding ProgramProgram
Multiple-trait selection first step towards Multiple-trait selection first step towards more effective selection, but challenges more effective selection, but challenges remain:remain:
1. Rate of improvement in any one trait 1. Rate of improvement in any one trait decreasesdecreases
2. Unfavorable genetic correlations remain for 2. Unfavorable genetic correlations remain for economiceconomic
relative traits (ERT)relative traits (ERT)
Selection of Breeding Selection of Breeding ProgramProgram
Multiple-trait selection first step towards more Multiple-trait selection first step towards more effective selection, but challenges remain:effective selection, but challenges remain:
3.3. MethodsMethodsa.a. Tandem – emphasis on one trait until desired Tandem – emphasis on one trait until desired levellevel
attained and then move to next traitattained and then move to next traitb.b. Independent culling Independent culling - choosing minimum or- choosing minimum or
maximum levels for each traitmaximum levels for each trait- more traits added, more relaxation occurs in order- more traits added, more relaxation occurs in order
to find animals meeting criteriato find animals meeting criteria- once thresholds identified, application of this- once thresholds identified, application of this
method is easy and popularmethod is easy and popular
Selection of Breeding Selection of Breeding ProgramProgram
3.3. MethodsMethods
c.c. Selection indexes – incorporate the cost and Selection indexes – incorporate the cost and incomeincome
resulting from productionresulting from production1.) A description of every index should include:1.) A description of every index should include:
a.) Traits included in the indexa.) Traits included in the indexb.) Description of information used in the b.) Description of information used in the
index, suchindex, suchas EPD or individual phenotypic performanceas EPD or individual phenotypic performance
c.) source of economic information and c.) source of economic information and performanceperformance
levels used to calculate economic weightslevels used to calculate economic weightsd.) Relative economic emphasis of each trait d.) Relative economic emphasis of each trait
to the overall indexto the overall index
Selection of Breeding Selection of Breeding ProgramProgram
c.c. Selection indexes – incorporate the cost and Selection indexes – incorporate the cost and incomeincome
resulting from productionresulting from production
2.)2.) Successful application of generalized Successful application of generalized indexes reliesindexes relies
on logical implementation:on logical implementation:
a.) Identify production and marketing systema.) Identify production and marketing system1.) When will animals be marketed (at what 1.) When will animals be marketed (at what
age)age)2.) How will animals be marketed2.) How will animals be marketed3.) What is current performance and genetic 3.) What is current performance and genetic
level oflevel ofherdherd
Selection of Breeding Selection of Breeding ProgramProgram
c. c. Selection indexes – incorporate the cost and incomeSelection indexes – incorporate the cost and incomeresulting from productionresulting from production
2.)2.) Successful application of generalized indexes reliesSuccessful application of generalized indexes relieson logical implementation:on logical implementation:
b.)b.) Identify the index appropriate to the productionIdentify the index appropriate to the productionsystem outlined above - questions to be addressedsystem outlined above - questions to be addressed
1.) What traits are included in the index1.) What traits are included in the index2.) What are the relative economic values used to2.) What are the relative economic values used to
weigh the traitsweigh the traits3.) Decide on the appropriate index for evaluation3.) Decide on the appropriate index for evaluation
based on the most similarity between above points 1 and 2 based on the most similarity between above points 1 and 2
Selection of Breeding Selection of Breeding ProgramProgram
c.c. Selection indexes – incorporate the cost and incomeSelection indexes – incorporate the cost and incomeresulting from productionresulting from production
3.)3.) Most breed selection indexes are generalized forMost breed selection indexes are generalized foroverall breed improvement and use average costs andoverall breed improvement and use average costs andincome from production rather than accounting for aincome from production rather than accounting for aspecific producer’s marketing and production systemsspecific producer’s marketing and production systems
a.) Has led to the development of Interactivea.) Has led to the development of InteractiveDecision Support (IDS) systems which allow breeders toDecision Support (IDS) systems which allow breeders toinput parameters specific to their production systems – twoinput parameters specific to their production systems – twoclasses:classes:
Selection of Breeding Selection of Breeding ProgramProgram
1.)1.) Herd – level systems Herd – level systems
a.)a.) Designed to evaluate overall genetic Designed to evaluate overall genetic changes in herdchanges in herd
level – not individualslevel – not individuals
b.)b.) Angus Assoc. Optimal Milk Model – Angus Assoc. Optimal Milk Model – designed fordesigned for
producers to decide the appropriate range of milk producers to decide the appropriate range of milk EPDEPD
given the mature weight of their cows, annual cow given the mature weight of their cows, annual cow costscosts
and variability in feed resourcesand variability in feed resources
Selection of Breeding Selection of Breeding ProgramProgram
2.)2.) Individual animal systemsIndividual animal systems
a.)a.) Designed to evaluate individual animal Designed to evaluate individual animal selectionselection
decisions and the impact of those decisions on decisions and the impact of those decisions on profitabilityprofitability
b.)b.) Charolais Assoc. Terminal Sire Profitability Charolais Assoc. Terminal Sire Profitability IndexIndex
(TS) – designed to evaluate the selection of sires (TS) – designed to evaluate the selection of sires based onbased on
their relative impact on profitability in a terminal sire their relative impact on profitability in a terminal sire matingmating
system; allows input of current herd productionsystem; allows input of current herd productioncharacteristics and sources of income by the producercharacteristics and sources of income by the producer
Selection of Breeding Selection of Breeding ProgramProgram
Mating systemsMating systems
1.1. Inbreeding –Inbreeding –a. Main genetic effect is to increase the a. Main genetic effect is to increase the
numbernumberof pairs of homozygous genesof pairs of homozygous genes
b. Usually results in a decline in traits b. Usually results in a decline in traits related torelated to
physical fitnessphysical fitness
1.)1.)2.)2.)
Selection of Breeding Selection of Breeding ProgramProgram
Mating systemsMating systems
2.2. Outbreeding –Outbreeding –a. Main genetic effect is to increase the a. Main genetic effect is to increase the
numbernumberof pairs of heterozygous genesof pairs of heterozygous genes
b. By increasing heterozygosity there is b. By increasing heterozygosity there is aa
tendency to cover up detrimental recessive tendency to cover up detrimental recessive genes andgenes and
improve traits related to physical fitnessimprove traits related to physical fitness1.)1.)2.)2.)
Selection of Breeding Selection of Breeding ProgramProgram
Mating systemsMating systems
Crossbreeding –Crossbreeding –two reasons for its use:two reasons for its use:
1.1. For certain traits may result in heterosisFor certain traits may result in heterosis2.2. Breed complementarity Breed complementarity
Selection of Breeding Selection of Breeding ProgramProgram
Table 1. Summary of heritability and level of heterosis by trait Table 1. Summary of heritability and level of heterosis by trait type. type. AA
Trait Trait Heritability Heritability Level of HeterosisLevel of HeterosisCarcass / end product Carcass / end product High High Low Low Skeletal measurements Skeletal measurements (0 to 5 %) (0 to 5 %)Mature weightMature weight Growth rate Growth rate Medium Medium Medium Medium Birth weightBirth weight (5 to 10 %) (5 to 10 %)Weaning weight Weaning weight Yearling weight Yearling weight Milk production Milk production Maternal ability Maternal ability Low Low High High Reproduction Reproduction (10 to 30 %) (10 to 30 %)Health Health Cow longevity Cow longevity Overall cow productivityOverall cow productivity aa Adapted from Kress and MacNeil. 1999 Adapted from Kress and MacNeil. 1999
Selection of Breeding Selection of Breeding ProgramProgram
1.1. For certain traits may result in heterosisFor certain traits may result in heterosis
average of average ofaverage of average ofa. % heterosis =a. % heterosis = crossbred - purebreds crossbred - purebreds x 100 x 100
average of purebreds average of purebreds
1.)1.)
b. Traits not expressing heterosis will equal the b. Traits not expressing heterosis will equal the averageaverage
of the parent breeds for that trait in the crossbred of the parent breeds for that trait in the crossbred offspringoffspring
Selection of Breeding Selection of Breeding ProgramProgram
1.1. For certain traits may result in heterosisFor certain traits may result in heterosisc. Why important in beef cattle businessc. Why important in beef cattle business
1.)1.) Largest benefit to commercial production isLargest benefit to commercial production iscrossbred cows – improves:crossbred cows – improves:
a.)a.)b.)b.)c.)c.)d.)d.)
d.d. Keys for successful crossbreeding program:Keys for successful crossbreeding program:1.)1.)2.)2.)
e.e. Crossbreeding systemsCrossbreeding systems
Selection of Breeding Selection of Breeding ProgramProgram
2.2. Breed complementarity – implies using Breed complementarity – implies using breeds inbreeds in
a crossbreeding program where their a crossbreeding program where their strengths andstrengths and
weaknesses complement one anotherweaknesses complement one another
a. Examplea. Example
1.)1.)
Selection of Breeding Selection of Breeding ProgramProgram
Composite breeds –Composite breeds –
1.1. Maintain heterosisMaintain heterosis2.2. Utilize breed complementarityUtilize breed complementarity3.3. Once formed, can be managed like a Once formed, can be managed like a purebred herdpurebred herd
Formed Formed Retained %Retained % Improved Improved produc. produc. fromfrom maximum heterosis maximum heterosis of cow herd(%) of cow herd(%)2-breed2-breed 50 50 12123-breed3-breed 67 67 15154-breed4-breed 75 75 1717
Table 1. Breed performance levels for seven traits in beef cattle. Table 1. Breed performance levels for seven traits in beef cattle. a,b.a,b.
Table 2. 2004 Adjustment factors to add to EPD of 15 different breeds to Table 2. 2004 Adjustment factors to add to EPD of 15 different breeds to estimate across-breed EPD. estimate across-breed EPD. a,b.a,b.
BreedBreed Birth Weight Weaning WeightBirth Weight Weaning Weight Yearling WeightYearling WeightMilk Milk . . Angus Angus 0.0 0.0 0.0 0.0 0.0 0.0 0.00.0Beefmaster Beefmaster 9.7 9.7 39.0 39.0 37.9 37.9 ------BrahmanBrahman 13.0 13.0 34.8 34.8 -4.4 -4.4 24.624.6BrangusBrangus 5.7 5.7 20.0 20.0 20.4 20.4 ------BraunviehBraunvieh 6.5 6.5 30.0 30.0 13.9 13.9 22.222.2CharolaisCharolais 10.5 10.5 38.4 38.4 53.4 53.4 2.62.6GelbviehGelbvieh 5.4 5.4 7.1 7.1 -21.1 -21.1 1.71.7HerefordHereford 3.4 3.4 -2.0 -2.0 -13.7 -13.7 -17.8-17.8LimousinLimousin 4.5 4.5 1.8 1.8 -19.9 -19.9 -15.9-15.9Maine AnjouMaine Anjou 6.7 6.7 17.6 17.6 5.5 5.5 7.67.6PinzgauerPinzgauer 7.7 7.7 28.3 28.3 25.5 25.5 6.16.1Red AngusRed Angus 3.6 3.6 -1.4 -1.4 0.7 0.7 -7.8-7.8South DevonSouth Devon 6.7 6.7 21.7 21.7 40.8 40.8 3.53.5SalersSalers 4.9 4.9 30.7 30.7 46.1 46.1 9.09.0Shorthorn Shorthorn 7.8 7.8 31.4 31.4 44.5 44.5 12.112.1Simmental Simmental 6.4 6.4 22.4 22.4 21.9 21.9 10.010.0TarentaiseTarentaise 3.6 3.6 30.1 30.1 13.4 13.4 17.817.8
aa Van Vleck and Cundiff, 2004 Van Vleck and Cundiff, 2004b b Updates to across-breed EPD adjustments can be found at Updates to across-breed EPD adjustments can be found at
www.beefimpovement.orgwww.beefimpovement.org
Table 3. Average across-breed EPD for nonparent animals born in 2002-2003 Table 3. Average across-breed EPD for nonparent animals born in 2002-2003 by breed. by breed. a.a.
BreedBreed Birth Weight Weaning WeightBirth Weight Weaning Weight Yearling WeightYearling WeightMilk Milk .. Angus Angus 2.6 2.6 35 35 65 65 1717Beefmaster Beefmaster 10.1 10.1 45 45 49 49 ------BrahmanBrahman 15.1 15.1 51 51 22 22 3232BrangusBrangus 7.7 7.7 41 41 54 54 ------BraunviehBraunvieh 7.6 7.6 37 37 21 21 2222CharolaisCharolais 12.0 12.0 57 57 85 85 88GelbviehGelbvieh 6.4 6.4 44 44 48 48 1919HerefordHereford 7.2 7.2 33 33 46 46 -5-5LimousinLimousin 6.9 6.9 36 36 44 44 22Maine AnjouMaine Anjou 9.2 9.2 34 34 37 37 1111PinzgauerPinzgauer 7.6 7.6 29 29 26 26 55Red AngusRed Angus 4.1 4.1 27 27 49 49 66SalersSalers 7.8 7.8 34 34 60 60 1212Shorthorn Shorthorn 6.7 6.7 44 44 66 66 1111Simmental Simmental 9.7 9.7 65 65 102 102 1818South DevonSouth Devon 6.4 6.4 40 40 45 45 16 16 ..
aa Adjustment using the 2004 across-breed EPD adjustments listed in Table 2. Adjustment using the 2004 across-breed EPD adjustments listed in Table 2.
Selection of Breeding Selection of Breeding ProgramProgram
Successful breeding program depends on:Successful breeding program depends on:
1.1.
2.2.
a.a.
b.b.