A deterministic model for the optimization of dairy cattle breeding based on BLUP breeding value estimates

1989 ◽  
Vol 49 (2) ◽  
pp. 193-202 ◽  
Author(s):  
T. H. E. Meuwissen
Keyword(s):  
Steady State ◽  
Dairy Cattle ◽  
Genetic Gain ◽  
Variance Reduction ◽  
Deterministic Model ◽  
Age Distribution ◽  
Breeding Value ◽  
Progeny Testing ◽  
Age Classes ◽  
Testing Scheme

ABSTRACTA deterministic model was developed to examine the optimization of open nucleus breeding schemes in order to maximize the rate of genetic response in dairy cattle. By changing the parameters, the model was able to simulate both a closed nucleus and a progeny testing scheme. The model implicitly optimized the generation interval and the selection across tiers by means of truncation across age classes and tiers respectively. The effects of size of the progeny test group and the nucleus size were assessed by comparing alternative plans. It is possible to optimize a breeding plan given the reproduction rates of the animals, the availability of different sources of information, the age distribution of the animals (survival rates) and the phenotypic and genetic parameters of the trait.The steady state selection response was assessed by calculating the genetic progress year after year until it stabilized. The genetic gain was corrected for the effects of reduced variances due to previous selections and increased variances due to genetic differences between parental age classes.In an example, the model was used to predict the improvement in milk yield in a closed artificial insemination breeding scheme. The genetic gain of a conventional progeny testing scheme was about one-third lower than the genetic gain of the optimized breeding plan. The variance reduction due to selection decreased the steady state genetic gain by a factor 0·3

Expectation and variance of genetic gain in open and closed nucleus and progeny testing schemes

1991 ◽  
Vol 53 (2) ◽  
pp. 133-141 ◽  
Author(s):  
T. H. E. Meuwissen
Keyword(s):  
Genetic Gain ◽  
Variance Reduction ◽  
Deterministic Model ◽  
Finite Size ◽  
Response Rates ◽  
Progeny Test ◽  
Progeny Testing ◽  
Individual Record ◽  
Open Nucleus ◽  
Selection Of

AbstractOpen and closed nucleus and conventional and modern progeny testing schemes were compared for expectation and variance of genetic gain. Generation intervals were optimized, with minimum values of 2 and 6 years (progeny test results available) for males in nucleus and progeny testing schemes, respectively. Females had a minimum generation interval of 2 years, except in the conventional progeny testing schemes, which had a minimum of 4 years (one individual record available). Apart from the generation intervals and the progeny test, open nucleus and progeny testing schemes were identical, since ‘nucleus females’ are also born in progeny testing schemes, being full-sibs of the young bulls and dispersed over commercial herds. The number of nucleus sires (bull sires) selected was varied between four and 32. Selection was for milk production.A deterministic model was used, that accounted for variance reduction due to selection and the effects of finite size and family structure on the selection differentials. Prediction of the variance of the selection response accounted for selection of full- and paternal half-sibs.Closed nucleus schemes gave a factor 0·03, 0·13 and 0·19 larger response rates than open nucleus and modern and conventional progeny testing schemes, respectively. Reduction of genetic variance of open nucleus schemes was larger than that of closed nucleus schemes, which caused the slightly higher response rates of closed nucleus schemes. Standard deviations of selection responses of closed nucleus schemes were a factor 0·46, 0·79 and 0·86 larger, respectively.Preference for the schemes was assessed using a quadratic utility function expressing risk and inbreeding aversion. The increase in genetic gain due to shortening of generation intervals more than compensated for its increased variance. Whether the increased genetic gain due to closing the nucleus compensated for its increased variance depended on the amount of risk aversion. Selection of four sires and eight to 16 sires had the highest utility in progeny testing and nucleus schemes, respectively.

scholarly journals Coefficients of relationship and inbreeding among Finnish Ayrshire and Holstein-Friesian

2008 ◽  
Vol 13 (4) ◽  
pp. 338 ◽  
Author(s):  
T. VAHLSTEN ◽  
E. MÄNTYSAARI ◽  
I. STRANDÉN
Keyword(s):  
Dairy Cattle ◽  
Breeding Value ◽  
Pedigree Data ◽  
Age Classes ◽  
Holstein Friesian ◽  
Average Coefficient ◽  
The Mean ◽  
Coefficient Of Relationship ◽  
Relationship Of ◽  
Friesian Cows

Pedigree data from national breeding value evaluations were used in calculation of the coefficient and rate of inbreeding, average coefficient and rate of relationship and generation intervals for the Finnish Ayrshire and Holstein-Friesian dairy cattle populations. The data had 1,366,555 Ayrshire and 377,869 Holstein-Friesian animals. The mean coefficient of inbreeding for Ayrshire and Holstein-Friesian animals born in the 1990s was 2.29% and 0.90%, respectively, and the trend was towards higher inbreeding values. The average coefficient of relationship, mean increase in inbreeding and generation interval was calculated for bulls born between 1976 and 1999, and for cows born between 1986 and 1999. The mean coefficient of relationship of Ayrshire bulls increased 2.22 %-units per generation and inbreeding increased 0.20 %-units per generation during the years studied. The mean coefficient of relationship of Finnish Holstein-Friesian bulls increased 0.96 %-units per generation and inbreeding 0.17 %-units per generation. The mean coefficient of relationship and inbreeding of Ayrshire cows increased 0.38 %-units and 0.31 %-units per generation, respectively. For Holstein-Friesian cows the mean coefficient of relationship and inbreeding increased 0.25 %-units and 0.11 %-units per generation, respectively. Results show that inbreeding is low and it is increasing slowly in both breeds. However, especially the coefficients of relationship of Ayrshire bulls are high in some age classes and this may lead into faster increase in coefficients of inbreeding.;

Responses of multi-trait selection in open nucleus schemes for dairy cattle breeding

1993 ◽  
Vol 56 (3) ◽  
pp. 293-299 ◽  
Author(s):  
T. H. E. Meuwissen ◽  
J. A. Woolliams
Keyword(s):  
Food Intake ◽  
Genetic Correlation ◽  
Milk Production ◽  
Deterministic Model ◽  
Economic Value ◽  
Estimation Method ◽  
Breeding Value ◽  
Progeny Testing ◽  
Secondary Traits ◽  
Open Nucleus

AbstractResponses of selection for milk production and secondary traits were predicted in open nucleus schemes using a deterministic model. Secondary traits considered were: traits recorded during lactation (e.g. mastitis resistance; calving ease); traits recorded in the nucleus only (e.g. food intake); traits recorded early in life (e.g. growth rate); and traits recorded late in life (e.g. longevity). Also, genotype × environment interactions between nucleus and commercial herds and predictors of merit in juveniles were considered.Extension of the breeding goal to include an uncorrelated secondary trait, which was recorded at each lactation, had the same heritability as milk production (assumed throughout to be 0·25) and half its economic value, increased total economic gain by a factor of 0·12. This increase was only 0·04, if the heritability of the secondary trait was 0·1. The situation for traits of low heritability was not improved by progeny testing of young bulls due to the short optimized generation intervals. Gain increased only by a factor of 0·04, if the economic value was 0·25.Including a secondary trait of heritability 0·25 and a genetic correlation with yield of 0·5 in the index, only increased economic response rates by a factor of 0·04. However, when the genetic correlation was –0·5 the benefits were greater with increases of 0·09, 0·10 and 0·22 for heritabilities of 0·05, 0·10 and 0·25, respectively. Hence, including traits with low heritability but with strong negative correlations with yield, which might apply to fertility and disease resistance, increased rates of gain moderately.If an uncorrelated secondary trait was recorded in the nucleus only, e.g. food intake, and had half the economic value of milk production, total gains increased by a factor of 0·10. Hence, recording of secondary traits can be restricted to the nucleus with only minor loss of gain. The extra economic benefit was greatest from secondary traits measured early in life compared with late in life, e.g. longevity, with benefits increased by factors of 0·24 and 0·06, respectively.Open nucleus schemes are robust in the presence of genotype × environment interactions between nucleus and commercial herds, if the breeding value estimation method accounts for these interactions, juvenile indicator traits of milk production may increase rates of gain by a factor of 0·11, if the heritability of the indicator trait is 0·25 and the correlation with milk production is 0·5.

scholarly journals Designing dairy cattle breeding schemes under genomic selection: a review of international research

2012 ◽  
Vol 52 (3) ◽  
pp. 107 ◽  
Author(s):  
J. E. Pryce ◽  
H. D. Daetwyler
Keyword(s):  
Dairy Cattle ◽  
Genomic Selection ◽  
Genetic Gain ◽  
Reproductive Technologies ◽  
Progeny Testing ◽  
Genomic Breeding ◽  
Breeding Values ◽  
Scheme Design ◽  
Dairy Cattle Breeding ◽  
Breeding Schemes

High rates of genetic gain can be achieved through (1) accurate predictions of breeding values (2) high intensities of selection and (3) shorter generation intervals. Reliabilities of ~60% are currently achievable using genomic selection in dairy cattle. This breakthrough means that selection of animals can happen at a very early age (i.e. as soon as a DNA sample is available) and has opened opportunities to radically redesign breeding schemes. Most research over the past decade has focussed on the feasibility of genomic selection, especially how to increase the accuracy of genomic breeding values. More recently, how to apply genomic technology to breeding schemes has generated a lot of interest. Some of this research remains the intellectual property of breeding companies, but there are examples in the public domain. Here we review published research into breeding scheme design using genomic selection and evaluate which designs appear to be promising (in terms of rates of genetic gain) and those that may have unfavourable side-effects (i.e. increasing the rate of inbreeding). The schemes range from fairly conservative designs where bulls are screened genomically to reduce numbers entering progeny testing, to schemes where very large numbers of bull calves are screened and used as sires as soon as they reach sexual maturity. More radical schemes that incorporate the use of reproductive technologies (in juveniles) and genomic selection in nucleus herds are also described. The models used are either deterministic and more recently tend to be stochastic, simulating populations of cattle. A key driver of the rate of genetic gain is the generation interval, which could range from being similar to that in conventional testing (~5 years), down to as little as 1.5 years. Generally, the rate of genetic gain is between 12% and 100% more than in conventional progeny testing, while the rate of inbreeding tends to be lower per generation than in progeny testing because Mendelian sampling terms can be estimated more accurately. However, short generation intervals can lead to higher rates of inbreeding per year in genomic breeding programs.

Effects of a breeding scheme combined by genomic pre‐selection and progeny testing on annual genetic gain in a dairy cattle population

2014 ◽  
Vol 85 (6) ◽  
pp. 639-649
Author(s):  
Takeshi Yamazaki ◽  
Kenji Togashi ◽  
Satoru Iwama ◽  
Shigeo Matsumoto ◽  
Kimihiro Moribe ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Genetic Gain ◽  
Progeny Testing ◽  
Cattle Population ◽  
Breeding Scheme

scholarly journals Estimated Breeding Values of Beef Sires Can Predict Performance of Beef-Cross-Dairy Progeny

2021 ◽  
Vol 12 ◽  
Author(s):  
Natalia Martín ◽  
Lucy Coleman ◽  
Nicolás López-Villalobos ◽  
Nicola Schreurs ◽  
Stephen Morris ◽  
...  
Keyword(s):  
New Zealand ◽  
Dairy Cattle ◽  
Dairy Cows ◽  
Carcass Traits ◽  
Breeding Value ◽  
Gestation Length ◽  
Similar Amount ◽  
Progeny Testing ◽  
Eye Muscle ◽  
Beef Breed

On average, half of the animal’s estimated breeding value (EBV) is passed on to their progeny. However, it is not known how the performance of beef-cross-dairy cattle relates to the EBV of their beef sire. Such information is required to determine the genetic potential of beef sires selected based on existing EBV to be used on dairy cows in New Zealand. This study evaluated the relationship between the EBV of 30 Angus and 34 Hereford sires and the performance of their progeny for birth, growth, and carcass traits, via progeny testing of 975 beef-cross-dairy offspring born to dairy cows and grown on hill country pasture. Overall, BREEDPLAN EBV did predict progeny performance of the beef-cross-dairy cattle from this study. Gestation length and birthweight increased with increasing sire EBV (mean 0.37–0.62days and 0.52–0.64kg, respectively, p<0.05). Age at weaning decreased with increasing sire EBV for liveweight at 200days (0.17–0.21days per extra kilo of sire EBV, p<0.05) but sire EBV for liveweight at 200days had no effect on the liveweight of the progeny at 200days for either breed (p>0.05). Liveweight increased with sire EBV for liveweight at 400, 600, and 800days, by a similar amount for both breeds (between 0.23 and 0.42kg increase in progeny liveweight per extra kilo of sire EBV, p<0.05). The relationships were more inconsistent for carcass traits. For Hereford, carcass weight and eye muscle area increased with increasing sire EBV (0.27kg and 0.70cm2, respectively, p<0.05). For Angus, marble score increased by 0.10 with 1% extra in sire EBV for intramuscular fat (p<0.05). Rib fat depth tended to increase with sire EBV for both breeds (p<0.1). EBV derived from beef-breed data work in dairy-beef systems but maybe slightly less than the expected 0.5units of performance per unit of EBV. New Zealand farmers should consider BREEDPLAN EBV when selecting sires to mate dairy cows or when buying beef-cross-dairy calves for beef production, to ensure the resulting calves are born safely and on time and then grow well to produce carcasses of suitable meat and fat composition.

A genetic and economic analysis of nucleus breeding plans designed to improve dairy breeds in Brazil

1999 ◽  
Vol 68 (1) ◽  
pp. 87-96
Author(s):  
C. H. Lobo ◽  
F. R. Allaire
Keyword(s):  
Dairy Cattle ◽  
Genetic Gain ◽  
Age Distribution ◽  
Net Income ◽  
Genetic Merit ◽  
Net Returns ◽  
Investment Value ◽  
Commercial Population ◽  
Nucleus Breeding ◽  
The Difference

AbstractThe objective of this research was to design and compare nucleus breeding plans that might be recommended to the breeders of Brazilian dairy cattle. Plans for native dairy breeds were compared for the change of genetic merit in milk yield and in the economic return at 25-year investment periods. Effects of nucleus herd and commercial population sizes on genetic gain and net income were examined. Investment value of plans was studied for differences in the efficiency of embryo transfer techniques and in the sale price of cows and young bulls on genetic merit. Parent selection was based on records on individuals (for females), their full- and half-sibs, their dam, full-and half-sibs of their sire and their dam and their grandam. Within herd sire selection was restricted to a maximum of one bull per full-sib family. No matings of full-sibs were allowed. Annual economic summaries considered the age distribution of animals within herds. Alternative plans were investigated for their revenue, expense and net income streams and their investment value. The cumulative genetic gain of selected animals in lactational milk production was 1639 kg and 1435 kg for large plans with 64 donors (L) and small plans with 32 donors (S), respectively. The initial genetic lift for a population size of 20 000 animals was equal to 279 kg. When the size of the commercial population was increased to 50 000 animals, the lift was increased by 10%. Profitability in the different plans was achieved after the sale of cows and young bulls. The difference between cumulative discounted net returns at year 25 for L and S was proportional to the sale prices placed on the genetic merit of cows and bulls. The programmes of genetic improvement described were profitable and should be recommended to the breeders of Brazilian dairy cattle. Considering the criteria of gain to cost, the smaller plan seems to be the most reasonable to implement.

COMPARATIVE ANALYSIS OF THE EVALUATION RESULTS OF HOLSTEIN BLACK-MOTLEY BREEDING BULLS BY THEIR DAUGHTERS’ PRODUCTIVITY BASED ON OFFICIAL INSTRUCTIONS AND BLUP MODEL

2020 ◽  
pp. 155-163
Author(s):  
K.ZH. ZHUMANOV ◽  
◽  
T.N. KARYMSAKOV ◽  
M.A. KINEEV ◽  
M.V. TAMAROVSKIY ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Milk Fat ◽  
Cattle Breed ◽  
Breeding Value ◽  
Cattle Breeding ◽  
Lower Efficiency ◽  
Dairy Cattle Breeding ◽  
The Usa ◽  
Current Instruction ◽  
The Republic

According to the current “Instruction” used in dairy cattle selection and breeding in the Republic of Kazakhstan, bulls-producers of dairy breeds are assessed according to the their offspring quality based on the principle of “peer daughter”. This means that the phenotypic indicators of the daughters of the tested bulls are compared with the corresponding indicators of their peers. In European countries with developed dairy cattle breeding, as well as in Canada, the USA, etc., to ensure a reliable forecast of the genetic value of individuals (primarily, bulls-producers), use is made of the best linear unbiased forecast method (BLUP method). This method implies that the breeding value of producers is determined by the deviation values of the development of traits of the examined animal from its average values in the population. Especially urgent area is the research aimed at improving breeding programs, including assessing the breeding value of bulls-producers of dairy breeds using BLUP methods based on the productive qualities of the mass of dairy cattle in the Republic of Kazakhstan. The research material included the data on the phenotypic indicators of the milk productivity of first-calf cows (the amount of milk yield, the content of fat and protein in milk, the yield of milk fat and protein) of the Holstein black-motley dairy cattle breed, obtained from the information and analytical database of the Republic of Kazakhstan for 2016–2017. It was found that when evaluating according to the official “Instruction”, 16 sires out of 256 bulls (6.2%) got the stud category in 2016, 14 sires (9.2%) out of 152 bulls in 2017, and – 30 sires of 249 bulls (12.0%) over the cumulative period. The results of the conducted research prove that the use of the classic “Instructions” in dairy cattle breeding has lower efficiency (by 42.8–90.0%) as compared with the assessment of the breeding value of bulls based on the BLUP method.The selection of sire bulls into breeding groups based on the “peer daughter” methodology is not reliable enough and rather ineffective. Comparing the results of assessing the breeding qualities of sire bulls, obtianed using two methods in all compared periods (2016, 2017, 2016–2017), the authors established a clear superiority of the BLUP method over the current Instruction used in the Republic of Kazakhstan.

scholarly journals Prediction of Genetic Contributions and Generation Intervals in Populations With Overlapping Generations Under Selection

Genetics ◽  
1999 ◽  
Vol 151 (3) ◽  
pp. 1197-1210 ◽  
Author(s):  
Piter Bijma ◽  
John A Woolliams
Keyword(s):  
Gene Flow ◽  
Overlapping Generations ◽  
Selective Advantage ◽  
Turnover Time ◽  
Breeding Value ◽  
Age Classes ◽  
Generation Interval ◽  
Young Parents ◽  
Genetic Contributions

Abstract A method to predict long-term genetic contributions of ancestors to future generations is studied in detail for a population with overlapping generations under mass or sib index selection. An existing method provides insight into the mechanisms determining the flow of genes through selected populations, and takes account of selection by modeling the long-term genetic contribution as a linear regression on breeding value. Total genetic contributions of age classes are modeled using a modified gene flow approach and long-term predictions are obtained assuming equilibrium genetic parameters. Generation interval was defined as the time in which genetic contributions sum to unity, which is equal to the turnover time of genes. Accurate predictions of long-term genetic contributions of individual animals, as well as total contributions of age classes were obtained. Due to selection, offspring of young parents had an above-average breeding value. Long-term genetic contributions of youngest age classes were therefore higher than expected from the age class distribution of parents, and generation interval was shorter than the average age of parents at birth of their offspring. Due to an increased selective advantage of offspring of young parents, generation interval decreased with increasing heritability and selection intensity. The method was compared to conventional gene flow and showed more accurate predictions of long-term genetic contributions.

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