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 A simulation study for optimizing the use of dairy bulls in breeding programs

1987 ◽  
Vol 59 (2) ◽  
pp. 79-86
Author(s):  
J. Juga ◽  
J. Syväjärvi ◽  
V. Vilva
Keyword(s):  
Milk Production ◽  
Breeding Value ◽  
Progeny Testing ◽  
Genetic Response ◽  
Breeding Programs ◽  
Negative Effect ◽  
Selection For ◽  
Selected Traits ◽  
Dairy Bulls ◽  
Lactation Record

Different breeding program alternatives in dairy cattle population were studied by simulation. Traits studied were milk production and a low heritability trait that is negatively correlated with milk production, e.g. fertility. The variable factors in the study were the number of young bulls to be tested, the number of daughters per bull in progeny testing, the number of tested bulls to be used and the weights for selected traits in an overall index of the bull’s breeding value. The influence of variable factors on genetic response in milk production and fertility was studied by calculating the average of real genotypic values on both traits for all cows born in the same year and having a complete first lactation record. This was done for a 25 year period. The population structure used in simulation was like the Finnish milk recorded Ayrshire population in which there are ca. 250000 cows. The genetic response in milk production was improved by increasing the selection intensity amongst bulls. The negative effect of selection for milk yield on fertility could be decreased by giving the fertility a larger indexed weight. If the milk production had a weight of 1 and genetic correlation between traits was —0.20 then increasing the weight of fertility from 0.1 to 0.3 did not affect significantly the response in milk production.

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 Milk protein genes CSN1S1, CSN2, CSN3, LGB and their relation to genetic values of milk production parameters in Czech Fleckvieh

2011 ◽  
Vol 51 (No. 6) ◽  
pp. 241-247 ◽  
Author(s):  
J. Kučerová ◽  
A. Matějíček ◽  
Jandurová OM ◽  
P. Sørensen ◽  
E. Němcová ◽  
...  
Keyword(s):  
Protein Content ◽  
Milk Production ◽  
Milk Protein ◽  
Breeding Value ◽  
Likelihood Method ◽  
Genetic Constitution ◽  
Progeny Testing ◽  
Breeding Values ◽  
Production Parameters ◽  
Milk Protein Genes

Genotypes of milk protein genes, alpha<sub>S1</sub>-casein (CSN1S1), beta-casein (CSN2), kappa-casein (CSN3) and beta-lactoglobulin (LGB), were detected in 440 individuals of Czech Fleckvieh breed using a PCR-RFLP method. Breeding values of genotyped animals were obtained from the Official Database of Progeny Testing. A granddaughter design including 5 grandsires, 33 sons and 402 granddaughters was used for evaluation. Statistical analysis was carried out in SAS program using a restricted maximum likelihood method (REML). The aim of this study was to determine allele and genotype frequencies of observed genes and to find the relation between genotypes of genes and milk production parameters expressed by the breeding values of animals. The positive findings of frequencies of CSN3 allele B (0.38) and genotype BB (13%) were detected in the observed population. Significant differences were found between genotypes of loci CSN1S1, CSN2 and CSN3 and breeding values for milk production parameters. Genotypes of LGB locus were not significantly related to any of the milk production parameters. Significant effects were found between CSN1S1 locus and average breeding value for milk yield, CSN2 locus and breeding values for all parameters except for protein content and CSN3 locus and breeding values for protein content and protein yield. These findings contribute to a better understanding of the genetic constitution of Czech Fleckvieh breed and help with the application of the information to breeding. &nbsp; &nbsp;

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

Selection of dairy cattle for growth rate and milk production

1966 ◽  
Vol 8 (1) ◽  
pp. 109-119 ◽  
Author(s):  
M. Soller ◽  
R. Bar-Anan ◽  
H. Pasternak
Keyword(s):  
Growth Rate ◽  
Milk Production ◽  
Economic Value ◽  
Performance Testing ◽  
Live Weight ◽  
Economic Conditions ◽  
Progeny Testing ◽  
Genetic Progress ◽  
Weight For Age ◽  
Selection Of

The genetic progress in live-weight-for-age (LFA), milk production, and in overall economic value expected as a result of performance and progeny testing of young bulls with respect to milk production and LFA was computed. It was shown that performance testing can contribute considerably to overall progress in economic value, while under certain circumstances progeny testing for LFA can also contribute to genetic progress in overall economic value, but to a lesser degree than performance testing. The relative economic value of LFA and milk production was derived and found to be relatively stable under differing economic conditions.

Effect of the sire on the subsequent lactation performance in the dam

1981 ◽  
Vol 32 (2) ◽  
pp. 155-158 ◽  
Author(s):  
S. B. Basu ◽  
S. S. Tomar
Keyword(s):  
Birth Weight ◽  
Milk Production ◽  
Post Partum ◽  
Breeding Value ◽  
Progeny Testing ◽  
Lactation Performance ◽  
Length Of Service ◽  
Lactation Length ◽  
Sire Evaluation ◽  
Service Period

ABSTRACTThe effects of 18 buffalo sires, used in 2 years of a progeny-testing programme, on the subsequent lactation performances of their mates, were investigated from a study of 685 lactation records. The traits studied were: milk production, lactation length, length of post partum anoestrus, number of services per conception and length of service period (calving to conception). Parity of calving and sire had a significant effect on 305-day milk yield and lactation length of the mates. Between the 2 years, the sires did not differ for any of the traits of their mates. Although the breeding value of the sires, high or low, did not differ significantly, the sires with high breeding value tended to depress the milk production in the subsequent lactation of their mates and vice versa (r= −0·05). The birth weight of the calves significantly affected milk production. It was concluded that all methods of sire evaluation are likely to be biased by the effect of sires.

Relationship between sires transmitting ability and daughter performance in a high yielding dairy herd

1990 ◽  
Vol 1990 ◽  
pp. 11-11 ◽  
Author(s):  
P Persaud ◽  
G Simm ◽  
H Parkinson ◽  
W G Hill
Keyword(s):  
Milk Production ◽  
Dairy Herd ◽  
Breeding Value ◽  
Feed Consumption ◽  
Correlated Response ◽  
Progeny Testing ◽  
Production Traits ◽  
Gross Efficiency ◽  
The Uk ◽  
Milk Solids

In the UK feed accounts for 0.80 to 0.90 of the variable costs of dairy production. In recent years the imposition of milk quotas has served to emphasise the importance of efficient milk and milk solids production. In field progeny testing schemes, sires’ transmitting ability or breeding value can be predicted for milk production traits, but not for feed Intake or for efficiency of milk production. As breeders continue to select on production traits, using sires of high genetic merit for production, the important question then is, ‘what correlated response occurs in gross efficiency and in feed consumption?’.

Genotype by environment interaction for yearling weight in Nellore cattle applying reaction norms models

2018 ◽  
Vol 58 (11) ◽  
pp. 1996
Author(s):  
S. Ribeiro ◽  
J. P. Eler ◽  
V. B. Pedrosa ◽  
G. J. M. Rosa ◽  
J. B. S. Ferraz ◽  
...  
Keyword(s):  
Genetic Correlation ◽  
Environmental Gradient ◽  
Genotype By Environment Interaction ◽  
Reaction Norms ◽  
Breeding Value ◽  
Environment Interaction ◽  
Genotype By Environment ◽  
Genotype Environment Interaction ◽  
Nellore Cattle ◽  
Gradient Variation

In the present study, a possible existence of genotype × environment interaction was verified for yearling weight in Nellore cattle, utilising a reaction norms model. Therefore, possible changes in the breeding value were evaluated for 46 032 animals, from three distinct herds, according to the environmental gradient variation of the different contemporary groups. Under a Bayesian approach, analyses were carried out utilising INTERGEN software resulting in solutions of contemporary groups dispersed in the environmental gradient from –90 to +100 kg. The estimates of heritability coefficients ranged from 0.19 to 0.63 through the environmental gradient and the genetic correlation between intercept and slope of the reaction norms was 0.76. The genetic correlation considering all animals of the herds in the environmental gradient ranged from 0.83 to 1.0, and the correlation between breeding values of bulls in different environments ranged from 0.79 to 1.0. The results showed no effect of genotype × environment interaction on yearling weight in the herds of this study. However, it is important to verify a possible influence of the genotype × environment in the genetic evaluation of beef cattle, as different environments might cause interference in gene expression and consequently difference in phenotypic response.

A simulation study of open nucleus and closed nucleus breeding systems in a sheep population

1995 ◽  
Vol 60 (1) ◽  
pp. 117-124 ◽  
Author(s):  
J. A. Roden
Keyword(s):  
Genetic Gain ◽  
Live Weight ◽  
Breeding Systems ◽  
Breeding Value ◽  
Linear Unbiased Prediction ◽  
Sheep Population ◽  
Best Linear Unbiased ◽  
Nucleus Breeding ◽  
Open Nucleus ◽  
Selection Of

AbstractStochastic simulation was used to compare the results of alternative breeding systems in a sheep population divided into 10 flocks of 120 ewes. The breeding systems compared were selection within closed flocks (CF), a closed nucleus system (CNS), an open nucleus system (ONS) and open nucleus systems with the selection of nucleus replacements being restricted to either nucleus born males (ONSRm) or nucleus born females (ONSRf). Selection was for a best linear unbiased prediction of breeding value for lamb live weight which had a heritability of 0·17. The open nucleus breeding systems (ONS, ONSRm, ONSRf) resulted in higher rates of genetic gain, more predictable selection responses and lower rates of inbreeding than either the closed nucleus system (CNS) or selection within closed flocks (CF). Initial genetic differences between flocks resulted in higher rates of genetic gain in the nucleus breeding systems due to the use of between flock genetic variance. In the ONS system up to 25% of nucleus sires and approximately 50% of nucleus dams were born in base flocks. Nevertheless if selection of either nucleus sires or dams was restricted to nucleus born animals there was very little change in genetic gain or rate of inbreeding.

The effects of days-open on milk yield and on breeding policy post partum

1979 ◽  
Vol 29 (1) ◽  
pp. 109-119 ◽  
Author(s):  
R. Bar-Anan ◽  
M. Soller
Keyword(s):  
Milk Production ◽  
Milk Yield ◽  
Post Partum ◽  
Economic Value ◽  
Total Yield ◽  
Annual Production ◽  
Initial Yield ◽  
Days Open

ABSTRACTThe effects of days-open on milk yields in current lactations and in following lactations were estimated from 71 911 current and 68 693 following lactation records. Yields were expressed as 305-day, total and annual records, where annual record = 365 × (total yield/days between calvings).The data were grouped according to current days-open, corrected for initial yield differences and analysed separately for heifers and cows in Moshav (moderate-yielding) and Kibbutz (high-yielding) herds. Current 305-day records increased by 15 to 18 kg milk/day-open up to 90 days-open, and 2 to 3 kg/day-open thereafter. In contrast, the effects of increasing days-open on annual yields were generally small and negative, being positive only for heifers up to 90 days-open. Thus 305-day records heavily under-rated annual yields of fertile cows. For current lactations, 70 to 100 days-open for heifers and 30 to 50 days-open for cows resulted in the highest annual production. Yields in following lactations were positively associated with days-open in the previous lactation. The effect was highest in high-yielding herds, suggesting that high-yielding cows respond positively to some rest between calvings.Combining the effects of days-open on current and following lactation yields and on the calf crop: in high-yielding herds heifers had the highest productivity when mated not earlier than 70 days post partum, while in moderately-yielding herds days-open did not affect productivity. Cows in high-yielding herds achieved highest productivity at 41 to 90 days-open, while cows in moderately-yielding herds were most productive when mated as early as possible.A comparison of the economic value of sire fertility and sire transmitting ability for milk production showed that fertility may often be over-rated.

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