Genetic improvement of dairy cattle.

2014 ◽  
pp. 371-396 ◽  
Author(s):  
V. Ducrocq ◽  
G. Wiggans
Keyword(s):  
Dairy Cattle ◽  
Genetic Improvement

ARE TODAY’S DAIRY CATTLE BREEDING PROGRAMS SUITABLE FOR TOMORROW’S PRODUCTION REQUIREMENTS?

1980 ◽  
Vol 60 (2) ◽  
pp. 253-264 ◽  
Author(s):  
A. J. McALLISTER
Keyword(s):  
Dairy Cattle ◽  
Genetic Improvement ◽  
Herd Size ◽  
Breeding Program ◽  
Genetic Trend ◽  
Genetic Progress ◽  
Breeding Programs ◽  
Holstein Breed ◽  
Dairy Cattle Breeding ◽  
National Production

In the last decade the dairy cattle population has declined to a level of 1.9 million cows in 1978 with about 56% of these cows bred AI and nearly 20% of the population enrolled in a supervised milk recording program. The decline in cow numbers has been accompanied by an increase in herd size and production per cow. The current breeding program of the dairy industry is a composite of breeding decisions made by AI organizations, breeders who produce young bulls for sampling and all dairymen who choose the sires and dams of their replacement heifers. Estimates of genetic trend from 1958–1975 for milk production in the national milk recorded herd range from 21 to 55 kg per year for the four dairy breeds with Holsteins being 41 kg per year. Both differential use of superior proven sires and improved genetic merit of young bulls entering AI studs contribute to this genetic improvement. Various national production and marketing alternatives were examined. Selection is a major breeding tool in establishing a breeding program to meet national production requirements for milk and milk products once the selection goal is defined. AI and young sire sampling programs will continue to be the primary vehicle for genetic improvement through selection regardless of the selection goal. The current resources of milk-recorded cows bred AI is not being fully utilized to achieve maximum genetic progress possible from young sire sampling indicate that the number of young bulls sampled annually in the Holstein breed could be tripled with the existing milk-recorded and AI bred dairy cow population. Expanded milk recording and AI breeding levels could increase the potential for even further genetic improvement. The potential impact of selection for other traits, crossbreeding and the use of embryo transfer of future breeding programs is highlighted.

Bos indicus and Bos taurus crossbred dairy cattle in Australia. IV.* Progeny testing and expected rate of genetic improvement

1976 ◽  
Vol 27 (2) ◽  
pp. 309 ◽  
Author(s):  
IR Franklin ◽  
RH Hayman ◽  
RO Hewetson
Keyword(s):  
Dairy Cattle ◽  
Heat Tolerance ◽  
Genetic Improvement ◽  
Bos Taurus ◽  
Bos Indicus ◽  
Progeny Testing ◽  
Dairy Farmers ◽  
Improvement Program ◽  
Tropical Environments ◽  
Tick Resistance

A dairy improvement program designed to develop a breed of cattle adapted to tropical environments is described. Each year young crossbred (Bos indicus x Bos taurus) bulls are screened for heat tolerance and tick resistance, and then progeny-tested in the herds of cooperating dairy farmers. Estimates of phenotypic and genetic means, variances and correlations are presented for production of milk and milk components, and the rate of genetic improvement is discussed. In particular the heritability of milk yield in the crossbred progeny is 0.27, and the theoretical rate of improvement is 2.6% per year. ____________________ *Part III, Aust. J. Agric. Res., 25: 1023 (1974).

The use of loci associated with quantitative effects in dairy cattle improvement

1978 ◽  
Vol 27 (2) ◽  
pp. 133-139 ◽  
Author(s):  
M. Soller
Keyword(s):  
Dairy Cattle ◽  
Genetic Improvement ◽  
Significant Contribution ◽  
Breeding Value ◽  
Genetic Progress ◽  
Young Males ◽  
Genetic Components ◽  
Minor Contribution ◽  
A Minor ◽  
Selection Of

ABSTRACTThe use in dairy cattle improvement of loci associated with quantitative effects that might be found by genetic analysis is discussed. These methods can make a significant contribution only if they result in the identification of quantitative loci whose inheritance can be followed in a simple Mendelian manner. Another possibility, the identification of genetic components of production having a higher heritability than overall production, would make only a minor contribution to increased genetic progress. Selection of young males, according to the estimated breeding value associated by linkage with particular marker alleles in their sire, will not make a detectable contribution to genetic improvement.

Dairy genetic improvement through artificial insemination, performance recording and genetic evaluation

2003 ◽  
Vol 83 (3) ◽  
pp. 385-392 ◽  
Author(s):  
B. J. Van Doormaal ◽  
G. J. Kistemaker
Keyword(s):  
Dairy Cattle ◽  
Artificial Insemination ◽  
Genetic Improvement ◽  
Genetic Evaluation ◽  
Production Traits ◽  
Genetic Progress ◽  
Genetic Gains ◽  
Holstein Breed ◽  
The Past ◽  
Genetic Evaluations

Artificial insemination (AI) of dairy cattle in Canada was started more than half a century ago and today it is estimated that at least 75% of all dairy cattle nationally are bred using this common reproductive technology. A Best Linear Unbiased Prediction sire model for estimating genetic evaluations for production traits was introduced in 1975. The combination of extensive use of AI with genetic evaluations for bulls and cows has resulted in significant phenotypic and genetic gains over the past 20 yr. In the Holstein breed, mature equivalent yields have increased by an average of 200 kg milk, 7.0 kg fat and 6.3 kg protein per year since 1980. Genetically, the relative emphasis realized for production traits versus overall type during the past 5 yr has followed the 60:40 breeding goal represented in the Lifetime Profit Index, which has increased at an average rate of 0.28 standard units per year. Examination of the generation interval in the Canadian Holstein breed, associated with each of the four pathways for genetic improvement, indicates a 46% increase in the rate of annual genetic gain today compared to 20 yr ago. The increased accuracy and intensity of selection associated with the use of AI and genetic evaluations have also contributed to the rates of phenotypic and genetic progress achieved over the years. In the future , AI will continue to be a critical component of the genetic gains possible in dairy cattle breeding but it will be complemented by other reproductive technologies aimed at further reducing generation intervals and increasing the accuracy and selection of intensity, especially on the female side. Key words: Dairy cattle, artificial insemination, genetic progress, genetic evaluation

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