Current and future developments in dairy cattle breeding: a research viewpoint

1995 ◽  
Vol 19 ◽  
pp. 1-7
Author(s):  
W. G. Hill ◽  
S. Brotherstone ◽  
P. M. Visscher

AbstractRates of genetic improvement in dairy cattle breeding programmes have increased substantially in the last decade, not only in Europe where there has been substantial immigration of North American stock. More accurate statistical evaluation procedures, including the use of best linear unbiased prediction (BLUP) with the animal model, have been introduced; higher selection intensities have been achieved, particularly on production traits, through better organized and focused schemes; and developments in multiple ovulation and embryo transfer (MOET) have been both a stimulus and to some extent a cause. Continued rapid improvement can be expected as research and development enables more accurate and timely use to be made of recording data, because there is evidence that heritability values for milk production are rising, perhaps because of better cow management, and as competition among breeders internationally increases. There are a number of consequent challenges to geneticists and breeders. Attention will have to be given to maintaining the fitness of very high producing animals by recording health, fertility, longevity and parlour traits, and using the results of research to give them appropriate weight in selection decisions. Developments in molecular methods and in reproductive technologies present new opportunities, but are unlikely to do more for some time than complement progress from conventional selection on the important production traits.

1987 ◽  
Vol 44 (1) ◽  
pp. 29-38 ◽  
Author(s):  
M. E. Goddard

ABSTRACTIn the breeding of dairy cattle the selection of bulls to breed young bulls for progeny testing is a crucial process. This paper compares several policies for making this selection based on the criteria-selection response, inbreeding depression, loss of genetic variance and variability of response. A number called the ‘effective number of new bulls to breed bulls selected each year’ (NBBe) is defined which is closely related to the last three of these criteria. Past studies of the design of dairy cattle breeding programmes have assumed that selection is within a group of bulls progeny tested in the same year (policy I). However, modern sire evaluation methods allow comparison of sires tested in different years. To evaluate the effect of selecting bulls to breed bulls from all available bulls (policy II) a computer simulation program was used. Policy II results in an increase in the response to selection but a substantial decrease in NBBe. When compared at the same NBBe, policy II results in a smaller selection response than policy I. A policy which allows the best bulls to be used for more than 1 year but which limits the maximum number of years for which they can be used, results in the best compromise. If bulls are to be used for several years there is little advantage to be gained from making more matings within each year to more high-rated bulls or to older, more reliably evaluated bulls.


2010 ◽  
Vol 39 (suppl spe) ◽  
pp. 247-255 ◽  
Author(s):  
Stephen Miller

Genomics will improve the efficiency of beef cattle genetic improvement programs through the incorporation of genomic predictions into traditional genetic evaluations. The global dairy cattle breeding industry has been changed considerably in the last year through the implementation of genomic selection. Now proven to work in dairy cattle breeding, the challenge remains for the beef industry to successfully implement this technology. The primary challenge in beef cattle is the required resource population that relates genomic profile to phenotypic performance, which is quite large and its establishment will require collaboration or a significant investment by any one enterprise. Another challenge in beef cattle is the requirement for genomic predictions to function across breeds, which will require denser marker panels. Opportunities to increase genetic progress include increased accuracy of selection, reduced generation interval, increased selection intensity and better utilization of limited recording capacity, such as individual feed intake, along with opportunities to genetically change novel traits. Implementation of a low density panel at the commercial level will allow informative decisions based on genetic potential at all levels of the production chain. This reduced panel will include predictive SNP based on fine QTL mapping efforts, combined with additional SNP to enable imputation of genotypes from a high density SNP panel, when combined with high density genotypes of key ancestors, such as sires. With electronic recording in cattle, a single genotyping event on each animal would provide information throughout the beef production chain, which will create the incentive for genetic change. Genomics will create new opportunities for reproductive technologies such as embryo transfer as elite females will be identified with increased accuracy. Potential changes to the structure of the breeding industry are discussed including changes to recording strategies and the development of novel beef products.


2001 ◽  
Vol 2001 ◽  
pp. 219-219
Author(s):  
H. Farhangfar ◽  
P. Rowlinson ◽  
M.B. Willis

Traditionally, in most dairy cattle breeding programmes genetic evaluation of dairy sires and cows has been primarily based on 305-day lactation yield. To provide 305-day lactation yields many partial lactations have to be extended by adjustment factors resulting in overestimation or underestimation of 305-day yields which in turn leads to biased prediction of breeding values. Over the past decade there has been a considerable interest in using monthly test day records instead of 305-day lactation yield to predict breeding values of dairy cattle as early as possible and also to increase genetic gain through reducing generation interval. The main objective of present research was to estimate the genetic correlations between 305-day and monthly test day milk yields in Iranian Holstein dairy heifers.


1994 ◽  
Vol 74 (2) ◽  
pp. 217-221
Author(s):  
A. J. Lee ◽  
A. J. McAllister ◽  
C. Y. Lin ◽  
T. R. Batra

Direct comparisons of industry Holsteins to project Holsteins and to crossbred C lines in the National Cooperative Dairy Cattle Breeding Project were made at Ottawa. The industry Holstein group was composed of the eight Holstein young bulls in AI units awaiting proof in 1984, which had the highest pedigree indexes for protein yield. They were mated to both Holstein and crossbred C line females at Ottawa. Project Holstein and C line bulls were mated to females of their respective lines. Matings within the crossbred C line resulted in greater calving ease and fewer retained placentae (P < 0.05) than matings of Holsteins to either Holstein or C line females. Crossbred C line cattle were smaller and produced less milk, fat and protein in the first 24 wk of first lactation than Holsteins. Project and industry Holstein progeny were equivalent in early first lactation, milk fat and protein yield, but progeny of industry bulls were larger at all ages. Selection for protein yield over 14 yr in a 300 milking cow population produced young bulls of comparable genetic merit for production traits to that of intensely pedigree selected industry bulls. Key words: Holstein, selection, crossbred, yield, heifer


2000 ◽  
Vol 2000 ◽  
pp. 109-109 ◽  
Author(s):  
H. Farhangfar ◽  
P. Rowlinson ◽  
M.B. Willis

In dairy cattle breeding programmes the knowledge of cow's lactation curve could be an effective tool to make selection decisions. In order to obtain an accurate shape of lactation curve a variety of mathematical models have been used in which parameters of production peak, inclining and declining phases of milk production over the course of lactation have been estimated by linear or non-linear techniques. The main purpose of this research was to compare four non-linear functions for the estimation of first lactation curve of Iranian Holstein dairy cows.


2016 ◽  
Vol 15 (3) ◽  
pp. 379-385
Author(s):  
Sara Azizian ◽  
Abdol Ahad Shadparvar ◽  
Navid Ghavi Hossein-Zadeh ◽  
Sahereh Joezy-Shekalgorabi

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