Genetic evaluation of Iranian Holstein dairy cows with the use of a Covariance Function Model

2002 ◽  
Vol 2002 ◽  
pp. 189-189
Author(s):  
H. Farhangfar ◽  
P. Rowlinson ◽  
M.B. Willis
Keyword(s):  
Animal Model ◽  
Dairy Cattle ◽  
Covariance Function ◽  
Genetic Evaluation ◽  
Cattle Breeding ◽  
Factors Influencing ◽  
Lactation Curve ◽  
Function Test ◽  
Dairy Cattle Breeding ◽  
Breeding Programmes

The use of test day models has increasingly become of interest in genetic evaluation of dairy cattle. Traditionally, in most dairy cattle breeding programmes genetic evaluation of dairy sires and cows has been primarily based on using 305-day lactation yield. Since in this system of evaluation many incomplete lactation records have to be extended to complete lactations this could result in biased prediction of breeding values due to any over or underestimation of total lactation yields. In genetic evaluation of dairy cattle, test day models have many advantages over the traditional method (Lactation Animal Model) because of the fact that they can account for the lactation curve of individual cows and take more accurate account of the effects of environmental factors influencing test day milk yield over the course of lactation. The main aim of this study was to use a Covariance Function Test day Animal Model (CFTAM) in genetic evaluation of first parity Iranian Holsteins.

scholarly journals Wechselwirkung zwischen Vater und Mutter in der Milchrinderzüchtung

1999 ◽  
Vol 42 (6) ◽  
pp. 527-534
Author(s):  
W. Brade ◽  
E. Groeneveld
Keyword(s):  
Animal Model ◽  
Dairy Cattle ◽  
Genetic Evaluation ◽  
Cattle Breeding ◽  
Additional Information ◽  
Dairy Cattle Breeding ◽  
Interaction Component

Abstract. Title of the paper: Interaction between sire and dam in dairy cattle breeding The traditional animal model in genetic evaluation has been extended by a sire * dam interaction component demonstrating the computational feasibility. The expected additional information response from including a sire * dam component is small, however, this effect come larger with an increase in the number of animals produced by biotechnical means which will likely get special treatments.

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
Keyword(s):  
Dairy Cattle ◽  
Reproductive Technologies ◽  
Production Traits ◽  
Rapid Improvement ◽  
Cattle Breeding ◽  
Evaluation Procedures ◽  
Selection Decisions ◽  
Dairy Cattle Breeding ◽  
Breeding Programmes ◽  
Selection Intensities

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.

Policy of selecting bulls to breed bulls

1987 ◽  
Vol 44 (1) ◽  
pp. 29-38 ◽  
Author(s):  
M. E. Goddard
Keyword(s):  
Dairy Cattle ◽  
Genetic Variance ◽  
Selection Response ◽  
Progeny Testing ◽  
Cattle Breeding ◽  
Sire Evaluation ◽  
Dairy Cattle Breeding ◽  
Breeding Programmes ◽  
Computer Simulation Program ◽  
Selection Of

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.

scholarly journals Relevance of genomic evaluation for egg quality traits in layers

2019 ◽  
Author(s):  
David Picard Druet ◽  
Amandine Varenne ◽  
Florian Herry ◽  
Frédéric Hérault ◽  
Sophie Allais ◽  
...  
Keyword(s):  
Dairy Cattle ◽  
Genomic Selection ◽  
Egg Quality ◽  
Pure Line ◽  
Genetic Evaluation ◽  
Evaluation Methodology ◽  
Quality Traits ◽  
Genomic Evaluation ◽  
Cattle Breeding ◽  
Dairy Cattle Breeding

AbstractBackgroundGenomic evaluation, based on thousands of genetic markers, has become the standard evaluation methodology in dairy cattle breeding programs over the past few years. Despite the many differences between dairy cattle breeding and poultry breeding, genomic selection seems very promising for the avian sector, and studies are currently being conducted to optimize avian selection schemes. In this optimization perspective, one of the key parameters is to properly predict the accuracy of genomic evaluation in pure line layers.MethodsBoth genetic evaluation and genomic evaluation were performed on three candidate populations (male and female), using different sizes of phenotypic records on five egg quality traits and at two different ages. The methodologies used were BLUP & ssGBLUP, and variance-covariance matrices were estimated through REML. To estimate evaluation accuracy, the LR method was implemented. Four statistics were used to assess the relative accuracy of the estimated breeding values of candidates, their bias and dispersion, as well as the differences between genetic evaluation and genomic evaluation.ResultsIt was observed that genomic evaluation, whether performed on males or females, always proved more accurate than genetic evaluation. The gain was higher when phenotypic information was narrowed and an augmentation of the size of the reference population led to an increase in accuracy prediction, for what regards genomic evaluation. By taking into account the increase of selection intensity and the decrease of the generation interval induced by genomic selection, the expected annual genetic gain would be higher with ancestry-based genomic evaluation of male candidates than with genetic evaluation based on collaterals. This advantage of genomic selection over genetic selection requires to be studied in more details for female candidates.ConclusionsIn conclusion, in the population studied, genomic evaluation for egg quality traits of breeding birds at birth seems a promising strategy, at least for what regards males selection.

The Progeny Test as a Method of Evaluating the Dairy Sire.

1932 ◽  
Vol 22 (4) ◽  
pp. 811-837 ◽  
Author(s):  
Joseph Edwards
Keyword(s):  
Dairy Cattle ◽  
Milk Yield ◽  
Progeny Test ◽  
Cattle Breeding ◽  
Physiological Factors ◽  
Factors Influencing ◽  
Accurate Indication ◽  
Dairy Cattle Breeding ◽  
Minimum Number ◽  
Dairy Sire

A survey of some environmental and physiological factors influencing milk yield and an analysis of theories of and experiments on milk and butterfat inheritance have been made.Further evidence is given of the fact that the proved dairy sire is the outstanding medium through which improvement in dairy cattle breeding may be effected. The need of (1) prolonging the breeding life of such an animal and (2) evolving a scheme for the regular progeny-recording of all dairy sires is emphasised.The minimum number of unselected daughters necessary to give a reasonably accurate indication of their sire's transmitting ability is six.

Genetic correlations between 305-day and monthly test day milk yield records in primiparous Iranian Holsteins

2001 ◽  
Vol 2001 ◽  
pp. 219-219
Author(s):  
H. Farhangfar ◽  
P. Rowlinson ◽  
M.B. Willis
Keyword(s):  
Dairy Cattle ◽  
Genetic Gain ◽  
Genetic Correlations ◽  
Cattle Breeding ◽  
Breeding Values ◽  
Dairy Heifers ◽  
The Past ◽  
Dairy Cattle Breeding ◽  
Adjustment Factors ◽  
Breeding Programmes

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.

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