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Estimation of phenotypic and genetic correlations between production traits and herd life in Iranian Holstein Heifers

Published online by Cambridge University Press:  20 November 2017

H. Rezaee
Affiliation:
Department of Animal Science, Birjand University, Birjand, Iran
A.A. Shadparvar
Affiliation:
Department of Animal Science, Guilan University, Rasht, Iran
H. Farhangfar
Affiliation:
Department of Animal Science, Birjand University, Birjand, Iran
P. Rowlinson
Affiliation:
Animal Science Department, University of Newcastle upon Tyne, Newcastle upon Tyne, UK
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Extract

In practical dairy cattle breeding programmes many traits of major economic importance such as milk yield, type and herd life (longevity) are usually included in genetic evaluation systems. Herd life, as a complex trait associated with longevity of animals, has been long considered to be related to profitability of dairy herds due to increase the proportion of more mature, higher yielding cows in the herds, increase the opportunity for voluntary culling, reduce replacement costs and increase the proportion of farm resources used for the milking herd rather than for replacements (Brotherstone et al., 1998). In fact, as pointed out by Burnside et al. (1984), lifetime profitability is affected by many factors such as production per lactation, length of productive life, age at first calving, calving interval as well as input and output prices. The main aim of the present study is to estimate phenotypic and genetic correlations between production traits (milk yield and fat percentage) and herd life (defined as the interval between first calving and culling dates) in Iranian Holstein heifers.

Type
Poster Presentations
Copyright
Copyright © The British Society of Animal Science 2004

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References

Brotherstone, S., Veerkamp, R.F. and Hill, W.G. 1998. Predicting breeding values for herd life of Holstein-Friesian dairy cattle from lifespan and type. Animal Science 67, 405411.Google Scholar
Burnside, E.B., McClintock, A.E. and Hammond, K. 1984. Type, production and longevity in dairy cattle: A review. Animal Breeding Abstracts 52, 711719.Google Scholar
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