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Selection indexes using calving interval, condition score and milk yield in dairy cattle

Published online by Cambridge University Press:  20 November 2017

J.E. Pryce
Affiliation:
Animal Breeding and Genetics, Scottish Agricultural College, West Mains Road, Edinburgh, EH9 3JG, UK
M.P. Coffey
Affiliation:
Animal Breeding and Genetics, Scottish Agricultural College, West Mains Road, Edinburgh, EH9 3JG, UK
S.H. Brotherstone
Affiliation:
Institute of Cell, Animal and Population Biology, University of Edinburgh, West Mains Rd, Edinburgh, EH9 3JT, UK
J.A. Woolliams
Affiliation:
Roslin Institute, Roslin, Midlothian, EH25 9PS, U.K.
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Extract

Increasing genetic merit for production has been associated with a decline in dairy cow fertility. In order to sustain lactation it appears that appreciable amounts of body condition are being mobilised, which may impinge on fertility. Body condition score (BCS) of first lactation heifers is recorded by Holstein UK and Ireland (HUKI) as part of its national type classification scheme. BCS may be a useful selection criterion for improving fertility. Calving dates and hence calving interval (CI) are generally very reliably recorded, but the usefulness of CI as a selection criterion is hampered for a number of reasons, one being that only the most fertile cows have two consecutive calving dates. This is a serious issue that still needs to be addressed. Our aim here was to investigate if there is genetic covariation between BCS and CI after adjustment for milk yield and to investigate selection responses in all three traits when selection is for each trait in turn and how responses are affected by restrictions imposing no genetic change in one of the traits. Restricting a trait to no change when it is correlated to a trait under selection may be important in developing customised indexes to satisfy specific requirements.

Type
Threatre Presentations
Copyright
Copyright © The British Society of Animal Science 2001

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References

Cameron, N.D. 1997. Selection indices and prediction of genetic merit in animal breeding. CAB international, Wallingford.Google Scholar
Pryce, J.E. Coffey, M.P. and Brotherstone, S. 2000. The genetic relationship between calving interval, body condition score and linear type and management traits in registered Holsteins. Journal of Dairy Science 83: 26642671 Google Scholar