Elsevier

Journal of Dairy Science

Volume 87, Issue 11, November 2004, Pages 3953-3957
Journal of Dairy Science

Article
Infrequent Milk Progesterone Measurements in Daughters Enable Bull Selection for Cow Fertility*

https://doi.org/10.3168/jds.S0022-0302(04)73535-3Get rights and content
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Abstract

The interval from calving to first luteal activity (CLA) has been suggested as an unbiased and, therefore, preferable measure for selection on female fertility in dairy cattle. However, measurement of this interval for individual cows is not feasible for reasons of cost and labor associated with the necessary frequent (milk) progesterone measurements. The objective of this study was to test the hypothesis that mean sire progesterone profiles based on individual progesterone measurements of daughters at 3- to 6-wk intervals have prospects as a measure for female fertility when selecting sires in a progeny testing scheme. In this study, progesterone concentrations were measured in milk samples collected at routinely performed milk recordings during the first 100 d of lactation of daughters of 20 test bulls. It is demonstrated that a) mean progesterone profiles can be used to calculate the earliest stage of lactation at which at least 50% of the daughters of a test bull has a milk progesterone level >3 ng/mL (indicating luteal activity) and that b) this stage, at which 50% of the daughters of a bull have an active corpus luteum (CLA50%), varies largely between test bulls. We conclude that selecting sires based on daughter CLA50% may improve female fertility.

Key words

bull selection
cow fertility
milk progesterone
first luteal activity

Abbreviations key

CLA
interval from calving to first luteal activity
CLA50%
lactation stage at which 50% of the daughters of a bull have an active corpus luteum
NR56
nonreturn rate at 56 d after insemination

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*

This study was financed by Holland Genetics, partly through a grant of the Dutch Ministry of Economic Affairs, Project BTS 98194.

Current address: Division Animal Resources Development, Animal Sciences Group, Wageningen University and Research Center, 8200 AB Lelystad, The Netherlands.

Current address: NRS B. V., P.O. Box 454, 6800 AL Arnhem, The Netherlands.