Genetic Correlation Between Days Until Start of Luteal Activity and Milk Yield, Energy Balance, and Live Weights
| Autor: | J.K. Oldenbroek, Roel F. Veerkamp, J. H. J. van der Werf, H. J. Van Der Gaast |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Genetic correlation
medicine.medical_specialty Time Factors Energy balance Ice calving Biology Eating Animal science Corpus Luteum Internal medicine Lactation Live weight Genetics medicine Animals Dry matter Instituut voor Dierhouderij en Diergezondheid Dairy cattle ID-Lelystad Body Weight food and beverages Heritability Milk Proteins Lipids ID Lelystad Milk Fertility medicine.anatomical_structure Endocrinology ID-Lelystad Instituut voor Dierhouderij en Diergezondheid ID Lelystad Institute for Animal Science and Health Cattle Female Animal Science and Zoology medicine.symptom Energy Metabolism Weight gain Institute for Animal Science and Health Food Science |
| Zdroj: | Journal of Dairy Science, 83(3), 577-583 Journal of Dairy Science 83 (2000) 3 |
| ISSN: | 0022-0302 |
| DOI: | 10.3168/jds.s0022-0302(00)74917-4 |
| Popis: | The objective of this study was to estimate genetic correlations among fertility and measures of energy balance, dry matter intake, and live weight (change). Data from 622 first lactation cows (fed ad libitum a complete ration) included milk, fat, and protein yields; energy balance; and live weights for the first 15 wk of lactation. For a subset of the heifers (n = 329) and 91 contemporaries, progesterone values were measured in the milk twice a week and were used to determine the interval between calving and first luteal activity (CLA). To obtain correlations, a series of bivariate animal model analyses was performed. The heritabilities for CLA and energy balance were 0.16 and 0.33, respectively. Heritability for live weights were 0.48 to 0.61 and for live weight changes were 0.17 and 0.24. Genetic correlations of CLA with milk, fat, and protein yields were high and unfavorable (0.51, 0.65, and 0.48, respectively), whereas energy balance, live weight during lactation, and weight gain all had a favorable genetic correlation with CLA (range -0.40 to -0.80). When genetic variation in CLA was adjusted genetically for milk, fat, and protein yields, the correlation with feed intake became -0.49 and explained approximately half of the genetic variance in CLA. This supports that increasing genetic merit for feed intake, at a common genetic merit for yield, improved CLA. Furthermore, selection on an index including protein yield and energy balance or live weight (change) allowed 0.71 to 0.80 of the maximum response in protein yield without a negative selection effect on CLA. |
| Databáze: | OpenAIRE |
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