Genetic Component of Heat Stress in Dairy Cattle, Parameter Estimation
Top Cited Papers
Open Access
- 1 September 2000
- journal article
- Published by American Dairy Science Association in Journal of Dairy Science
- Vol. 83 (9), 2126-2130
- https://doi.org/10.3168/jds.s0022-0302(00)75095-8
Abstract
Our data included 119,205 first-parity, test-day records from 15,002 Holsteins in 134 Georgia farms with temperature and humidity data from 21 weather stations throughout Georgia. The test-day model included the effects of herd test date, days-in-milk (DIM) classes, age, milking frequency, general additive effect, random regression on the heat-humidity index for heat-tolerance additive effect, general permanent environment, and the random regression on the heat-humidity index for a permanent environment. The general effects, which corresponded to effects in the current repeatability models, were assumed to be correlated with the heat-tolerance effects. Variance components were estimated by REML. For heat-humidity indices below 72, heritability for milk was 0.17, and additive variance of heat tolerance was 0. For a heat-humidity index of 86 (which would correspond to temperatures of 36 degrees C at 50% humidity), the additive variance of heat tolerance was as high as for general effect, and the genetic correlation between the two effects was -0.36. Results for fat and protein were similar. Current selection for production reduces heat tolerance. Joint selection for heat tolerance and production is possible.Keywords
This publication has 7 references indexed in Scilit:
- Genetic Component of Heat Stress in Dairy Cattle, Development of Heat Index FunctionJournal of Dairy Science, 2000
- Economic Viability of Crosses of Bos taurus and Bos indicus for Dairying in Warm ClimatesJournal of Dairy Science, 1996
- Estimation of Genetic Parameters for Test Day Records of Somatic Cell ScoreJournal of Dairy Science, 1995
- Use of test day yields for genetic evaluation of dairy sires and cowsLivestock Production Science, 1993
- Heat Stress as it Affects Animal ProductionJournal of Animal Science, 1981
- Improving Tropical Beef Cattle by Simultaneous Selection for Weight and Heat Tolerance. Heritabilities and Correlations of the Traits1Journal of Animal Science, 1973
- Heritability of Heat Tolerance in Dairy CattleJournal of Dairy Science, 1947