Year: 2005
Type: article
Abstract: Heat stress is an important factor that has a substantial impact on production of dairy cattle in the United States. Estimated total annual economic losses to the dairy industry due to heat stress range from $897 to $1500 million (St-Pierre et al., 2003). Therefore selection for heat tolerance could be cost effective. However, a major obstacle is the availability of data for such selection on a national basis. A temperature-humidity index (THI) is a widely used indicator of external heat load caused by a combination of temperature and relative humidity. Ravagnolo and Misztal (2000) presented a methodology for genetic evaluation for heat tolerance based on data from weather stations. When that method was applied for milk yield of Holsteins in Georgia, the genetic correlation between a traditionally predicted transmitting ability (PTA) and a PTA for heat tolerance was about −0.4, and the variance of heat-tolerance PTA was large at high THI. The objective of this study was to apply genetic evaluation methodology at the national level and to identify bulls with genetic extremes for tolerance to heat stress.
Language: English
Subfield: Animal Science and Zoology
Domain: Life Sciences
SDG: Zero hunger
Open Access status: diamond
OpenAlex ID: W1560765486