JDS
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
QUICK SEARCH:   [advanced]


     

Journal of Dairy Science Vol. 85 No. 6 1586-1589
© 2002 by American Dairy Science Association ®
This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Ravagnolo, O.
Right arrow Articles by Misztal, I.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Ravagnolo, O.
Right arrow Articles by Misztal, I.

Studies on Genetics of Heat Tolerance in Dairy Cattle with Reduced Weather Information via Cluster Analysis

O. Ravagnolo 1 and I. Misztal 1

1 Department of Animal and Dairy Science, University of Georgia, Athens 30602

The objective of this study was to explore the possibility of reducing the number of weather stations for studies on genetics of heat tolerance in dairy cattle. The similarity of information from 21 Georgia weather stations was analyzed by cluster analysis. Two major clusters have been found, separating Georgia along the NE and SW line. One weather station was selected for each of the clusters based on the minimal distance to all the remaining weather stations and on completeness of the weather information. The production dataset consisted of 114,751 first-parity test-day records for milk on 14,297 Holsteins from 120 herds in Georgia. Analyses using a model for daily milk yield with temperature-humidity index classes and several other fixed effects showed no increase in error sum of squares when using only two weather stations. The threshold of heat stress was different for each of the two regions but the rate of decline after the threshold was similar. After accounting for different thresholds, the genetic component of heat tolerance for milk was higher with the two-station model. Genetic studies on or evaluation for heat tolerance based on information from a few carefully selected weather stations can be as accurate as those based on information from numerous such stations.

Key Words: heat stress • dairy • random regressions

Submitted on September 4, 2001
Accepted on January 9, 2002




This article has been cited by other articles:


Home page
 J DAIRY SCIHome page
J. Bohmanova, I. Misztal, and J. B. Cole
Temperature-Humidity Indices as Indicators of Milk Production Losses due to Heat Stress
J Dairy Sci, April 1, 2007; 90(4): 1947 - 1956.
[Abstract] [Full Text] [PDF]

Home page
 J DAIRY SCIHome page
R. J. Collier, G. E. Dahl, and M. J. VanBaale
Major advances associated with environmental effects on dairy cattle.
J Dairy Sci, April 1, 2006; 89(4): 1244 - 1253.
[Abstract] [Full Text] [PDF]


HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright © 2002 by the American Dairy Science Association ®.