JDS (none)
HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
 QUICK SEARCH:   [advanced]
Author:
Keyword(s):
Year:  Vol:  Page: 


This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Interpretive Summary
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 Alert me to new issues of the journal
Right arrow Download to citation manager
Google Scholar
Right arrow Articles by Bohmanova, J.
Right arrow Articles by Cole, J. B.
PubMed
Right arrow Articles by Bohmanova, J.
Right arrow Articles by Cole, J. B.
J. Dairy Sci. 90:1947-1956
American Dairy Science Association, 2007.

Temperature-Humidity Indices as Indicators of Milk Production Losses due to Heat Stress

J. Bohmanova*,1,2, I. Misztal* and J. B. Cole{dagger}

* Department of Animal and Dairy Science, University of Georgia, Athens 30602
{dagger} Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705

1 Corresponding author: jbohmano{at}uoguelph.ca

Meteorological data (1993 to 2004) from 2 public weather stations in Phoenix, Arizona, and Athens, Georgia, were analyzed with test day milk yield data from herds near weather stations to identify the most appropriate temperature-humidity index (THI) to measure losses in milk production due to heat stress in the semiarid climate of Arizona and the humid climate of Georgia. Seven THI with different weightings of dry bulb temperature and humidity were compared. Test-day data were analyzed using 2 models to determine threshold of heat stress and rate of decline of milk production associated with a specific THI. Differences in thresholds of heat stress were found among indices and between regions. Indices with higher weights on humidity were best in the humid climate, whereas indices with larger weights on temperature were the best indicators of heat stress in the semiarid climate. Humidity was the limiting factor of heat stress in humid climates, whereas dry bulb temperature was the limiting factor of heat stress in dry climates.

Key Words: temperature-humidity index heat stress milk loss







HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS
Copyright 2007 by the American Dairy Science Association.