HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Ingraham, R. H. Articles by Wagner, W. C. Search for Related Content PubMed PubMed Citation Articles by Ingraham, R. H. Articles by Wagner, W. C.

Relationship of Temperature and Humidity to Conception Rate of Holstein Cows in Hawaii¹

School of Veterinary Medicine, Louisiana State University, Baton Rouge 70803
Department of Animal Science, University of Hawaii, Honolulu 96822
College of Veterinary Medicine, Iowa State University, Ames 50010

ABSTRACT

Weather data and breeding records for a Holstein herd of 1300 cows in Hawaii were evaluated to determine effects of climate on reproductive performance. The dairy is in a coastal climate near latitude 21°N. Average maximum temperature, relative humidity, and resulting temperature-humidity index for the warmest month of the year were 31 C, 44%, and 79. Average minimum temperature and attending values for the same period were 20 C, 96%, and 68. From late April to November, conception rates were correlated negatively with the average temperature-humidity index of each day of the estrous cycle beginning 11 days prior to breeding. Slopes of regression lines differed, suggesting varying sensitivity of conception rate to heat stress on different days of the cycle. The temperature-humidity index of the 2nd day prior to breeding was most closely correlated with conception rate. Conception rates declined from 66% to 35% as the index increased from 68 to 78. Only the temperature-humidity index of the 2nd day prior to breeding had a significant partial correlation coefficient when the index of the 2nd and 1st day prior to breeding, the day of breeding, and the day followin breeding were each evaluated with the index of the others held constant.

¹ Journal Series No. 1941 of the Hawaii Agricultural Experiment Station. Supported by Hawaii under Project 230 in the Department of Animal Sciences and the General Research Support Grant FR-05565 from the National Institute of Health to the College of Veterinary Medicine at Iowa State University.

This article has been cited by other articles:

				J. M. Morton, W. P. Tranter, D. G. Mayer, and N. N. Jonsson Effects of Environmental Heat on Conception Rates in Lactating Dairy Cows: Critical Periods of Exposure J Dairy Sci, May 1, 2007; 90(5): 2271 - 2278. [Abstract] [Full Text] [PDF]

				M. Speroni, G. Pirlo, and S. Lolli Effect of Automatic Milking Systems on Milk Yield in a Hot Environment J Dairy Sci, December 1, 2006; 89(12): 4687 - 4693. [Abstract] [Full Text] [PDF]