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 Gwazdauskas, F. C. Articles by McGilliard, M. L. Search for Related Content PubMed PubMed Citation Articles by Gwazdauskas, F. C. Articles by McGilliard, M. L.

Environmental and Management Factors Affecting Estrous Activity in Dairy Cattle

Department of Dairy Science, College of Agriculture and Life Sciences, Virginia Agricultural Experiment Station, Virginia Polytechnic Institute and State University, Blacksburg 24061

ABSTRACT

One thousand periods of estrus of Holstein and Jersey cows and heifers of breeding age during 27 mo were used to evaluate environmental and management factors related to estrous behavior during twice-daily heat checks. Mounting activity at the first observation of estrus was influenced by sire within genetic selection group for milk yield, lactation number, primary housing location, time of day estrus first observed, and maximum temperature the day of estrus. Mean number of times an estrous cow was mounted increased from 6.0 mounts/h in the morning to 7.7 mounts/h in the evening. Barn-housed cattle had 8.7 mounts/h compared to 6.1 and 5.5 for dry-lot and pasture groups. Estrous activity was least for heifers and increased for older cows. Mounting activity increased with increasing maximum daily temperature to approximately 25°C. Only 17.7% of the cattle initially observed in estrus displayed mounting behavior at the 12-h heat check. Estrous activity at 12 h was affected by lactation number and genetic grouping. Daily milk production near estrus was associated with longer duration between heats but had no effect on conception. Lactation number and service number were related to fertility.

This article has been cited by other articles:

				R. Flores, M. L. Looper, D. L. Kreider, N. M. Post, and C. F. Rosenkrans Jr. Estrous behavior and initiation of estrous cycles in postpartum Brahman-influenced cows after treatment with progesterone and prostaglandin F2{alpha} J Anim Sci, July 1, 2006; 84(7): 1916 - 1925. [Abstract] [Full Text] [PDF]

				F. J. White, R. P. Wettemann, M. L. Looper, T. M. Prado, and G. L. Morgan Seasonal effects on estrous behavior and time of ovulation in nonlactating beef cows J Anim Sci, December 1, 2002; 80(12): 3053 - 3059. [Abstract] [Full Text] [PDF]