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 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 Hall, J. G. Articles by Stone, E. J. Search for Related Content PubMed Articles by Hall, J. G. Articles by Stone, E. J.

Estrus, Estrous Cycles, Ovulation Time, Time of Service, and Fertility of Dairy Cattle in Louisiana¹

Dairy Department, Louisiana State University, Baton Rouge

ABSTRACT

The mean duration of estrus for 1,460 estrous periods for 270 cows and heifers was 11.9 hr., with heifers having significantly longer estrous periods than parous cows. Nonstanding estrus was observed in 10.1% of the estrous periods. Estrus after conception was exhibited by 14.4% of the animals and involved 3.4% of the estrous periods. Ovulation occurred 12.4 hr. after the end of estrus. Optimum time for insemination was 7–12 hr. after the onset of estrus. Anestrus occurred one or more times in 33.4% of the animals, representing 10.6% of the expected estrous periods. It was calculated that anestrus would have increased 19.9% with only 0600 and 1800 hr. observations; whereas, an additional check at 1,200 hr. increased the incidence only 10.0% above that which occurred during 6-hr. observational periods. Monthly PBI levels were inversely related to environmental temperature and humidity.

¹ Data in part taken from a thesis submitted by the senior author to the Graduate School of the Louisiana State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy.

² Present address: Louisiana Artificial Breeding Coop., Inc., Baton Rouge, Louisiana.

This article has been cited by other articles:

				R. Sartori, R. Sartor-Bergfelt, S. A. Mertens, J. N. Guenther, J. J. Parrish, and M. C. Wiltbank Fertilization and Early Embryonic Development in Heifers and Lactating Cows in Summer and Lactating and Dry Cows in Winter J Dairy Sci, November 1, 2002; 85(11): 2803 - 2812. [Abstract] [Full Text] [PDF]