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 Google Scholar Google Scholar Articles by Hansel, W. Articles by Wagner, W. C. Search for Related Content PubMed Articles by Hansel, W. Articles by Wagner, W. C.

Luteal Inhibition in the Bovine as a Result of Oxytocin Injections, Uterine Dilatation, and Intrauterine Infusions of Seminal and Preputial Fluids¹

Department of Animal Husbandry and New York State Veterinary College, Cornell University, Ithaca, New York

ABSTRACT

Four experiments were conducted in which the effects of oxytocin injections, uterine dilatations, and uterine infusions of raw semen and sediment obtained by centrifuging seminal and preputial fluids on luteal development and estrous cycle length were studied. The following conclusions were drawn:

1. Oxytocin injections in heifers during Days 3–6 inclusive of the estrous cycle shorten the cycle length to 8–12 days.
   
2. Oxytocin injections during the first six days of the estrous cycle similarly shorten the cycle length in mature lactating cows, but much larger doses are required.
   
3. Milk production declines in mature lactating cows while they are being injected with large amounts of oxytocin, and returns to approximately normal levels when the injections are stopped.
   
4. Uterine dilatation during the first seven days of the cycle causes a large proportion of cows and heifers so treated to have shortened estrous cycles which are often 8–12 days in length.
   
5. Infusion of 2–5 ml. of raw semen, or the sediment obtained by centrifuging raw semen and preputial fluids into the uterus of heifers at estrus, causes a large proportion of them to return to estrus between the sixth and thirteenth days of the cycle.
   
6. All three of these treatments result in marked inhibition of the development of the corpus luteum. In some cases, cystic corpora lutea result; in others, the corpora lutea are simply quite small. Relatively few normal functional luteal cells are present in either case.
   
7. These results suggest that the uterus plays an important role in regulating estrous cycle length and luteal development in the bovine. This mechanism may be an important factor in determining whether or not an embryo survives during the critical first 30 days of pregnancy.
   

¹ Supported in part by funds provided by the regional project NE-41 entitled, Endocrine Factors Affecting Reproduction and Lactation in Dairy Cattle, a cooperative study by Agricultural Experiment Stations in the Northeastern Region and the Dairy Husbandry Research Branch, ARS, USDA.