Document Type

Thesis - Open Access

Award Date


Degree Name

Master of Science (MS)

Department / School

Animal Science

First Advisor

A. Lowell Slyter


Synchronization of estrus has been attempted by using hormone or hormone-like substances to bring females into estrus simultaneously. The objective of a synchronization program is to manipulate the reproductive process so that all females may be bred during a short pre-defined interval with normal fertility at this breeding. The concept of estrus control and synchronization is intriguing, offering the possibility of more uniform offspring, better use of facilities and labor, concentration of parturition and, in particular, the better utilization of outstanding sires through artificial insemination. The breeding season is the period during which ewes come into heat and will receive the ram. The length of the breeding season varies with the breed of sheep. Some breeds of sheep mate only during a short period in the fall and not any other time of year. Others may come into heat more or less throughout the year at 16- to 17-day intervals but usually miss one or more heat cycles in the spring. During the normal breeding season, ewes come into heat on different days, conceive on different days and, consequently, the lambing period is quite lengthy, with some lambs being dropped almost daily during the entire period. This study was centered around the relative merits of prostaglandin for estrous synchronization of sheep. This review will examine some of the techniques and problems associated with controlling estrus using various regimes of hormones and methods of administration.

Library of Congress Subject Headings

Sheep -- Breeding
Ewes -- Breeding



Number of Pages



South Dakota State University