United States Department of Agriculture: Agricultural Research Service, Lincoln, Nebraska
United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications
Accessibility Remediation
If you are unable to use this item in its current form due to accessibility barriers, you may request remediation through our remediation request form.
Document Type
Article
Date of this Version
1979
Abstract
Exposure of rams during the nonbreeding season (anestrous period) to short daylengths will initiate a new sexual cycle characterized by testicular growth, increased mating activity and improved semen quality. Lambing results accumulated from 300 potential matings indicate that rams exposed to artificial photoperiods of 8 hr light and 16 hr darkness for 10 weeks (referred to as rams on short-days) are more fertile than control rams maintained under the relatively long days of spring. When five control rams were penned individually with 30 ewes synchronized with progestogen and PMSG, 67% of the ewes were mated. Eighty-nine percent of the ewes were mated with rams on short-days. Expressed as a percentage of the total ewes exposed per ram, 32% lambed from control matings; whereas, 67% lambed following exposure to rams on short-days. Combined with a higher number of lambs born per ewe lambing, rams on short-days sired 2.5 times more lambs than did control rams. Results of this study show that the ram contributes significantly to the fertility of single-sire matings and that lamb production can be increased substantially by experimental manipulation of photoperiod. Exposure of both rams and ewes to artificial photoperiods may be a useful management tool to distribute the lamb crop to predetermined, specified times of the year.
Comments
Published in Journal of Animal Science (1979) 49:4, 927-932