The effect of decreased light and injections of ergocryptine (trial 1) or feeding of melatonin (trial 2) during the normal summer anestrous season of the ewe was studied. Decreased light (8 hr light:16 hr dark) and feeding of melatonin was effective in increasing the number of ewes cycling and conceiving. Decreased lighting also increased the total weight of all lambs born per ewe lambing compared to ewes in natural daylight during summer months. Ergocryptine appeared to have no effect on the ewe other than depressed prolactin levels.
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South Dakota State University
Copyright © 1985 South Dakota State University
Luhman, Cindie and Slyter, A. L., "The Effect of Controlled Photoperiod, Ergocryptine, and/or Melatonin on Reproduction in the Anestrous Ewe" (1985). South Dakota Sheep Field Day Proceedings and Research Reports, 1985. 5.