A. H. Mimeo Series 63-02
The idea of controlling the heat period of female farm animals is not new, but intensive research in this area had not started until just a few years ago. As interest in artificial insemination increased, the desirability of controlling (synchronizing) the estrous cycle of swine became evident. It was soon discovered that boar sperms could not be frozen and still retain their fertilizing capacity in a similar manner as used for dairy cattle or beef cattle sperm. While research in this country on freezing boar spermatozoa is making progress and scientists are optimistic there has been no major breakthrough in keeping the sperm viable beyond two to four days after collection. Controlling the estrous cycle would greatly enhance the artificial insemination program, especially if fresh semen must be used. Knowledge of the time of heat would permit the scheduling of semen collection, delivery of the semen to the farm, and insemination of the gilts. Several sows and gilts could be bred on one day by the technician rather than one or two animals at a time which would require several trips to breed the herd.
Number of Pages
Agricultural Experiment Station and Extension Service, South Dakota State College
Seerley, R.W.; Fritschen, R.D.; and Ray, D.E., "Estrus Synchronization in Gilts" (1963). South Dakota Swine Field Day Proceedings and Research Reports, 1963-01. 3.