A.S. Series 67-33
Although the role of the boar in achieving a high conception rate among sows in a herd has long been recognized, the sow has gene rally been considered to be solely responsible for litter size. Litter size is determined by (l) the number of eggs ovulated, (2) the quality of eggs ovulated as evidenced by the ability of the eggs to be fertilized and develop into normal embryos, (3) the ability of the uterus to provide the proper environment for implantation and the development of normal embryos during pregnancy and (4) the number and quality of sperm received by the female at mating as evidenced by the ability of the sperm to fertilize the eggs and insure normal development of the embryo. The factors which determine litter size may be affected by nutrition, age of animals, temperature, light, hormone balance, disease and various other stresses on the animal. This study was made to determine if differences in fertility level exist among boars and to determine whether these differences, if they exist, can affect litter size.
Number of Pages
Agricultural Experiment Station, South Dakota State University
Shelby, D.R., "Influence of the Boar on Litter Size" (1967). South Dakota Swine Field Day Proceedings and Research Reports, 1967. 10.