| Popis: |
The studies included in this thesis evaluated the use of hormonal control of ovulation and different catheter designs to attempt to improve reproductive efficiency as well as examine the factors which affect weaning weights. The first study explored combining a fixed-time insemination protocol with a novel insemination catheter, however, this combination resulted in a reduction in farrowing rate and litter size when a lower dose of sperm was used. Manipulating the time of breeding does result in reducing the variability of when a group of sows farrow and can be used to ensure weaning ages of a group of pigs is uniform. The second study examined factors affecting weaning weights and found that in addition to age at weaning other factors that influenced weaning weight included; birth weight, sex, fostering and litter characteristics such as total born, stillbirths, and mortality. This research was funded in part by Ontario Pork and the Ontario Ministry of Agriculture, Food and Rural Affairs - University of Guelph Research Partnership, Genes Diffusion, and Eastgen. The semen, foam-tipped and Gedis catheters were supplied by Ontario Swine Improvement (OSI). |
