Discipline: Veterinary Medicine
This study was conducted to determine the physiological effect of zinc methiotine supplementation of feeds on the reproductive performance of boars, with emphasis on the boar's semen quality. The experiment involved 20 boars (10 Landrace boars and 10 boars of another breed or cross), from 2 to 4 years of age. An initial collection and evaluation for semen quality was obtained from a ll boar s. Each boar was randomly distributed into two groups; those fed boar rations supplemented with zinc methionine and the control. Semen was collected from each boar every four days for five months. The collected semen samples were evaluated for total semen volume, sperm concentration, sperm motility, and the total doses produced. After the second month of zinc methionine supplementation semen samples from five out often boars from each group were randomly selected for AI. These were used in inseminating an average of ten sows per boar. The Farrowing Rate, Total Litter Size Litter Size Born Alive as well as the percent stillbirths and mummified fetuses of the inseminated sows were then evaluated. Zinc methionine supplemented boars had consistently higher sperm concentration and volume throughout the five-month study. Significant differences in boar semen density, total sperm per ejaculate and the total number of doses produced were found after the second month of supplementation. Differences in semen volume were found significant on the fifth month of the study. Zinc methionine supplementation did not affect farrowing rates, though sows inseminated with semen from zinc-supplemented boars had significantly higher litter size born alive.