The Libido and Semen Quality of Bali Bulls Supplemented with Micro-Nutrients of Zinc, Selenium, Vitamin A and Vitamin E

Abstract

Low quality and quantity of food intake of bulls in the tropics might adversely affect libido and semen quality through their effects on spermatogenesis process. The purpose of this study was to evaluate the effect of micro-minerals (Zn and Se) and vitamins (A and E) on the libido and semen quality of Bali bulls. 2 (two) Bali bulls, aged 4-5 years old with a body weight 300-350 kg. The study was divided into 2 periods and each period was conducted for 8 weeks. At the first period (control), the experimental bulls were fed with natural grasses and concentrates (1% of body weight). Furthermore, at the second period (treatment period), they were fed diet similar to that used in the first period with an additional of a mineral mix (Zn and Se) and vitamin (A and E). Evaluation of libido and semen quality were carried out simultaneously twice a week. Libido was measured by calculating the time required for the bulls from approaching the teaser until they mounted for the first time and from approaching until they ejaculated, respectively. Semen was collected by using an artificial vagina. The volume, colour, pH, and, viscosity, as were recorded. Evaluation of semen quality in the form of the sperm concentration, motility, viability and abnormality were done by using Computer Assisted Semen Analyser (CASA). Fresh semen was diluted by Andromed®. The diluted semen was preserved at the temperature 50C for 144 hrs. Motility, viability and abnormality were observed every 12 hrs. Data were reported as mean and standard error of mean analysed by using the paired student’s t-test. Mean interval between the bulls approaching and mounting the teaser for the first time and between approaching and ejaculation after the supplementation of micro-nutrients were significantly shorter (P<0.05) in compared to those before the supplementation (2.68 vs. 6.52 and 5.09 vs. 10.06 minutes, respectively). The sperm viability after the supplementation of micro-nutrients was significantly higher in compared to that before supplementation. (82.25 vs. 87.50 %). Preservation of diluted bull semen at the temperature of 50C for 144 hrs showed that the sperm viability was significantly higher (P<0.05) and sperm abnormality was significantly lower (P<0.05) after the supplementation of micro-nutrients in compared to those before the supplementation. It can be concluded that the supplementation micro-nutrients in Bali bulls could increase libido, sperm viability and reduce the sperm abnormality.