The Potentiality of Using Bull Semen at Room Temperature after Short Term Preservation in Different Extenders

Abstract

Bull semen quality was evaluated following short term preservation 1n four extenders and at different ambient temperatures and cold storage. Three  extenders  were  formulated  using  locally  available  diluents  and  were  compared to one commercial extender used at the National Artificial Insemination Centre (NAIC), Usa River, Arusha. The four extenders were coconut milk (CME), egg yolk citrate (EYCE), skim milk (SME) and Laisphos®. Extended semen samples were stored at five different temperatures namely deep freezer (-l8°C), refrigeration (5 °C), and ambient (20 -22 °C), or incubation (2 5 °C and 27°C) to simulate warmer environments. Semen quality was evaluated for percentage motility and lives sperm cells. A 4 x 4 x 5 factorial experiment was used in the study.  Extended  semen  samples  from  eight  dairy bulls  were  evaluated   every 24  hours  for  96 hours. Storage temperature had a highly significant effect on the quality of sperm cells (0.001). Storage at -18 °C and 27 °C had significantly lower sperm cell quality compared to samples that were stored at 20-22°C, 25°C and 5°C. Refrigeration temperature however, had intermediate values. The type of extender did not have significant effect (P >0 .0 5) on spermatozoa quality during the entire storage period at different temperatures.  Sperm quality decreased with storage period. Laisphos® had figures comparable to CME and EYCE while SME was the least efficacious in the preservation of spermatozoa viability. Temperatures between 20-25 °C gave the best results compared to the other temperatures under study. The study showed that both CME and EYCE could be used in preservation of room temperature semen for use within 72 hours provided the ambient temperatures did not exceed 25 °C. This was enough to enable the operation of artificial insemination (AI) based on room temperature  semen  within  a  small  radius  area  with  high  population  of dairy cows.