The Quality of Cryopreserved Dairy Bulls Semen along Supply-Chain Used for Artificial Insemination in Tanzania

Several factors are said to influence semen quality in breeding bulls. This research was carried out to investigate the effect of season and cold value chains on semen quality parameters. A total of 1652 semen production records from 2018 to 2021 from 10 dairy bulls preserved at the National Artificial Insemination Centre (NAIC), USA River, Arusha, Tanzania, and 540 cryopreserved semen examined were analyzed using Analysis of Variance (ANOVA) and the results were expressed as mean ± standard error of the mean using statistical analysis system (SAS, 2004), to determine whether there were significant differences among variables tested. All semen traits (VOL, SPC, PM, TM, PM, TM, VER, MP, and HP) were significantly (P <0.05) affected by season and cold value chain. During the cold season, the highest values of SPC, PM, TM, PM, TM, VER, MP, and HP were observed as compared to that of the warm season. Furthermore, semen quality decreased gradually from pre-state (before freezing) to post-state (after freezing for 48 hours) with minor affection for semen motility. There was a higher decrease (P <0.05) in quality from cryo-stored semen straw to those of the same batch retrieved back from the field. The semen quality parameters were satisfactory in the first three stages when compared to the semen straw from the field which was observed to have poor motility which could be due to poor handling, leakage of storage and transportation containers, and sometimes the delay of refilling the LN2. Finally, during the cold season and in all stages of semen production the semen is qualitatively and quantitatively good.