Pregnancy rates from ambient and frozen semen in Mpwapwa breed cattle after synchronisation

Artificial insemination (AI) services for the TALIRI breed of cattle in Tanzania have been in abeyance for many years, largely due to difficulties of supply of liquid nitrogen to remote and rural areas. Historically, AI using unfrozen ambient temperature or chilled semen have been effective alternatives to cryopreserved (frozen) semen, so, potentially, AI using ambient temperature semen could form the basis of an AI service for the TALIRI region (and other similar areas across East Africa). However more testing is needed. In this study 301 TALIRI cows were synchronised using a standard 14-day double prostaglandin (PG) programme and randomly assigned to insemination with either frozen semen (F) or ambent temperature semen (AT). Cows that showed oestrus after the first PG were inseminated to that oestrus; all other cows were inseminated after second PG. Bulls were then run with the cows for 60 days, after which conception rates to AI and overall pregnanvcy rates were determined by transrectal ultrasonography. Conception rates to AI for AT cows were 62% (94/151) and 38% (58/152) for F (RR for AT versus F: 1.63 (1.27–2.1)), while final pregnancy rates were 96% (145/151) for AT semen and 92% (140/152) for F semen. In this study, the conception rate to AI with ambient temperature semen was at least as good as that with frozen semen. It therefore demonstrates the feasibility of using PG synchronization and fixed time AI with AT to breed Mpwapwa cattle in rural Tanzania.