Comparison of Fixed-time Artificial Insemination and Natural Mating on Pregnancy rates in Mpwapwa Breed Cattle

Abstract

The goal of this study was to assess if a designed prostaglandin (PGF2?)-protocol when used against natural mating (NM) in well-managed Mpwapwa cattle would improve pregnancy rates during the breeding season. Of the PGF2? oestrus synchronization protocols, a standard 14-day PGF2? protocol accompanied with fixed-time artificial insemination (FTAI) was tested against NM.  Totals of 39 and 49 cows became pregnant in the FTAI and NM groups respectively following completion of the study of 100 cows for each group. Statistically, the difference between the two groups was not significant (P=0.21), even though there was a lower risk of pregnancy in the FTAI group compared to the NM group (unadjusted relative risk: 0.8, 95%CI: 0.58-1.09). The results from this study suggest that PGF2?–based synchronization protocol and FTAI, especially when combined with NM in Mpwapwa breed cattle, can yield better reproductive performance and enhance greater genetic improvement compared to being naturally serviced. Few cows (only 10/100 cows) displayed behavioural oestrus signs after receiving the first PGF2? injection. The poor oestrus response might be due to either ineffective detection of oestrus or cows lacked a responsive corpus luteum (CL) at the time of synchronisation. Therefore, this might reflect a large number of cows to have been in anoestrus. Further investigation on the reproductive status and performance of Mpwapwa cows is needed to identify the effects of anoestrus