Impact of stillbirth and abortion on the subsequent fertility and productivity of Holstein, Brown Swiss and their crosses in subtropics.

Stillbirth and abortion are serious problems in cattle breeding, from both economic and animal welfare standpoints. The aim of this study was to estimate the incidence and implications of stillbirth and abortion on the subsequent reproductive and production performance of the pure Holstein (HO), Brown Swiss (BS), and their F1 crosses (BF) in Egypt. The total number of records was 9275. The pure BS heifers had significantly (P < 0.05) lower incidence of stillbirth, abortion, and twinning (4.5, 2.3, and 1.5 %, respectively), compared with pure HO heifers (15.4, 5.3, and 4.8 %, respectively). Pure BS and BF cows coped with the harsh conditions of abnormal births, even though their subsequent reproductive indices were slightly reduced after stillbirths. In contrast, pure HO cows had significantly (P < 0.05) longer calving intervals and days open (475 and 198 days and 427 and 151 days, respectively) after stillbirths and abortions, compared with those that had normal births (381 and 149 days, respectively). Stillbirths decreased 305-day milk yield (305-MY, 14.5 %) and peak milk yield (Peak-MY, 29.1 %) in pure HO cows when compared with those calved normally. However, productive indices of pure BS and BF cows exposed to stillbirth or abortion were more tolerant. In conclusion, pure BS and BF cows can endure the difficult consequences of stillbirths or abortions under subtropical conditions. Nevertheless, fertility and milk yield had been deteriorated in pure HO.