H. ATASHI - Department of Animal Science, College of Agriculture, Shiraz University, Shiraz, I. R. Iran
M. J. ZAMIRI - Department of Animal Science, College of Agriculture, Shiraz University, Shiraz, I. R. Iran
M. B. SAYYADNEJAD - Animal Breeding Center, Karaj, I. R. Iran

The aim of this study was to determine the factors affecting stillbirth and the consequences of stillbirth on longevity, production, and reproductive performance in Holstein cows of Iran. Calving records from March ۲۰۰۰ to April ۲۰۰۹ comprising of ۲۲۰,۰۴۳ calvings on ۱۰۲,۱۹۹ cows in ۳۳ herds were used. The results showed that ۴.۰۶% of the newborn calves died within ۴۸ h of birth. The stillbirth rate was significantly higher for first parity cows (Pvs. ۴۰۵.۵ (±۱.۰۵) d (P<۰.۰۱), respectively]. The overall mean longevity was affected by stillbirth while the shortest lifetime was observed for cows with stillbirth at their first parity (P<۰.۰۱).

Calving Interval, Holstein cows, Lactation Performance, Stillbirth