Wpływ ciąży mnogiej na powikłania porodu i śmiertelność cieląt

The aim of the research was to determine the influence of multiple pregnancy on delivery complications and calf mortality. The experiment was conducted on 6755 cows in which at least one multiple calving took place. Data came from the documentation of the Polish Federation of Cattle Breeders & Milk Producers and concerned calving type, sex structure of the newborn calves, as well as their perinatal mortality. The results of the investigation showed that twin pregnancies constituted over 99% of all multi pregnancies. In the fetal sex structure of twin pregnancies the share of heterosexual fetuses was the greatest (36.4%), whereas unisexual male the smallest (29.7%). Almost 75% of cows with multiple pregnancies needed some human assistance during the delivery. Difficult calvings occurred most often in the case of heterosexual pregnancy, and seldom in unisexual male fetation. The percentage of stillborn calves and the ones dead in the perinatal period amounted to 8.58% and was higher by 1.19% in bull calves than in heifer calves. The obtained results together with the large percentage of stillborn calves as well as those that died during the perinatal period indicate the decreasing profits from an increased amount of calves from multiple and twin pregnancies.