TDK conference 2018

Dairy cattle is basically a uniparous animal, mostly they give birth only one calf per gestation. However sometimes it happens they give birth two or more calves at the same time. The presence of twin calving of cattle is between 1-5%, or even higher in dairy industry. The possible reproductive problems of twin-calving and weaker surviving abilities of newborn calves, may cause significant economic losses. The goal of this study is to compare the reproductive characteristics of twinning cows before and after calving, to the characteristics of non-twinning ones.

The reproductive data of more than 4000 cattle has been processed during the period of 2000-2010. The following time periods have been compared among the three above mentioned groups: calving to service period, open days, gestation length and calving interval. The LOG-transformed reproductive figures have been processed by general linear model, then the geometric means have been computed.

There is no significant difference between twinning cows before twinning and non-twinning cows in the length of calving the service period and open days. After twin-calving these two traits became statistically proven longer by 1 (calving to service period, p=0.002) and 3 (open days, p<0.001) weeks.

However, there were significant differences in gestation length and calving interval among all the three cattle groups. The shortest gestation length (274.4 days) was typical for cows with twin pregnancy, while the longest gestation length was found in cows after twinning (279.3 days, p<0.001). The shortest calving interval could be observed in cows with twin pregnancy (399.8 days), meanwhile the longest one in twinning cows after twinning (420.9 days, p<0.001).

The twin-calving mothers have shown the best economical results before the twin-calving period. Their performances were identical (calving to service period) with performances of non-twinning cows or were proven to be shorter (open days, gestation length, calving interval) than those of them. These results allow to conclude that twin pregnant cows before twinning could be in a better condition, reproductive status and they become pregnant sooner than the others. On the other hand, these animals require longer regeneration period, and longer time by re-breeding after twinning, probably because of their weaker condition and complications in postpartum period.