TDK conference 2017

The incident of twinning in Holstein Friesian cattle breed is of 3 to 5 %, and it is followed by reproductive and economic problems in most of the cases.

The aim of this evaluation was to compare the service period and the lactation milk production in cows with single- and twin birth at a Hungarian large scale dairy operation. The data processed was collected from 2000 until 2010.

In Cox’s regression model (service period) and general linear model (milk production traits) as fixed effects the type of calving (single or twin), the construction code (which refers to blood proportion of the Holstein Friesian breed), and the season and number of calving, furthermore the year of calving (as covariate) were considered.

The outcome of this analysis is that there is no significant difference in the length of service period between the two groups of cows. The total lactation milk yield has a meaningful difference in performance: we could see that single calving cows are giving more milk yield (P= 0.013), fat yield (P= 0.030), and more protein yield (P= 0.028) than cows with twins.

For the standard lactation milk yield we could noticed the same tendency at a higher accuracy, but of course on a lower level of production (305-milk yield, 305-fat yield, and 305-protein yield P= 0.002, P= 0.001, and P= 0.004, respectively).

With our result we can demonstrate that there is no disparity for cows after twinning regarding the length of service period. This unexpected result which seems to be contradictory to our experiences will be explained with a much longer open days in twinning cows known from a previous research (Keary, 2017). In regards to the milk production an involuntary decrease for cows after twin calving was revealed.