The evaluation of gestation length range for different breeds of Polish dairy cattle

For over 2.5 million dairy cows subject to assessment in Poland in 2005–2010, gestation length was analyzed. This trait follows a normal distribution, and it was found that the acceptable upper limit of gestation length for the Montbéliard and Simental breeds was 306 days, this being significantly different from other breeds. For the remaining dairy cattle breeds the value was 298 days. For cows with gestation length exceeding these limiting values, parentage control would be advisable.