[Losses from sterility in cows].

Stated are the drop in milk productivity and the total losses in a value expression as determined by a definite formula. The observations were carried out on four large dairy farms. The cows on each farm were divided into groups according to the number of lactation and the length of the intercalving period. It was found that in 84 per cent of the cases of cows with a prolonged intercalving period the average daily milk yield for the same period was lower than in the case of cows with a normal duration of this period. Calculated were also the K coefficients, showing the milk loss, per lost service-period day. With a small group of cows there was an increase in the milk yield per each lost service-period day. The K coefficients were shown to vary with the individual groups of animals. At the same time most of the calculated values, indicating the loss of milk in sterility, were statistically insignificant. This was due to the expressed individual character of the response of sterile cows with regard to the drop in milk productivity. It was rather difficult to refer to a certain definite and general normativ as attempted by some authors. The guiding principle in the culling of sterile cows should be based on the individual approach. The data are given in two tablets.