The effect of drying length on cow production and lactation persistence

Abstract

Effects of drying length on production level and lactation persistence were sought on the Simmental cows in Jagodina. During studies, all the cows were at the stage of second lactation and raised in equal conditions of diet and keeping. The cows were split up into two groups, according to drying length. The groups had 30 cows each. The first group included cows with normal drying length of 61.93 days, and the second those with a short one of 19.5 days.

The cows of the first group produced 5641 kg milk and 217.5 kg milk fat for 305 days of lactation, whereas those of the second group produced 4446 kg milk and 192.25 kg milk fat for the same period of drying. The differences were tested by t-test, showing the differences of 1194.5 kg in milk production and 41.4 kg in lactic acid per lactation thus being highly statistically significant (P<0.001).

The data helped graphic outline of lactation curvatures in both cow groups studied, with the first having normal lactation persistence, and the second indicating unsatisfactory course of lactation.