Effect of Dry Period Length on Holstein Milk Production and Selected Disorders at Parturition

Abstract

A 42-mo field trial was initiated in 65 New York Dairy Herd Improvement herds to evaluate the effects of length of dry period on disorders at calving and subsequent milk production. Common disorders and udder edema at parturition were not associated with the length of the preceding dry period.Cows were assigned to treatment group dry periods of 20, 30, 40, 50, and 60 days by modulus 5 of their index numbers. Cows which averaged 10 to 40 days dry produced from 450 to 680 kg less milk in the following lactation than cows with average dry periods of 40 days or longer. Although there was some gain in milk production during the previous lactation from the longer lactation – shorter dry periods, it was less than half the loss in the following lactation. The depressing effect of the short dry periods did not carry over to the second lactation. Cows with dry periods of 40±10 days produced as much as cows with 50 days dry or more.