Effect of Chemical Drying Agents on Alfalfa Hay and Milk Production Response When Fed to Dairy Cows in Early Lactation

Abstract

Third-cutting alfalfa hay cut at bud stage was treated with a drying agent consisting of potassium carbonate, sodium carbonate, and citric acid at the rate of 280.6L/ha (1 kg/37.47L water) to alternate swaths 4.27-m wide. Hay samples were taken at cutting and at 4-h intervals during daylight until baling was initiated. Twenty lactating Hoistein cows were randomly assigned to untreated and treated alfalfa hay treatments in a switchback design. Individual feed intakes and milk yields were recorded daily. Milk composition was analyzed once weekly. Drying rates were: .40 and .48% moisture/h for control and Na2-K2CO3-citrate treatments, respectively. There was no significant difference between treatments in feed composition parameters nor in vitro DM digestibility parameters. Cows fed the hay treated with Na2-K2CO3-citrate had a higher mean daily milk yield, adjusted for feed intake, compared with cows fed untreated hay (33.0 versus 32.5 kg/d). There were no significant differences in milk composition between treatments.