The Value of Winter Pasture and Sweet Potato Meal for Lactating Dairy Cows

Abstract

Fifteen dairy cows of the University herd were used to study the value of winter pasture and sweet potato meal for lactating dairy animals during the winter of 1947. The project was conducted for three 28-day periods in accordance with the latin square design (1, 19). Analysis of variance was employed in analyzing the milk, butterfat and flavor data. The cows that were on winter grazing consumed approximately 46 per cent less dry roughage and produced 15.6 per cent more milk and 18 per cent more butterfat than did the animals that were dry-lot fed. These differences in yields were highly significant. The mean flavor scores of the afternoon milk samples were 36.2, 37.6 and 36.9 when the cows were fed ration B (containing pasture and corn), ration C (containing dry roughage and corn) and ration D (containing dry roughage and sweet potato meal), respectively. The differences in the flavor scores of the milk from cows fed rations B and C were statistically significant. The differences in the flavor scores of the milk from cows fed rations C and D were non-significant. The differences in the mean flavor scores of the morning milk samples from cows fed each of the rations were non-significant. There was no significant difference in the amount of milk and butterfat produced or in the flavor score of the milk when the cows were fed a concentrate mixture consisting of 30.2 per cent of either corn or sweet potato meal. The animals ate one ration just as readily as the other. The sweet potato meal did not cause an excessive or objectionable laxative effect upon the digestive system of the cows. © 1948, American Dairy Science Association. All rights reserved.