The Effect of Season on the Milk and Fat Production of Jersey Cows

Abstract

A study of more than 2900 Register of Merit Records of Jersey cows showed the following:1.The cows which freshened in May and July gave the richest milk on the average in the ninth and seventh month respectively of the lactation period. The cows which freshened in June averaged a higher test of fat for the eighth to tenth month in period lactation than they did in twelfth month. The average per cent of fat in the milk, for a year for cows freshening in July, September, and August was the highest, being at least 5.45 per cent.2.The yearly milk production was highest for the cows freshening in July, October, November, December, January, February, and March, all being over 8800 pounds. April, May, June, August, and September were the low months, although on the average the difference between the two groups was not great.3.The yearly fat production averaged the highest for cows which freshened in July, October, November, and December, all being above 477 pounds of fat. April, May, and August were the low months all being below 468 pounds of fat. The cows which freshened during the month of July averaged 27 pounds of fat more than those which freshened in April and August.4.The season of freshening as well as the period of lactation affects the richness of milk from a cow. The richest milk may be produced at some time before the end of the lactation period depending on the month in which the cow freshened.