Inheritance of Butterfat Percentage in Jersey Cows

Summary 1. Butterfat is a variable factor although the degree of variability is less than for milk yield. 2. Both the sire and dam contribute to the inheritance of their daughters, governing fat percentage. 3. A parent may be prepotent in increasing the fat percentage of the offspring separately from affecting the milk yield, or may increase or decrease both the percentage of fat and the milk yield. 4. Although there is a negative correlation between milk yield and fat percentage, there is a positive correlation between total fat production and fat percentage. 5. Improvement in total butterfat production can be accomplished by selection for high fat percentage as well as selection for large milk yields.