116. Factors affecting Milk and Butterfat Secretion. II. The Colour of the Butterfat

Abstract

1. The colours of the butter for individual cows at the London Dairy Show have been measured on a colour scale of yellow shades on cellulose strips, and the results analysed statistically.2. The mean values and variability curves of the ranges of butter colour in the different breeds of dairy cattle are given. Circumstances which may affect these values are indicated.3. The two most important factors affecting butter colour are the genetic character of the cow and the method of feeding.4. A slight increase in the shade of colour was found to occur under most of the various conditions which give rise to increased milk yield. It is suggested that this may be due to the greater intake of colouring matter (associated with the greater food intake) in proportion to butterfat produced, since increase in yield is usually associated with decrease in fat percentage.