THE INFLUENCE OF THE PLANE OF NUTRITION 
UPON THE PERCENTAGE OF FAT IN MILK 
AND THE PROPERTIES OF THE FAT 
C. H. Eckues 
It is a well-known fact that the percentage of fat present 
in milk is subject to wide variations. ‘Among the most im- 
portant causes known to be responsible for these variations 
are breed of animal, stage of lactation and the individuality 
of the animal dependent upon heredity. In addition the 
author has found ¢ertain other factors not previously recog- 
nized to be of considerable importance. Among these are 
seasonal variations,’ fatness of the cow at parturition,’ and 
plane of nutrition." Although -the second and third factors 
are not identical, they are closely related and some material 
concerning both is included in the present paper. 
The fat percentage of milk may be increased decidedly 
above the normal for the animal concerned for a short time 
after parturition, and imereased to a less extent for a longer 
period, provided the animal has been fed on a high plane 
of nutrition for a sufficient time previous to parturition to 
make it possible for a large amount of fat to be deposited in 
the body tissues and that the plane of nutrition following 
parturition is reduced to a point below the actual requirements 
ot the body. The underfeeding following parturition does 
not necessarily result from feed being purposely withheld 
by the feeder but because the animal when in high flesh at the 
1C, H. Eckles, Jahrezeitliche Schwankugen des prozentischen Fettge- 
haltes in Kuhmilch in Milchwirtschaftliches Zentralblatt, Heft 11, pp. 
488-502, 1909. 
4 Ibid., Influence of Fatness of Cow at Parturition on Per Cent of Fat in 
Milk, Bulletin 100, Mo. Agr. Exp. Station, 1912. 
°C. H. Eckles and L. S, Palmer, Influence of the Plane of Nutrition of 
the Cow Upon the Composition and Properties of Milk and Butter Fat. 
Overfeeding, Research Bulletin 24, p. 35; Underfeeding, Bulletin 25, P. 
106, Mo. Agri. Exp. Station, 1916. 
