Volume VIII MARCH, 1917 Part II 



STUDIES IN MILK SECRETION. 



By J. HAMMOND, M.A., and J. C. HAWK, B.A. 



{School of Agriculture, Cambridge.) 



I. THE EFFECT OF NUTRITION ON YIELD New y^^^ 



AND COMPOSITION. '**^'^>*'vic^ 



Introduction. 



Much work has been done on the effects of various foods and rations 

 on milk secretion both as regards yield and composition. It has, 

 however, with one or two exceptions, failed to establish clearly any 

 fundamental principles with regard to the effect of nourishment on 

 milk production. 



For the most part the experimenters have been working with cows 

 kept partially for commercial purposes and so they have been unable 

 to go to the extremes necessary for the elucidation of fundamental 

 principles. 



Ingle^ found that foods rich in albuminoids improved both the 

 yield of milk and proportions of fat and solids not fat, while large 

 quantities of carbohydrates although increasing the yield appeared to 

 diminish its quality. Crowther^ demonstrated the fact that a change 

 from a highly nitrogenous diet to one relatively poor in nitrogen resulted 

 in the secretion of more milk but that this was poorer in fat content; 

 the reverse of this — a change of diet to one relatively rich in nitrogen — 

 was followed by a decrease in the yield but an increase in the fat content. 



Physiologists, while studying the origin of the lactose of milk, have 

 found that as a result of limiting the supply of sugar in the blood, by 

 the action of drugs, the yield of milk has been affected. 



Lusk^ found that phloridzin when administered to a goat caused a 

 decrease in the yield of milk but the percentage of fat was increased. 



1 Bui Yorks. Coll., Leeds, No. 25, 1901. 2 ^„j^, <,/ Leeds, Bui. No. 44, 1903. 



3 Ztschr.f. Biol. Bd. XLii, 1901. 

 Joum. of Agric. Sci. viii 10 



