FOOD EFFECT ON MILK SECRETION. 211 



about the same during the periods of activity, until the age of eleven or 

 twelve years, and then it decreases. 



PREGNANCY. This state always has the effect of decreasing the flow, 

 first due to a tendency for the body to take on flesh for a time after con- 

 ception, and in a later period the nutrition is utilized for the foetus. It is 

 in respect to the period of lactation that individuals show the widest varia- 

 tion. With many, the effect of again becoming pregnant is so slight as 

 to be scarcely noticeable, and with others it is so great as to interfere with 

 the usefulness of the animal. 



THE INFLUENCE OF FOOD UPON MILK SECRETION. 

 During the period when physiologists attempted to explain practically 

 all changes upon chemical and physical bases, the teaching was that milk 

 resulted from a separation of its constituent elements from the blood, the 

 separation taking place in the udder. Upon this teaching the belief became 

 fixed that the quantity and quality of the milk secretion was in a measure 

 dependent upon the amount and kind of food the animals received. The 

 influence of this teaching is still potent; many elaborately planned experi- 

 ments have been made by individuals and Government Experiment Sta- 

 tions to determine the truth or falsity of this view. The results have been 

 very confusing, unless all the data be known. It must be admitted that a 

 large per cent, of practical dairymen believe they can take poor or average 

 cows, and by good feed and management greatly increase the quantity and 

 better the quality of the milk produced. The results at Experiment Sta- 

 tions have not been wholly in accord with this view. No doubt but that the 

 dairyman taking a cow in poor condition, scarcely receiving sufficient food 

 to maintain the body nutrition, and giving her good care and abundant 

 feed, will be able to increase both the yield and quality. The Experiment 

 Station or person who takes an animal in a good state of nutrition, and 

 feeds highly, may still further increase the flow or maintain it, and may 

 improve the quality for a short time but not permanently. The error too 

 often committed by the dairyman in drawing a proper conclusion, is, first, 

 testing the milk for quantity and quality which is below the normal for the 

 animal because of her impoverished condition, and second, in drawing the 

 conclusions from the temporary change occurring soon after the change in 

 food. The experiment stations, as a rule, use only well nourished cattle, 

 and consequently do not find such marked changes, and furthermore they 

 keep the records for a longer period of time, so that the conclusions are not 

 biased by the incomplete data obtained from the temporary changes. 

 Among those who believe that the quality of milk is practically a fixed 

 character in any given individual and not subject to more than temporary 

 variation by the feeding, are G. H. Whitcher and S. M. Babcock. 1 The latter 

 sums up the matter as follows: "My opinion is, that the quality of milk so far 

 as it is measured by the per cent, of fat, depends almost entirely upon 



1 Rural New Yorker, July 15, 1891. 



