352 FEEDS AND FEEDING 



tends to return to its normal composition. Lindsey of the Massachusetts 

 Station 31 likewise found .that feeding large quantities of oil, either lin- 

 seed, cottonseed, com, or soybean oil, caused a temporary increase in 

 the richness of the milk. That the feeding of fat does not always cause 

 a temporary increase in the richness of the milk is shown in 2 trials 

 by Wing at the New York (Cornell) Station 32 in which tallow was 

 fed to 10 cows while on pasture or on winter feed. Beginning with a 

 small amount, the allowance of tallow was gradually increased until 

 each cow was consuming about 2 Ibs. daily, this allowance being con- 

 tinued for several weeks. The tallow feeding had no uniform effect 

 either on the yield of milk or the fat content. 



561. Effects of feed on fat composition. The fat of milk is a composite 

 of many kinds of fat palmitin, olein, stearin, butyrin, etc. While the 

 kind of feed given the cow does not materially change the percentage of 

 total fat in her milk, in some cases it does seem to alter the relative 

 proportion of the several component fats or otherwise change the charac- 

 ter or nature of the fat, as shown. by the resultant butter. Many years 

 ago investigators began to study diligently the influence of various feeds 

 on the composition of the fat of milk, and their work is still in progress. 

 The results thus far secured are conflicting in some respects, but in 

 general it has been found 33 that feeds rich in vegetable oils (which con- 

 tain a large amount of olein) produce milk fat high in olein. This 

 usually tends to make the butter softer, for olein is a liquid fat, but 

 in some instances this tendency is offset by still other changes in the 

 composition of the fat. For instance, tho the feeding of cottonseed 

 meal, cotton seed, or cottonseed oil increases the amount of olein in 

 the butter fat, yet it raises the melting point and makes the butter 

 harder. Eckles and Palmer 34 believe that this effect is due to the fact 

 that these feeds decrease the amount of volatile fatty acids in the butter 

 fat, which more than counterbalances the effect of the increase in the 

 amount of olein. Cocoanut meal also produces a firm, hard butter. A 

 change from dry feed to pasture generally produces fat higher in olein 

 and results in softer butter. 



562. Influence of underfeeding and overfeeding. In extensive experi- 

 ments at the Missouri Station 35 Eckles and Palmer studied the effects 

 of underfeeding dairy cows in milk ; i.e., supplying them with insufficient 

 feed to furnish the nutrients required for milk production and maintain 

 their weight, and also studied the effects of overfeeding. 



When cows are underfed immediately after calving they will maintain 

 their milk flow at a nearly constant level for a time under the most ad- 

 verse conditions, drawing on their bodies for nutrients and losing in 

 weight rapidly. In one case a cow kept up a normal flow of milk for a 

 month when given only as much feed as would have been required to 



3l Mass. Rpt. 1908, pp. 109-112. N. Y. (Cornell) Bui. 92. 



^Lindsey, Mass. Rpt. 1908, pp. 109-112; Hunzicker, Ind. Bui. 159. 

 ^Mo. Res. Bui. 27. "Mo. Res. Buls, 24, 25. 



