4 MASS. EXPERIMENT STATION BULLETIN 406 



Rations Fed 



The rations fed to the several groups were identical except for the grain mix- 

 tures. They consisted of a fair grade of hay from mixed grasses (no legumes), 

 good quality corn silage, dried beet pulp moistened with water before feeding, 

 molasses mixed with the beet pulp at the rate of one pound per cow daily, and the 

 grain allowance. A schedule of the grain mixtures is given in Table 2. Cornstarch 

 was used in the urea mixtures to make good the deficiency in energy caused by 

 purposely omitting from these mixtures the protein concentrates contained in 

 the regular grain. Starch was the only readily available material which could be 

 used which would not introduce some protein also. 



Table 2. 



Formulas of Grain Mixtures Used — Pounds 



Mixtures 



Ingredient 



Regular 



Urea 

 No. 1 



Urea 

 No. 2 



Control 



Dry Cow Mixtures for 



Groups Group Group 

 A & B C D 



Hominy feed 600 



Ground oats 400 



Ground barley 



Wheat bran 500 



Corn gluten feed 200 



Yellow corn meal 



Lin.seed meal 



Soybean meal 100 



Cottonseed meal 200 



Cornstarch 



Urea 



Salt 20 



Bone meal 



Vitamin A concentrate 5 



400 

 400 



500 

 200 



600 

 600 



660 

 600 



300 

 300 



300 

 100 



600 

 300 

 300 

 200 



550 



50 



20 



40 



5 



600 

 300 

 300 

 600 



200 



20 

 5 



Urea mixture No. 1, was used only for a short time at the beginning of the 

 experiment in order to accustom the cows gradually to the change. It was 

 followed by the No. 2 mixture which, with one slight modification, was con- 

 tinued for the duration of the work. The modification mv^olved the substitution 

 of 100 pounds of corn gluten feed for a like amount of cornstarch in July, 1940. 

 During the latter part of the experiment cottonseed meal was omitted from the 

 "regular" mixture because of its high price, and a like amount of soybean meal 

 was substituted for it, so that the total amount of the latter was then 300 pounds 

 per ton. The reason for omitting bone meal from some of the combinations was 

 that they carried sufficient phosphorus without it. The vitamin A concentrate 

 was omitted from the dry cow mixtures for groups A and B because these cows 

 when dry received a roughage ration which, it was considered, carried adequate 

 amounts of carotene. The control mixture, similar to urea No. 2 mixture except 

 that it contained no urea, was fed at several intervals throughout the course of 

 the experiment, for periods varying from a few weeks to seven months, to ten^ 

 cows in groups of from two to six cows at a time. This was done in an attempt to 

 ascertain whether or not the basal ration minus urea would adequately support 

 milk production; if not, then any difference between the performance of these 

 cows and those getting the urea, or any improvejnent noted when urea was fed 

 later to this control group, coukl presumabK be credited to the effect of the urea. 



'Four of these were in addition to the twenty-four included in the main part of the leeding trial. 

 The others were a group of six composed of three each from Groups C & D, which were used for 

 this phase of the work in a third lactation (1942). subsequent to the conclusion of the more compre 

 hcn.s-ive trral^. 



