18 MASS. EXPERIMENT STATION BULLETIN 315 



DEPARTMENT OF ANIMAL HUSBANDRY 



Victor A. Rice in Charge 



As noted elsewhere (see report of Chemistry Department), the work in animal 

 nutrition formerly carried on by that department was transferred during the 

 year to the Department of Animal Husbandry. One old project has been brought 

 to completion and another is being continued in cooperation with Chemistry 

 (see report of that department), and two new projects have been organized. 



The Proper Supplementary Ration for Milking Cows on Pasture. (J. G. Archi- 

 bald, V. A. Rice, R. C. Foley, and C. H. Parsons.) This project is a further 

 development of work done in 1931 and 1932 on the possibilities of greatly reducing 

 the grain fed to cows on pasture. The abnormally dry season and consequent 

 short pasturage interfered somewhat with the progress of the work but some re- 

 sults were secured that appear significant. 



One group of cows receiving only 43 percent as much grain as did another 

 group gave 93 percent as much milk, maintained their weight, and did not show 

 a markedly higher shrinkage in milk flow (37.3 percent contrasted with 34.9 

 percent). The ratio of grain fed to milk produced in this group was 1: 10.7 for 

 the entire season, while in the other group it was 1: 4.3. From May 21 to Jul)' 

 20 it averaged 1:12.8 for the low grain group and at one time in June was as 

 wide as 1:14.8, some of the cows receiving no grain at all. The tentative con- 

 clusion has been drawn that "the necessity for even moderate grain feeding when 

 pastures are good is not apparent." The work will be repeated next season. 



The Relative Efficiency for Milk Production of Proteins from Animal and 

 Vegetable Sources. (J. G. Archibald, V. A. Rice, and C. H. Parsons.) This 

 project has only recently been started. This season the relative value for milk 

 production of dry rendered tankage versus a mixture of soybean meal and cotton- 

 seed meal is being investigated. Twenty-four cows are included in the trial, being 

 divided into two groups of twelve each, which are fed identically except that about 

 half of the protein for one group is obtained from tankage, and a similar amount 

 for the other group is from soybean and cottonseed meals. The cows are being 

 fed by the double reversal method, feeding periods being thirty days in length 

 with a preliminary period of ten days. The experiment will continue to the 

 close of the barn feeding season in April, 1935. 



The Comparative Efficiency of Dairy Cattle in Converting Feed into Milk. 

 (V. A. Rice and W. T. Smith.) This study was divided into three phases. First, 

 a preliminary study was conducted with six Holstein Advanced Registry Class A 

 test cows in the Massachusetts State College dairy herd. These animals varied 

 from two to ten years in age, and from nearly fresh to eleven months along in 

 lactation. An accurate record was kept of all feed consumed and all milk pro- 

 duced for one week. 



For purposes of computation and comparison, the milk of each cow was reduced 

 to a 4 percent fat corrected basis according to Gaines and Davidson's formula 

 (4/10 M. + 15 F. where M.=Milk and F. =Fat). The amount of T. D. N. in- 

 gested was ascertained and the amount of T.D.N, yielded in the milk. The 

 latter figure divided by the former gave the average efficiency of converting feed 

 into milk, which for this group was 32.22 percent. 



Second, a number of records as compared in the Guernsey Advanced Register, 

 volumes 18 to 21, were studied by similar methods, and an average efficiency of 

 31.20 percent was found. 



