BUREAU OF ANIMAL INDUSTRY. 97 



DISPOSAL OF CREAMERY WASTES. 



In cooperation with the Pubhc Health Service the proper size of 

 settling tank and sand filter bed has been determined for creameries. 

 Much of the previous difficulty has been due to holding sewage too 

 long in the settling tank and using too small a filter bed. 



DAIRY CATTLE UUEEDING 



The need has long been felt for a thorough and comprehensive 

 study of the breeding problems connected with dairy cattle. Little 

 definite information is available regarding the inliuence of inbreeding, 

 line breeding, and crossbreeding. Plans have been prepared and 

 part of the necessary animals have been purchased to undertake 

 comprehensive experiments on these questions and at the same time 

 to collect data from breeders. These experiments, which will cover 

 a long period of years, will be carried out in cooperation with a number 

 of State agricultural colleges and other institutions in order that the 

 greatest possible number of data may be obtained through the use 

 of a large number of animals. 



DAIRY EXPERIMENT FARM. 



The Dairy Division experiment farm at Beltsville, Md., is used as 

 an experimental field for various lines of experimental and practical 

 work in dairying and also as a laboratory for research work. 



INFLUENCE OK WATER UPON MILK AND BUTTERFAT PRODUCTION. 



The effect of water upon the production of milk and butterfat has 

 been studied in a preliminary manner by using different systems of 

 watering the cows. Watering once or twice a day was compared 

 with allowing the cows to drink at will and the latter was found to 

 have a slight advantage, especially over watering once a day. 



F.ACTORS CAUSING VARIATION IN PERCENTAGE OF BUTfERFAT IN MILK. 



Previous experiments had indicated that a ration high in mineral 

 and water content influenced the percentage of butterfat in milk. 

 An experiment in which a ration of high mineral and high water 

 content was compared with one of low mineral and low water content 

 gave negative results. 



MILK SUBSTITUTES FOR CALVES. 



Various combinations of grain have been tried as milk substitutes 

 for feeding calves, but a combination has not been found as yet which 

 is considered fully satisfactory. 



FEED REQOIRED FOR RAISING HEIFERS. 



The feed necessary to raise five dairy heifers for one year was found 

 to average 125 pounds of whole milk. 2,420 pounds of skim milk 

 889.9 pounds of grain, 568.3 pounds of alfalfa hay, and 4,411.9 pounds 

 of corn silage. At birth the average weight was 79 pounds, and at 

 one year the weight had increased to an average of 520 pounds. The 

 grain mixture used consisted of 375 pounds of corn-and-cob meal 

 200 pounds of wheat bran and 100 pounds of linseed-oil meal. 



