BUREAU OF ANIMAL INDUSTRY. 203 



Sevei-al new motion pictures were prepared during the year by the 

 •department Motion Picture Office, from scenarios prepared in vari- 

 ous bureau offices. " Molly of Pine Grove Vat," telling in story form 

 how a southern community eradicated cattle ticks, has been especially 

 beneficial in preliminary tick-eradication work. "A Tale of Two 

 Bulls," another new film, deals with bull-association activities. " The 

 Horse in Motion " is the title of a popular film showing the gaits of 

 various classes of horses, and is among the most popular in the 

 •department's collection. Other new films are in various stages of 

 making. 



REPORTS BY DIVISIONS. 



The year's work as conducted by the various divisions of the bu- 

 reau is pi'esented more full}^ in the following pages. 



ANIMAL HUSBANDRY DIVISION. 



The work of the Animal Husbandry Division, consisting chiefly of 

 research in animal husbandry, including poultry husbandry, was 

 conducted under the direction of E. W. Sheets, acting chief of the 

 division. 



Cooperation with other branches of the department and with State 

 agricultural colleges in the study of regional and national problems 

 and in promoting livestock improvement has been developed to a 

 larger extent. The division assisted in the better-sires campaign and 

 in outlining a national plan for the better feeding of farm animals. 



ANIMAL HUSBANDRY EXPERIMENT FARM. 



Further improvements were made at the United States Experiment 

 Farm, Beltsville, Md., and at other station farms in different parts 

 of the country. The addition of the nutrition laboratory and the 

 enlarging of the laboratory for meat investigations at Beltsville pro- 

 vide improved facilities for these important lines of work. This farm 

 is used as a practical laboratory and proving ground for solving 

 animal-husbandry problems. The experimental work is reported 

 under other headings. 



ANIMAL GENETICS. 



The study of the effects of different systems of mating was con- 

 tinued as the major subject. Experiments on the effects of inbreed- 

 ing, crossbreeding, and selection were carried on with guinea pigs. 

 The conclusions to date are presented in Department Bulletins 1090 

 and 1121. The effects to be expected from different systems of mating 

 according to the Mendelian theory of heredity have been worked out 

 and compared with the experimental results. They are in agreement 

 as far as determined. This study has led to a method of comparing 

 the theoretical consequences of the irregular systems of mating found 

 in actual pedigrees with regular systems and with experimental re- 

 sults. A detailed study of the breeding of Bates's Duchess family of 

 Shorthorn cattle has been made by this method, and similar studies 

 with other noted strains of livestock and with samples of the breeds 

 are in progress. The conclusions derived from these studies on the 

 effects of different systems of mating are being applied to inbreeding 

 experiments with hogs and poultry. 



