770 



EXPERIMENT STATION RECORD. 



[Vol. 40 



constant amounts which are little, if at all, influenced by the amounts eaten or 

 the amounts digested. From these data it appears that about 1.7 gm. of phos- 

 phoric acid, 2.8 gm. of lime, and 1 gm. of magnesia are required per day by 

 sheep weighing about 100 lbs. in order to maintain a mineral balance. About 

 0.2 gm. of potash a*id 0.54 gm. of magnesia per day were stored by these sheep. 



In experiments 1-18 data are furnished as to the sulphur trioxicl content of 

 feed and feces. The coefficients of digestibility averaged 47.9. Since most of the 

 sulphur was probably in combination with the protein of the rations, the co- 

 efficients of digestibility of the latter are given for comparison. Their average 

 is stated as 48.4. 



Relation of breed and age of service to prolificacy {Washington Sta. Put. 

 158 (1919), pp. 9, 10). — Statistics collected from the records of the college herd 

 of swine from 1908 to 1916 are published. The average litter size by breed 

 was for Tamworth 7.94, Poland China 7.1". Puroc 7.14. and Berkshire 



6.25. The number of Utters upon which the averages arc based is apparently 

 16, 67, 56, and 53, respectively. The average litter size by age of sow at service 

 was found to be: Yearlings 6.12, 2-year olds 7.7. 3-year olds 7.8, and 4 year olds 

 7.9. The number of records were it;. 17, 10, and 4, respectively. 



Self-balanced rations by individual pigs, R. < '. Ashhy (Amrr g Inim, 



Prod. Proc. 1916, pp. 197-209, figs. 6).- This paper reports the Brsl years re- 

 sults of an investigation at the Minnesota Experiment station to determine the 

 individual differences of young pigs in the Choice of feeds and the Influent 

 the rations selected on the economy of gain, the type of hog produced, and the 

 quality of the product Two groups of 5 pigs each were fed for 12S days, ended 

 November 15, 1915. The pigs in the first group were Belected (Tom B litter of 

 Berkshlre-DuroCS and were started OD individual feeding at the age of LOG 

 days. The second comprised a litter of Poland-DuroCS and were started when 

 93 days old. Kach animal was kept in an individual pen with access to a self- 

 feeder in which shelled corn, shorts, and tankage (60 per cenl protein) were 

 supplied separately. The following table in which the pigs Of each -roup are 

 arranged in the order of Increasing economy of gain summarizes some of the 

 results : 



Results of individual selection of frrds hy young pigs. 



Other data given include the proportion of each feed selected by 3 week 

 periods, the total daily consumption expressed as b percentage of bod] weight 



by weekly periods, and the average nutritive ratio and the maximum and mini- 



