20 Journal of Agricultural Research voi. xvii. no. t 



yield of milk and the butter-fat content was of greatest consequence. 

 These results are of little benefit in the solution of this problem, other 

 ,than to show the great variation that occurs between different breeds 

 and within the breeds. This problem will include only such breeds as 

 are common to this section of the country. Among the above-mentioned 

 investigations, only two give figures upon breeds that will be included 

 in this work. Filhol and Joly * give figures upon the Southdown, and 

 Hucho ^ upon the Hampshire breed. These results serve only to verify 

 the results of other investigators, and show the variation between breeds. 



Fuller and Kleinheinz,^ of the Wisconsin Station, made a study of the 

 yield, fat, and total solids of the milk of five breeds of sheep; the Oxford, 

 Southdown, Dorset, Shropshire, Merino, and the Montana grade. They 

 included two ewes of each breed in their study, and took the average of 

 the two results as the average of the breed. In determining the milk 

 yield, the lamb was weighed before and after sucking the mother ewe. 

 This was repeated at frequent interv'als during a 48-hour period, from 

 which the yield of milk for 24 hours was calculated. They observed 

 that, when the ewes were milked by hand, only about one-half the 

 quantity of milk was obtained as when the first method was used. The 

 results on the two ewes of each breed show a wide variation in milk 

 yield and percentage of fat between the breeds. 



Ritzman,* of the New Hampshire Station, in a recent publication has 

 made a valuable contribution to the present knowledge of ewes' milk. 

 His work dealt especially with the fat content and its relation to growth 

 of lambs. A summary of his results on the fat content of 6 distinct 

 breeds and 11 crossbreeds over a considerable period of years showed a 

 great variation in the percentage of fat. The outstanding feature was 

 that not only did breeds differ in fat content of milk, but individual 

 ewes within the breed differed greatly. Moreover, these individual ewes 

 showed marked differences in fat percentage at different lactation periods. ' 

 This fact was observed by the writers during a preliminary investigation 

 of ewes' milk carried on a year previous to this present investigation. 

 Ritzman concluded that the growth of the lamb was not dependent 

 upon the percentage of fat, but he was of the opinion that it depended 

 mainly on the quantity of milk. No actual milk yields were obtained 

 by him, but an estimation of the yields made by observ^ation was tabu- 

 lated as "high-", "good-", "fair-", and "poor-milking" ewes. 



From a revievr of the literature it is evident that an accurate estima- 

 tion of the quantity and composition of ewes' milk is necessary in order 



' FiLHOL, and Joly. aralysbs du lait de brebis APPARTB^fANT A DIFPERE^fTEs races. In Compt. 

 Rend. Acad. Sci. [Paris] t. 47, no. 35. p. 1013-1014. 1858. 



' Hucho, Hermann, xtntersucetungen uber scHAPMacH mit bbesonderBR ERUCKSiomoCNa 

 DSR OSTFRIESISCHEN MiLCHSCUAFE. In Landw. Jahrb., Bd. 36, Heft 3/3, p. 496-547. 1897. 



■^ Fuller, J. G., and Kleinheinz, Frank, on the daily yield and composition of milk prom ewes 

 OP VARIOUS BREEDS. In Wis. Agr. Exp. Sta. 31st Ann. Rpt. 1903/04, p. 48-50. 1904. 



* Ritzman, E. O. B'ags' milk: its fat content and relation to the growth of lambs. In Jour. 

 Agr. Research, v. 8, 110. 2, p. 2';-36, i fig. 1917. Literature cited, p. 35-36. 



