DAIRY FARMING DAIRYING— AGROTECHNY. 879 



taking, while the results from the standpoint of jjrofit will be practically the 

 same." 



Report of the composition of milk from herds competing for advanced 

 registration, M. H. Pingree (Pennsylvania Sta. Rpt. J 906, pp. 5fi-i)3, charts 

 3). — Otficial examination of about 1,500 milk samples, representing the product 

 of 128 cows from 11 herds, was made in cooperation with the Dairy Breeders' 

 Association in connection with the advanced registration of dairy cows. 

 Records of 18 Guernsey cows and of 24 Ayrshire cows are reported in detail. 

 Those of tlie Guernsey breed are discussed witli respect to clianges of com- 

 position during the lactation period and to the influence of change from barn 

 feeding to pasturage upon the composition of the milk, and tliose of botli 

 breeds with respect to tlie relative variability in composition of milks from a 

 breed yielding very rich millc as compared with those from a breed yielding 

 niillv of moderate richness. The following conclusions were drawn from the 

 study : 



" Changes during advance of lactation period. — The percentages of butter fat 

 showed on the average a tendency to increase throughout the entire lactation 

 period, but the increase was most marked during the first five months and last 

 month. 



" Effect of changes from barn to pasture. — The percentage of solids-not-fat 

 decreased somewhat as the lactation period advanced. In the majority of 

 cases studied both the percentages of fat and the solids-not-fat, but particu- 

 larly the latter, suffered a slight depression immediately following the change 

 of the animals from barn to pasture, but tended to increase thereafter under 

 the influence of advancing lactation. Tlie average fat results, however, were 

 somewhat higher for the pasture months than for the barn period, due probably 

 to a disproportionately largo number of the cows being in an advanced stage 

 of lactation during tlie summer months. 



" Relative variability of Guernsey and Ayrshire milks. — The range of varia- 

 tion in the percentages of fat for both the Guernsey and Ayrshire breeds was 

 about 39 per cent of the respective fat averages, which were 5.1.3 per cent for 

 the Guernseys and 4.00 per cent for the Ayrshires." 



Rules relative to testing dairy cows (Ifassaeliusctts Sta. (J ire. 9, pp. 6). — 

 -A statement regarding the conditions under which the station cooperates with 

 the various breeders' associations in offlcial tests of pure-bred cows, the duties 

 of the supervisor, the testing of samples, additional rules with the churn test, 

 special rules of the different associations, yield of milk and butter fat required 

 for advanced I'egistry, and ap])aratus required and furnished. 



The significance of leucocytes and streptococci in the production of a 

 high-grade milk, M. E. Pennington and E. L. Roberts (Jour. Infect. Diseases, 

 5 (J90S), No. 1, pp. 72-(S'.)). — The authors discuss in considerable detail the 

 results obtained in examinations of milk, with special regard to pus cells and 

 streptococci, from a herd of about 70 cows which is l>eing maintained for the 

 commercial production of a high-grade milk, and the relation of the findings 

 to the physical condition of the cows. Their deductions from the investigations 

 follow: 



"A correlation of the finding of streptococci or of many leucocytes in milk 

 by the laboratory, with the physical condition of the cows in a herd main- 

 tained for the production of a very clean milk, would seem to show that in 

 many cases there is a connection between such findings and the condition of 

 the cow, both in relation to specific udder and to syjjteniic affections. Such 

 pai-allelism seems to obtain for the end of the laclation i)eriod. for tlie beginning 

 of an udder inflammation, for an attack of cowpox, and, possibly, for chemo- 



