776 EXPERIMENT STATION RECORD. [Vol.35 



Two lots of two pure-bred Jersey cows each were fed a basal ration of silage, 

 corn meal, and alfalfa hay from December 20, 1915, to January 16, 1916, when 

 lot 1 was also given 0.5 lb. cotton-seed oil per head daily for two weeks, then 

 increased to 1 lb. daily for two weeks, after which no cotton-seed oil was fed. 

 Lot 2 received the basal ration throughout. Samples of butter from the mixed 

 milk of each lot, morning and evening milking, were collected at the end of 

 the second week of each period and at weekly intervals from the second week 

 until the end of the test. 



The milk fat fi'om the two lots on the basal ration was almost identical in 

 composition, but during the oil feeding period the saponification number for 

 the fat of lot 1 decreased from 229.24 to 224.65, while with lot 2 there was little 

 change. The soluble fatty acids decreased with oil feeding and the insoluble 

 acids rose from 88.41 per cent to 89.3 per cent. The mean molecular weight of 

 the insoluble acids increased from 259.06 to 264.75 during the oil feeding period. 

 The mean molecular weight of the insoluble fatty acids of the cotton-seed oil 

 was 292.8. The iodin number increased from 29.56 to 34.32 during the oil 

 feeding period. The unsaponifiable matter in the butter remained practically 

 constant throughout the experiment, and the variations in acid number, 

 Reichert-Meissl number, and acetyl value were insignificant. With the Halphen 

 test the fat of lot 1 showed a coloration corresponding to 0.5 or 0.6 per cent 

 cotton-seed oil content during the period when 0.5 lb. oU was fed daily and 1 

 per cent oil content during the period when 1 lb. of oil was fed. The specific 

 gravity of the milk fat was somewhat lowered and the melting point slightly 

 raised while on the oil ration. 



From these data the authors conclude that some change other than a simple 

 transfer of cotton-seed oil to the milk fat had occurred. It was found that 

 the addition of oil to the ration had the same general effect on the constants 

 of the milk fat as an advance, in this instance, of five weeks in the lactation 

 period. 



" Cotton-seed oil, when fed in small quantities, was not transferred in any 

 considerable amounts directly to the milk fat. Some of the substances of which 

 the oil is composed apparently were transferred in a greater amount than 

 others. The constituents of the oil did not reach the milk fat in those same 

 combinations or proportions in which they exist in cotton-seed oil." 



The more important literature pertaining to the subject is reviewed. 



Important factors afEecting machine milking', C. Laesen (South Dakota 

 Sta. Bid. 166 {1916), pp. 394-421, figs. 9). — As a result of tests ranging from 

 7 months to 5 years and 3 months with seven makes of machines, the author 

 points out factors other than the merits and demerits of different kinds of 

 machines which have been found important in making machine milking a 

 success. A comparison of the different makes of milking machines was not 

 involved in these experiments. 



In an experiment upon the germ content of machine-drawn milk the pail, 

 rubber tubes, and all cups of a milking machine were thoroughly cleaned and 

 scalded. The tubing and cups were kept in a disinfectant solution between 

 milkings. The milk pail after being cleaned, rinsed, and steamed was kept in 

 the milk room in an inverted position on a shelf between milkings. The aver- 

 age number of germs per cubic centimeter in the milk from the first cow with 

 the machine was 5,325, from the second cow 3,017, and from the third cow 

 3,012. It is stated that thoroughly steaming the milk pails just before milk- 

 ing has been the means of greatly reducing the germ content of milk. 



Results of experiments with disinfectants for the parts of milking machines 

 showed that several substances are satisfactory, nothing being better for cheap- 

 ness and simplicity than ordinary lime. 



