372 EXPERIMENT STATION EECORD. 



It is stated that these records are from one of the oldest and best herds of 

 Red Danish cattle in Denmark, and that this may account in part for the strong 

 showing of the 2-year-olds. 



World's record for a dairy cow broken {Hoard'' s Dairyman, 47 {1914), No. 

 13, p. 480, fig. 1). — An account of a 7-year-old Guernsey cow, May Rilma, which 

 has recently completed a 365-day test in which she gave 19,639.5 lbs. milk, con- 

 taining 1,059.59 lbs. milk fat. This record is said to surpass that of any cow 

 thus far. 



Hereditary transmission of fat percentage, J. J. Dunne {Hoard's Dairyman, 

 41 {1914), No. 15, p. 553). — Observations made for 12 years on a herd of red 

 Danish cows tend to support the theory that Mendel's law dominates the 

 variations of the fat percentages. It is believed that there are only two con- 

 stant types in the herd, namely the cows with a tendency to give rich milk, 

 i. e., 4 per cent, and those with a tendency to give poor milk. i. e., 3.3 per cent, 

 while the animals with an intermediate fat percentage might be described as 

 the crossbred product of the two foregoing types. 



Cells in milk derived from the udder, R. S. Breed {Netc York State Sta. 

 Bui. 380 {1914), pp. 139-200, figs. 4). — The purpose of this investigation was to 

 determine the normal number of cells present in milk, to discover the reason 

 for variation in the cell content of the milk of individual cows, and to study the 

 influence of the milking machine on the number of cells present in the milk. 

 The method used in counting the cells was the direct microscopical method in 

 which, the counting was done under an oil-immersion lens (E. S. R., 26, p. 274), 

 The method of preparing dried milk smears here used gave excellent results 

 and is deemed more accurate than where the cells are counted in centrifuge 

 sediments. 



It is pointed out that cells of two entirely different kinds are discharged in 

 the milk of all cows throughout the entire lactation period. The larger num- 

 ber of the cells are leucocytes (white blood corpuscles) while a smaller number 

 are epithelial cells, nuclei, or other fragments of such cells. It was found that 

 the largest average number of the cells present in milk occur in colostral milk 

 but equally large numbers are occasionally found in milk drawn at any portion 

 of the lactation period. High counts are more common during the latter part 

 of the lactation period than during the height of lactation, although the average 

 total number of cells discharged per milking is less. There are marked daily 

 variations in the number of cells discharged which do not show a close correla- 

 tion with any of the suggested causes for such variations. No constant rela- 

 tion exists between the number of cells in fore milk and that obtained later, 

 although there is an increase in the number of cells in the strippings which 

 may possibly be due to manipulation of the udder or to other factors. 



The four quarters of the udder do not act as a unit in the discharge of the 

 cells but show as wide variations in number and character of the cells dis- 

 charged as do separate udders. 



Of 122 cows whose milk has been examined, 59 gave cell counts under 500,000 

 per cubic centimeter, 36 gave counts between 500,000 and 1,000,000, and 27 gave 

 counts over 1,000.000 per cubic centimeter. The average cell count was 868,000 

 per cubic centimeter. The milk of all these cows was apparently normal. In 

 an examination of goat's milk the numbers of cells found were uniformly high, 

 the average count for 11 goats being 7,465,000 per cubic centimeter. 



Changes of a considerable amount in the vacuum used to operate milking 

 machines were found to be entirely without effect on the cell content of the milk. 

 The station herd which has been accustomed to machine milking showed a 

 much lower average cell content than the milk of other herds, indicating that 

 the number of cells present in machine drawn milk is somewhat less than that 



