354 FEEDS AND FEEDING 



Cows exposed to cold rains or other severe weather shrink in milk 

 flow and may yield milk low in fat. 



When cows are turned from winter stables to spring pastures, usually 

 both the yield of milk and its richness are slightly increased, but after 

 2 to 4 weeks the percentage of fat falls to normal. Especially when the 

 grass is soft and lush, cows lose in weight for a short time when first 

 turned to pasture. 41 The temporary increase in percentage of fat may be 

 due to the fact that such early spring pasture is so watery that the cows 

 cannot secure from it sufficient nutrients to meet the needs for their 

 production and hence are forced to draw on their bodies. Such under- 

 feeding, as has been pointed out, usually increases the fat content of 

 the milk, if the cows are in a good state of nutrition. 



564. Exercise and grooming. Moderate exercise tends to increase the 

 yield of milk and the richness of all constituents except casein, while 

 too much exercise or hard work, such as milk cows are often used for 

 in Europe, decreases the yield and injures the quality of the milk. 



In trials in Germany 42 grooming increased the flow of milk 4 to 8 

 per ct. while in tests by Hills at the Vermont Station, 43 where the un- 

 groomed cows were not allowed to become filthy, it brought no increase. 

 Tho grooming may not increase the yield of milk, it does improve its 

 quality by lessening the amount of sediment and the number of bacteria 

 in the milk and may improve the health of the animals. 



565. Milking machines. Because of the difficulty of securing efficient 

 hand milkers, the use of milking machines attracts wide-spread interest. 

 The various types of machines have now been improved and long-con- 

 tinued trials at various stations 44 show that when cows are milked with 

 the best machines by careful operators and with well-adjusted teat cups 

 there is no injurious effect on the yield or quality of the milk, or on the 

 health of the animals. While with most cows the machine does not draw 

 quite all the milk from the udder and it is necessary to strip by hand, 

 nevertheless a considerable saving in time results from the use of ma- 

 chines. Hooper and Nutter of the Kentucky Station 45 found at the 

 Elmendorf dairy that 2 men required 3 hours to milk 50 cows by hand, 

 aided by a boy to carry the milk to the house. Using 2 units per 

 man, the men, aided by the boy as before, milked these cows in 1 hour 

 and 15 minutes. Later, using 3 units per man, the 2 men alone milked 

 the cows in 1 hour and 45 minutes. When the machines are properly 



"Humphrey and Woll, Wis. Bui. 217; Hills, Vt. Rpt. 1907; Linfield, Utah 

 Bui. 68; Copenhagen Station Rpt. 45. 



^Jour. Landw., 41, 1893, p. 332. 



Vt. Rpts. 1899, 1900. 



"Mairs, Penn. Bui. 85; Price, Tenn. Bui. 80; Haecker and Little, Nebr. Bui. 

 108; Woll and Humphrey, Wis. Res. Bui. 3, also Bui. 173; McMillan, Agr. Gaz., 

 N. S. Wales, 22, 1911, pp. 859-868; Smith and Harding, N. Y. (Cornell) Bui. 353; 

 Larsen, White, and Fuller, S. D. Bui. 144; Hooper and Nutter, Ky. Bui. 186; 

 Larsen, S. D. Bui. 166. 



Ky. Bui. 186. 



