FIFTY-SECOND ANNUAL CONVENTION 223 



pond, but the roughage can be fed twice a day. Some dairy- 

 men feed grain on the silage. 



Water 



A plentiful supply of fresh, clean water is essential on 

 the dairy farm. The demand for water by the dairy cow 

 depends mainly upon the air temperature, the quantity of 

 milk produced and of succulent feed in the ration. The 

 quantity of water drunk in cold weather is about the same 

 as in moderate weather, but is much less than in hot weath- 

 er. If large quantities of such feeds as beets or mangels 

 are fed, very little water is required. 



In experiments at the Beltsville station cows were 

 watered once, twice and at will from watering cups. Cows 

 watered once a day drank less and produced less than 

 when watered twice a day or at will. Cows watered twice 

 a day drank as much but produced less than when watered 

 at will. The cows used were average producers and the 

 maximum difference found in production, between watering 

 once a day and at will, was only about 5 per cent. The 

 higher the production the greater the benefit to be derived 

 from frequent watering. Sorne low-producing cows fed 

 silage, hay, and grain refused to drink more than once a 

 day in cold weather. With cows similar in production and 

 receiving the same kind of feed, water consumption was 80 

 per cent greater in hot summer than in cold winter weather. 

 The demand for water was greatest after eating hay. In 

 cold weather cows prefer water than has been warmed and 

 will drink more of it, though experiments at several stations 

 show that the amount of production is influenced but little 

 by warming the drinking water. 



Salt 



Dairy cows should have all the salt they want. The 

 quantity consumed will vary with the kind of feed and size 

 of the animal. Experiments have shown that ordinary cows 

 in milk will require about 1 ounce of salt a day. Heavy 

 producers should get more. Many dairymen mix salt with 



