344 IOWA DEPARTMENT OP AGRICULTURE 



Succulent feeds are very essential in profitable milk production. Dur- 

 ing the summer months succulence may be obtained from pasture grass, 

 until the hot, dry weather makes it necessary to add corn silage or 

 soiling crops. For winter feeding, corn silage is the most economical 

 source of succulence under most farm conditions. Succulence is needed 

 partly because the dairy cow is producing a product high in per cent of 

 water, and partly because it has a good effect upon her system. 



What "Balance" Means. 



By balance of nutrients is meant a proper proportion between the di- 

 gestible nutrients, protein, carbohydrates, fat and ash. Every food nu- 

 trient has several functions to perform in the body. The carbohydrates 

 are used largely for the production of heat and energy, but may also be 

 converted into body fat and stored as such. In the case of the milk- 

 producing cow, a large quantity of the carbohydrates is used in the pro- 

 duction of butter fat and milk sugar. 



The fats are more concentrated heat and energy producers than car- 

 bohydrates, a given quantity having two and one-fourth times the heat 

 and energy value. They serve the same purpose as the carbohydrates in 

 the ration. 



Proteins are used for building up and replacing muscular and other 

 active tissues. In the case of milk-producing cows they are used in the 

 production of the casine and albumin of milk. In the case of pregnant 

 animals, proteins are used for the growth of the fetus. Proteins cannot 

 be replaced by either fats or carbohydrates for the building of body and 

 milk protein. Owing to the fact that their cost is usually much greater 

 than that of the carbohydrates, where they are only equal in value to 

 the carbohydrates in heat and energy production, proteins should not be 

 fed in excess of the amount necessary for body maintenance and milk 

 secretion. 



The ash or mineral matter has not received the attention it merits 

 from the feeders of live stock, but experimental work in progress at a 

 number of the stations indicates that in the near future this nutrient 

 will receive much more attention. The main function of the ash is to 

 build up bone in the growing animal and also in the fetus, and to form 

 the mineral portion of milk. 



The best combination of these nutrients will vary with the individual 

 cow, the quantity and quality of milk she gives, the prices of feed-stuffs, 

 and her condition as to whether she is pregnant or not. Cows that have 

 a tendency to become too fleshy need less carbohydrates and more pro- 

 tein in proportion, and cows with the opposite tendency more carbohy- 

 drates. As milk contains relatively large amounts of protein, fats and 

 ash, the ration fed should carry a liberal supply of these nutrients so 

 that the cow will not have to draw from her own body to make up a 

 deficit. At the Wisconsin Experiment Station it was found that in 110 

 days a dairy cow, fed a liberal ration, yet one deficient in lime, gave up 

 25 per cent of all the lime of her skeleton; Similar results have been 

 secured where cows have been fed rations sufficient only to maintain 



