104 MAINE STATE COLLEGE 



the digestible dry substance of the ration, for instance, whether be 

 shall buy skimmed milk or corn meal to furnish part or all the rest 

 of the ration must be decided by the cost of these articles of food. 

 According to the Station experiments eight pounds of skimmed 

 milk, will, under such circumstances make about the same growth 

 as one pound of corn meal. 



But if it is a question of feeding swine and no skimmed milk is 

 furnished from the farm, then the farmer can afford to pay for 

 some milk much more than a price corresponding to the cost of 

 corn meal. The foregoing experiments show that a certain mini- 

 mum amount of skimmed milk paid at the rate of twenty-five cents 

 per hundred pounds, at least, with corn meal at one dollar per 

 hundred, and peas at two dollars per hundred. 



To sum up, corn meal is just as good as skimmed milk for part 

 of the ration, and so far market values should determine which is 

 to be used, but for the remaining part of the ration the milk has a 

 special and superior value that may overrule the considerations of 

 the market. The same would be true of any nitrogenous food that 

 is, needed to add a certain kind of strength to a ration. 



Summary of Feeding Experiments With Swine. 



(1.) The foregoing experiments teach that the profits of 

 feeding swme may depend, in part upon the way in which 

 foods are combined, and not wholly upon market values. A 

 certain proportion of nitrogenous foods like skimmed milk 

 pea meal and gluten meal increased the eflB.cieney of the ration 

 in a marked manner. 



In six feeding periods where the rations compared contained 

 practically the same digestible material, 2643 pounds of diges- 

 tible food with a nutritive ratio* ranging from 1:5.2 to 1:6.1 

 produced 890 pounds of growth, while 2651 pounds of digesti- 

 ble ford with a nutritive ratio varying from 1:8.9 to 1:9.4 pro- 

 duced 617 pounds of growth. It took nearly one-Half more 

 food to produce a pound of growth with one set of rations 

 than with, the other. 



(2.) There seemed to be no advantage in putting into the 

 rations more than a certain proportion of protein. A ratio 

 of 1:6 was compared with one of 1:3.6, and one of 1:5.6 was 

 compared witn another of 1:4.4, the resulting growth being 

 practically the same. 



* The nutritive ratio is the relation of the digestible protein to the digestible 

 carbohydrates and fats. A ration having a nutritive ratio of 1 :6 contains one 

 pound of digestible protein to six pounds (or the equivalent) of digestible carbo- 

 hydrates. A narrow ratio is one having much protein, and a wide ratio means 

 a small proportion of protein. 



