FEEDS FOR SWINE 643 



It has been emphasized before that skim milk, buttermilk, or whey 

 should always be pasteurized at the creamery or cheese factory before 

 being returned to the farm, in order to prevent the spread of tuber- 

 culosis and other diseases. Swine are especially susceptible to tuber- 

 culosis and may contract the disease not only from infected milk, but 

 as Kennedy and Dinsmore found at the Iowa Station, 67 by following 

 tuberculous cattle to work over the droppings. (269) 



958. Skim milk. Many trials have been carried on by the experiment 

 stations to determine the feeding value of skim milk, but in most of the 

 early trials balanced rations of grain and skim milk were compared with 

 unbalanced and inefficient rations of grain alone. This is obviously 

 not a fair basis for determining the value of skim milk, for no progressive 

 farmer now feeds his pigs such an inefficient ration as grain alone when 

 they are not on pasture. To find the actual feeding value of skim milk 

 we should compare it with the best common commercial substitute, which 

 is tankage, or meat meal. Furthermore, just enough skim milk and just 

 enough tankage should be fed to make well-balanced rations, or the 

 comparison will be unfair to one of the feeds. The value of skim milk 

 as a supplement to corn for pigs not on pasture has been directly com- 

 pared with that of tankage in 12 trials 68 at 4 different stations. In each 

 of these trials, which are summarized in the following table, one lot of 

 pigs was fed a ration of skim milk and corn (yellow corn in nearly all 

 cases) in the proper proportions to make a well-balanced ration, and 

 another lot was fed proper proportions of tankage and corn. These com- 

 parisons therefore furnish an accurate measure of the actual feeding 

 value of skim milk for growing and fattening pigs. The trials included 

 a total of 138 pigs, averaging 75 Ibs. in weight at the start, fed for 

 periods averaging 97 days. 



Skim milk vs. tankage as supplement to corn for fattening pigs 



Daily Feed for 100 Ibs. gain 



gain Corn Skim Tankage 



Average ration milk 



Lbs. Lbs. Lbs. Lbs. 



Lot I, fed skim milk 



Skim milk, 7.1 Ibs. 



Corn, 4.6 Ibs 1.36 346 535 



Lot 77. fed tankage 



Tankage, 0.47 Ib. 



Corn, 4.9 Ibs 1.24 404 39 



The pigs fed skim milk and corn in these extensive trials gained 1.36 

 Ibs. a head daily, which was 0.12 Ib. more than those fed tankage and 

 corn. On skim milk and corn there were required only 346 Ibs. corn and 

 535 Ibs. skim milk for 100 Ibs. gain, while the pigs on tankage and corn 

 consumed 404 Ibs. corn and 39 Ibs. tankage for each 100 Ibs. gain. By 



67 Iowa Bui. 107. 



08 Average of 6 trials by Morrison, Bohstedt, and Fargo, Wis. Station (un- 

 published data); 4 trials by Robison, Ohio Buls. 316 and 349; 1 trial by Dvora- 

 chek, Ark. Cir. 38; and 1 by Skinner and Cochel, Ind. Bui. 137. 



