Investigations with Swine. 513 



It is shown that the small, immature, unfinished pig yields the 

 least, and the large, mature fat one the greatest per cent of dressed 

 carcass. For each 100 Ibs. of live weight over the first 100 Ibs. the 

 yield is approximately 4 per ct. more dressed carcass. 



838. Tuberculosis thru feeding. At the Iowa Station 1 Kennedy, 

 Robbins, and Bouska selected 40 pigs believed to be free from tuber- 

 culosis. Two lots of 10 pigs each were kept on separate pastures 

 and 2 other lots of 10 pigs each confined in dry yards. Corn and 

 creamery skim milk which had been pasteurized to destroy all dis- 

 ease germs was fed to all alike. The milk of one lot on pasture and 

 one lot in the yard was, before feeding, infected with the germs of 

 tuberculosis. When the pigs were slaughtered at the end of 196 days 

 it was found that all that had been fed on infected milk, 20 in 

 number, were tuberculous. Of those not given infected milk, 2 

 proved tuberculous and 18 were free from the disease. 



This experiment shows the supreme necessity of pasteurizing all 

 creamery by-products before they are returned to the farm for feed- 

 ing purposes, a practice required by law in Denmark, and now fol- 

 lowed by some creameries in this country. 



Kennedy and Dinsmore of the same Station 2 grain-fed a carload 

 of tuberculous cattle on pasture from October to December. Thirty 

 healthy, vigorous pigs followed the cattle to work over the droppings, 

 while 6 less thrifty pigs from the same lots were kept in a separate 

 enclosure as a check. When the pigs were slaughtered in February, 

 80 per ct. of those that had run with the steers were found tuber- 

 culous, while all in the check lot were free from the disease. This 

 shows that pigs running with tuberculous cattle may thereby become 

 quickly infected with the disease. 



II. BACON PRODUCTION. 



839. Canadian bacon requirements. The " Wiltshire side" of the 

 English bacon trade is the entire half of the dressed pig, minus the 

 head and feet. Day of the Ontario Agricultural College 3 states that 

 to produce a good Wiltshire side requires in the pig " certain definite 

 peculiarities as to weight, condition, and conformation." He places 

 the live-weight limits at between 160 and 200 Ibs., preferably 175 to 

 190 Ibs. The bacon pig should be long from shoulder to ham, and 

 light in the shoulders, neck, and head. The fat should be so placed 

 that when the carcass is split lengthwise along the back the layer of 



1 Bui. 92. 2 Bui. 107. 3 Swine, p. 13. 



34 



