The effect of decreased growth rate on frequency and severity of osteochondrosis in pigs.

Rapid weight gain seems to be related to high incidence and severity of osteochondrosis. For this reason the effect of weight gain on osteochondrosis was investigated. In one experiment including 18 pigs, frequency and severity of osteochondrosis in pigs on a low caloric intake and in those on a high caloric intake (ad libitum feeding) were compared. In another experiment 8 pigs from 2 litters of pigs with a mainly wild hog ancestry were studied. These pigs had a much lower growth rate than modern domestic pigs and their constitution was different. The results of these two experiments were unequivocal. Animals with a low weight gain, nutritionally or genetically induced, had an incidence of osteochondrosis which was close to zero. It was considered that the very high growth rate in the modern domestic pig is the main reason for the high incidence of osteochondrosis. High growth rate is the result of selective breeding and intensive feeding. There are some morphologic characteristics of the modern domestic pig similar to those seen in acromegaly in man and in animals treated with growth hormone.