Preliminary studies of "posterior paralysis" in swine

Abstract

A study is in progress of the frequently occurring trouble in swine, commonly referred to as “leg weakness” or “posterior paralysis.” Some preliminary observations are here described. In connection with another experiment, a group of 4 pigs, each about 12 weeks of age, were fed in dry lot for 90 days on a ration consisting of 1 part of yellow hominy feed and 1.4 parts of pasteurized skim milk, together with a mineral mixture made up of charcoal, ground limestone and common salt. At or near the end of the 90-day period, 3 of the 4 pigs developed symptoms of trouble. A stiffness of the hind legs first became evident. The skin became dry, scaly and covered with large, livid spots. The stiffness increased, accompanied by pain. A swelling of the knee joints was noted in one individual. Finally, paralysis developed in the hind legs of 2 of the animals, they being able neither to rise nor to stand. A rapid loss in weight set in at this stage. At the close of the 90-day period, the writer changed the diet for 2 of the pigs. One of them, number 122, was unable to rise or stand, was obviously in pain and was losing rapidly in weight; the other, No. 107, was markedly stiff behind but was still able to walk. To the hominy-skim milk ration, was added 4 ozs. of carrots per animal daily. The mineral mixture was replaced by precipitated bone meal, precipitated calcium carbonate and salt. After 10 days, a decrease in the stiffness and in the skin troubles was noted in pig 107, and rapid growth was resumed. At the end of 5 weeks the stiffness had disappeared and the skin was nearly normal.