Studies on the Control of Parakeratosis in Swine

돼지 부전각화증(不全角化症)의 예방(豫防)에 관한 연구(硏究)

Two experiments were conducted to establish a program for the prevention of swine parakeratosis occurred recently in Korea. In the first experiment, 11 rations which were considered to be related clinico-pathologically to the incidence of parakeratosis and 5 rations not to be related were collected at farms during the period from June, 1979 to December, 1980. In addition, 23 commercial rations and 10 ingredients were also collected at feed dealers or farms. The feed samples were analyzed for calcium, zinc and unsaturated fatty acid. In the second experiment, the efficiencies of adding zinc carbonate (150mg/kg diet) with or without soybean oil (5ml/kg diet) to two control rations were tested using 20 weanling pigs. One of the control rations had low zinc (41mg/kg) and normal calcium (0.64%) and the other low zinc (57mg/kg) and high calcium (1.42%). The results obtained are as follow: 1. Content of zinc in the rations induced parakeratosis ranged from 35 to 80mg/kg with a mean of 49mg/kg; whereas those of rations not induced ranged from 97 to 182mg/kg with a mean of 182mg/kg. The difference between two means was highly significant (p<0.01). 2. The calcium content in rations related to parakeratosis was ranged from 0.56 to 1.80% with a mean of 1.30% whereas that of not related was ranged from 0.63 to 1.37% with a mean of 1.07%. The highly significant difference of calcium content between two rations were recognized (p<0.01). The calcium contents of both rations were markedly higher than that of generally recommended value of 0.40~0.80%. 3. The contents of unsaturated fatty acid in induced rations was a mean of 4.42% and it was significantly lower (p<0.01) compared with those in not induced rations with a mean of 6.70%. The content of unsaturated fatty acid of commercial rations was ranged from 5.25 to 7.81% with a mean of 6.29%. 4. Zinc content of 15 commercial ration samples among 23 were less than 97mg/kg and 21 rations contained more than 1.03% of calcium. 5. Addition of zinc carbonate to the two control rations which are low in zinc content or high in calcium content were resulted in preventive effect on the incidence of swine parakeratosis. 6. It may be concluded that the incidence of swine parakeratosis was closely related to the low zinc, excess calcium and low unsaturated fatty acid in rations, most of the commercial rations contained low in zinc and high in calcium as compared with the recommended contents. Content of Unsaturated fatty acids in the commercial rations, however, were sufficient for the prevention of parakeratosis in swine.