Purdue University Agricultural Experiment Station Lafayette, Indiana
LEVELS OF CALCIUM WITH AND WITHOUT ADDED ZINC FOR GROWING FATTENING SWINE IN DRYLOT
M. P. Plumlee, J. H. Conrad, M. H. Kennington and W. M. Beeson
PURDUE UNIVERSITY
The calcium content of corn and soybean oil meal is low, but animal by-products, such as meat and bone scraps, tankage or fish meal are fairly high in this essential mineral element*. A typical corn-soy growing fattening ration will contain from 0.1% to 0.2/£ total calcium, unless a calcium supplement is added. The reconanended calcium requirement of swine of different weights expressed as percent of the total ration are:	25 to 50 pounds, 0.8Q£; 150 to 250 pounds, 0.55^5 and al 1 breeding stock, 0.6%.
Parakeratosis in Early Weaned Pigs
Previous research at Purdue and other experiment stations has shown that rations high in calcium (above the recommended levels) may cause parakeratosis in swine unless supplemental zinc is added to the ration. In the Purdue study, one trial was conducted using a limited number of pigs to check the effect of calcium level on the incidence of parakeratosis and the growth rate of early weaned pigs. Pigs 3 weeks of age were fed a semi-purified diet of Drackett (isolated soybean protein), corn starch, cerelose, fat, minerals and vitamins. One group of Duroc pigs was fed a diet containing 0.68$ calcium and the other was fed a diet containing 1.06$ calcium. The parakeratosis pig and the normal pig on the cover are representative of pigs from these treatments.
In another experiment, in which 6 pigs showed various degrees of parakeratosis, the addition of zinc as zinc oxide brought about an immediate improvement in the condition.	The	level of zinc added was 100 p.p.m.	(5-65 grams of zinc oxide	per ICO
pound).	Six	Duroc pigs fed a diet	identical to	the high calcium diet in table 1
gained an average of 0.16 pound per day for the 2 weeks period prior to the addition °f zinc.	(The high calcium ration	contained 28	p.p.m. by analysis). For	the two
weeks period	immediately following	the addition	of 100 p.p.m. zinc, these	same pigs
gained 0.84 pound daily and showed a rapid improvement in their skin and hair condition.
Effect of Calcium Levels and Zinc on Practical Swine Rations
The purpose of this experiment was:
1.	To determine the effect of corn-soy rations containing different levels of calcium for growing-fattening swine.
2.	To determine the effect of adding zinc to corn-soy rations containing different levels of calcium for growing-fattening swine.
Mimeo. A. H. 187 September 14, 1956 Report)