Research Progress Report 103
March, 1964
Comparison of Protein Supplements for Swine fed Free-Choice or in a Mixed Ration
J.R. Foster, H.W. Jones and R.A. Pickett, Animal Sciences Department
Summary
Pigs fed a complete mixed ration gained faster than those fed shelled corn and supplement free-choice except when Purdue Supplement 5 was used. However, the pigs fed free-choice consumed less total feed, required significantly less feed per lb. of gain, and made more economical gains than those fed a complete mixed ration.
A variation in calcium and phosphorus levels in the soy supplement and Purdue Supplement 5 did not affect rate of gain significantly.
There were no statistically significant differences in backfat, length or percent ham and loin between treatments. Those pigs fed Purdue Supplement 5 had significantly lower dressing percentages than pigs fed the other supplements.
Supplements
Recent research at Purdue compared three supplements fed free-choice with shelled corn for growing-finishing swine (RPR 38). Pigs fed a fortified supplement of soybean meal,
20 percent meat and bone scraps and 10 percent dehydrated alfalfa meal, gained significantly faster than pigs fed a fortified soybean meal supplement or Purdue Supplement 5.
The objectives of this experiment were to repeat the comparison of these three supple-
ments fed free-choice with corn as well as fed in complete mixed rations and to compare modification of the calcium and phosphorus levels in the supplements.
Procedure
Twelve lots of six barrows and six gilts each averaging 54 pounds were formed by allotting pigs according to sex, weight and litter. The treatments were as follows:
(see Table 1 for supplement details)
Supplement	Complete mix lot number	Free-choice lot number
SBM- "A”	1	2
5-”A"	5	6
Mod. 2	3,9	4, 10
SBM-"B"	7	8
5-"B"	11	12
Supplements SBM-"A", Mod. 2, and Supp. 5-"A" contain 3.25 percent calcium and 2.0 percent phosphorus but contain 38.7, 40.0, and 45.8 percent protein, respectively. The calcium and phosphorus levels of supplement SBM-"B" and Supp. 5-"B" were adjusted to provide 36 gm. calcium and 22 gm. phosphorus per pound of protein. This same ratio existed in Modified Supplement 2.
Pigs receiving the complete mixed rations were fed a 16 percent protein mixture of
PURDUE UNIVERSITY • Agricultural Experiment Station • Lafayette, Indiana