Purdue University Agricultural Experiment Station Lafayette, Indiana
Mimeo A.H. 209 June, 1957
PRODUCING LEANER MARKET HOGS BY DIFFERENT FEED COMBINATIONS AND CONTROLLED CORN INTAKE
C. E. Jordan, W. M. Beeson and J. R. Wiley Department of Animal Husbandry
Increasing consumer demand for pork meats with more lean and less fat, and a declining market for lard, have caused much interest in meat-type market hogs. Research has shown that the type of ration fed to market hogs can be used as a means of increasing the proportion of lean meat in the carcasses. There is general agreement that limited feed intake, particularly during the fattening period, results in reduced fat deposition. This may be accomplished either by actually reducing the amount of a ration fed daily or by using some type of "filler” to dilute the ration.
With these facts in view, this research was initiated. The basic objectives were? (l) to determine diets and methods of feeding hogs which would produce satisfactory growth rates, efficient feed utilization, and carcasses with less fat and more lean tissue; (2) to correlate economy of production with the production of leaner hog carcasses of acceptable quality; and (3) to determine an easy yet accurate method of estimating the leanness of hog carcasses.
Experimental Procedure
Feeding Trials;
This study consists of four pasture trials. The pigs were purebred Durocs from the Station herd. Pasture was a mixture of Ladino clover and alfalfa. It was clipped as necessary to provide a succulent growth at all times. Automatic waterers were provided in each lot. The pigs were weighed at the beginning and end of each experiment and at 14-day intervals. Pigs were randomly allotted, keeping sex distribution equal and initial weight as uniform as possible. Each pig was fed to a slaughter weight of 215 to 230 pounds.
Experiment 1; Five lots of 12 pigs per lot (6 barrows and 6 gilts) were fed on pasture. The average initial weight was approximately 47 pounds. With exceptions noted later, the treatments were as follows? Lot 1 - High energy (shelled corn, protein supplement, mineral mixture .and salt self-fed, free choice); Lot 2 - High energy, followed by medium energy (shelled corn, protein supplement, mineral mixture and salt self-fed, free choice, to an average weight of 125 pounds; then crimped oats was substituted for the shelled corn); Lot 3 - Medium energy (crimped oats, protein supplement, mineral mixture and salt self-fed, free choice); Lot 4 - High energy, followed by low energy (shelled corn, protein supplement, mineral mixture and salt self-fed, free choice, to an average weight of 125 pounds; then the grain was omitted and protein supplement limited to 0.75 pound hand-fed per pig daily); and Lot 5 - Low energy (limited protein supplement hand-fed at the rate of 0.75 pound per pig daily, mineral mixture and salt self-fed, free choice).
The protein supplement fed in all lots was Purdue Supplement C fortified with a vitamin	supplement (Table 1), Iodized salt was used.
Experiment 2:	Four lots of 10 barrows each were hand-fed limited amounts of
shelled corn on pasture. The average initial weight was approximately 54 pounds. No protein supplement was fed during the experiment, but mineral mixture and iodized