Research Progress Report 333 April, 1968

Supplementation of a Full-feed of Corn for Steers on Pasture with Various Levels of Supplement A or Purdue 64
W.M. Beeson, T.W. Perry and M.T. Mohler
Department of Animal Sciences

Summary
Under pasture finishing conditions, steers self-fed on rolled shelled corn plus either 5 per cent or 10 per cent of Supplement A or either 2.5 per cent or 5 per cent of Purdue 64 gained more rapidly (P < .01) than those fed only rolled shelled corn. Steers fed corn which was supplemented with either level of Supplement A gained more rapidly (P    .01) than those fed corn supplemented with Purdue 64. This indicates that the natural protein contained in Supplement A was better utilized than the predominantly urea protein contained in Purdue 64 (Table 4).

Cattle fed no supplement with their corn consumed from 1.5 to 2.0 pounds less feed per day indicating they were compensating the protein deficiency of their ration by consuming more pasture. The similarity of calculated TDN requirement per pound of gain in all lots would tend to substantiate this assumption.

Pasture apparently afforded very little TDN saving in this research since the cattle required an average of 506 pounds TDN per 100 pounds of gain as contrasted to a normal of 528 pounds for cattle in dry lot.

Cattle fed supplement in addition to corn, dressed nearly 1 per cent more (61.5% vs. 60.4%), had an average of 8 per cent larger (P <.05) loin eye (10.7 sq. in. vs. 10.0 sq. in.) and had a greater (P < .01) backfat thickness (0.57 in. vs. 0.48 in.). No difference in carcass grades among the treatments was found.

The feeding of supplement increased the feed cost per pound of gain by an average of 12 per cent (13.9¢ vs. 12.4¢).

Introduction
In the first year's research (Research Progress Report 301 - April 1967) which was designed to determine the optimal level of supplementation of high energy rations for beef steers on pasture, 0, 5 or 10 per cent corn cobs and either Supplement A or Purdue 64 were compared. The 1967-published data demonstrated that cattle fed the various levels of added ground corn cobs gained at essentially the same rate, but that those fed the lower levels of ground corn cobs required less concentrates per pound of gain than those fed higher levels of ground corn cobs.

In the protein supplement comparisons, those fed Purdue 64 gained at essentially the

PURDUE UNIVERSITY • Agricultural Experiment Station • Lafayette, Indiana