The Effect of Protein Level on Feedlot Performance and Carcass Characteristics of Texas Rambouillet Ewes

Abstract

Aged Rambouillet ewes, 5 to 7 years old, are usually culled in Texas.  Some producers have chosen to feed their aged ewes high energy diets, a feedlot practice, before they send them to harvest.  This practice may prove to be profitable as the ewes will gain extra weight and bring more money at sale time.  Research on the feedlot performance of aged ewes is very limited.  The purpose of this research is to compare different protein level on feedlot performance (rate and efficiency of gain) and carcass composition in aged Rambouillet ewes.  A total of 28 ewes were blocked by weight and BCS and randomly assigned to a pen.  The pens measured 3.048 m by 9.144 m.  The trial consisted of 28 ewes placed in one of 14 pens with two ewes per pen.  Pens were allocated to one of three different treatments consisting of four pens on WH (wheat hay), five pens on SBH (soybean hulls), and five pens on GR (grain ration).  These treatments resulted in varying amounts of protein.  Ewes were weighed every 28 days and kept on trial for 84 days.  Carcass characteristics were measured after carcasses were chilled for 24 hours.  Performance was greater (P<0.05) for ewes on GR for total gain, ADG as well as BCS and BCS change.  Feed efficiency was also better (P<0.05) for GR as compared to WH and SBH.  Ewes on GR had greater (P<0.05) fat depth at the twelfth rib than SBH or WH and SBH ewes were fatter than WH with no differences (P>0.05) across treatments in carcass weights or dressing percents.  Upon evaluation of the economic data, the feeding of aged ewes in a down market appears to be unprofitable and actually resulted in a loss.  However, if the market remained steady, profit could be gained by feeding aged ewes.  This research only shows that further focus of commercial operations is needed to determine the actual profitability of feeding aged ewes.