GROWTH, CARCASS TRAITS, AND FATTY-ACID PROFILES OF ADIPOSE TISSUES FROM STEERS FED WHOLE COTTONSEED

To investigate the impact of dietary whole cottonseed (WCS) level on fatty acid composition, growth, and carcass traits, 45 Hereford steers were assigned to diets containing 0, 15, or 30% dietary WCS. The 15 and 30% WCS contributed an estimated 3.3 and 6.6% additional lipid, respectively, to the diets. After being fed for 54 d, all animals were weighed and slaughtered, and carcass measurements were obtained. There were no differences (P > .05) among dietary treatment groups in live weight or ADG for the 54-d feeding period. Control steers had larger (P < .05) longissimus muscle areas than steers fed 30% WCS, which accounted for the advantage in yield grade (P < .05) exhibited by the control group. Feeding of 30% WCS resulted in minor increases in linoleic and total polyunsaturated fatty acid content of perinephric fat expressed in both normalized (area percentage) and gravimetric (g/100 g of fresh tissue) formats. There were no significant differences in the monounsaturated or saturated fatty acid content of adipose tissues from animals fed the different diets. Subcutaneous adipose tissue samples were higher (P < .01) in total unsaturates but had lower (P < .05) proportions of C18:0 and C18:1 than perinephric samples. Feeding WCS at the levels reported herein only had minor effects on fatty acid composition of beef adipose tissues.