Effects of Zilmax feeding on market dairy cow performance, carcass characteristics, cutability, muscle quality of selected added value beef cuts, and subcutaneous fat quality

Abstract

Thirty-four cull dairy cows were used to investigate effects of zilpaterol hydrochloride (ZH) supplementation on feedlot performance, carcass characteristics, cutability, muscle quality of selected added-value cuts, and subcutaneous fat quality. Feeding ZH had no effect (P > 0.05) on ADG, G:F, DMI, BCS, LS, or BW. Feeding ZH increased (P < 0.05) REA while having no effect on BF, ribeye ratio, or IMF ultrasound measurements. Feeding ZH caused improvements (P < 0.05) in dressing percent, REA, and YG. Zilpaterol hydrochloride had significant effects in increasing primal, subprimal, and cut yields while having no adverse effects on quality. Feeding ZH resulted in less tender steaks that required longer aging times to become comparable to steaks from control (CT) cows. Feeding ZH caused increases (P = 0.03) percentages of C18:1, cis-9, whereas CT cows had higher (P = 0.02) percentages of C14:0. Percentage of PUFA for CT cows tended (P = 0.09) to be higher than ZH-fed cows. Zilpaterol hydrochloride is an effective method for improving muscle and leanness of market dairy cows, however, this treatment has not shown any improvements in tenderness.