Lifetime implant protocols can affect both the eating quality and tenderness of beef. Thus, it's important to choose implant programs based on specific marketing targets for cattle.

Colorado State University researchers studied the effects of repetitive use of anabolic implants on beef carcass quality, tenderness and consumer ratings for palatability in crossbred steer calves. Steers from five ranches were randomly allocated to one of 10 different lifetime implant strategies or to a nonimplanted control group. Cattle were implanted at some or all of five phases of production (branding, weaning, backgrounding, feedlot entry or reimplant time).

  • Carcasses from the control group had higher marbling scores than carcasses in all other treatment groups.

  • Implanting steers at branding, weaning or backgrounding vs. not implanting steers at these production stages did not affect marbling scores.

  • Steers implanted twice during their lifetime produced carcasses with higher marbling scores than did steers receiving a total of four or five implants.

  • Steaks obtained from carcasses in the control group had lower Warner-Bratzler shear force values and were rated by consumers as more desirable for tenderness than steaks from carcasses in all other treatment groups.

  • Implanting steers at branding or weaning did not affect shear force values or percentage of consumers rating overall eating quality of steaks as satisfactory.

  • Implanting steers at backgrounding vs. not implanting steers at this production stage increased shear force values, but did not influence consumer ratings of overall eating quality of steaks as satisfactory.

  • Steaks from nonimplanted steers were rated as more desirable for overall eating quality than steaks from steers implanted two, three, four, or five times.

  • Use of implants increased average daily gain by 11.8-20.5% from weaning to harvest compared with nonimplanted controls.

  • Implant strategies increased hot carcass weights of steers by 8.9-13.8% compared with the control group.

  • Use of implants also increased longissimus muscle area and decreased estimated percentages of kidney/pelvic/heart fat, but did not affect dressing percentage or adjusted fat thickness.

The scientists say producers retaining ownership of steer calves destined for marketing on a “quality-oriented,” value-based grid, may choose not to implant cattle until backgrounding or feedlot entry to minimize the risk of detrimental effects on beef quality associated with “aggressive” lifetime implant strategies.

J. Anim. Sci., May, 2003. 81:984-996

Meanwhile… Texas research shows using a moderate implant program in Bos indicus-influenced cattle has no detrimental effects on beef tenderness and consumer acceptability.

Texas Tech University scientists in Lubbock addressed concerns that the use of implants, particularly those containing trenbolone acetate, may have detrimental effects on carcass quality and beef tenderness. The objectives of the study were to determine the effects of various commonly used implant regimens on Warner-Bratzler shear force values, sensory properties and consumer satisfaction of beef top loin steaks from cattle of Bos indicus influence.

Steaks sampled after 3, 7 and 14 days of aging indicated that unimplanted cattle had lower shear force values than those from implanted animals. No differences in shear force values were found between the two treatments or the control groups for steaks sampled following a 21-day aging period.

Steaks from implanted animals sampled after 3, 7 and 14 days of aging were rated lower for initial and sustained trained sensory panel tenderness scores. Consumers failed to detect any differences in steak samples related to implant treatment after 7 and 14 days of aging.

Consumer education level and family income did not affect overall acceptability or tenderness acceptability; however, consumers with postgraduate degrees recorded lower overall quality, beef flavor, juiciness and tenderness scores than consumers in all other education classifications. Additionally, family income had no effect on overall quality, beef flavor, juiciness or tenderness scores.

J. Anim. Sci., Dec. 2003. 81:3052-3056

To submit items for “Research Roundup,” e-mail or send fax to 952/851-4601.