Effects of hormonal growth promotants (HGP) on growth, carcass characteristics, the palatability of different muscles in the beef carcass and their interaction with aging

Abstract

Abstract. Effects of hormonal growth promotant (HGP) implantation on liveweight, carcass and meat quality measurements were examined using 80 Angus yearling cattle. After entry to the feedlot, 40 steers and 40 heifers were implanted with Revalor-S (28 mg oestradiol and 140 mg trenbolone acetate) and Revalor-H (20 mg oestradiol, 200 mg trenbolone acetate), respectively. Cattle were slaughtered after 55 and 65 days on feed. Samples from the Mm. longissimus dorsi, biceps femoris (the cap and body portions), gluteus medius (the eye and D portions), infraspinatus and triceps brachii were prepared for sensory testing after aging for 5 and 21 days after slaughter. A total of 854 muscle samples were cooked by grill (601) or roast (253) methods and served to consumers using the Meat Standards Australia taste panel protocols.When adjusted to the same initial liveweight, implantation with Revalor-H and Revalor-S resulted in a 4 and 7% increase in slaughter weight, respectively. Implantation resulted in an increased ossification score in steers (P < 0.05), but not in heifers. There was a significant interaction (P < 0.05) between HGP implantation and days aged for shear force. There was a small effect of HGP implants on compression (P < 0.05), but not on cook loss and intramuscular fat percentage. Muscles differed in their response to HGP implantation (P < 0.05) for tenderness, overall liking and palatability scores. Muscles also differed in their aging rates after slaughter (P < 0.05). The greatest response in sensory scores to HGP implantation was found in those muscles that had the highest aging rates. Possible mechanisms by which muscles differed in their response to HGP implantation are discussed.

Meta-analysis of the published effects of HGP use on beef palatability in steers as measured by objective and sensory testing

“…et al (1991) 0.12 0.20 Huck et al (1991) 0.23 0.20 Hunt et al (1991) -0.15 0.39 Gerken et al (1995) 0.40 0.25 Samber et al (1996) 0.24 0.10 Foutz et al (1997) 0.32 0.17 Rumsey et al (1999) 0.95 0.33 Pritchard et al (2000) 0.00 0.20 Roeber et al (2000) 0.37 0.11 Barham et al (2003) 0.37 0.11 Platter et al (2003) 0.63 0.19 Reiling & Johnson (2003) WA-1 trial: Thompson et al (2008a) This trial, utilising three cooking methods, covered a wide range of muscles for heifers and steers. The details are covered in full in Thompson et al (2008a). Here only the details for the M. longissimus for steers are extracted.…”

“…The studies considered in this meta-analysis are papers that have appeared in refereed journals for which estimates and standard errors are available, including the recent Australian studies (Hunter et al 2001;Thompson et al 2008aThompson et al , 2008bWatson et al 2008b;McIntyre et al unpubl. data) summarised in the Results section.…”

Production and processing studies on calpain-system gene markers for beef tenderness: Consumer assessments of eating quality1

“…In addition, Thompson et al (2008) showed that the effects of HGP interact with muscle, being larger in muscles with the greatest ageing rate, such as the striploin, and also that the reductions in consumer panel scores (for steers implanted with Revalor-S and heifers implanted with Revalor-H) were greater for steaks aged for 7 d (the time at which our MSA consumer assessments are conducted) than those aged for 21 d.…”

Development of the Meat Standards Australia (MSA) prediction model for beef palatability

“…The use of HGPs has been studied extensively in the database (Thompson et al 2008a;Watson 2008;Watson et al 2008b), and in a range of associated experiments reported elsewhere. The result was an HGP penalty of the order of 3-6 MQ points on meat palatability, depending on the muscle which is further adjusted with aging.…”