Effect of hormonal growth promotants on palatability and carcass traits of various muscles from steer and heifer carcasses from a Bos indicus - Bos taurus composite cross

Abstract

Abstract. The effect of several different hormonal growth promotant (HGP) implant strategies on the palatability and carcass traits of different muscles in beef carcasses was investigated using samples from heifer and steer carcasses from a Bos indicus composite breed. In experiment 1, there were seven different implant strategies evaluated in heifers that were given different combinations of up to three implants (implanted at weaning, during backgrounding and at feedlot entry). A total of 112 heifers were slaughtered and 11 muscles or portions were collected from both sides [Mm. adductor femoris, gracilus, semimembranosus, longissimus dorsi lumborum, triceps brachii caput longum, semispinalis capitis, serratus ventralis cervicis, spinalis dorsi, biceps femoris (syn. gluteobiceps), tensor fasciae latae, gluteus medius (both the 'D' and the 'eye' portions) rectus femoris, vastus intermedius, vastus lateralis and vastus medialis]. These muscles were used to prepare a total of 1030 sensory samples which were aged for either 7 or 21 days and frozen. Thawed samples were cooked using different cooking methods (grill, roast and stir frying) before being evaluated by a consumer taste panel that scored samples for tenderness, juiciness, like flavour and overall liking. Experiment 2 used the steer portion from the same calving, which were treated to a similar array of HGP strategies, except that they were given up to four implants between weaning and slaughter at 3 years of age. In experiment 2, there was a total of 12 different HGP implant strategies tested. At boning, three muscles (Mm. psoas major, longisimuss dorsi thoracis and lumborum portions) were collected from each of 79 carcasses with a total of 237 steak samples that consumers tested as grilled steaks.For both experiments, the mean of the HGP implant strategies resulted in increased ossification scores (P < 0.05) and decreased marbling scores (P < 0.05) compared with the controls, with the effect on ossification being much larger in the older steer groups. In both experiments, the different HGP strategies decreased (P < 0.05) all sensory scores compared with the controls, for all cooking method and muscle combinations. In experiment 1, there was no interaction between the mean HGP effect and muscle (P > 0.05), and aging rates differed among the muscles (P < 0.05). In experiment 2, there was a significant (P < 0.05) muscle · HGP treatment interaction, with a decrease in tenderness score due to HGP implant strategies in the M. longisimuss thoracis and lumborum portions, compared with no significant effect in the M. psoas major. For both experiments, there were no significant differences among the different implantation strategies on sensory scores (P > 0.05).

International perspective: characterisation of United States Department of Agriculture and Meat Standards Australia systems for assessing beef quality

“…(4) The use of HGP results in a penalty of the order of three to six meat quality points on meat palatability, depending on the cut. Watson et al (2008c) reported that: (i) significant changes in carcass weight, skeletal maturity and marbling were associated with HGP use in both steers and heifers, with the effects being greater in steers; and (ii) in both heifers and steers, HGP use was associated with significant reductions in flavour, juiciness, tenderness and marbling. Thompson et al (2008bThompson et al ( , 2008c concluded that the effects of HGP use in reducing flavour, tenderness and overall palatability are much greater in beef from 100% B. indicus cattle than in beef from 50% B. indicus cattle, but that all implant strategies used caused a reduction in meat quality.…”

“…highest to lowest, of five star (premium), four star (better than everyday), three star (good everyday) and no star (unsatisfactory). Watson et al (2008aWatson et al ( , 2008c reported that:…”

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.…”

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

“…psoas major, longisimuss dorsi thoraics and lumborum portions. Details of the procedure and the results can be found in Watson et al (2008b). In this trial, only the sensory (tenderness) scores were available.…”

“…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.…”