Summary
There are benefits of hormonal growth promotants (HGP) for production efficiency, profit, and environmental effects of beef cattle. Questions remain; however, about the effects of HGP on meat quality, particularly on measures of toughness such as Warner-Bratzler shear force (WBSF), tenderness, and other consumer tested attributes of meat such as juiciness, tenderness, flavour, and connective tissue. This meta-analysis used 31 experiments containing 181 treatment comparisons to evaluate the effects of HGP on WBSF and sensory measures on meat quality, almost all using Longissimus dorsi. The experiments varied greatly in design in using many different hormonal treatments and combinations, which were single or repeated, in different breeds and sex groups of cattle, with or without electrical stimulation, and with different lengths of meat ageing and feeding. The effects of multiple treatment comparisons in experiments were evaluated using robust regression models and compared to Knapp-Hartung and permutation meta-analytical methods. In general, the true variance of experiments, tau2 (τ2) was low <0.1, but heterogeneity, i2 was high>50% indicating that much of the variance was due to measurement error. Increased WBSF was associated with HGP treatment; in particular, use of multiple HGP implants was associated with an increase in WBSF of 0.248 kg (95% CI 0.203 to 0.292), but a single implant had more limited effects with an increase in WBSF of 0.176 kg (95% CI 0.109 to 0.242). Ageing did not significantly alter the HGP association with increased WBSF (P = 0.105); however, the point direction was towards a reduced effect with ageing (ES = −0.005 per d aged). Studies using trenbolone acetate treatments did not differ in WBSF from those using other implants (P > 0.15). The experiment also provides information on other sensory aspects of meat quality. The findings on tenderness, as assessed by sensory methods differ, from those using WBSF as HGP treatment was not associated with reduced tenderness (P > 0.3) and multiple treatments increased tenderness (ES = 0.468) compared to a single implant. Further, juiciness, flavour, and connective tissue were not associated with HGP use; whereas, there was a marked 5.5-point decrease in meat quality score (Meat Standards Australia Australia quality scoring system, CMQ4), albeit with limited experiments and treatments. There is a need for more targeted studies on the role of HGP in influencing meat quality to examine the effects of different HGP treatments and ageing on WBSF, tenderness, juiciness, and other sensory measures.
