The effect of different cropping methods on the meat quality of various game species

[摘要] ENGLISH ABSTRACT: The production and especially the export of game meat from Southern African are steadily increasing andwith this growth, it is inevitable that more emphasis is being placed on the quality of game meat. Researchregarding the effect of different cropping methods on ante-mortem stress, and as a result, on meat quality inwild ungulates, is lacking and thus the purpose of this study was to investigate the effect of some of thecommonly used cropping methods on the meat quality of red hartebeest, impala, gemsbok and kudu. Antemortemstress was measured using serum cortisol levels (nmol/L), a subjective stress score allocated toeach animal as well as the rate and extent of pH decline in the M. longissimus dorsi. Special emphasis wasalso placed on the meat quality parameters drip loss, cooking loss, colour and Warner-Bratzler shear force(kg/1.27 cm diameter).The effect of day and night cropping on the meat quality of red hartebeest, gemsbok and kudu wasinvestigated. An exponential decay model, y = a + b-ct, was fitted to the pH data of the gemsbok and redhartebeest, and pHu measurements taken at 24 hours post-mortem. Only pHu readings taken at 48 hourspost-mortem were analysed in the kudu. Day-cropped kudu had a lower mean pHu (5.40 ± 0.030) than nightcroppedkudu (5.48 ± 0.041). No differences in pHu were found for the red hartebeest although night-croppedgemsbok had a higher mean pHu (5.54 ± 0.013) than day-cropped gemsbok (5.49 ± 0.014). None of theconstants of the exponential decay model differed for the red hartebeest although day-cropped gemsbokproduced a lower constant than night-cropped gemsbok. Mean stress scores and cortisol levels were foundto be higher in day-cropped animals for both the gemsbok and kudu while only cortisol levels were higher indie day-cropped red hartebeest. Stress score and cortisol levels were found to be correlated in all threespecies (red hartebeest: r = 0.51; gemsbok: r = 0.786; kudu: r = 0.823). No treatment differences in drip lossor cooking loss were found for either the red hartebeest or gemsbok, while day-cropped kudu had a highermean drip loss % (2.76 ± 0.261%) than night-cropped kudu (1.36 ± 0.361%). Night-cropped gemsbok andkudu produced higher mean shear force values (gemsbok = 4.19 ± 0.138; kudu = 4.06 ± 0.237 kg/1.27 cmdiameter) than day-cropped animals (gemsbok = 3.57 ± 0.154; kudu = 3.45 ± 0.171 kg/1.27 cm diameter).Colour differences indicated that day-cropped gemsbok and kudu produced lighter meat than night-croppedanimals. The results indicate no difference in the effects of day and night cropping in red hartebeest althoughday-cropped gemsbok and kudu experienced more ante-mortem stress than their night-croppedcounterparts.The effect of conventional hunting during the day and night cropping on impala meat was also investigated. No differences were found in pH45 or pHu (taken at 45 minutes and 24 hours post-mortem respectively)although the exponential decay model, y = a + b-ct, fitted to the pH data revealed differences in all theconstants (day: a = 5.424 ± 0.039, b = 1.405 ± 0.034, c = -0.385 ± 0.022; night: a = 5.295 ± 0.033, b = 1.556± 0.029, c = -0.184 ± 0.019). No differences were found for drip loss, cooking loss or shear force althoughday-cropped animals produced higher a* and chroma values. The results indicate that, althoughconventional hunting caused a faster and more severe post-mortem pH decline, both treatments producedmeat of similar quality.

[发布机构] Stellenbosch University