Stress indicators, carcass characteristics and meat quality of Xhosa goats subjected to different watering regimen and vitamin C supplementation

Abstract

Limited water intake in small ruminants induced by water scarcity may result in pre-slaughter stress. A possible management practice could be the supplementation of exogenous antioxidant during the period of water stress. The effect of water restriction (W) levels with or without single and/or multiple vitamin C (VC) supplementations were evaluated on plasma hormones (cortisol, β-estradiol, thyroxine (T4), tri-iodothyronine (T3), prolactin, FSH, LH, insulin) carcass and non-carcass components and physicochemical characteristics of the longissimus thoracis et lumborum (LTL) muscle of Xhosa ear lobe goats. Forty-two goats were divided equally and randomly assigned into seven treatments; without water restriction (W0, control); water restriction of 70% of ad libitum water intake (W70); water restriction of 50% ad libitum water intake (W50); water restriction of 70% of ad libitum water intake plus 3g VC daily (W70+); water restriction 50% of ad libitum water intake plus 3g VC daily (W50+); water restriction of 70% of ad libitum water intake plus 3g VC and extra 5gVC given every eight-day (70++); water restriction of 50% of ad libitum water intake plus 3g VC and extra 5gVC given every eight-day (W50++). At the end of the 75-day experimental trial, the goats were humanely slaughtered and dressed. Increased plasma cortisol concentration due to water stress was lessened (P < 0.05) by VC. FSH, LH and insulin were not affected (P > 0.05) by levels of water restriction. The decreased (P < 0.05) hot and cold carcass weights in W70 and W50 were reduced in W70+ and W50+ respectively. The weights of the head and spleen were not affected by water restriction levels while that of the liver, skin and kidney decreased significantly (P < 0.05) with increased water restriction levels. VC treated goats had much-improved redness (a*) than the untreated (W70 and W50) and control groups (W0). The shear force and cooking loss increased with levels of water restriction while thaw loss, pH45min and pH24h were not affected by water restriction levels. VC may be used to minimize body weight loss, carcass traits and other stressors induced in animals during the period of water scarcity.