VITAMIN D3 EVALUATION ON ANIMAL PERFORMANCE, CARCASS TRAITS AND MEAT TENDERNESS OF BRAHMAN CATTLE AND ITS CROSSES. GUALACA, PANAMÁ. 2003.

Abstract

The purpose was to evaluate the effect of vitamin D₃, on the animal performance (AP), carcass traits (CT) and beef tenderness (TRN) of Brahman and its crosses. Two fattening (A) were done: (110 days) and A2 (133 days) with two racial groups (GR): Brahman (Br) y Crossbred (Cx). Levels of vitamin D₃ (T) were: 0 (T1), 2.5 (T2), 5.0 (T3) y 7.5 (T4) x 10⁶ UI/animal/d, supplied 10 days before finished fattening period. Samples of the Longissimus dorsi were taken from the 11^th and 12^th rib from both carcass sides. Performance traits were: initial weight (PI), final weight (PF), daily weigth gain  (GDP), last month weight (PUM) y daily weight gain at last month (GDPUM); from the carcass: slaughter weight (PM), hot carcass weight (PCC), dressing percentage (RC), carcass length (LC), proportion of pelvic fat (PGP) and USDA yield grade (YG); from the beef (Longissimus dorsi): rib eye area (AL), fat thickness (GD), bone proportion (HP), beef proportion (MP), fat proportion (GP) and tenderness (TRN), measure at four aging time (TM): 7, 14, 21 and 28 days postmortem. Dependent variables were analyzed by a generalized linear model using PI as covariable. PI was effective (P<0.10 a P<0.01) for PF, PM, PUM, PCC, AL, MP and GP. As blocking criteria (A) was significant (P<0.05 a P<0.01) for PF, GDP, PM, PUM, GDPUM, PCC, LC, PGP, AL and TRN. Besides, T only affected negatively to PUM y GDPUM (P<0.01), but while level of vitamin D₃ increased, TRN value decreased to 18.8% (T4 vs T1). Cx overcame (P<0.01) in 29.0% and 14.7% to Br in YG and AL, respectívely. T*GR was significant (P<0.10 a P<0.01) in PF, GDP, PUM, LC, YG, GD, AL and TRN. TM improved (P<0.05) TRN as days increased (21.2% between day 7th and day 28th). T*TM resulted signíficant (P<0.05). lt was concluded that vitamin D₃  and aging  time have great effects on TRN, but little on AP and CT.