Age End-Point Effects on Performance, Carcass Measurements, and Tenderness in Goats.

摘要

Goat meat is consumed all across the world, especially in developing countries. Moreover, the meat goat industry is growing in popularity in the United States due to ethnic demand of an increasing immigrant population. The objective of this study was to measure age end-point effects on performance, carcass measurements, and tenderness in goats. Intact Kiko x Boer F 1 male (n = 46) kids were born on pasture in the spring of 2014 and 2015, weaned at approximately 100 d of age, and weighed monthly. Creep feed was offered to kids from birth to weaning and a high concentrate diet was offered after weaning in a dry lot. Animals were allocated by birth weight, date of birth, and previous treatments (high vs. low parasite resistance) and assigned randomly to slaughter age end-points (135, 180, 225, 270, 315, 360, 405, or 450 d of age). At slaughter, animals were transported 450 km (4.5 h) from Lincoln University's Carver Farm to the University of Arkansas Red Meat Abattoir. After overnight lairage with water, animals were humanely slaughtered at 0900. Kids grew at a linear (P < 0.001) rate as d of age increased. As expected, hot carcass weight, cold carcass weight, and individual muscle weights increased (P ≤ 0.05) as chronological age advanced. Range of dressing percentage (DP) was 40 to 50 % with 315 d old kids having the highest (P ≤ 0.001) DP. Kids from 315 and older slaughter age groups had a more desirable ( P = 0.003) carcass conformation compared with younger slaughter age groups. Longissimus (LM), semimembranosus (SM), biceps femoris (BF), and rectus femoris (RF) muscle L* values decreased (P ≤ 0.004) with increasing age at slaughter. Warner-Bratzler shear force values increased (P ≤ 0.001) in the SM and BF as d of age increased. Longissimus muscle sarcomere lengths were longer (P ≤ 0.05) at 270 d of age, whereas BF sarcomere length increased (P ≤ 0.05) as d of age advanced; SM sarcomeres were not different (P = 0.588) across slaughter age groups. Therefore, goat producers can efficiently raise goats to slaughter from approximately 225 to 360 d of age to produce larger carcasses to provide more meat for increased demand in the market without detrimentally effecting meat tenderness.