Abstract
A study was conducted to examine the effect of the castration time on growth, meat quality and fatty acid composition of Korean black goats. Forty five male kids were divided into five groups, including control (without castration) and four groups with the kids castrated at 0.5, 3, 5 and 7 months of age, respectively. Average daily body weight gain (ADG) for control was significantly (P<0.05) higher than the castrated groups. ADG did not differ between the castrated groups. The ADG of the male kids castrated at 3 and 5 months of age tended to be higher than the other castrated groups. Dressing percentage for 0.5 months-castrated group was higher than 7 months-castrated group. Retail cut percentages for control was higher (P<0.05) than others, but the retail cut percentages did not differ between the castrated groups. Compared with control, higher fat percentages of carcasses appeared in the castrated groups (P<0.05). The fat percentages gradually increased in earlier castrated animals. As castrated earlier, moisture contents tended to decrease, whereas crude protein and fat contents tended to increase. The different castration time did not affect physical properties of goat meat (shear force, cooking loss, and water holding capacity). Results from panel tests showed that juiciness or tenderness of meats for 5 months-castrated group tended to be higher than those for the other groups. The flavor of meatfor 7-months castrated group appeared to be more favorable compared with 0.5- or 3-months castrated groups (P<0.05). The proportion of saturated fatty acid in meat washigher for 5-months castrated group and lower for 3-months castrated group as compared to the other castrated groups, whereas the proportion of unsaturated fatty acid was vice versa (P<0.05). Mono-unsaturated fatty acid contents did not differ between thecastrated groups. Present results indicatedthat castration at 3 or 5 months of age increased growth performance and meat quality of Korean black goats.
본 시험은 거세시기가 흑염소의 발육, 육질 및 지방산 조성에 미치는 효과를 구명하기위하여 흑염소 육성축 수컷 45두를 공시하여 거세시기를 각각 달리하여 2008년 3월 21일부터 2008년 10월 31일까지 225일간 실시하였으며 그 결과는 다음과 같다. 일당증체량은 거세시기별로 차이는 없었으나 3개월령과 5개월령에 거세한 것이 다소 높은 경향이었고, 비거세가 거세보다 높은 것으로 나타났다(P<0.05). 도체율은 15일령 거세가 7개월령 거세보다 높았고(P<0.05), 정육율은 거세시기별로 차이가 없었으나 비거세가 거세보다 높았다(P<0.05). 지방율은 거세시기가 빠를수록 높았고 거세가 비거세보다 높았다(P<0.05). 흑염소고기의 일반조성분인 수분함량은 거세시기가 빠를수록 감소하는 경향이었고, 조단백질과 조지방 함량은 거세시기가 빠를수록 증가하는 경향이었다. 육질의 물리적 특성인 전단력, 가열감량 그리고 보수력은 거세시기별로 차이가 없었으며 관능검사 결과 다즙성과 연도는 5개월령 거세가 다소 우수한 경향이었고, 향미는 7개월령 거세가 15일령과 3개월령 거세보다 우수하였다(P<0.05). 포화지방산 함량은 5개월령 거세가 높았고 3개월령 거세가 낮았다(P<0.05). 불포화지방산 함량은 반대로 3개월령 거세가 가장 높았고 5개월령 거세가 낮았으며(P<0.05) 거세와 비거세간에는 차이가 없었다. 단가불포화지방산 함량은 거세기기별로 차이가 없었으나 3개월령 거세가 비거세보다 높았다(P<0.05). 이러한 결과를 종합적으로 고려하면 흑염소의 발육과 육질 개선에 유리한 거세시기는 3~5개월령이 적정할 것으로 사료된다.