한우의 육성 및 비육기간중 배합사료 급여 수준에 따른 사료섭취량 조사

Abstract

배합사료와 볏짚을 사료원으로 하여 한우 수소와 거세우를 비육 할 때의 사료섭취량을 조사하고자 5~7개월된 한우 수송아지 20두와 거세 송아지 60두를 공시하여 육성기(체중 300kg 이하), 비육 전기 (체중 300~450kg), 비육 후기 (체중 450kg 이후) 3단계로 나누어 육성우 배합사료 (CP 14.1%, TDN 70.0%), 비육 전기 배합사료(CP 12.1%, TDN 70.6%), 비육 후기 배합사료(CP 11.2%, TDN 71.9%)를 각각 성장단계별로 급여하면서 1) 수소와 거세우의 무제한 급여시의 사료 섭취량 (원물 기준)과 2) 거세우를 성장단계에 따라 배합사료를 ① 전기간 무제한 급여 ② 1.0%－1.5%－무제한급여, ③ 1.5%－2.0%－무제한급여의 3유형으로 사양관리 하면서 사료 섭취량 (원물 기준)의 변화를 조사하였다 1. 수소의 1일 사료섭취량은 직선적으로 증가된 반면에 거세우의 사료섭취량은 521 kg 까지는 증가되다가 감소되었다. 2. 체중대비 사료 섭취량은 시험 시작시인 150 kg 에서는 체중의 3.5% 정도를 섭취하였으나 600 kg에서 수소는 체중비 2.0% 내외로 거세우는 1.5% 정도로 감소되었다 3. 거세우의 1일 사료 섭취량은 전기간 무제한 급여시는 비육 전기까지는 완만하게 증가 하다가 비육 후기에는 다시 완만하게 감소된 반면 육성기와 비육 전기에 배합사료를 체중비 1.0%와 1.5%로 제한하여 급여 하였을 때는 사료 섭취량이 직선적으로 증가하였으며 1.5%와 2.0%로 제한하여 급여하였을 때는 비육 전기까지는 비교적 빠르게 증가되고 비육 후기(체중 455 kg)에는 비교적 빠른 속도로 감소되었다. 4. 배합사료 급여수준에 따른 거세우의 단위체중당 사료 섭취량은 무제한 급여시는 시험 시작시 (체중 150 kg 내외)에는 3.5% 내외에서 체중 600kg 내외에서는 1.5%까지 감소되었고 배합사료 제한 급여시는 육성기에는 2.0%에서 3.0%로 증가되다가 다시 1.5-2.0% 정도로 감소되었다 5. 거세우에 배합사료 급여수준에 따른 볏짚 섭취량은 배합사료 제한급여시 무제한 급여에 비하여 육성기에는 2-3배로 비육 전기에는 2배로 증가되었으나 비육 후기에는 차이가 없었다. A study was conducted to evaluate feed intake of Hanwoo bulls and steers fed diets of compound feed and rice straw. Twenty bull calves and sixty steers at 5 to 7 months old were used. The experimental period was divided into three feeding stages which are growing period (〈300 kg body weight (BW)), early fattening period (300-450 kg BW) and late fattening period (〉450 kg BW). The animals were given the diets containing 14.1% crude protein (CP) and 70.0% total digestible nutrients (TDN) in the growing period, 12.1% CP and 70.6% TDN in the early fattening period, and 11.2% CP and 71.9% TDN in the late fattening period, respectively. Experiment 1 was designed to compare feed intake (as-fed basis) between Hanwoo bulls and steers fed the experimental diets ad libitum. In Experiment 2, Hanwoo steers were allocated in one of three compound feed feeding treatments to investigate feed intake (as-fed basis). The treatment groups were ① feeding level 1 group fed compound feed ad libitum through the whole periods; ② feeding level 2 group fed 1.0% compound feed per kg BW in the growing period, 1.5% compound feed per kg BW in the early fattening period and compound feed ad libitum in the late fattening period; and ③ feeding level 3 group fed 1.5% compound feed per kg BW in the growing period, 2.0% compound feed per kg BW in the early fattening period and compound feed ad libitum in the late fattening period. In Experiment 1, the average daily feed intake of bulls increased linearly through the whole experimental period while the feed intake of steers increased until their body weight was reached upto 521 kg, afterward reduced. Average daily feed intake was about 3.5% per kg BW of both bulls and steers at the beginning (150 kg BW) of Experiment 1 while bulls and steers at 600 kg BW consumed the diets of 2.0 and 1.5% per kg BW, respectively. In Experiment 2, the average daily feed intake of steers in the feeding level 1 group gradually increased through the growing and early fattening periods and then steadily reduced over the late fattening period. The average daily feed intake in the feeding level 2 group linearly increased through the whole period while the feed intake in the feeding level 3 group showed a relatively rapid increase and reached a peak at 455 kg BW, and then sharply dropped. The average daily feed intake of steers in the feeding level 1 at the beginning (150 kg BW) of Experiment 2 was about 3.5% per kg BW but there was a reduction (1.5% per kg BW) at 600 kg BW. Besides, The feed intake of steers in the feeding level 2 and 3 in which compound feed was given with limitation increased to 2.0-3.0% per kg BW in the growing period and then reduced to 1.5-2.0% per kg BW. The limited compound feed feeding of steers in Experiment 2 resulted in higher rice straw intakes up to two to three folds and two folds in the growing and early fattening periods, respectively, than the ad libitum feeding.