Effect of the Level of Concentrates and Pasture Grazing on Growth, Reproductive Performance and Feed Efficiency in Spring born Hanwoo Heifers

This study was conducted to investigate the effect of the level of concentrates and pasture grazing in 60 head of spring born Hanwoo heifers(initial body weight; 125.3kg) for 450days from six to 21 months in age. Feeding trial was conducted with 5 treatment(twelve heads/ treatment) which were T1(1.5% of apparent body weight in concentrates and indoor feeding for over-all period), T2(0.5% of apparent body weight in concentrates for pre-pasture grazing and pasture grazing), T3(1.0% of apparent body weight in concentrates for pre-pasture grazing and pasture grazing), T4(1.5% of apparent body weight in concentrates for pre-pasture grazing and pasture grazing), T5(2.0% of apparent body weight in concentrates for pre-pasture grazing and pasture grazing). During the total experimental period, average daily gains by treatments ranged from 0.322 to 0.465kg(average 0.405kg) and higher in the order of T5, T4, T1, T3 and T2, and increased with the level of concentrates feeding for pre-pasture grazing. TDN intakes required per unit of kilogram gain were 9.13 to 9.79kg(average 9.49kg) higher in the order of T1, T3, T5, T4 and T2, For the grazing period, they were ranged from 12.39 to 12.98kg(average 12.68kg), and were not significantly different. But TDN requirements of grazing groups was higher about 15.6% than the indoor feeding group’s. The rate of roughage to concentrates by treatments were 57.8 to 73.6%(average 63.7%). The body weight of 15 and 21 month in ages, that is, the ages at puberty and first conception by treatments were 201.2 to 230.7kg(average 223.8kg) and 270.2 to 331.4kg (average 307.6kg), respectively, and the latter were high per unit of 20.4kg by increasing the level of concentrates feeding for pre-pasture grazing every 0.5% addition of apparent body weight. The age of 225 and 275kg in body weight, that is, the body weight at puberty and first conception by treatments were 14.0 to 17.6 month (average 15.3 month) and 17.9 to 21.7 month(average 19.4), respectively, and the latter were shorter about 1.3 month by increasing the level of concentrates feeding every 0.5% addition of apparent body weight. According to the above results, it may be concluded that spring born Hanwoo heifers are raised at indoor have to feed with 1.8% of body weight in concentrates under full feeding of rice straws for all period from six to 21 months in age, but with 1.5% of apparent body weight in concentrates for grazing period.

농후사료 급여수준 및 방목이 춘계분만 한우 암송아지의 성장발육, 번식능력 및 사료이용성에 미치는 효과

봄에 태어난 한우 암송아지 60두를 방목전의 농후사료 급여수준 및 개량초지에서의 방목유무에 따라 5개 처리(T1: 전기간 우사 내 사육, 농후사료 체중의 1.5%, T2: 방목전 농후사료 체중의 0.5%, 방목, T3: 방목전 농후사료 체중의 1.0%, 방목, T4: 방목전 농후사료 체중의 1.5%, 방목, T5 : 방목전 농후사료 체중의 2.0%, 방목)를 두어 450일간 사양 시험한 결과를 요약하면 다음과 같다. 1. 전기간의 일당증체량은 T5, T4, T1, T3 및 T2가 각각 0.465, 0.428, 0.423, 0.387kg 및 0.322 kg으로 방목전 육성기의 농후사료 급여수준이 증가할수록 높았으며, 방목기의 일당증체량도 방목전 육성기의 농후사료 급여수준이 증가할수록 높았다. 2. 공시기간 동안 kg 증체에 소요된 TDN량은 9.13-9.79kg(평균 9.49kg)이었고, T1, T3, T5, T4 및 T2의 순으로 사료이용성이 높았으며, 방목전 사사기의 농후사료 급여수준이 증가할수록 TDN 이용성이 높았다. 방목기간의 처리구별 kg 증체에 소요된 TDN량은 12.39-12.98 kg(평균 12.68kg)으로 방목전의 농후사료 급여수준에 따른 차이는 없었으나 축사내 사육시 보다 TDN 소요량이 15.6% 증가하였다. 그리고 전기간동안 농후사료에 대한 조사료비율은 57.8-73.6%(평균 63.7%)이었다. 3.성성숙기인 15개월령 체중은 201.2-237.3 kg(평균 223.8kg)으로 육성기 농후사료 급여수준이 증가할수록 증가하였고, 초임시기인 21개월령 체중은 270.2-331.4kg(평균 307.6kg)으로 방목전 사사기의 배합사료 급여수준이 체중대비 0.5% 증가할수록 20.4kg이 증가하였다. 또한 체중 225kg에 도달되는 시기는 14.0-17.6개월령(평균 15.3개월령), 그리고 체중 275 kg에 도달되는 시기는 17.9-21.7개월령(평균 19.4개월령)으로 육성기의 배합사료 급여수준이 체중 대비 0.5% 증가함에 따라 초임시기가 약 1.3개월씩 단축되었다. 이상과 같은 결과들을 종합해 볼 때 봄에 태어난 한우 암송아지를 축사에서 볏짚 위주로 사육할 때의 농후사료 급여수준은 체중의 1.8% 그리고 개량초지에서 방목사육 할 때에는 체중의 1.5%가 적정 수준인 것으로 판단된다.