본 실험은 한우 400두를 공시하여 사양조건에 따른 blood urea nitrogen(BUN)의 농도가 암소의 번식에 미치는 영향을 조사하였으며 또한 body condition score(BCS)가 번식효율에 미치는 영향을 조사하였다. 1 화본과 식물이 주종인 초지에서 방목을 하였을 때 BUN의 평균농도는 7.392.65 mg/㎗ 이었으며 발정이 육안적으로 확인된 암소의 58.2%가 4∼8 mg/㎗ 사이에 분포하였으며 수태율도 높은 경향을 보였다. 2
The environmental impact of nutrient waste from agriculture has become an area of concern as ways to produce more food and of offspring. In dairy cattle, as the genetic capacity for milk production has increased, decreased fertility has become a severe problem by feeding high dietary protein, resulting in high concentration of blood urea nitrogen (BUN). There are numerous reports on BUN which is associated with reduced conception rates and closely related to body condition score (BCS) in lactating cattle, but not in Korean native cattle. This study was therefore performed to investigate the relation of BUN to both BCS and conception rates in Korean cattle. A total of 400 female Korean cattle (2∼5 years) in Daewanryong were used for this experiment. Feeding condition divided into two groups depending on grazing and darn feeding period. In grazing period, the mixture of Timothy, Orchard grass and Tall fescue, and concentrates (2.5 kg/day) was fed whereas hay (6.5 kg/day) and corn silage (20 kg/day) were fed while barn feeding period. Average BUN concentration at grazing and barn feeding were 7.392.65 mg/㎗ and 12.362.92 mg/㎗, respectively. During grazing period, high rates of pregnancy showed at 4∼8 mg/㎗ BUN concentration. In barn feeding period, 66%, of cattle were in pregnant at 8∼l4 mg/㎗ BUN concentration. The BCS for obtaining high rate of pregnancy raged at 2.5∼3.5. However, BUN did not directly relate to BCS in Korean cattle.