Abstract
This study was carried out to estimate the effects of environmental factors on the activities and rectal temperatures(heat tolerance) of Holstein dairy cows in a summer season. An activity-meter(Alpro system$^{\circledR}$) was used to record activities of 77 cows for 24 hours. The feeding standards for milking and dry cow were formulated with concentrates and corn silages based on the NRC(1998). Cows to check temperature were kept in stanchions and temperature was checked in rectum. Ambient temperature was $29.0^{\circ}C$ between 1 p.m. and 3 p.m. of the day. The rectal temperatures were affected by parities and status of milking or dry(p<0.01). The activities recorded between 9 a.m. and 12 a.m., and between 1 p.m. and 4 p.m. were not effected by the status of lactating and dry. The rectal temperature of lactating cow was 39.0${\pm}0.03^{\circ}C$, it was higher than dry cow(38.6${\pm}0.04^{\circ}C$). A higher activity of cow under third parity at 1 p.m. to 4 p.m. was observed comparing with fourth and above. The activities were tended to decrease with an increase of parity. Rectal temperature was negatively correlated with milk compositions, which were fat, protein, solid-not-fat and total solid except lactose.
본 연구는 하절기 홀스타인 젖소의 행동과 체온(내서성)에 관하여 환경효과를 추정하기 위하여 1999년 7월 6일부터 13일까지 수행하였다. 행동지수를 조사하기 위하여 Holstein 젖소 77두를 공시하였으며 사양은 NRC 사양표준에 의거 농후사료와 옥수수 사일리지 위주로 관리하였다. 체온은 스탄촌에 계류된 상태에서 오후 1시부터 3시 사이에 직장내 온도를 측정하였으며 이때 기온은 $29.0^{\circ}C$ 이었다. 건유 및 착유 상태, 산차에 따라 체온이 달랐으나(p<0.01), 행동지수에 대하여 착유우와 건유우는 오전 9시부터 정오까지, 오후 1시부터 4시까지는 차이가 없었다. 착유우의 직장내 체온은 39.0${\pm}0.03^{\circ}C$으로서 건유우의 체온(38.6 ${\pm}0.04^{\circ}C$)보다 높았다. 오후 1-4시까지는 3산차 이하의 개체들이 4산차 이상의 개체들에 비하여 행동지수가 높았고, 산차의 증가에 따라 감소하는 경향이었다. 우유 성분과 체온과의 상관에 대하여 유당을 제외한 지방, 단백질, 무지고형분율 및 총고형분 등과는 부의 표현형 상관을 나타내었다.
