Ortigues I, Martin C, Vermorel M, Anglaret Y
Laboratoire Croissance et Métabolismes des Herbivores, INRA, Theix, Saint Genès Champanelle, France.
J Anim Sci. 1994 Aug;72(8):2131-40. doi: 10.2527/1994.7282131x.
An experiment was conducted with four preruminant calves to measure the energy cost and the diurnal pattern of physical activity in tethered, fed calves and to determine whether differences in activity could interfere with the interpretation of circadian changes in heat production. Measurements were carried out in large respiration chambers (3,650 L of inner volume), and a computation method was presented that allowed the calculation of the energy cost of standing for each standing period. This cost averaged 449 cal.kg BW-1.h-1 (SE = 41.6, n = 4). It represented a 23 to 27% increase in heat production above that measured in the lying state. This estimate and its standard error were lower than values obtained by regression (2,131 cal.kg BW-1.h-1, SE = 862.2, n = 8). The energy cost of standing was highest after meal times and lowest at night. These variations could reflect the nonuniform activity patterns of calves while standing. The time spent standing per hour showed the same variations during the day as the energy cost of standing. Noteworthy, the elevated energy expenditure measured in the 1st h after the morning meal was due to activity cost rather than to meal thermogenesis. Standardization of diurnal heat production profiles to a given activity pattern thus seemed to be necessary.
对四头反刍前犊牛进行了一项实验，以测量拴系饲养的犊牛的能量消耗和身体活动的昼夜模式，并确定活动差异是否会干扰对产热昼夜变化的解释。测量在大型呼吸室（内部容积3650升）中进行，并提出了一种计算方法，可计算每个站立时间段的站立能量消耗。该消耗平均为449卡路里·千克体重-1·小时-1（标准误=41.6，n=4）。这表示产热比躺卧状态下测量的值增加了23%至27%。该估计值及其标准误低于通过回归获得的值（2131卡路里·千克体重-1·小时-1，标准误=862.2，n=8）。站立的能量消耗在进食后最高，夜间最低。这些变化可能反映了犊牛站立时不均匀的活动模式。每小时站立时间在白天的变化与站立的能量消耗相同。值得注意的是，早餐后第1小时测量到的能量消耗升高是由于活动成本而非食物热效应。因此，将昼夜产热曲线标准化为给定的活动模式似乎是必要的。
