Renal energy losses of horses are high in comparison with other species. In the present study, more data were obtained on this parameter to improve predictive equations for renal energy losses. Four adult ponies (247–344 kg body weight [BW]) were fed with eight different diets based on first cut hay, second cut hay, early first cut fresh grass, late cut herbs–grass mix, early cut clover–grass mix, sugar beet pulp, rice bran and straw. Feed intake was measured, and urine and faeces were quantitatively collected for 3 × 12 hr at daytime and afterwards 3 × 12 hr at nighttime. Feed was analysed for crude nutrients, gross energy, amino acids and neutral‐detergent‐insoluble crude protein (NDICP); faeces were analysed for crude nutrients and gross energy; and urine was analysed for nitrogen (N) and gross energy. Renal energy losses per gram dry matter (DM) intake (y; kJ/g DM) were strictly correlated to protein content in DM (x; g/kg DM): y = 0.325 + 0.00431x; r² = .81; n = 38; p < .001. The data suggest that the intercept represents energy losses by detoxification products such as hippuric acid and the regression coefficient by protein metabolites such as urea.

中文翻译：

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日粮中粗蛋白含量对马肾能量损失的影响。

与其他物种相比，马的肾脏能量损失高。在本研究中，获得了更多关于该参数的数据，以改善肾能量损失的预测方程。给四只成年小马（体重247-344公斤[BW]）喂食八种不同的食物，分别是第一割干草，第二割干草，早期第一割鲜草，后期割草-草混合，三叶草-草混合，甜菜浆，米糠和稻草。测量采食量，白天定量收集尿液和粪便3×12小时，夜间定量收集3×12小时。分析饲料中的粗养分，总能量，氨基酸和中性-不溶性不溶性粗蛋白（NDICP）；分析粪便中的粗养分和总能量；并分析尿液中的氮（N）和总能量。r ²  = 0.81；n  = 38；p  ＜.001。数据表明，截距代表排毒产物（如马尿酸）的能量损失，代表蛋白质代谢产物（如尿素）的回归系数。