In mammals, excess energy is stored primarily as triglycerides, which are mobilized when energy demands arise and cannot be covered by feed intake. This review mainly focuses on the role of long chain fatty acids in disturbed energy metabolism of the bovine species. Long chain fatty acids regulate energy metabolism as ligands of peroxisome proliferator-activated receptors. Carnitine acts as a carrier of fatty acyl groups as long-chain acyl-CoA derivatives do not penetrate the mitochondrial inner membrane. There are two different types of disorders in lipid metabolism which can occur in cattle, namely the hypoglycaemic-hypoinsulinaemic and the hyperglycaemic-hyperinsulinaemic type with the latter not always associated with ketosis. There is general agreement that fatty acid β-oxidation capability is limited in the liver of (ketotic) cows. In accord, supplemental L-carnitine decreased liver lipid accumulation in periparturient Holstein cows. Of note, around parturition concurrent oxidation of fatty acids in skeletal muscle is highly activated. Also peroxisomal β-oxidation in liver of dairy cows may be part of the hepatic adaptations to a negative energy balance (NEB) to break down fatty acids. An elevated blood concentration of nonesterified fatty acids is one of the indicators of NEB in cattle among others like increased β-hydroxy butyrate concentration, and decreased concentrations of glucose, insulin, and insulin-like growth factor-I. Assuming that liver carnitine concentrations might limit hepatic fatty acid oxidation capacity in dairy cows, further study of the role of acyl-CoA dehydrogenases and/or riboflavin in bovine ketosis is warranted.

在哺乳动物中，多余的能量主要以甘油三酸酯的形式存储，当能量需求出现时，甘油三酸酯就会动员起来，并且不能被采食量所覆盖。这篇综述主要集中在长链脂肪酸在牛种能量代谢中的作用。长链脂肪酸作为过氧化物酶体增殖物激活受体的配体调节能量代谢。肉碱充当脂肪酰基的载体，因为长链酰基辅酶A衍生物不会穿透线粒体内膜。牛体内可能发生两种不同类型的脂质代谢异常，即低血糖-低胰岛素血症和高血糖-高胰岛素血症，后者并不总是与酮症相关。人们普遍认为，（酮）奶牛的肝脏中脂肪酸β-氧化能力受到限制。一致，补充左旋肉碱减少了围产期荷斯坦奶牛的肝脂质蓄积。值得注意的是，分娩前后骨骼肌中脂肪酸的同时氧化被高度激活。此外，奶牛肝脏中的过氧化物酶体β-氧化可能是肝脏适应负能量平衡（NEB）分解脂肪酸的一部分。血液中非酯化脂肪酸的浓度升高是牛NEB的指标之一，其中包括β-羟基丁酸酯浓度升高，葡萄糖，胰岛素和胰岛素样生长因子-I浓度降低。假设肝肉碱的浓度可能会限制奶牛的肝脏脂肪酸氧化能力，则有必要进一步研究酰基辅酶A脱氢酶和/或核黄素在牛酮症中的作用。