A comparison of different metabolic types between goat kids and lambs: Keyblood constituents at different times in the first two months after birth

With the aim of establishing the metabolic causes of the differences in the corporal development of goat kids vs, lambs, diurnal patterns of serum con centrations of some key metabolites in relation to the energy and protein u tilization were determined. For this, every 5 days from the 10th until the 60th day after birth, the pre-feeding and 1, 2, 4 and 8 h post-feeding leve ls of glucose, non-esterified and esterified fatty acids, urea and total pr otein were determined. Between goat kids and lambs, there were no outstandi ng differences for the diurnal mean values of glucose, urea and total prote in concentrations in the serum. With the exception of the values measured a t 0 and 8 h post-feeding and at 10 and 45 days of age, mean values of serum non-esterified fatty acid concentrations in kids were higher (p<0.05) than in lambs. Mean values of esterified fatty acid concentrations measured at 35 and 40 days of age and at 1, 2 and overall at 4 h post-feeding, were gen erally higher (p<0.05) in kids' serum than in lambs' serum. Pre-feeding mea n levels of non-esterified fatty acids for kids and lambs were very similar , resulting at the same time values, two and seven times higher than those measured 1 h post-feeding; 419 vs. 235 mu mol/l for kids and 386 vs. 56 mu mol/l for lambs, respectively. From these results it is concluded that goat kids may have a higher rate of fat mobilization than lambs, understanding this as the net result of the balance between the processes of lipogenesis, lipolysis and re-esterification of the fatty acids released during lipolys is. At the same time, and in spite of that, goat kids utilize dietary prote in with a higher efficiency than lambs; this difference was not supported b y blood levels of nitrogenous metabolites. (C) 1998 Elsevier Science B.V. A ll rights reserved.