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. 1999. Daily variation in blood enzymes and metabolites in ewes under three levels of feed intake. Can. J. Anim. Sci. 79: 157-164. Daily variations in the concentration of albumin, creatinine, non-esterified fatty acids, globulins, glucose, total lipids, total protein, triglycerides, urea, β-hydroxybutyrate, and in the activity of alkaline phosphatases, aspartate aminotransferase, glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase and pyruvate kinase were evaluated in the serum or plasma of ewes fed 30, 100 and 200% of theoretical maintenance energy requirements. A daily profile was observed in almost all variables, which may be of importance when interpreting data for these blood indicators. Daily variations were found even for albumin and total protein serum concentrations, showing a significant decrease of their levels after the meal. In order to maximize the diagnostic value of these indicators, the most suitable times for blood collection seem to be 16 h after the meal and (or) just before the meal. Collection 16 h after the meal apparently allows the characterisation of a relatively steady metabolic state, intermediate between the effects of food intake and the final phase of the intensification of body reserve mobilization. Collection just before the meal will give a good indication of the level of activity of those mobilization mechanisms. La variation quotidienne d'albumine, créatinine, acides gras non estérifiés, globulines, glucose, lipides totaux, protéines totales, triglycérides, urée, β-hydroxybutyrate, phosphatases alcalines, aspartate aminotransférase, glucose-6-phosphate déshydrogénase, glutamate déshydrogénase, isocitrate déshydrogénase, pyruvate kinase fut évaluée dans le sérum ou le plasma des brebis ayant reçu dans l'alimentation 30 %, 100 % et 200 % des besoins énergétiques d'entretien théoriques. Nous avons observé, dans presque toutes les variables, un type de profile quotidien susceptible d'influencer l'interprétation de ces indicateurs sanguins. Des variations quotidiennes ont été trouvées même pour des concentrations d'albumine et de protéine totale dans le sérum, montrant une diminution significative de leurs niveaux après le repas. Pour maximiser la valeur diagnostique de ces indicateurs, les moments les plus appropriés pour faire la prise de sang semblent être 16 heures après le repas et (ou) juste avant le repas. La prise de sang 16 heures après le repas permet de caractériser un état métabolique relativement constant, intermédiaire entre les effets proches de l'ingestion et la phase finale d'intensification de la mobilisation des réserves corporelles. La prise de sang juste avant le repas donne une bonne image du niveau d'activité de ces mécanismes de mobilisation.

Twenty eight non-lactating and non-pregnant adult Serra da Estrela ewes, ranging in body condition score (BCS) from 1 to 4 were used to study the relationships between BCS, live weight (LW), body composition and fat partition. Ewes were slaughtered and their kidney knob and channel fat (KKCF), sternal fat (STF) and omental plus mesenteric fat (OMF) were separated and weighed. Left sides of carcasses as well as the respective lumbar joints were then dissected into muscle, bone and subcutaneous (SCF) and intermuscular fat (IMF). The relationship between LW and BCS was studied using data from 1,396 observations on 63 ewes from the same flock and it was found to be linear. Regression analysis was also used to describe the relationships among BCS and/or LW and weights (kg) and percentages in empty body weight (EBW) of dissected tissues. The prediction of weights and percentages in EBW of total fat (TF) and of all fat depots afforded by BCS was better than that provided by LW. Only the weight of muscle and the percentage of bone in the EBW were more efficiently predicted by LW than by BCS. IMF represented the largest fat depot with a BCS of 1 and 2, whereas SCF was the most important site of fat deposition with a BCS of 3 and 4. Allometric coefficients for each fat depot in TF suggest that the fat deposition order in ewes from this breed is: IMF, OMF, SCF and KKCF. Results demonstrate that BCS is a better predictor than LW of body reserves in this breed and that LJ is a suitable anatomical region to evaluate BCS.

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