Effect of physiological stage and nutritional management on some serum metabolite concentrations in Assaf ovine breed

Abstract. The Assaf breed represents a small percentage of the total dairy ovine census in the Castilla-León region and there are no studies conducted solely on this breed for understanding their physiology, nutritional requirements, diseases, management and appropiate beeding methods. The aim of the present report is to evaluate and to comment, in field conditions on, the nutritional management developed in a flock of Assaf ewes, studying the effects on energy metabolism during different physiological conditions (Anoestrus, Pregnancy and Lactation). On the other hand, the effect of litter size was also recorded. The study was conducted on thirty-five ewes of the Assaf breed housed in an intensive management system and randomly assigned to experimental and control groups, the latter divided into singles and twins. All the animals were housed in the same environmental conditions, and received the same diet. The metabolic parameters measured were serum glucose, cholesterol, tnglycendes and NEFA. Our results demonstrate that it is important to consider two critical moments: firstly the early pregnancy period, where the administration of a maintenance diet based on low-energy foods (alfalfa hay) is not enough for energy demands, as was shown by the significant decrease in glucose and triglyceride values; and secondly, late pregnancy, where excessive concentrate intake must be avoided in order to prevent future metabolic diseases and obesity. It has been observed that serum glucose and NEFA values are influenced more by nutritional management than by physiological conditions