PREDICTION OF ENERGETIC CONTENT OF EWES MILK FROM DIFFERENT CHEMICAL-ANALYSES - PROPOSAL FOR A STANDARD MILK FOR DAIRY EWES

The aims of this study were: 1) to establish equations of prediction f or ewe's milk energy from chemical analyses, and 2) to propose a proce dure for standardization of milk for dairy ewes. Ewe's milk samples (3 65) were taken at different stages of lactation from Lacaune dairy ewe s (276 from adult ewes at 6 stages of lactation, ie from 41 to 118 d p ost-lambing and 89 from primiparous ewes at 79 and 99 d). They were an alysed by classical (fat Gerber protein: amido-black, energy: calorime try) and infrared methods (Pro-milk or Multispec) adapted to ewe milk. For fat and protein, IR methods were reliable when compared to classi cal methods; and can be used to measure milk composition for routine d etermination as well as for research purposes. The prediction of milk gross energy has been made using different equations according to avai lable results (fat, protein, lactose) and to the analytical method (cl assical or IR). Previously published equations for different species ( ewe, cow and multi-species) were tested with our data. The range of pr ecision was often close to ours (1.8-3.0%), but there were important b iases with some cow's milk equations (max = 19%). Based on these equat ions (table III) of prediction of milk energy content, we propose a pr ocedure for the calculation of a standard milk for dairy-ewes (eSM), o n the basis of a standard caloric value of 5.0 MJ/l.