Morphometric analysis of fat globules in ewe's milk and correlation with qualitative parameters

Abstract

In this study the morphometric characteristics of fat globules from ewe’s milk have been correlated with the chemical and technological parameters of the milk.Milk samples were taken from twenty-five Massese ewes, subdivided according to the parity; the animals were homogeneous for lactation phase and diet. The morphometric analysis of fat globules (n./ml, diameter, surface area/volume), the standard chemical analysis, SCC and determination of the rheological parameters were performed on milk samples obtained during the morning milking.The mean number of fat globules/ml was 3.09 x 109, with a mean diameter of 3.93 µm, ranging from 1.20 µm to 12.30 µm. For all parities, a fat globule diameter ranging from 3.21 to 4.20 µm was found most frequently. Animals in the first lambing order showed a significantly lower percentage (5.26%) of large globules (>5.21µm), while animals in the fifth lambing order showed a higher percentage (20.75%). The number of globules/ml was negatively correlated to milk production (P≤0.01) and curd firmness at 45 min (P≤0.05); whereas it was positively correlated to protein content, non-fat dry matter, and curd firming time (P≤0.05). Fat globule dimensions varied according to the parity of the animals and influenced various qualitative parameters of the milk.