EFFECTS OF INTRAMAMMARY INFECTIONS ON SOMATIC CELL SCORE AND MILK YIELD IN SARDA SHEEP

AIM: To evaluate the effects of intramammary infections (IMI) on somatic cell score (SCS) and milk yield in dairy ewes. METHODS: Monthly milk samples were collected from a flock of 202 Sarda sheep, over a period of 7 months, for bacteriological culture and measurement of somatic cell counts (SCC). During the same period, milk yield was measured daily using electronic milk meters connected to each half-udder cluster of the milking machine. SCC was transformed to SCS using a base-2 log transformation. One SCS is equivalent to a SCC of 25,000 cells/ml, and each increase of 1 in SCS is associated with doubling of the SCC. IMI was defined by the presence of five or more colonies of similar morphology isolated from a milk sample (500 cfu/ml). The effect of IMI on SCS and milk yield was assessed using a generalised estimating equation (GEE).