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).