Acute phase protein response of ewes and the release of PGFM in relation to uterine involution and the presence of intrauterine bacteria

The rate of uterine involution postpartum was monitored in 13 suckling mule ewes by using radio-opaque markers and radiography, and each ewe was also monitored for intrauterine bacterial contamination during the first week, u sing a sterile guarded swab. Peripheral plasma or serum concentrations of h aptoglobin, seromucoid, ceruloplasmin and 15-keto-13,14-dihydro-prostagland in F-2 alpha (PGFM) were measured up to six weeks postpartum The maximum re duction in the length of the uterine body and in the diameters of the horns occurred by 28 days postpartum, except in one ewe in which the size of the uterus continued to decrease for 42 days. Four ewes were positive for intr auterine bacterial contamination; Escherichia coli, clostridial species, St aphylococcus aureus, Streptococcus uberis and Enterococcus species were iso lated in pure or mixed culture. The presence of intrauterine bacteria did n ot affect the time for the completion of uterine involution. No bacteria we re isolated from the ewe in which involution was delayed, but it had a diff erent acute phase protein response and was therefore excluded from further analyses. In the remaining 12 ewes the mean postpartum haptoglobin response increased, with peak concentrations occurring on day , and decreased slowl y as uterine involution progressed, but the four contaminated ewes had a si gnificantly greater response. There was no difference between the prepartum and postpartum concentrations of seromucoid in the eight sterile ewes, but significant increases were observed in the : contaminated group; the conce ntrations of ceruloplasmin did not vary in either group. The concentrations of PGFM were higher during the early postpartum period in the ewes with co ntaminated uteri.