Sows Intramammarily Inoculated withEscherichia coli: Influence of Time of Infection, Hormone Concentrations and Leucocyte Numbers on Development of Disease

Abstract

The aim of this study was to identify factors that in¯uence the development of disease in sows inoculated with Escherichia coli in the mammary gland. Ten cross-bred primiparous sows were intramammarily inoculated with living E. coli bacteria at different time points before parturition: seven sows within 48 h before parturition and three sows approximately 96 h before parturition. Before and after inoculation, blood samples and mammary gland biopsy specimens were collected and clinical observations were made. All seven sows inoculated close to parturition developed a rectal temperature of >39.5°C during the ®rst 48 h post-partum and two of them also showed other signs of clinical disease. In the sows inoculated 4 days before parturition, the rectal temperature never exceeded 39.5°C during the ®rst 48 h post-partum and none of them showed any other sign of clinical disease. There was a tendency (P < 0.1) that histological signs of mastitis were more frequent in the sows inoculated close to parturition. There were no overall differences between the two groups of sows in plasma concentrations of cortisol, oestradiol-17b and 15-ketodihydro-PGF 2a before inoculation. Before inoculation, the number of neutrophils in the blood was overall higher (P < 0.05) in the group of sows that were inoculated close to parturition. In comparison, the number of lymphocytes before inoculation had a tendency (P < 0.1) to be lower in that group. The data suggest that the time of infection of the mammary gland relative to parturition and the number of circulating neutrophils at the time of infection in¯uence the development of clinical coliform mastitis in the sow.

Bacteria associated with clinical postpartum dysgalactia syndrome in farmed sows in the Republic of Macedonia

“…Armstrong et al (23), Nachreiner and Ginther (24), and Morkoc et al (25) supported the theory that the uterus has a minor role in the etiology of PDS, since gram-negative bacteria were less frequently isolated from this organ. The importance of E. coli in the etiology of PDS has been emphasized and confirmed in several studies (16,17,(26)(27)(28) of prolactin by the pituitary gland, increasing cortisol concentration and decreasing circulating thyroid hormone concentrations (27). All these changes negatively affect the milk production in lactating sows.…”

“…Although bacterial invasion of the mammary gland via the teat canal is currently the major route of infection, urinary and genital infections are also considered to be a major source for subsequent infection of the uterus and the mammary glands (8,14). It is generally accepted that coliform bacteria from the genera Escherichia, Enterobacter, Citrobacter, and Klebsiella are the most important pathogens strongly related to PDS in sows (1,(15)(16)(17). There is a lack of data about the prevalence of bacteria associated with PDS in farmed sows in the Republic of Macedonia.…”