|Holaskova, Ida - WEST VIRGINIA UNIV|
|Elliot, M. - WEST VIRGINIA UNIV|
|Blemings, K. - WEST VIRGINIA UNIV|
|Dailey, R. - WEST VIRGINIA UNIV|
Submitted to: Journal of Reproductive Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: September 4, 2004
Publication Date: N/A
Interpretive Summary: Spontaneous mastitis or induced infections that mimick mastitis reduce pregnancy rates in ruminants. Immunization against organisms that are associated with mastitis could reduce the incidence of mastitis and improve reproductive performance. However, immunization with isolated peptidoglycan-polysaccharide (PG-PS) or with heat killed Streptococcus pyogenes did not prevent pregnancy reduction either in Rambouillet or in cross-bred ewes. Indeed, the probability of pregnancy decreased with total dose of PG-PS in Rambouillet ewes. Moreover, the incidence of mastitis was not reduced in immunized mixed breed ewes during and after weaning. These data are consistent with the onset of hypersensitivity rather than tolerance or effective humoral immunity in sheep after repeated inoculation with gram-positive PG-PS.
Technical Abstract: Spontaneous mastitis or induced infections that mimick mastitis reduce pregnancy rates in ruminants. Immunization against organisms that are associated with mastitis could reduce the incidence of mastitis and improve reproductive performance. Thus, the effects of immunization with peptidoglycan-polysaccharide (PG-PS) or killed Streptococcus pyogenes on pregnancy, fever, and incidence of mastitis were investigated. Ewe lambs (n=118) were immunized with PG-PS or killed S. pyogenes cells, or they were not immunized (Control, n=117). Titers of PG-PS IgG were detected with an ELISA. Ewes were bred at synchronized estrus. All immunized and half of the ewes that were not immunized were challenged with PG-PS on day 5 after breeding. The proportion of ewes pregnant at day 42 after breeding did not differ among treatments. However, the probability of pregnancy decreased with total dose of PG-PS (P < 0.05). The incidence of mastitis (middle and the end of lactation) did not differ among groups. Immunization of ewe lambs with PG-PS or killed S. pyogenes cells neither improved pregnancy rate nor decreased the incidence of mastitis after PG-PS challenge.