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ARS Home » Midwest Area » Ames, Iowa » National Animal Disease Center » Ruminant Diseases and Immunology Research » Research » Publications at this Location » Publication #106189
Title: EFFECTS OF THE PRESENCE OF THE MAMMARY GLAND ON EXPRESSION OF NEUTROPHIL ADHESION MOLECULES AND MYELOPEROXIDASE ACTIVITY IN PERIPARTURIENT DAIRY COWS

Author
item KIMURA, KAYOKO - IOWA STATE UNIV., AMES
item GOFF, JESSE
item KEHRLI, JR, M - FORMER ARS EMPLOYEE

Submitted to: Journal of Dairy Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/21/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: All cows are immunosuppressed around the time of giving birth to calves. This is why they often develop mastitis, salmonellosis, and Johne's disease shortly after calving. The cause of the immunosuppression is unknown. The dairy cow produces so much milk that she quickly goes into negative energy and calcium status after calving. The question we asked in this study was "Does milk production contribute to the immune suppression observed in the dairy cow around the time of calving?" We compared immune cell function in intact cows and cows that had been mastectomized early in pregnancy - which eliminated milk production but allowed the cows to experience all the hormone changes normally associated with calving. The function of white blood cells, called neutrophils, was examined. Expression of adhesion molecules, which allow neutrophils to invade sites of infection, was not affected by the lack of milk production in the cows. However, the ability of the white blood cells to kill microbes they have attacked was different in intact and mastectomized cows. Both groups showed a significance decrease in the ability of the neutrophils to kill microbes as the time of calving approached. However, after calving the mastectomized cows regained the ability to kill microbes within a few days. Intact cows producing milk did not recover their neutrophil function until at least 3 wk after calving. This suggests that hormonal factors associated with the act of calving will immunosuppress the cow and that milk production slows recovery of the cow from the immunosuppression. Results of this study will greatly benefit the dairy producers world-wide.

Technical Abstract: Neutrophil function is diminished in the periparturient period, especially in the dairy cow. Milk production negatively impacts energy, protein and calcium balance which may contribute to the severity of immunosuppression experienced by the cow around parturition. Using 10 mastectomized and 8 intact multiparous Jersey cows (all intact cows developed milk fever), we studied constitutive and platelet-activating factor activated expression of adhesion molecules (beta 2-integrins and L-selectin) on neutrophils by flow cytometry and assessed neutrophil myeroperoxidase activity during the periparturient period. Expression of beta 2-integrins in intact cows was highest at parturition. Expression of beta 2-integrins was greater in intact cows than in mastectomized cows throughout the study. L-selectin expression exhibited a sudden decrease at parturition with recovery within a day after parturition in both intact and mastectomized cows. The ability of neutrophils to kill microbes as assessed by neutrophil myeroperoxidase activity decreased before parturition in both groups. While there was a quick recovery of neutrophil myeroperoxidase activity in mastectomized cows, there was no recovery in intact cows after parturition throughout the study which lasted until d 20 postpartum. Milk production seems to exacerbate periparturient immunosuppression, especially with regard to recovery of neutrophil myeroperoxidase activity.