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Summary

The effects of coliform endotoxin (e) and recombinant bovine tumor necrosis factor α (tnf) were compared with respect to clinical signs of disease and changes in plasma metabolite and pituitary and pancreatic hormone concentrations in calves. In addition, changes in plasma tnf concentration during each challenge exposure were quantitated by use of radioimmunoassay. Healthy Holstein bull calves with mean body weight of 90 kg were each given, in order, on different days, saline solution (5.0 ml, iv, day 1, n = 4), e (type 055:B5, 1.0 μg/kg of body weight iv, day 2, n = 4) and tnf (5.0 μg/kg iv, day 9, n = 3). Jugular venous blood samples, rectal temperature reading, and pcv were obtained at hourly intervals before (2 hours) and after challenge exposure. The pcv increased (P < 0.05) after e and tnf administrations for the first 5 hours, then returned to normal in calves given E, but decreased and remained low in calves given tnf through 24 hours. Plasma triglyceride and nonesterified free fatty acids concentrations were increased through 10 hours (P < 0.05) after e administration, whereas triglyceride and nonesterified free fatty acids concentrations were not significantly affected by tnf administration. Increase in blood glucose concentration at 1 hour after administration of e and tnf was followed by prolonged hypoglycemia that lasted through 6 hours. Changes in plasma insulin concentration paralleled the observed changes in glucose concentration, initially increased at 2 hours after e and tnf (P < 0.05) administrations, but then tended to decrease below control values thereafter. Plasma growth hormone and luteinizing hormone concentrations decreased after e and tnf administrations to almost nondetectable values through 4 hours after dosing, returning to normal values by 8 hours. The data indicate similarities in physiologic response of calves to e and tnf and suggest a role for acute production of tnf as a mediator of e responses.

Free access
in American Journal of Veterinary Research

SUMMARY

Objective

To determine the influence of brucellosis vaccination on tumor necrosis factor-α (TNF-α) con-centrations in pregnant cattle and the possible role of the bovine placenta in TNF-α production.

Animals

Polled Hereford heifers obtained from a nonvaccinated, brucellosis-free herd and bred at 16 to 27 months at age. All cattle were seronegative for Brucella abortus by results of the standard tube agglutination test.

Procedure

At 6 months' gestation, cattle were vaccinated IV with B abortus strain RB51 (n = 10), SC with B abortus strain RB51 (n = 5), or SC with B abortus strain 19 (n = 5); controls received pyrogen-free saline solution SC (n = 2). Blood samples were collected periodically for TNF-α assays. At necropsy, 8 to 12 weeks after vaccination, placental fluids and fetal blood were collected for TNF-α analysis and placental tissues were collected for immunohistochemical detection of TNF-α.

Results

Radioimmunoassays indicated no increase in TNF-α concentration in blood from IV or SC vaccinated cattle, compared with controls. Similarly, TNF-α concentrations in amniotic and allantoic fluids from SC vaccinated cattle were not different from values for controls. Although only IV vaccinated cattle developed placentitis, immunohistochemical analysis for TNF-α revealed increased immunoreactivity within placental trophoblastic epithelial cells of SC and IV vaccinated cattle.

Conclusions

SC vaccination for prevention of brucellosis, using recommended adult dosages, does not result in increase of TNF-α concentration in plasma, serum, or placental fluids; however, vaccination of pregnant cattle stimulates trophoblastic epithelial cells to express TNF-α, although the physiologic and quantitative importance of this expression remains unknown. (Am J Vet Res 1998;59:153–156)

Free access
in American Journal of Veterinary Research