Investigations of the incidence of bovine trichomoniasis in nevada and of the efficacy of immunizing cattle with vaccines containing Tritrichomonas foetus.

Trichomonas cultures taken from 2389 bulls showed that approximately 4.7% of them were infected. Correlation of these data with the ranches from which diagnostic samples were obtained indicated that in the period of 1984 through 1987 26.7 to 44.1% of ranches had at least one infected bull. Thirty-four 18-month-old Holstein heifers were assigned to one of three groups, controls n = 12 animals, soluble vaccine n = 11 animals, and whole vaccine n = 11 animals to determine the effect of Tritrichomonas foetus vaccines on the reproductive performance of T . foetus infected animals. Heifers were bred with T . foetus infected bulls beginning two weeks after the second T . foetus vaccination. All immunized animals developed antibody titers of at least 1:1000 following vaccination. In addition, all control and immunized animals became infected with T . foetus . However, the duration of infection was approximately two weeks shorter in immunized animals. Approximately 42% (5 of 12) of control heifers remained infected with T . foetus for the duration of the experiment, while only 18% (2 of 11) of each of the vaccine groups remained infected for the duration of the experiment. Finally, 27% (3 of 11) of heifers in each of the vaccine groups were pregnant at slaughter, while none of the control heifers were pregnant at slaughter. Therefore, both vaccine formulations appeared to protect heifers (P<0.05) from fetal loss due to trichomoniasis.

The toxicology and composition of bovine tissues after parenteral administration of high levels of copper salts.

Copper toxicity was observed when crossbred cows were injected with 480 mg copper sc. Five head died after copper disodium EDTA (edetate) injections but no losses occurred with copper glycinate. Necropsy, histopathology and plasma enzyme values indicated severe hepatic necrosis in the affected cattle. Plasma copper levels peaked 2 hr postinjection (3.82 micrograms/ml) in cattle that lived after EDTA injections, but about half this level (2.00 micrograms/ml) of copper was observed in the animals that died and 0.65 in the glycinate-treated animals (P less than .01). Ceruloplasmin levels were low in all cattle (2.1 to 7.2 IU/L). Plasma iron increased between 2 (179 micrograms/dl) to 4 (422 micrograms/dl) hr after injection for all cattle and remained high at 8 hr (501 micrograms/dl postinjection; P less than .01). After copper was administered, plasma zinc decreased 45 to 75% of pre-injection levels (P less than .01). Plasma urea nitrogen was not modified by the treatments. Hemolysis was not observed in any of the animals.