Bovine vaccines and herd vaccination programs.

This review provides a framework for the establishment of rational bovine herd vaccination programs. Information is provided that can assist in the selection of specific vaccine products and the establishment of appropriate schedules for their administration. Advantages, disadvantages, indications, and contraindications of vaccine options are discussed.

Salmonellosis in hospitalized horses: seasonality and case fatality rates.

Salmonellosis was studied during an 11-year period (July 1971 through June 1982) in 245 hospitalized horses. Ten years' data (207 cases) were analyzed in a time series study. Peak seasonality of the disease was from June through September. The cycle curve revealed 3 major outbreaks, with no apparent periodicity. Eighteen Salmonella serotypes caused clinical salmonellosis in horses, but 84% of the cases and 90% of the deaths were caused by 5 serotypes: Salmonella typhimurium, S typhimurium var copenhagen, S anatum, S kottbus, and S saint-paul. Overall, the case fatality rate was 44.9%. Excluding mixed infections, horses infected with S typhimurium and S typhimurium var copenhagen, had a significantly higher (P less than 0.001) case fatality rate (60.4%) than those infected with other Salmonella serotypes (32.3%).

Risk factors for salmonellosis in hospitalized horses.

A case-control study to identify risk factors associated with isolation of Salmonella was accomplished, using data from records of horses hospitalized in the period July 1971 through June 1982. Horses in which nasogastric tubes were passed were at 2.9 times greater risk of having Salmonella isolated, compared with horses that did not undergo this procedure. Horses treated with antibiotics parenterally were at 6.4 times greater risk, and those treated with antibiotics orally and parenterally were at 40.4 times greater risk of developing salmonellosis, compared with horses not receiving such treatment. Horses admitted because of colic were 4.2 times as likely to have Salmonella isolated as those admitted for other reasons. Breed, age, and type of surgery did not appear to be risk factors. The risk factors identified and the magnitude of their association with Salmonella isolation were similar to those observed in a preceding study.

Effects of vaccination infectious bovine rhinotracheitis and simultaneous administration of levamisole on primary humoral responses in calves.

In a study on the primary humoral response of calves vaccinated against infectious bovine rhinotracheitis (IBR) and simultaneously given levamisole, mild but consistent suppression of the group's geometric mean serum-neutralization titer to IBR virus occurred between 12 and 59 days later. The quantitative determination of circulating immunoglobulins (Ig) over the same period indicated a slight decrease in the IgG concentrations from an initial geometric mean concentration of 18.28 mg/ml before calves were vaccinated to 15.29 mg/ml after vaccination, and the control calves (vaccinated and given saline solution only) maintained their prevaccination IgG geometric mean concentration of 20.92 mg/ml. Difference was not observed in the circulating IgM values of the 2 groups. Levamisole had no apparent effect on the circulating Ig-bearing lymphocyte values when compared with control calves during the 24 hours of treatment. It was concluded that a single treatment of levamisole may mildly suppress the primary humoral response to IBR vaccination in calves, but it is unlikely that this would affect the animal's capability to recover from, or maintain resistance to, IBR infection.

Effects of dietary molybdenum on the metabolism of copper and molybdenum in young cattle.

On separate occasions young cattle were injected intrarumenally with 99Mo or 64Cu or intravenously with 64Cu. The metabolism of the isotopes were compared to evaluate metabolic changes associated with molybdenum-induced copper deficiency. Molybdenum-99 metabolism was the same in both controls and experimental subjects. Marked differences in plasma kinetics were observed following intrarumenal 64Cu injection, with experimental animals displaying earlier plasma appearance and maintaining higher plasma levels than did controls. Similarly, higher plasma levels, more rapid plasma reappearance and greater fecal excretion were observed following intravenous injection of 64Cu in the experimental animals than in controls. A mechanism involving abnormal ceruloplasmin synthesis associated with the molybdenum-copper interaction is proposed.