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  • Author or Editor: Hugh G. Townsend x
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Abstract

Objective—To determine whether maternally derived antibodies interfere with the mucosal immune response following intranasal (IN) vaccination of newborn calves with a multivalent modified-live virus vaccine.

Design—Randomized controlled clinical trial.

Animals—23 newborn Holstein bull calves.

Procedures—Calves received colostrum and were assigned to group A (unvaccinated control calves), group B (IN vaccination on day 0), or group C (IN vaccination on days 0 and 35). Serum and nasal secretion sample (NSS) titers of antibodies specific for bovine herpesvirus 1, bovine viral diarrhea virus 1, and bovine viral diarrhea virus 2; WBC counts; and NSS interferon concentrations were determined up to day 77.

Results—Calves had high serum titers of maternally derived antibodies specific for vaccine virus antigens on day 0. High IgA and low IgG titers were detected in NSSs on day 0; NSS titers of IgA decreased by day 5. Group B and C NSS IgA titers were significantly higher than those of group A on days 10 through 35; group C IgA titers increased after the second vaccination. Serum antibody titers decreased at a similar rate among groups of calves. Interferons were not detected in NSSs, and calves did not develop leukopenia.

Conclusions and Clinical Relevance—IN vaccination of newborn calves with high concentrations of virus-neutralizing antibodies increased NSS IgA titers but did not change serum antibody titers. Revaccination of group C calves on day 35 induced IgA production. Intranasal vaccination with a modified-live virus vaccine was effective in calves that had maternally derived antibodies.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine comparative efficacy of vaccines administered IM and intranasally, used alone or sequentially, to protect puppies from infection with Bordetella bronchiseptica and determine whether systemic or mucosal antibody response correlated with protection.

Design—Randomized controlled trial.

Animals—50 specific-pathogen-free Beagle puppies.

Procedure—In 2 replicates of 25 dogs each, 14-weekold puppies that were vaccinated against canine distemper virus and parvovirus were vaccinated against B bronchiseptica via intranasal, IM, intranasal-IM, or IMintranasal administration or were unvaccinated controls. Puppies were challenge exposed via aerosol administration of B bronchiseptica 2 weeks after final vaccination. Clinical variables and systemic and mucosal antibody responses were monitored for 10 days after challenge exposure. Puppies in replicate 1 were necropsied for histologic and immunohistochemical studies.

Results—Control puppies that were seronegative before challenge exposure developed paroxysmal coughing, signs of depression, anorexia, and fever. Vaccinated puppies (either vaccine) that were seronegative before challenge exposure had fewer clinical signs. Puppies that received both vaccines had the least severe clinical signs and fewest lesions in the respiratory tract. Vaccinated dogs had significantly higher concentrations of B bronchiseptica-reactive antibodies in serum saliva before and after challenge. Antibody concentrations were negatively correlated with bacterial growth in nasal cavity and pharyngeal samples after challenge exposure.

Conclusions and Clinical Relevance—Parenterally and intranasally administered vaccines containing B bronchiseptica may provide substantial protection from clinical signs of respiratory tract disease associated with infection by this bacterium. Administration of both types of vaccines in sequence afforded the greatest degree of protection against disease. (J Am Vet Med Assoc 2001;218:367–375)

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To investigate risk factors for the development of pasture- and endocrinopathy-associated laminitis (PEAL) in horses and ponies in North America.

DESIGN Case-control study.

ANIMALS 199 horses with incident cases of PEAL and 351 horses from 2 control populations (healthy horses [n = 198] and horses with lameness not caused by laminitis [153]) that were evaluated in North America between January 2012 and December 2015 by veterinarian members of the American Association of Equine Practitioners.

PROCEDURES North American members of the American Association of Equine Practitioners were contacted to participate in the study, and participating veterinarians provided historical data on incident cases of PEAL, each matched with a healthy control and a lameness control. Conditional logistic regression analysis was used to compare data on PEAL-affected horses with data on horses from each set of controls.

RESULTS Horses with an obese body condition (ie, body condition score ≥ 7), generalized or regional adiposity (alone or in combination), preexisting endocrinopathy, or recent (within 30 days) glucocorticoid administration had increased odds of developing PEAL, compared with horses that did not have these findings.

CONCLUSIONS AND CLINICAL RELEVANCE The present study identified several risk factors for PEAL that may assist not only in managing and preventing this form of laminitis, but also in guiding future research into its pathogenesis.

Full access
in Journal of the American Veterinary Medical Association