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  • Author or Editor: Joanne Hewson x
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Objective—To develop a method for experimental induction of equine rhinitis A virus (ERAV) infection in equids and to determine the clinical characteristics of such infection.

Animals—8 ponies (age, 8 to 12 months) seronegative for antibodies against ERAV.

Procedures—Nebulization was used to administer ERAV (strain ERAV/ON/05; n = 4 ponies) or cell culture medium (control ponies; 4) into airways of ponies; 4 previously ERAV-inoculated ponies were reinoculated 1 year later. Physical examinations and pulmonary function testing were performed at various times for 21 days after ERAV or mock inoculation. Various types of samples were obtained for virus isolation, blood samples were obtained for serologic testing, and clinical scores were determined for various variables.

Results—ERAV-inoculated ponies developed respiratory tract disease characterized by pyrexia, nasal discharge, adventitious lung sounds, and enlarged mandibular lymph nodes. Additionally, these animals had purulent mucus in lower airways up to the last evaluation time 21 days after inoculation (detected endoscopically). The virus was isolated from various samples obtained from lower and upper airways of ERAV-inoculated ponies up to 7 days after exposure; this time corresponded with an increase in serum titers of neutralizing antibodies against ERAV. None of the ponies developed clinical signs of disease after reinoculation 1 year later.

Conclusions and Clinical Relevance—Results of this study indicated ERAV induced respiratory tract disease in seronegative ponies. However, ponies with neutralizing antibodies against ERAV did not develop clinical signs of disease when reinoculated with the virus. Therefore, immunization of ponies against ERAV could prevent respiratory tract disease attributable to that virus in such animals.

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in American Journal of Veterinary Research


Objective—To characterize the impact of Mannheimia haemolytica infection on feed intake and weight gain in feedlot heifers and to evaluate the clinical efficacy of isoflupredone acetate administered in combination with oxytetracycline.

Animals—96 weanling heifers in a research feedlot facility.

Procedures—Bronchopneumonia was induced by intrabronchial infusion of M haemolytica. Control heifers underwent a sham procedure. Infected heifers were treated with oxytetracycline alone or in combination with isoflupredone acetate (OXY-ISO) or with nothing. Clinical variables were recorded daily for 7 days following disease induction, and feedlot performance indices were measured over a 12-week period.

Results—Infection caused a reduction in dry-matter intake and average daily gain (ADG) in heifers that received no treatment. Oxytetracycline treatment alone did not prevent reductions in feed intake and ADG during the first week after infection was induced, whereas OXY-ISO treatment did prevent these reductions. Treatment with OXY-ISO also resulted in faster clinical improvement. No significant differences were evident between the oxytetracycline and OXY-ISO groups with respect to dry-matter intake or ADG throughout the study period.

Conclusions and Clinical Relevance—Isoflupredone acetate appeared to be a useful clinical adjunct to treatment with oxytetracycline in cattle with acute M haemolytica bronchopneumonia.

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in American Journal of Veterinary Research


OBJECTIVE To explore referring equine veterinarians' expectations of equine veterinary referral centers and specialists.

DESIGN Qualitative, focus group interview–based study.

SAMPLE 6 focus groups comprised of equine practitioners with experience in referral of clients and patients to equine specialists or referral centers (48 referring veterinarians [rDVMs]).

PROCEDURES Focus group sessions were conducted independently and followed a standardized discussion guide consisting of open-ended questions and follow-up probes. Discussions were recorded, and thematic analysis was performed on the content.

RESULTS The overarching theme of participants' discussions was that specialists and referral centers are an extension of the care that rDVMs provide to their clients and patients. The 5 areas that participants described as important to this expectation were rDVM-client relationships, rDVM involvement during referral care, collegial rDVM-specialist relationships, communication between rDVMs and specialists, and the boundaries of referral care. Participating practitioners wanted to be involved during the referral process, which was seen as being facilitated by having a collegial relationship with the specialist and through effective communication during the course of referral care.

CONCLUSIONS AND CLINICAL RELEVANCE Relationships and communications between rDVMs and specialists are important aspects of equine veterinary medicine. Both rDVMs and specialists are likely to benefit from pursuing opportunities to further their relationship by using up-front communication to establish clear role expectations and clear processes for sharing information.

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in Journal of the American Veterinary Medical Association