Comparative efficacy of tulathromycin versus florfenicol and tilmicosin against undifferentiated bovine respiratory disease in feedlot cattle

Four studies conducted at feedlots in Greeley and Wellington, Colorado; Nebraska; and Texas compared the efficacy of tulathromycin to florfenicol or tilmicosin for the treatment of cattle with undifferentiated bovine respiratory disease (BRD) and subsequent feedlot performance and carcass characteristics. In each study, 100 calves with BRD were treated with tulathromycin given SC at 2.5 mg/kg body weight. At the Greeley, CO, and Nebraska study locations, 100 calves were treated with florfenicol given SC at 40 mg/kg body weight, and at the Wellington, CO, and Texas study locations, tilmicosin was given SC at 10 mg/kg body weight. Cure rate, a derived variable that included assessments of mortality, rectal temperature, and attitude and respiratory scores from day 3 to day 28 and day 3 through harvest, was the primary assessment of BRD efficacy. Cure rates of calves treated with tulathromycin were significantly (P < or = .009) higher than those calves treated with florfenicol. At Wellington, CO, the cure rate of calves treated with tulathromycin was significantly higher (P < or = .018) compared with tilmicosin-treated calves. The differences in cure rates between tulathromycin and tilmicosin treatment groups in the Texas study were not significantly different (P > .05). Tulathromycin was more efficacious in the treatment of undifferentiated BRD compared with florfenicol and, in one study, compared with tilmicosin.     

Efficacy of tulathromycin injectable solution for the treatment of naturally occurring Swine respiratory disease

Tulathromycin, a novel triamilide antimicrobial, was evaluated for treatment of swine respiratory disease (SRD) in field efficacy studies involving 720 pigs in six North American swine herds. In each study, feeder pigs with clinical SRD were randomly assigned in equal numbers to a group treated with tulathromycin given as a single injection at 2.5 mg/kg of body weight or to a saline-treated control group. Four of the studies included a third group treated with ceftiofur sodium for 3 consecutive days at 3 mg/kg of body weight. Pigs were treated on day 0 and evaluated for treatment response on day 7. In each study, 10 or more nontreated pigs and saline-treated pigs that did not respond to treatment underwent necropsies to obtain lung samples that were evaluated for SRD pathogens. The overall cure rate was 46.4% for saline-treated pigs, 71.1% for tulathromycin-treated pigs, and 63.1% for ceftiofur-treated pigs. The cure rate for tulathromycin-treated pigs was significantly higher than for saline-treated pigs (P = .0116). Mortality from SRD occurred in 24 control pigs, seven tulathromycin-treated pigs, and one ceftiofur-treated pig. The mortality rate was significantly lower for both the tulathromycin- and ceftiofur-treated pigs compared with those treated with saline (P = .0148 and P = .0195, respectively). Actinobacillus pleuropneumoniae, Pasteurella multocida, Haemophilus parasuis, and Mycoplasma hyopneumoniae, bacteria commonly associated with SRD, were isolated from SRD-affected pigs. Under field conditions, tulathromycin injectable solution given as a single IM dose of 2.5 mg/kg of body weight was safe and effective in the treatment of SRD.     

Efficacy of tulathromycin compared with tilmicosin and florfenicol for the control of respiratory disease in cattle at high risk of developing bovine respiratory disease

Three studies conducted at feedlots in Colorado, Idaho, and Texas examined the comparative efficacy of tulathromycin injectable solution for the treatment of cattle at high risk of developing undifferentiated bovine respiratory disease (BRD). Each study randomly allocated 250 calves to receive tulathromycin at 2.5 mg/kg and 250 calves to receive either tilmicosin at 10 mg/kg (Colorado site) or florfenicol at 40 mg/kg (Idaho and Texas sites) on arrival at the feedlot. Calves were housed by treatment group in pens with 50 calves/pen. Beginning 3 days after antimicrobial treatment, cattle were observed for signs of BRD daily until harvest. In all three studies, the treatment success rates at 28 days after treatment and at harvest were significantly higher (P < or = .013) for cattle treated with tulathromycin than for cattle treated with either tilmicosin or florfenicol. Fewer tulathromycin-treated cattle were removed from the group as "chronics" or "mortalities" at 28 days posttreatment (P < or = .014) in all three studies. Tulathromycin demonstrated superior efficacy compared with tilmicosin and florfenicol when treating groups of high-risk cattle before the onset of signs of BRD.     

Evaluation of the induction and recovery characteristics of anesthesia with desflurane in cats

OBJECTIVE: To qualitatively and quantitatively evaluate the characteristics of desflurane with regard to the induction of and recovery from anesthesia in cats. ANIMALS: 6 cats. PROCEDURE: Anesthesia was induced and maintained with desflurane in oxygen. Individual minimum alveolar concentration (MAC) values were determined; anesthesia was maintained at 1.25 x MAC for a total anesthesia time (including MAC determination) of 5 hours. Cats were allowed to recover from anesthesia. Induction and recovery periods were video recorded and later scored by use of a grading scale from 0 to 100 (100 being the best outcome). Timing of events was recorded. RESULTS: The MAC of desflurane was 10.27 +/- 1.06%, and mean dose was 5.6 +/- 0.2 MAC-hours. Times to loss of coordination, recumbency, and endotracheal intubation were 1.3 +/- 0.4, 2.3 +/- 0.3, and 6.4 +/- 1.1 minutes, respectively. Median score for quality of anesthetic induction was 93 (range, 91 to 94). Times to first movement, extubation, standing, and ability to jump and land with coordination were 2.8 +/- 1.0, 3.8 +/- 0.5, 14.3 +/- 3.9, and 26.4 +/- 5.1 minutes, respectively. Alveolar washout of desflurane was rapid. Median score for quality of anesthetic recovery was 94 (range, 86 to 96). CONCLUSIONS AND CLINICAL RELEVANCE: Desflurane was associated with rapid induction of and recovery from anesthesia in cats; assessors rated the overall quality of induction and recovery as excellent. Results appear to support the use of desflurane for induction and maintenance of anesthesia in healthy cats.     

Expression, bioactivity, and clinical assessment of recombinant feline erythropoietin

OBJECTIVE: To determine the activity of recombinant feline erythropoietin (rfEPO) in murine bioassays and evaluate its efficacy and safety in cats with erythropoietin-dependent nonregenerative anemia. ANIMALS: 26 cats (group 1, 19 cats with anemia attributed to chronic kidney disease [CKD]; group 2, 7 cats with CKD and recombinant human erythropoietin [rhEPO]-induced red cell aplasia [RCA]). PROCEDURE: The rfEPO was synthesized by use of Chinese hamster ovary (CHO) cells transfected with feline erythropoietin complementary DNA. Preclinical assessments of rfEPO included an erythroid cell proliferation assay and measurements of reticulocytosis in Balb/C mice. Clinical assessments of cats included hematologic, biochemical, and clinical examinations during 12 (group 1) or 6 (group 2) months of rfEPO treatment. RESULTS: Biological activity of rfEPO was broadly equivalent to rhEPO in preclinical murine bioassays. Median Hct and absolute reticulocyte count in cats increased significantly during the first 3 weeks of rfEPO treatment, and median Hct generally could be maintained within a target range of 30% to 40% with periodic adjustments of rfEPO doses. Unexpectedly, 5 cats in group 1 and 3 cats in group 2 that initially responded to rfEPO treatment again developed anemia that was refractory to additional rfEPO treatments, even at higher doses. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment with rfEPO can reestablish active erythropoiesis in most cats with CKD, even those with anemia attributable to rhEPO-induced RCA. Unfortunately, development of RCA during treatment with CHO cell-derived recombinant erythropoietin proteins was not eliminated as a serious safety concern, even for this feline-specific preparation.     

Molecular epidemiologic features of Corynebacterium pseudotuberculosis isolated from horses

OBJECTIVE: To characterize isolates of Corynebacterium pseudotuberculosis from horses, cattle, and sheep in Colorado, Kentucky, Utah, and California in samples collected during perceived epidemics of infection (increased numbers of cases identified) in 2002 and 2003, and determine how closely isolates were related and their possible source. SAMPLE POPULATION: 54 isolates of C pseudotuberculosis from 49 horses, 4 cattle, and 1 sheep. PROCEDURES: Random amplified polymorphic DNA (RAPD) polymerase chain reaction (PCR) assay, PCR assay for the gene encoding the phospholipase D (PLD) toxin, biochemical analyses, and tests for susceptibility to 17 antimicrobial drugs were performed. RESULTS: All isolates reduced nitrate to nitrite, most yielded positive results for the PLD toxin gene, and all were susceptible to antimicrobial drugs. Ten genetic types were detected by use of RAPD PCR assay; types III to X were isolated from horses, cattle, or both in 1 or more states. Types III and IX were isolated from both horses and cattle. Types VII and VIII were isolated in only 1 state, but the number of isolates in these groups was small. In contrast, all other types were isolated in 2 or more states. All isolates from Utah were type III, but the other 3 states had isolates from more than 1 type. CONCLUSIONS AND CLINICAL RELEVANCE: These data are consistent with a clonally expanding epidemic of infection in Utah and an increase in number of infections caused by multiple strains of C pseudotuberculosis not derived from a single source in the other states. The increase in number of infections could be the result of reporting bias, environmental factors facilitating infection, or host factors such as greater herd susceptibility.     

Correlation of dominance as determined by agonistic interactions with feeding order in cats

OBJECTIVE: To determine whether the direction of dominance as determined by agonistic interactions away from food was different from the direction of dominance as determined by access to a resource in cats. ANIMALS: 28 cats. PROCEDURE: Dyadic relationships and hierarchy formed from observation of agonistic interactions away from food were compared with those formed from interactions at the food bowl. A cat was scored as subordinate to another cat if it lost 3 of 3 interactions or lost > or = 75% of the interactions when > 3 interactions occurred. RESULTS: Cats were observed for 449.4 hours. Hierarchy rank determined by agonistic interactions away from food was significantly correlated with rank determined by interactions at the food bowl. In 27 of 31 dyads, the direction of dominance was the same for food bowl and agonistic relationships, which was significant. In post hoc analyses, when considering the relationship between 2 cats, the heavier cat most likely ranked higher in each hierarchy; however, age was not significantly correlated with either hierarchy. On the basis of dyadic information, the older cat in a dyad was more often dominant in agonistic interactions. Males had a higher mean dominance rank than females; however, sex had no effect on rank determined by interactions at the food bowl. CONCLUSIONS AND CLINICAL RELEVANCE: Factors influencing dominant-subordinate relationships are of interest for understanding and treating behavior problems such as aggression and resource control. The outcome of agonistic interactions away from food was related to, but not perfectly correlated with, the outcome of interactions at the food bowl, although winners of those agonistic interactions tended to have control of food.     

Estimation of heritability of atopic dermatitis in Labrador and Golden Retrievers

OBJECTIVE: To estimate the heritability of atopic dermatitis in Golden and Labrador Retrievers. ANIMALS: 429 dogs related to 13 dogs with atopic dermatitis. PROCEDURE: Atopic dermatitis was defined on the basis of the type and frequency of clinical signs recorded in the clinical records, and each dog was classified with atopic dermatitis or probable atopic dermatitis or as nonatopic. By use of data from atopic and nonatopic dogs, regression analyses of parental status on offspring status were performed to estimate heritability. RESULTS: There was no difference in the frequency of atopic dermatitis between sexes or between breeds. There was a marked association between the atopic status of the parent and that of the offspring, particularly for sires. By use of data from 32 litters in which the status of both parents was known and considering only those dogs classified with atopic dermatitis or as nonatopic, the heritability (+/- SE) of atopic dermatitis was estimated to be 0.47 (+/- 0.17). CONCLUSIONS AND CLINICAL RELEVANCE: Atopic dermatitis has a strong genetic component, and breeding of dogs with clinical signs of atopic dermatitis should be discouraged.     

Evaluation of administration of West Nile virus vaccine to pregnant broodmares

OBJECTIVE: To determine whether administration of killed West Nile virus vaccine was associated with pregnancy loss among broodmares. DESIGN: Retrospective cohort study. ANIMALS: 595 mares. PROCEDURE: Records of pregnant mares with known vaccination history from 4 farms were reviewed. Information obtained from 595 mares included mare's identification; farm; age; breed; reproductive status; last breeding date; date last known pregnant; vaccination date; age of conceptus at vaccination; vaccination during the early embryonic, early fetal, and late fetal periods; and whether an early embryonic death (EED), early fetal loss (EFL), or late fetal loss (LFL) occurred. The relationships between the dichotomous outcomes of loss (eg, EED, EFL, LFL) and independent categoric variables (eg, vaccination during the early embryonic, early fetal, or late fetal periods) were examined. RESULTS: Vaccination of pregnant mares during any period of gestation was not associated with increased incidence of pregnancy loss. CONCLUSIONS AND CLINICAL RELEVANCE: Many mares are already pregnant at the onset of mosquito season, when mares are more likely to be vaccinated than at other times. Our findings provide evidence that vaccine administration will not compromise pregnancy in horses.     

Small intestinal volvulus in 115 horses: 1988-2000

OBJECTIVE: To evaluate the historical data, signalment, clinical signs, results of laboratory analyses, treatment, and outcome of horses with small intestinal (SI) volvulus. STUDY DESIGN: Retrospective study. SAMPLE POPULATION: One hundred and fifteen client-owned horses, aged 1 month to 21 years. METHODS: Clinical signs, laboratory data, surgical or necropsy findings, and outcome for horses with SI volvulus were obtained from medical records, identified by computer search and manual review. RESULTS: There was no statistical difference in signalment between cases and the hospital population. Seventy-four percent of horses were >/=3 years. There were considerable variations in clinical signs on admission; high heart rate and signs of severe pain were not consistent features. Examination per rectum identified distended small intestine in only 69% of horses. One hundred horses had surgery, and small intestine resection was performed in 25. Eighty-four horses were recovered from surgery, and 67 horses survived to hospital discharge (80% of horses recovered from surgery, 58% of 115 horses). Forty-eight percent that were ultimately discharged had a post-operative complication and these horses had a longer average stay than horses with no complication (11 days versus 8.9 days). CONCLUSIONS: We identified 115 horses with primary SI volvulus over a 12-year period. We found that the population of horses with this lesion was older than has previously been reported and that the prognosis for post-operative survival to hospital discharge is good (80%). Post-operative complications were common, and affected approximately half the horses that were ultimately discharged from the hospital. CLINICAL RELEVANCE: This information may aid diagnosis and prognosis and guide decision making for horses with this condition.