The fiber type, fiber size, and capillary geometric features were determined from the center of the proximal half of the left and right semitendinosus muscles in 5 mixed-breed dogs, 5 hound-type dogs, and 5 Beagles. There were no significant differences between the left and right muscles of each dog. Comparisons among the 3 groups of dogs revealed that the hound-type dogs had the largest fibers (type I and type II); however, the 3 groups were similar in their fiber-type percentages and their capillary geometric features.

Abruptly weaned crossbred steer calves (N = 271) were used in a randomized, blinded 2-arm clinical trial to assess the impact of a long-acting non-steroidal anti-inflammatory drug on bovine herpesvirus type 1, bovine respiratory syncytial virus, parainfluenza virus type 3, and coronavirus titers and health outcomes when administered concurrently with a modified live respiratory vaccine upon arrival at a feedlot. Treatment groups included a control (saline; n = 135) and an experimental group (injectable meloxicam; n = 136). Viral antibody titers and body weight were measured on arrival, day 7, and day 21, along with a final weight on day 45. Body weight and antibody titers for all viruses increased over time (P < 0.001); however, there were no differences by treatment group or a significant group × time interaction when evaluated using repeated measures analysis of variance. Interestingly, the use of meloxicam was associated with increased treatment risk (P < 0.05). In conclusion, the administration of meloxicam may adversely affect health; however, a decreased vaccine response is likely not a contributing factor.

OBJECTIVE To evaluate the effects of a medetomidine-ketamine combination on tear production of clinically normal cats by use of the Schirmer tear test (STT) 1 before and during anesthesia and after reversal of medetomidine with atipamezole. ANIMALS 40 client-owned crossbred domestic shorthair cats (23 males and 17 females; age range, 6 to 24 months). PROCEDURES A complete physical examination, CBC, and ophthalmic examination were performed on each cat. Cats with no abnormalities on physical and ophthalmic examinations were included in the study. Cats were allocated into 2 groups: a control group (n = 10 cats) anesthetized by administration of a combination of medetomidine hydrochloride (80 μg/kg) and ketamine hydrochloride (5 mg/kg), and an experimental group (30) anesthetized with the medetomidine-ketamine combination and reversal by administration of atipamezole. Tear production of both eyes of each cat was measured by use of the STT I before anesthesia, 15 minutes after the beginning of anesthesia, and 15 minutes after administration of atipamezole. RESULTS Anesthesia with a medetomidine-ketamine combination of cats with no ophthalmic disease caused a significant decrease in tear production. The STT I values returned nearly to preanesthetic values within 15 minutes after reversal with atipamezole, whereas the STT I values for the control group were still low at that point. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that a tear substitute should be administered to eyes of cats anesthetized with a medetomidine-ketamine combination from the time of anesthetic administration until at least 15 minutes after administration of atipamezole.

OBJECTIVE To evaluate pharmacokinetics of ammonium tetrathiomolybdate (TTM) after IV and oral administration to dogs and effects of TTM administration on trace mineral concentrations. ANIMALS 8 adult Beagles and Beagle crossbreds (4 sexually intact males and 4 sexually intact females). PROCEDURES Dogs received TTM (1 mg/kg) IV and orally in a randomized crossover study. Serum molybdenum and copper concentrations were measured via inductively coupled plasma mass spectrometry in samples obtained 0 to 72 hours after administration. Pharmacokinetics was determined via noncompartmental analysis. RESULTS For IV administration, mean ± SD terminal elimination rate constant, maximum concentration, area under the curve, and half-life were 0.03 ± 0.01 hours−1, 4.9 ± 0.6 μg/mL, 30.7 ± 5.4 μg/mL•h, and 27.7 ± 6.8 hours, respectively. For oral administration, mean ± SD terminal elimination rate constant, time to maximum concentration, maximum concentration, area under the curve, and half-life were 0.03 ± 0.01 hours−1, 3.0 ± 3.5 hours, 0.2 ± 0.4 μg/mL, 6.5 ± 8.0 μg/mL•h, and 26.8 ± 8.0 hours, respectively. Oral bioavailability was 21 ± 22%. Serum copper concentrations increased significantly after IV and oral administration. Emesis occurred after IV (2 dogs) and oral administration (3 dogs). CONCLUSIONS AND CLINICAL RELEVANCE Pharmacokinetics for TTM after a single IV and oral administration was determined for clinically normal dogs. Absorption of TTM after oral administration was variable. Increased serum copper concentrations suggested that TTM mobilized tissue copper. Further studies will be needed to evaluate the potential therapeutic use of TTM in copper-associated chronic hepatitis of dogs.

Objective-To compare the efficacy of gamithromycin with that of tulathromycin for control of undifferentiated bovine respiratory disease complex (BRDC) in feedlot calves. Animals-2,529 weaned crossbred beef calves. Procedures-At each of 2 feedlots, calves at risk of developing BRDC were administered a single dose of gamithromycin (6.0 mg/kg, SC; n = 1,263) or tulathromycin (2.5 mg/kg, SC; 1,266) metaphylactically. Health (BRDC morbidity, mortality, case-fatality, and retreatment rates) and performance (average daily gain, dry matter intake, and feed-to-gain ratio) outcomes were compared between treatments via classical hypothesis testing. Bioequivalence limits for gamithromycin and tulathromycin were established for outcomes for which no significant difference between treatments was detected. Results-Mean BRDC morbidity rate (31.0%) for calves administered gamithromycin was greater than that (22.9%) for calves administered tulathromycin; otherwise, health and performance did not differ between treatments. Limits for mean differences within which gamithromycin was considered bioequivalent to tulathromycin were +/- 10% for BRDC retreatment rate, +/- 3.5% for BRDC mortality rate, ± 16% for case-fatality rate, +/- 37 kg for final body weight, +/- 0.1 kg/d for average daily gain, +/- 0.3 kg/d for dry matter intake, and +/- 0.7 for feed-to-gain ratio. Conclusions and Clinical Relevance-The efficacy of gamithromycin did not differ from that of tulathromycin for all outcomes except morbidity rate; calves administered gamithromycin had a higher BRDC morbidity rate than did calves administered tulathromycin. On the basis of the bioequivalence limits established for this dataset, gamithromycin was considered equivalent to tulathromycin for the control of BRDC.

The objective of this study was to evaluate the endocrine and immune responses of steers challenged with infectious bovine rhinotracheitis virus (IBRV). For the study, twelve crossbred beef steers weighing approximately 228.82 kg were fitted with indwelling rectal temperature monitoring devices and randomly assigned to a Control (CON) or IBRV treatments. Immune challenged steers received an intra-nasal dose of IBRV (4 ml total volume; 2ml/nostril) and CON steers received an intra-nasal dose of saline (2 ml/nostril). On day 0, steers were challenged and placed into isolated paddocks. At 72 hours post-inoculation, steers were fitted with indwelling jugular catheters and placed into individual stanchions. Blood samples were intensively collected on days 4 through 8 post-inoculation. Serum was analyzed for cortisol, interleukin-6, interferon-gamma, tumor necrosis factor-alpha, growth hormone, and insulin-like growth factor-1. On day 2, IBRV challenged steers had increased rectal temperature compared to CON steers (P < 0.05); the greatest rectal temperatures were observed on day 4, after which rectal temperatures returned to baseline by day 6. Serum concentrations of cortisol, interferon-gamma, and growth hormone exhibited a similar response pattern increasing by day 2 for the IBRV challenged steers, with the greatest increases observed on day 4, and subsiding on day 6. There was a decrease (P = 0.04) in growth hormone production in IBRV challenged steers, but no difference in insulin-like growth factor-1. Collectively, the data revealed that alterations in the somatotrophic axis were not associated with large increases in circulating pro-inflammatory cytokines. Results suggest that the dose of the virus used in the present study, while sufficient to elicit a febrile response, was not enough to elicit a robust pro-inflammatory immune response.

Objective—To determine whether a mutation in the fibrillin 2 gene (FBN2) is associated with canine hip dysplasia (CHD) and osteoarthritis in dogs. Animals—-1,551 dogs. Procedures—Hip conformation was measured radiographically. The FBN2 was sequenced from genomic DNA of 21 Labrador Retrievers and 2 Greyhounds, and a haplotype in intron 30 of FBN2 was sequenced in 90 additional Labrador Retrievers and 143 dogs of 6 other breeds. Steady-state values of FBN2 mRNA and control genes were measured in hip joint tissues of fourteen 8-month-old Labrador Retriever–Greyhound crossbreeds. Results—The Labrador Retrievers homozygous for a 10-bp deletion haplotype in intron 30 of FBN2 had significantly worse CHD as measured via higher distraction index and extended-hip joint radiograph score and a lower Norberg angle and dorsolateral subluxation score. Among 143 dogs of 6 other breeds, those homozygous for the same deletion haplotype also had significantly worse radiographic CHD. Among the 14 crossbred dogs, as the dorsolateral subluxation score decreased, the capsular FBN2 mRNA increased significantly. Those dogs with incipient hip joint osteoarthritis had significantly increased capsular FBN2 mRNA, compared with those dogs without osteoarthritis. Dogs homozygous for the FBN2 deletion haplotype had significantly less FBN2 mRNA in their femoral head articular cartilage. Conclusions and Clinical Relevance—The FBN2 deletion haplotype was associated with CHD. Capsular gene expression of FBN2 was confounded by incipient secondary osteoarthritis in dysplastic hip joints. Genes influencing complex traits in dogs can be identified by genome-wide screening, fine mapping, and candidate gene screening.

Ten adult dogs (5 Beagles and 5 mixed-breed dogs) were inoculated IV with canine platelets containing Ehrlichia platys. Inclusions and morulae of E platys developed in platelets of infected dogs at 10 to 14 days after inoculation, followed by marked thrombocytopenia at 14 to 21 days. Parasitemia and marked thrombocytopenia recurred at 24 to 28 days after inoculation. Increased numbers of megakaryocytes were observed in marrow aspirate smears from infected dogs, indicative of regenerative thrombocytopenia. Prior to infection, platelet-rich plasma from these dogs was determined to have similar aggregatory response to arachidonate. After infection with E platys, the aggregatory response of platelet-rich plasma to collagen or 3 dilutions of adenosine diphosphate was evaluated. A statistically significant (P < 0.05) inhibition of platelet aggregatory response to the lowest dilution of adenosine diphosphate was detected for mixed-breed dogs, whereas aggregation responses were unchanged in Beagles. Results indicate that platelet activation may occur in dogs with acute ehrlichial infection.