Objective—To determine the disposition of gamithromycin in plasma, pulmonary epithelial lining fluid (PELF), bronchoalveolar lavage (BAL) cells, and lung tissue homogenate in cattle. Animals—33 healthy Angus calves approximately 7 to 8 months of age. Procedures—Calves were randomly assigned to 1 of 11 groups consisting of 3 calves each, which differed with respect to sample collection times. In 10 groups, 1 dose of gamithromycin (6 mg/kg) was administered SC in the neck of each calf (0 hours). The remaining 3 calves were not treated. Gamithromycin concentrations in plasma, PELF, lung tissue homogenate, and BAL cells (matrix) were measured at various points by means of high-performance liquid chromatography with tandem mass spectrometry. Results—Time to maximum gamithromycin concentration was achieved at 1 hour for plasma, 12 hours for lung tissue, and 24 hours for PELF and BAL cells. Maximum gamithromycin concentration was 27.8 μg/g, 17.8 μg/mL, 4.61 μg/mL, and 0.433 μg/mL in lung tissue, BAL cells, PELF, and plasma, respectively. Terminal half-life was longer in BAL cells (125.0 hours) than in lung tissue (93.0 hours), plasma (62.0 hours), and PELF (50.6 hours). The ratio of matrix to plasma concentrations ranged between 4.7 and 127 for PELF, 16 and 650 for lung tissue, and 3.2 and 2,135 for BAL cells. Conclusions and Clinical Relevance—Gamithromycin was rapidly absorbed after SC administration. Potentially therapeutic concentrations were achieved in PELF, BAL cells, and lung tissue within 30 minutes after administration and persisted for 7 (PELF) to > 15 (BAL cells and lung tissue) days after administration of a single dose.

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.

Objective-To determine the effects of once-daily oral administration of N-acetyl-d-glucosamine (NAG) on plasma and urine glycosaminoglycan (GAG) concentrations in cats with idiopathic cystitis (IC). Animals-19 cats with IC and 10 clinically normal cats. Procedures-Cats with IC were randomly assigned to receive 250 mg of NAG in capsule form orally once daily for 28 days (n = 12) or a placebo (capsule containing cellulose) orally once daily for the same period (7). In cats with IC, plasma and urine GAG concentrations and urine creatinine concentration were measured on days 0 (immediately before first dose), 7, 14, 21, 28, and 56. For purposes of comparison, those variables were measured in 10 clinically normal cats on day 0. Results-Mean +/- SEM urine GAG-to-creatinine concentration ratios (day 0 data) for cats with IC and clinically normal cats differed significantly (3.11 +/- 0.62 μg/mL and 14.23 +/- 3.47 μg/mL, respectively). For cats with IC, mean plasma GAG concentration in NAG-treated cats (39.96 +/- 5.34 micrograms/mL) was higher than that in placebo-treated cats (24.20 +/- 3.35 micrograms/mL) on day 21. In the NAG-treated cats, plasma GAG concentration on days 21 (39.96 +/- 5.34 micrograms/mL) and 28 (39.91 +/- 6.74 micrograms/mL) differed significantly from the day 0 concentration (27.46 +/- 3.90 micrograms/mL). Conclusions and Clinical Relevance-Cats with IC have lower urinary GAG-to-creatinine concentration ratios than did clinically normal cats. Administration of NAG (250 mg, PO, q 24 h) significantly increased plasma GAG concentrations in cats with IC after 21 days of treatment.

The objective of this study was to experimentally infect calves with bovine viral diarrhea virus (BVDV) isolated from free-ranging white-tailed deer. Twelve colostrum-deprived male Holstein calves were used. Eight were inoculated intranasally with a BVDV type 1a isolated from free-ranging white-tailed deer, and the other four were inoculated with the cell culture medium only and served as a control group. Whole blood, saliva, and nasal and rectal secretions were collected on days 0, 3, 7, 10, 14, 17, and 21 after inoculation for virus isolation and real-time reverse-transcriptase polymerase chain reaction (RT-PCR). On days 14 and 21, 4 calves in the infected group and 2 in the control group were euthanized; multiple tissue samples were collected for histopathologic study. Histopathologic changes included thymic atrophy and lymphoid depletion of the Peyer's patches in all 8 infected calves. The RT-PCR gave positive results with the buffy coat of all 8 infected calves, the nasal samples of 7, and the saliva samples of 2. Virus neutralization testing of the serum gave positive results for 4 of the 8 infected calves, and enzyme-linked immunosorbent assay of the serum gave positive results for 3. All of the samples from the control calves yielded negative results.

Tissues unsuitable for standard immunohistochemical and histopathological examinations for chronic wasting disease (CWD) in cervids and for scrapie in sheep are frequently submitted for testing. This study investigated the effects of experimental autolysis on the detection of abnormal prion protein (PrPsc) in lymphoid and central nervous system (CNS) tissues from elk and sheep. The PrPsc was detected using a Western blotting (WB) test following PrPsc enrichment using sodium phosphotungstic acid (PTA) precipitation (PTA-WB). A commercial enzyme-linked immunosorbent assay (ELISA) was used as a reference test for quantitative measurement. This study showed that the amount of PrPsc in lymphoid and CNS tssues from elk and sheep decreased gradually as a result of autolysis, but PrPsc was still detectable after 5 and 15 d incubation at 37°C by PTA-WB for all lymphoid and CNS samples. The results of the ELISA supported those of PTA-WB, particularly for CNS tissues. In conclusion, autolysis at 37°C for 15 d would not significantly affect the detection of PrPsc in lymphoid and CNS tissues by WB and ELISA and, particularly, PTA-WB is a valuable and alternative confirmatory test to detect PrPsc in autolyzed lymphoid and CNS samples.

We investigated vascular access ports for feline blood donation. Eight cats were anesthetized for conventional blood collection by jugular venipuncture at the beginning and end of the study. In-between conventional collections, vascular access ports were used for collection with or without sedation every 6 to 8 wk for 6 mo. Ports remained functional except for one catheter breakage, but intermittent occlusions occurred. Systolic blood pressure was lower during conventional collection. Behavioral abnormalities occurred during 3 port collections. Packed red cells prepared from collected blood were stored at 4°C for 25 d and assessed for quality pre- and post-storage. With both collection methods, pH and glucose level declined, and potassium level, lactate dehydrogenase activity and osmotic fragility increased. There were no differences between methods in pre-storage albumin and HCO3− levels, and pre and post-storage hematocrit, lactate dehydrogenase activity, and glucose and potassium levels. Pre-storage pH and pCO2 were higher with conventional collection, and pre- and post-storage osmotic fragility were greater with port collection. One port became infected, but all cultures of packed red cells were negative. Tissue inflammation was evident at port removal. In a second study of conventional collection in 6 cats, use of acepromazine in premedication did not exacerbate hypotension. The use of vascular access ports for feline blood donation is feasible, is associated with less hypotension, and may simplify donation, but red cell quality may decrease, and effects on donors must be considered.

Objective-To evaluate tendon injuries in horses over a 16-week period by use of ultrasonography and low-field magnetic resonance imaging (MRI). Sample-Tendons of 8 young adult horses. Procedures-The percentage of experimentally induced tendon injury was evaluated in cross section at the maximal area of injury by use of ultrasonography and MRI at 3, 4, 6, 8, and 16 weeks after collagenase injection. The MRI signal intensities and histologic characteristics of each tendon were determined at the same time points. Results-At 4 weeks after collagenase injection, the area of maximal injury assessed on cross section was similar between ultrasonography and MRI. In lesions of > 4 weeks' duration, ultrasonography underestimated the area of maximal cross-sectional injury by approximately 18%, compared with results for MRI. Signal intensity of lesions on T1-weighted images was the most hyperintense of all the sequences, lesions on short tau inversion recovery images were slightly less hyperintense, and T2-weighted images were the most hypointense. Signal intensity of tendon lesions was significantly higher than the signal intensity for the unaltered deep digital flexor tendon. Histologically, there was a decrease in proteoglycan content, an increase in collagen content, and minimal change in fiber alignment during the 16 weeks of the study. Conclusions and Clinical Relevance-Ultrasonography may underestimate the extent of tendon damage in tendons with long-term injury. Low-field MRI provided a more sensitive technique for evaluation of tendon injury and should be considered in horses with tendinitis of > 4 weeks' duration.

Objective-To investigate shedding of chlamydiae from conjunctiva and genital tracts of cats without clinical signs of conjunctivitis or other infectious disease in relation to their titers of serum antibodies against chlamydiae and to serum amyloid A (SAA) and serum alpha1-acid glycoprotein (AGP) concentrations. Animals-62 healthy cats. Procedures-Serum from each cat was analyzed for antibodies against chlamydiae and for SAA and AGP concentrations. Swab samples from the conjunctival sac and genital tract were analyzed with a real-time PCR assay for Chlamydiaceae. Results-4 of 8 of cats with high antibody titers (ie, 1,600) shed chlamydiae, but only from the conjunctiva. Chlamydiae could not be detected in samples from cats with lower antibody titers nor from any genital tract samples. In cats with antibody titers of 1,600, mean +/- SD SAA concentration was significantly higher when chlamydiae were detected in conjunctival swab samples (3.9 +/- 1.0 mg/L) than when no chlamydiae were detected (1.4 +/- 1.0 mg/L). However, SAA concentration was greater than the limit for an acute-phase response in only one of those cats. There was no significant difference in serum AGP concentrations between cats with high titers that were or were not shedding chlamydiae. Nine of 30 (30%) cats (5 with and 4 without detectable serum antibodies against chlamydiae) that had been mated developed reproductive disorders. Conclusions and Clinical Relevance-Clinically normal cats with high chlamydiae-specific antibody titers can shed and thus transmit chlamydiae. Venereal spread from cats without clinical signs of infection is likely not common.

Objective—To evaluate molecular and histologic characteristics of the superficial digital flexor tendon (SDFT), deep digital flexor tendon (DDFT), and suspensory ligament (SL) and assess trace-mineral concentrations in serum, liver, and hair of juvenile llamas with metacarpophalangeal and metatarsophalangeal joint hyperextension. Animals—12 juvenile llamas (6 with bilateral hyperextension of metacarpophalangeal joints, metatarsophalangeal joints, or both and 6 clinically normal control llamas). Procedures—Radiography and ultrasonography of metacarpophalangeal and metatarsophalangeal regions were performed. Llamas were euthanized, and SDFT, DDFT, and SL samples were collected for histologic evaluation of collagen and elastin content and orientation, proteoglycan content, and collagen type III immunohistochemistry. Total RNA was isolated from SL tissue, and gene expression of collagen types I and III, lysyl oxidase, and matrix metalloproteinase-13 was evaluated via real-time quantitative reverse transcriptase PCR assay. Liver, serum, and hair samples were evaluated for trace mineral content. Results—Collagen type III gene expression and proteoglycan content were significantly increased in SL samples of affected juvenile llamas, compared with those of control llamas. No difference was detected in collagen and elastin content and orientation or in gene expression of collagen type I, lysyl oxidase, or matrix metalloproteinase-13 between groups. Affected llamas had significantly increased serum molybdenum and decreased liver cobalt concentrations, compared with values for control llamas. Conclusions and Clinical Relevance—Increased collagen type III gene expression and proteoglycan content in SL samples of affected juvenile llamas provided evidence of ongoing SL matrix repair. Trace mineral differences may have been attributable to dietary imbalances in affected llamas.

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.