OBJECTIVE To evaluate safety and toxicokinetic profiles associated with daily oral administration of grapiprant, a new analgesic that selectively blocks the prostaglandin E2 EP4 receptor, to cats. ANIMALS 24 healthy domestic shorthair cats (12 males and 12 females). PROCEDURES Cats were randomly assigned (3 of each sex/group) to receive a placebo capsule or grapiprant at 3, 9, or 15 mg/kg, administered PO once daily for 28 days, beginning on day 0. Food consumption and behavior were observed daily, body weight was measured weekly, and clinicopathologic tests were performed on blood and urine samples collected on days −7, 14, and 25. Blood samples for toxicokinetic analyses were collected after treatment on days 0 and 27. Cats were euthanized on day 28, and full necropsies and histologic evaluations were performed. RESULTS Grapiprant rapidly reached peak serum concentrations and maintained substantial concentrations throughout the 28-day period. By day 27, maximum serum concentrations ranged from 683 ng/mL to 4,950 ng/mL, which were attained by 1 to 4 hours after administration. Serum half-lives on day 27 ranged from approximately 2 to 14 hours (median, approx 5 to 6 hours). Grapiprant was well tolerated, and no adverse effects were detected at doses ≤ 15 mg/kg. No significant effects of grapiprant were identified on body weight, food consumption, clinicopathologic variables, or gross or histologic necropsy findings. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested the safety of daily oral administration of grapiprant to cats. Additional studies are needed to evaluate the efficacy of grapiprant for treatment of cats with osteoarthritis.

OBJECTIVE To determine the effects of topical ocular application of 1% trifluridine ophthalmic solution in dogs with experimentally induced recurrent ocular canine herpesvirus-1 (CHV-1) infection. ANIMALS 10 specific pathogen–free Beagles. PROCEDURES 12 months prior to the beginning of the randomized, masked, placebo-controlled 30-day trial, latent ocular CHV-1 infection was experimentally induced in each dog by topical ocular inoculation of both eyes with a field strain of CHV-1. Recurrent ocular CHV-1 infection was induced by oral administration of prednisolone for 7 days (starting day 1). Starting on the fourth day of prednisolone administration, each dog received 1% trifluridine solution or artificial tears (placebo) topically in both eyes 6 times daily for 2 days and then 4 times daily for 12 days. Ophthalmic examinations were performed every 2 days, and ocular disease scores were calculated. Ocular samples for CHV-1 PCR assays and blood samples for clinicopathologic analyses and assessment of CHV-1 serum neutralization antibody titers were collected at predetermined intervals. RESULTS Conjunctivitis was clinically detected in all dogs by day 4. Compared with dogs receiving placebo, mean and total clinical ocular disease scores were significantly lower and median CHV-1 shedding duration was significantly shorter for the trifluridine-treated dogs. Both groups had increasing CHV-1 serum neutralization antibody titers over time, but no significant differences between groups were detected. Clinicopathologic findings were unremarkable throughout the study. CONCLUSIONS AND CLINICAL RELEVANCE Topical ocular application of 1% trifluridine ophthalmic solution was well tolerated and effective at reducing disease scores and viral shedding duration in dogs with experimentally induced ocular CHV-1 infection, but may require frequent administration.

OBJECTIVE To evaluate changes in systemic and ocular antibody responses of steers following intranasal vaccination with precipitated or partially solubilized recombinant Moraxella bovis cytotoxin (MbxA). ANIMALS 13 Angus steers with ages ranging from 318 to 389 days and weights ranging from 352 to 437 kg. PROCEDURES Steers were assigned to receive 500 μg of a precipitated (MbxA-P; n = 5) or partially solubilized (MbxA-S; 5) recombinant MbxA subunit adjuvanted with polyacrylic acid. A control group (n = 3) received the adjuvant alone. Each steer received the assigned treatment (1 mL/nostril) on days 0 and 28. Serum and tear samples were collected on days 0 (before vaccination), 14, 28, 42, and 55. Changes in MbxA-neutralizing antibody titers and MbxA-specific IgG concentrations in serum and tears and changes in MbxA-specific IgA concentrations in tears were measured. RESULTS Mean fold changes in MbxA-specific IgG concentration in serum and tears and MbxA-neutralizing antibody titer in tears for the MbxA-P group were significantly greater than those for the MbxA-S and control groups. Mean serum MbxA-neutralizing antibody titer did not differ among the 3 groups. Although the mean fold change in tear MbxA-specific IgA concentration differed significantly among the groups in the overall analysis, post hoc comparisons failed to identify any significant pairwise differences. CONCLUSIONS AND CLINICAL RELEVANCE Systemic and ocular immune responses induced by intranasal administration of the MbxA-P vaccine were superior to those induced by the MbxA-S vaccine. Additional research is necessary to determine whether the MbxA-P vaccine can prevent naturally occurring infectious bovine keratoconjunctivitis.

OBJECTIVE To develop and assess the feasibility, repeatability, and safety of an ultrasound-guided technique to stimulate the first cervical nerve (FCN) at the level of the alar foramen of the atlas of horses. ANIMALS 4 equine cadavers and 6 clinically normal Standardbreds. PROCEDURES In each cadaver, the FCN pathway was determined by dissection, and any anastomosis between the first and second cervical nerves was identified. Subsequently, each of 6 live horses underwent a bilateral ultrasound-guided stimulation of the FCN at the alar foramen 3 times at 3-week intervals. After each procedure, horses were examined daily for 5 days. RESULTS In each cadaver, the FCN passed through the alar foramen; a communicating branch between the FCN and the accessory nerve and anastomoses between the ventral branches of the FCN and second cervical nerve were identified. The anastomoses were located in the upper third of the FCN pathway between the wing of the atlas and the nerve's entry in the omohyoideus muscle. Successful ultrasound-guided electrical stimulation was confirmed by twitching of the ipsilateral omohyoideus muscle in all 6 live horses; this finding was observed bilaterally during each of the 3 experimental sessions. No complications developed at the site of stimulation. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that ultrasound-guided stimulation of the FCN at the alar foramen appears to be a safe and straightforward procedure in horses. The procedure may have potential for use in horses with naturally occurring recurrent laryngeal neuropathy to assess reinnervation after FCN transplantation or nerve-muscle pedicle implantation in the cricoarytenoideus dorsalis muscle.

OBJECTIVE To evaluate optimal isolation of endothelial colony-forming cells (ECFCs) from peripheral blood of horses. SAMPLE Jugular and cephalic venous blood samples from 17 adult horses. PROCEDURES Each blood sample was divided; isolation was performed with whole blood adherence (WBA) and density gradient centrifugation (DGC). Isolated cells were characterized by uptake of 1,1’-dioctadecyl-3,3,3’,3’-tetramethylindocarbocyanine perchlorate–labeled acetylated low-density lipoprotein (DiI-Ac-LDL), vascular tubule formation, and expression of endothelial (CD34, CD105, vascular endothelial growth factor receptor-2, and von Willebrand factor) and hematopoietic (CD14) cell markers by use of indirect immunofluorescence assay (IFA) and flow cytometry. RESULTS Colonies with cobblestone morphology were isolated from 15 of 17 horses. Blood collected from the cephalic vein yielded colonies significantly more often (14/17 horses) than did blood collected from the jugular vein (8/17 horses). Of 14 cephalic blood samples with colonies, 13 were obtained with DGC and 8 with WBA. Of 8 jugular blood samples with colonies, 8 were obtained with DGC and 4 with WBA. Colony frequency (colonies per milliliter of blood) was significantly higher for cephalic blood samples and samples isolated with DGC. Cells formed vascular tubules, had uptake of DiI-Ac-LDL, and expressed endothelial markers by use of IFA and flow cytometry, which confirmed their identity as ECFCs. CONCLUSIONS AND CLINICAL RELEVANCE Maximum yield of ECFCs was obtained for blood samples collected from both the jugular and cephalic veins and use of DGC to isolate cells. Consistent yield of ECFCs from peripheral blood of horses will enable studies to evaluate diagnostic and therapeutic uses.

The objective of this study was to assess the minimum dose, antigen content, and immunization duration of a trivalent vaccine containing inactivated Haemophilus parasuis serovars 4, 5, and 12 and the Montanide GEL 01 PR adjuvant in piglets and pregnant sows. Our results demonstrated that the minimum vaccine dose was 2 mL per pig and the optimal antigen content 2.0 × 10(9), 1.0 × 10(9), and 1.0 × 10(9) colony-forming units/mL of serovars 4, 5, and 12, respectively. The vaccine provided effective protection 14 d after the 2nd vaccination, and the period of immune protection was 180 d (6 mo) after the 2nd vaccination. Maternal antibodies provided early protection for the piglets, and vaccinating the sows before farrowing helped to control disease and protected the piglets during lactation; the piglets were protected during the finishing period by being vaccinated during lactation. Our findings provide a basis for developing a commercial trivalent vaccine of inactivated H. parasuis serovars 4, 5, and 12 against Glässer’s disease.

Tumor necrosis factor alpha (TNF-α) plays an important role in the immune system. In this study, TNF-α expression was analyzed in 11 tissues of 8 piglets resistant to enterotoxigenic Escherichia coli (ETEC) F18 and 8 ETEC F18-susceptible piglets from the Large White breed. The expression levels of TNF-α were high in immune organs (spleen, lung, thymus, and lymph nodes). The levels were higher in ETEC F18-resistant piglets than in ETEC F18-susceptible piglets, with significant differences in spleen, kidney, thymus, lymph node, and duodenum (P < 0.05). The mutation TNF-α −791(C→T) and 3 genotypes (CC, CT, and TT) were identified. The TNF-α expression levels in the spleen, kidney, lymph nodes, and duodenum were significantly higher in the TT pigs than in the CC pigs (P < 0.05). Thus, TNF-α −791(C→T) has significant effects on mRNA expression and may regulate ETEC F18 resistance of weaning piglets. Therefore, the −791(C→T) mutation of the TNF-α gene could be considered an important potential genetic marker of ETEC F18 resistance.

OBJECTIVE To assess effects of withholding feed on thyrotropin-releasing hormone (TRH) stimulation test results used in diagnosis of pituitary pars intermedia dysfunction in horses and determine effects of combined testing on results of the TRH stimulation test and the oral sugar test (OST) used in diagnosis of equine metabolic syndrome. ANIMALS 30 adult horses. PROCEDURES All horses underwent TRH stimulation tests under fed and nonfed conditions, an OST alone, and an OST combined with TRH stimulation testing. For TRH stimulation tests, plasma ACTH concentrations were measured before (baseline) and 10 minutes after (poststimulation) IV TRH administration. For the OST, plasma glucose and insulin concentrations were measured before (baseline) and 60 and 90 minutes after oral corn syrup administration. For combined testing, the TRH stimulation test was initiated immediately after 60-minute posttreatment sample collection for the OST. Results were compared among methods by Wilcoxon matched-pairs, signed rank tests, paired t tests, and Bland-Altman analysis. RESULTS Feeding conditions did not affect median ACTH concentrations when TRH stimulation tests were performed alone. Median baseline ACTH concentration did not differ between TRH stimulation tests performed alone (under fed or nonfed conditions) and those combined with OSTs. Median poststimulation ACTH concentration was significantly lower for combined tests than for solitary TRH stimulation tests. Mean 60-minute plasma glucose concentration was significantly lower for solitary OSTs than for combined tests, but this difference could not be attributed to TRH administration. CONCLUSIONS AND CLINICAL RELEVANCE Combined testing in the manner described impacted ACTH concentrations during TRH stimulation tests and is not recommended at this time.

OBJECTIVE To evaluate the efficacy of 4 commercially available multivalent modified-live virus vaccines against clinical disease, viremia, and viral shedding caused by bovine viral diarrhea virus (BVDV) and bovine herpesvirus 1 (BHV1) in early-weaned beef calves. ANIMALS 54 early-weaned beef steers (median age, 95 days). PROCEDURES Calves were randomly assigned to 1 of 5 groups and administered PBSS (group A [control]; n = 11) or 1 of 4 commercially available modified-live virus vaccines that contained antigens against BHV1, BVDV types 1 (BVDV1) and 2 (BVDV2), parainfluenza type 3 virus, and bovine respiratory syncytial virus (groups B [11], C [10], D [11], and E [11]). Forty-five days after vaccination, calves were exposed simultaneously to 6 cattle persistently infected with BVDV and 8 calves acutely infected with BHV1 for 28 days (challenge exposure). For each calf, serum antibody titers against BVDV and BHV1 were determined before vaccination and before and after challenge exposure. Virus isolation was performed on nasal secretions, serum, and WBCs at predetermined times during the 28-day challenge exposure. RESULTS None of the calves developed severe clinical disease or died. Mean serum anti-BHV1 antibody titers did not differ significantly among the treatment groups at any time and gradually declined during the study. Mean serum anti-BVDV antibody titers appeared to be negatively associated with the incidence of viremia and BVDV shedding. The unvaccinated group (A) had the lowest mean serum anti-BVDV antibody titers. The mean serum anti-BVDV antibody titers for group D were generally lower than those for groups B, C, and E. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated differences in vaccine efficacy for the prevention of BVDV viremia and shedding in early-weaned beef calves.

Humoral immune responses and protective efficacy by various doses of Salmonella ghost cells carrying enterotoxigenic Escherichia coli (ETEC) fimbrial antigens for protection against piglet colibacillosis were studied. All groups were orally primed and boosted at 11 and 14 wk of pregnancy, respectively. Group A sows were inoculated with phosphate-buffered saline (PBS), and groups B, C, and D sows were immunized with 2 × 10(9) 2 × 10(10), and 2 × 10(11) ghost cells, respectively. Serum immunoglobulin (Ig)G, and colostrum (Ig)G and (Ig)A levels of groups C and D sows were significantly higher than those of group A sows. In addition, serum (Ig)G and (Ig)A levels in group C and D piglets were significantly increased compared to those of group A piglets. After challenge with wild-type ETEC, diarrhea and mortality were not observed in group C and D piglets, while diarrhea was observed in 88.9% and 58.8% of groups A and B piglets, respectively, and 16.7% mortality was observed in group A piglets. These findings indicate that oral immunization of sows with 2 × 1010 or 1011 ghost cells can effectively protect their offspring from colibacillosis.