A real-time polymerase chain reaction (PCR) assay of the outer membrane protein (OMP) P2 gene was developed and used to test 97 putative Haemophilus parasuis pure cultures and 175 clinical tissue samples. With standard culture isolation as the gold standard, the diagnostic sensitivity and specificity of the PCR assay were determined to be 83% and 80%, respectively.

Objective—To determine the efficacy of a multivalent modified-live virus (MLV) vaccine containing a Mannheimia haemolytica toxoid to reduce pneumonia and mortality rate when administered to calves challenge exposed with virulent Bibersteinia trehalosi. Animals—74 Holstein calves. Procedures—Calves were assigned to 2 treatment groups. Calves in the control group (n = 36) were vaccinated by SC administration of 2 mL of a commercial 5-way MLV vaccine, and calves in the other group (38) were vaccinated by SC administration of a 2-mL dose of a 5-way MLV vaccine containing M haemolytica toxoid (day 0). On day 21, calves were transtracheally administered B trehalosi. Serum was obtained for analysis of antibody titers against M haemolytica leukotoxin. Nasopharyngeal swab specimens were collected from calves 1 day before vaccination (day −1) and challenge exposure (day 20) and cultured to detect bacterial respiratory pathogens. Clinical scores, rectal temperature, and death attributable to the challenge-exposure organism were recorded for 6 days after challenge exposure. Remaining calves were euthanized at the end of the study. Necropsy was performed on all calves, and lung lesion scores were recorded. Results—Calves vaccinated with the MLV vaccine containing M haemolytica toxoid had significantly lower lung lesion scores, mortality rate, and clinical scores for respiratory disease, compared with results for control calves. Conclusions and Clinical Relevance—Administration of a multivalent MLV vaccine containing M haemolytica toxoid protected calves against challenge exposure with virulent B trehalosi by reducing the mortality rate, lung lesion scores, and clinical scores for respiratory disease.

Objective—To evaluate analgesic effects of an improved sustained-release buprenorphine (BUP-SR) formulation administered to mice. Animals—36 male Swiss-Webster mice. Procedures—Mice were assigned to each of 3 treatment groups (n = 12 mice/group). Treatments were administered SC (vehicle [control treatment], 1.5 mg of buprenorphine hydrochloride [BUP-HCl]/kg, and 1.5 mg of BUP-SR/kg). Mice were evaluated (total activity, gastrointestinal tract motility, respiratory rate, cataleptic behavior, and tall-flick and hot plate nociception tests) to determine behavioral and physiologic responses at 4, 24, and 48 hours after treatment administration. Body weight and respiratory rate were measured before and at each time point after treatment administration. Results—SC administration of BUP-SR resulted in significant antinociception effects for 48 hours for the hot plate and tall-flick nociception tests without substantial adverse effects. Gastrointestinal tract motility and total activity were higher at 4 hours for mice receiving BUP-SR than for mice receiving the vehicle, but values were the same between these groups at 24 and 48 hours. The BUP-SR group had a lower respiratory rate than did the control group at all times after treatment administration. Mice treated with BUP-SR had no significant changes in body weight during the study, whereas mice treated with BUP-HCl had a significant decrease in body weight at 24 and 48 hours. Conclusions and Clinical Relevance—BUP-SR administration resulted in antinociception effects for 48 hours. Results of this study indicated that the improved BUP-SR formulation could be safely administered SC and conferred superior analgesia, compared with that for BUP-HCl, in mice.

Since there is no registered anthelmintic drug available for use in goats, extra-label use of drugs is a common practice in most countries. The aim of the present study was to compare the pharmacokinetic disposition of levamisole (LVM)-oxyclozanide (OXZ) combination in sheep and goats following per osadministration. Goats (n= 8) and sheep (n= 8) 12- to 16-months-old were used for this study. The animals received tablet formulation of LVM and OXZ combination orally at a dose of 7.5 mg/kg and 15 mg/kg body weight, respectively. Blood samples were collected by jugular vein at different times between 5 min and 120 h after drug administrations. The plasma concentrations of LVM and OXZ were analyzed by HPLC following liquid-liquid phase extraction procedures. The plasma concentrations and systemic availabilities of both LVM and OXZ in goats were lower and the plasma persistence of LVM was shorter compared with those observed in sheep. Terminal half-lives (t1/2-z) of both molecules are shorter in goats compared with those in sheep. Goats treated with LVM-OXZ combination at the recommended dose for sheep may result in a reduced efficacy, because of under-dosing, which may increase the risk of drug resistance in parasites. Increased or repeated dose could be a strategy to provide higher plasma Concentration and thus to improve the efficacy against the target parasites in goats compared with sheep. However, some adverse reactions may occur since LVM has relatively very narrow therapeutic index due to its nicotine-like structure and effect.

Mice were intranasally inoculated at various times to optimize the vaccination strategy with a new live candidate vaccine expressing the antigens CP39, FimA, PtfA, and ToxA of Pasteurella multocida and F1P2 of Bordetella bronchiseptica in an attenuated live Salmonella system to protect against progressive atrophic rhinitis (PAR). Sixty BALB/c mice were divided equally into 4 groups. The group A mice were vaccinated only at 12 wk of age, the group B mice received a primary vaccination at 9 wk of age and a booster at 12 wk of age, the group C mice received a primary vaccination at 6 wk of age and boosters at 9 and 12 wk of age, and the group D mice were inoculated intranasally with sterile phosphate-buffered saline as a control. The humoral and mucosal immune responses of groups A, B, and C increased significantly compared with those of the control group. Expression of the cytokines interleukin-4 and interferon-γ in splenocytes also increased significantly. In addition, the group B mice exhibited significantly fewer gross lesions in lung tissue compared with the other vaccinated groups after challenge with a virulent P. multocida strain. These results indicate that a strategy of double intranasal vaccination can optimize protection against PAR.

Objective—To determine renal arterial resistive index (RI) and pulsatility index (PI) and clinical signs of overhydration induced by IV administration of saline (0.9% NaCl) solution and to assess RI and PI as variables for monitoring of dogs to detect overhydration. Animals—10 clinically normal Beagles. Procedures—Each dog received saline solution at a maintenance rate (2.5 mL/kg/h) and a rate 3 times that of the maintenance rate (overhydration rate; 7. 5 mL/kg/h). Values of RI and PI were determined with pulsed-wave Doppler ultrasonographic examination of renal interlobar or arcuate arteries before saline solution administration, every hour during 5 hours of administration, and 1 hour after administration was stopped. Results—No significant changes in RI or PI were detected during administration of saline solution at the maintenance rate. However, RI (starting 1 hour after the beginning of fluid administration [mean ± SD value, 0.589 ± 0.012]) and PI (starting 2 hours after the beginning of fluid administration [value, 0.867 ± 0.052]) were significantly lower during administration at the overhydration rate than they were during administration at the maintenance rate. Clinical signs of overhydration were observed in all dogs starting 4 hours after the beginning of fluid administration at the overhydration rate. Conclusions and Clinical Relevance--Results indicated overhydration of dogs caused significant decreases in RI and PI prior to detection of clinical signs of overhydration. Ultrasonographic determination of renal arterial RI and PI seemed to be a noninvasive and sensitive method for evaluation of overhydration in dogs.

Objective-To characterize the effects of pentoxifylline on the gross and microscopic variables associated with immediate and late-phase inflammation following injection of IgE-specific antibodies in the skin of clinically normal dogs. Animals-6 healthy adult mixed-breed dogs. Procedures-Intradermal injections (0.1 mL each) of PBS solution, histamine phosphate, and cross-linking rabbit-origin anti-canine IgE antibodies (3 injections/dog) were administered at 0 hours on day 0; wheal sizes were evaluated at 20 minutes, 6 hours, and 24 hours. Biopsy specimens of injected and noninjected skin were collected 24 hours after injection. On day 2, treatment with pentoxifylline (20 mg/kg, PO, q 8 h) was initiated and continued until day 30. For each dog, injection, measurement, and biopsy procedures were repeated on days 30 to 31 and on days 37 to 38 (ie, after discontinuation of pentoxifylline administration). Results-Pentoxifylline administration was associated with a significant decrease in wheal size at 6 and 24 hours (but not at 20 minutes) after injection of anti-canine IgE. Repeated injections performed 1 week after drug discontinuation revealed partial recovery of the 6-hour cutaneous reaction and complete recovery of the 24-hour cutaneous reaction. Pentoxifylline administration was also associated with inhibition of mast cell degranulation and significant decreases in the total numbers of cutaneous inflammatory cells and eosinophils, compared with pretreatment findings. Conclusions and Clinical Relevance-In clinically normal dogs, pentoxifylline effectively impaired late-phase reactions but not immediate reactions at sites of intradermal injection of IgE-specific antibodies by inhibiting mast cell degranulation and recruitment of cutaneous inflammatory cells, especially eosinophils.

Impaired abomasal motility is common in cattle with abomasal disorders. The macrolide erythromycin has been demonstrated to be an effective prokinetic agent in healthy calves and in adult cattle with abomasal volvulus or left displaced abomasum. We hypothesized that 2 structurally related macrolides, spiramycin and tulathromycin, would also be effective prokinetic agents in cattle. Six milk-fed, male, Holstein-Friesian calves were administered each of the following 4 treatments: spiramycin, 75 000 IU/kg BW, IM, this dose approximates 25 mg/kg BW, IM; tulathromycin, 2.5 mg/kg BW, SC; 2 mL of 0.9% NaCl (negative control); and erythromycin, 8.8 mg/kg BW, IM (positive control). Calves were fed 2 L of cow's milk containing acetaminophen (50 mg/kg body weight) 30 min after each treatment was administered and jugular venous blood samples were obtained periodically after the start of sucking. Abomasal emptying rate was assessed by the time to maximal plasma acetaminophen concentration. Spiramycin, tulathromycin, and the positive control erythromycin increased abomasal emptying rate compared to the negative control. We conclude that the labeled antimicrobial dose of spiramycin and tulathromycin increases the abomasal emptying rate in healthy milk-fed calves. Additional studies investigating whether spiramycin and tulathromycin exert a prokinetic effect in adult cattle with abomasal hypomotility appear indicated.

Objective—To identify biomarkers of P-glycoprotein (P-gp) substrate neurotoxicity in transgenic mice expressing the mutant canine ABCB1 gene (ABCB1-1Δ). Animals—8 ABCB1 knock-in and knock-out transgenic mice expressing the ABCB1-1Δ gene and 8 control mice expressing the wild-type canine ABCB1 gene (ABCB1-WT). Procedures—Groups including 2 ABCB1-1Δ mutant mice and 2 ABCB1-WT mice were administered the P-gp substrates ivermectin (10 mg/kg, SC), doramectin (10 mg/kg, SC), moxidectin (10 mg/kg, PO), or digoxin (1.53 mg/kg, SC). A toxicogenomic approach based on DNA microarrays was used to examine whole-genome expression changes in mice administered P-gp substrates. Results—Compared with control ABCB1-WT mice, ABCB1-1Δ mutant mice developed neurotoxic signs including ataxia, lethargy, and tremors similar to those reported for dogs with the ABCB1-1Δ mutation. Microarray analysis revealed that gene expression was altered in ABCB1-1Δ mutant mice, compared with findings for ABCB1-WT mice, following administration of the same P-gp substrates. Gene pathway analysis revealed that genes with a ≥ 2-fold gene expression change were associated with behavior and nervous system development and function. Moreover, 34 genes were altered in the ABCB1-1Δ mutant mice in all 4 drug treatment groups. These genes were also associated with behavior, which was identified as the top-ranked gene network. Conclusions and Clinical Relevance—These study data have facilitated understanding of the molecular mechanisms of neurotoxicosis in ABCB1-1Δ mutant mice following exposure to various P-gp substrates. Some genes appear to be potential biomarkers of P-gp substrate neurotoxicity that might be used to predict the safety of those drugs in dogs with the ABCB1-1Δ mutation.

Objective—To determine effects of staple size, precompression time, and tissue thickness on staple shape and tissue approximation in side-to-side jejunocecal anastomosis in equine specimens. Sample—Cecum, ileum, and jejunum specimens obtained from 18 healthy horses at an abattoir. Procedures—Specimens were allotted into 2 groups. Anastomoses were stapled with 4.8-or 3.8-mm staples. Precompression time was 15 seconds for both groups. Staple lines were cut into proximal, middle, and distal sections. Thickness of intestinal walls was measured with a calibrated tissue micrometer, photographs were obtained, and intestinal tissues were digested. An investigator measured staples and assessed the shape of staples on high-definition digital images. Number of optimally shaped staples and staple height were compared among sections and between groups. Results—Use of 4.8-mm staples resulted in poor approximation of tissues in the distal sections of anastomoses. The percentage of optimally shaped staples was 538 of 551 (97.6%) and 616 of 634 (97.2%) for 4.8- and 3.8-mm staples, respectively. The percentage of optimally shaped staples did not differ significantly between groups for the same sections. There was a lower percentage of optimally shaped staples in the distal sections than in the proximal and middle sections of each group. Mean staple height did not differ significantly among sections of each group. Conclusions and Clinical Relevance—Use of 3.8-mm staples with an adequate precompression time for jejunocecal anastomosis in horses resulted in proper staple shape. These findings could be used to improve the technique and outcome for stapled jejunocecal anastomoses in horses.