In this study we examined the anti-tick properties of the essential oil of Tagetes minuta L. (Asteraceae: Asterales) against Hyalomma rufipes ticks. We obtained the essential oil of T. minuta by hydro-distillation of a combination of fresh flowers, leaves and soft stems, and analysed these by using gas chromatography (GC) and gas chromatography-linked mass spectrometry (GC-MS). The oil had a high percentage of monoterpenes and the major compounds identified were cis-ocimene (28.5%), beta-ocimene (16.83%) and 3-methyl-2-(2-methyl-2-butenyl)-furan (11.94%). Hyalomma rufipes adults displayed a significant (P < 0.05) dose repellent response to the essential oil of T. minuta. Probit analysis indicated a repellent EC50 of T. minuta essential oil for male ticks to be 0.072 mL/mL (CI 0.053 mL/mL to 0.086 mL/mL) and 0.070 mL/mL (CI 0.052 mL/mL to 0.084 mL/mL) for female ticks. There were no significant differences in repellent responses between male and female ticks. The oil also significantly (P < 0.05) delayed moulting of 60% of H. rufipes engorged nymphs. These results suggest that T. minuta may be a potential source of anti-tick agents.

Four hand-reared, naïve roan antelope, 4 months of age, were exposed to naturally infected pasture on a game farm in Mpumalanga Province, South Africa, where roan are known to die from theileriosis. Various clinical parameters were recorded during this period. The predominant ticks parasitising these animals at the time (January to February), were Rhipicephalus appendiculatus and Rhipicephalus evertsi evertsi adults. After a period of 5 weeks the animals developed signs of clinical theileriosis and were treated with buparvaquone to prevent mortality. Primary hyperplasia of the local draining lymph nodes (Lnn. anorectales) near the feeding site of adult R. evertsi evertsi indicated possible transmission of Theileria sp. (sable) by this tick species. After recovery from theileriosis, these animals were confirmed carriers of Theileria sp. (sable) by PCR (polymerase chain reaction) and DNA probe analysis. Laboratory-bred larvae and nymphs of R. evertsi evertsi and R. appendiculatus respectively, were fed on the ears of these roan antelope. Salivary glands from moulted and prefed adult ticks of each species were dissected and stained for Theileria spp., and the PCR and DNA probe applied to a representative batch of dissected glands. R. appendiculatus adults collected from grass in infected camps were also dissected after prefeeding them on rabbits. Salivary glands of both tick species showed infected acini on staining and were also positive for Theileria sp. (sable) only, on multiprotozoal PCR-screening analysis. There was no statistical significant difference between the infection rate and the intensity of infection between the two tick species. R. appendiculatus ticks collected from grass were also PCR-positive for Theileria sp. (sable)

Objective: To evaluate the effect of acepromazine maleate administered IV on platelet function assessed in healthy dogs by use of a modified thromboelastography assay. Animals: 6 healthy adult mixed-breed dogs. Procedures: Dogs received each of 3 treatments (saline [0.9% NaCl] solution [1 to 2 mL, IV] and acepromazine maleate [0.05 and 0.1 mg/kg, IV]) in a randomized crossover study with a minimum 3-day washout period between treatments. From each dog, blood samples were collected via jugular venipuncture immediately before and 30 and 240 minutes after administration of each treatment. A modified thromboelastography assay, consisting of citrated kaolin–activated (baseline assessment), reptilase-ADP–activated (ADP-activated), and reptilase-arachidonic acid (AA)–activated (AA-activated) thromboelastography, was performed for each sample. Platelet inhibition was evaluated by assessing the percentage change in maximum amplitude for ADP-activated or AA-activated samples, compared with baseline values. Percentage change in maximum amplitude was analyzed by use of Skillings-Mack tests with significance accepted at a family-wise error rate of P < 0.05 by use of Bonferroni corrections for multiple comparisons. Results: No significant differences were found in the percentage change of maximum amplitude from baseline for ADP-activated or AA-activated samples among treatments at any time. Conclusions and Clinical Relevance: Platelet function in dogs, as assessed by use of a modified thromboelastography assay, was not inhibited by acepromazine at doses of 0.05 or 0.1 mg/kg, IV. This was in contrast to previous reports in which it was suggested that acepromazine may alter platelet function via inhibition of ADP and AA.

Objective: To compare effects of 3 methods of topically applied cold treatment (cryotherapy) on digital laminar and venous temperatures in horses. Animals: 9 healthy adult Thoroughbreds. Procedures: Thermocouples were placed in palmar digital veins and digital laminae of both forelimbs of horses. Three methods of cryotherapy were applied to the distal aspects of the limbs: wader boot (63-cm-tall vinyl boot filled with ice and water [ice slurry]), ice bag (5-L fluid bag filled with ice slurry), and a gel pack boot (boot containing frozen gel packs). Gel packs and ice slurries were replenished every hour during cryotherapy. The forelimb that received the first treatment was randomly assigned; thereafter, control and treated forelimbs were alternated for each treatment. For each treatment, temperatures were recorded every minute during 15-minute pretreatment, 2-hour treatment, and ≥ 30 minute rewarming periods. Once temperatures had returned to within 3°C below pretreatment values, the experiment was repeated in a similar manner for other cryotherapy methods. Results: Digital venous temperatures were similar to laminar temperatures during each treatment. Ice bag and wader boot treatments caused similar cooling of digits. Gel boot treatment did not cause substantial cooling of digits. Conclusions and Clinical Relevance: Ice bag treatment caused laminar and digital venous cooling equivalent to that of wader boot treatment. Cryotherapy by use of 5-L fluid bags with an ice slurry may be a readily available, practical, and efficient method for prevention of laminitis in horses. Digital laminar and venous temperatures were similar in forelimbs of horses before and during cryotherapy.

Objective: To develop and evaluate a rapid and accurate assay involving PCR amplification and electrospray ionization mass spectrometry of nucleic acid extracts from whole blood samples for the detection of Dirofilaria immitis infection in dogs. Sample: Whole blood nucleic acid extracts from 29 dogs experimentally infected with D immitis (and in which circulating D immitis antigen was detected) and 10 uninfected dogs. Procedures: 16 of the 29 whole blood samples from infected dogs were examined at the time of collection for circulating microfilaria. Nucleic acids were extracted from all whole blood specimens and underwent PCR amplification with 12 PCR primer pairs designed to detect a wide range of pathogens (including the Wolbachia endosymbiont of D immitis) and electrospray ionization mass spectrometry. Results: On the basis of assay results, heartworm infection was detected in 13 of 13 antigen-positive dogs of unknown microfilaria status, 11 of 11 antigen-positive dogs with circulating microfilaria, 0 of 3 antigen-positive dogs tested at 3 months after larval infection, 0 of 2 antigen-positive dogs with occult infections, and 0 of 10 uninfected dogs. Conclusions and Clinical Relevance: With the assay under investigation, it was possible to identify D immitis infection in dogs with circulating microfilaria via detection of the obligate Wolbachia endosymbiont of D immitis. It was not possible to identify dogs with occult infections, which suggested that circulating microfilaria must be present to detect infection with this assay, although further studies would be required to verify that finding.

Objective-To assess gene expressions of cyclooxygenase-1 and -2 in oral, glandular gastric, and urinary bladder mucosae and determine the effect of oral administration of phenylbutazone on those gene expressions in horses. Animals-12 healthy horses. Procedures-Horses were allocated to receive phenylbutazone or placebo (6 horses/group); 1 placebo-treated horse with a cystic calculus was subsequently removed from the study, and those data were not analyzed. In each horse, the stomach and urinary bladder were evaluated for ulceration via endoscopy before and after experimental treatment. Oral, glandular gastric, and urinary bladder mucosa biopsy specimens were collected by use of a skin punch biopsy instrument (oral) or transendoscopically (stomach and bladder) before and after administration of phenylbutazone (4.4 mg/kg, PO, q 12 h) in corn syrup or placebo (corn syrup alone) for 7 days. Cyclooxygenase-1 and -2 gene expressions were determined (via quantitative PCR techniques) in specimens collected before and after the 7-day treatment period and compared within and between groups. Prior to commencement of treatment, biopsy specimens from 7 horses were used to compare gene expressions among tissues. Results-The cyclooxygenase-1 gene was expressed in all tissues collected. The cyclooxygenase-2 gene was expressed in the glandular gastric and bladder mucosae but not in the oral mucosa. Cyclooxygenase gene expressions were unaffected by phenylbutazone administration. Conclusions and Clinical Relevance-Cyclooxygenase-2 was constitutively expressed in glandular gastric and bladder mucosae but not in the oral mucosa of healthy horses. Oral administration of phenylbutazone at the maximum recommended dosage daily for 7 days did not affect cyclooxygenase-1 or -2 gene expression.

Objective: To determine the tissue distribution of enrofloxacin after intramammary or simulated systemic administration in isolated perfused sheep udders by measuring its concentration at various sample collection sites. Sample: 26 udders (obtained following euthanasia) from 26 healthy lactating sheep. Procedures: For each isolated udder, 1 mammary gland was perfused with warmed, gassed Tyrode solution. Enrofloxacin (1 g of enrofloxacin/5 g of ointment) was administered into the perfused gland via the intramammary route or systemically via the perfusion fluid (equivalent to a dose of 5 mg/kg). Samples of the perfusate were obtained every 30 minutes for 180 minutes; glandular tissue samples were obtained at 2, 4, 6, and 8 cm from the teat base after 180 minutes. The enrofloxacin content of the perfusate and tissue samples was analyzed via high-performance liquid chromatography with UV detection. Results: After intramammary administration, maximun perfusate enrofloxacin concentration was detected at 180 minutes and, at this time, mean tissue enrofloxacin concentration was detected and mean tissue enrofloxacin concentration was 123.80, 54.48, 36.72, and 26.42 μg/g of tissue at 2, 4, 6, and 8 cm from the teat base, respectively. Following systemic administration, perfusate enrofloxacin concentration decreased with time and, at 180 minutes, tissue enrofloxacin concentrations ranged from 40.38 to 35.58 μg/g of tissue. Conclusions and Clinical Relevance: By 180 minutes after administration via the intramammary or systemic route in isolated perfused sheep mammary glands, mean tissue concentration of enrofloxacin was greater than the minimum inhibitory concentration required to inhibit growth of 90% of many common mastitis pathogens in sheep. Use of either route of administration (or in combination) appears suitable for the treatment of acute mastitis in sheep.

Objective-To objectively describe morphometric features of the craniocervical junction region of Cavalier King Charles Spaniels (CKCSs) and non-CKCS dogs with suspected Chiari-like malformation (CLM) and identify associations between these features and the presence of other malformations in this region. Animals-216 CKCSs and 58 non-CKCS dogs. Procedures-Magnetic resonance and computed tomographic images of the head and craniocervical junction region of patients evaluated because of suspected CLM were assessed for cerebellar compression (CC), ventral spinal cord compression at the C1-C2 articulation (medullary kinking), and dorsal spinal cord compression at the C1-C2 articulation (dorsal compression). A compression index was calculated for each of these 3 locations in each dog. Multiple logistic regression analysis was performed to determine whether breed (CKCS vs non-CKCS) and compression index values were associated with the presence of other craniocervical junction abnormalities. Results-All 274 dogs had CC; medullary kinking was identified in 187 (68.2%) and dorsal compression was identified in 104 (38.0%). Atlantooccipital overlapping (AOO) was identified in 76 (27.7%) dogs. Breed of dog (CKCS vs non-CKCS) and value of CC index were the only significant predictors of AOO. The CKCSs had an almost 5-fold decrease in risk of AOO, compared with the non-CKCS dogs, and the risk of AOO nearly doubled for every 10% increase in CC index. Conclusions and Clinical Relevance-The anatomic abnormality responsible for CC was AOO in a substantial percentage of dogs suspected to have CLM. The CC index value may be used to help differentiate subtypes of craniocervical junction abnormalities in dogs.

The aim of this study was to describe early infections with porcine circovirus type 2 (PCV2) in naturally infected piglets and the piglets' serologic profiles. A total of 20 sows (15 PCV2-vaccinated and 5 unvaccinated) and 100 newborn piglets were studied. Colostrum and serum of the sows and serum of the presuckling piglets were obtained on the day of parturition. Milk samples were collected on day 20 postpartum. Blood samples were taken and the piglets weighed on days 1, 20, 42, 63, and 84 postpartum. Colostrum and milk were evaluated for infectious PCV2 and for PCV2 total antibody (TA), neutralizing antibody (NA), and IgA. Serum samples were evaluated for PCV2 TA, NA, IgA, IgM, and DNA. The sows had high levels of TA and NA in serum and colostrum; however, 11 and 5, respectively, of the 20 colostrum and milk samples contained infectious PCV2. In the serum, PCV2 DNA and IgM were detected in 17 and 5, respectively, of the 20 sows. Nine piglets were born with PCV2 antibodies, which indicates in utero transmission of PCV2 after the period of immunocompetence (> 70 d of gestation). On day 1 postpartum, PCV2 DNA was detected in 29 of the 100 serum samples from the piglets. There was no difference between the weights of viremic and nonviremic piglets throughout the study. In conclusion, even on farms with sows that have high PCV2 antibody titers, vertical transmission of PCV2 may occur, resulting in piglet infection.

Objective-To investigate whether submaximal aerobic exercise in dogs is followed by activation of all phases of coagulation as has been reported for humans. Animals-9 healthy Beagles. Procedures-30 minutes before dogs were exercised, a 16-gauge central venous catheter was placed in a jugular vein of each dog by use of the catheter-through-the-needle technique. Samples were collected before exercise, after running on a treadmill (6 km/h for 13 minutes), and at 60 minutes. Platelet activation was evaluated with platelet morphology indices (mean platelet component, mean platelet volume, and number of large platelets) provided by a laser-based hematology system. Platelet function was assessed in hirudin-anticoagulated whole blood with an impedance-based aggregometer with collagen as the agonist (final concentrations, 0, 1.6, 3.2, 5, and 10 micrograms/mL). Prothrombin time, activated partial thromboplastin time, and concentrations of fibrinogen, factor VIII, antithrombin, protein C, protein S, and fibrin D-dimer were determined automatically. Kaolin-activated thromboelastography variables R (reaction time), K (clot formation time), angle alpha, maximal amplitude, and G (clot stability) were measured in recalcified citrated whole blood. Results-Exercise resulted in a significant decrease in mean platelet volume and the number of large platelets but did not change the mean platelet component, which reflected platelet activation as well as platelet function. Secondary and tertiary coagulation did not change significantly, nor did thromboelastography variables. Conclusions and Clinical Relevance-Aerobic exercise resulted in a decrease in the number of large and thus most likely activated platelets but otherwise had no major impact on coagulation in dogs.