Pharmacokinetics of intravenous and intramuscular tramadol in llamas

The purpose of this study was to determine the pharmacokinetics of tramadol and its metabolite M1 after intravenous and intramuscular administration to llamas. Tramadol, a centrally acting analgesic whose efficacy is a result of complex interactions between opiate, adrenergic and serotonin receptor systems, has been used clinically to treat moderate to severe pain in humans. The pharmacokinetic parameters of tramadol and M1 in plasma were examined following intravenous and intramuscular administration to six healthy male llamas. Tramadol half-life, volume of distribution at steady-state and clearance after intravenous administration were 2.12 ± 0.37 h, 4.02 ± 1.16 L/kg and 1728.73 ± 152.82 mL/h/kg, respectively. The bioavailability was 110 ± 21% and half-life 2.54 ± 0.31 h following intramuscular administration of tramadol. M1 had a half-life of 10.40 ± 2.90 h and 7.71 ± 0.54 h following intravenous and intramuscular administration of tramadol.     

Genetic parameters of insect bite hypersensitivity in Dutch Friesian broodmares

Insect bite hypersensitivity (IBH) is a seasonal allergic skin disease in horses caused by bites of certain Culicoides spp. The aim of our study was to investigate the maternal effect on IBH and to estimate the heritability and repeatability of IBH in the Dutch Friesian horse population. Data consisted of 3,453 Dutch Friesian broodmares with 3,763 visual observations on IBH clinical symptoms scored by 12 inspectors during organized foal inspections in 2004 and 2008. Nine percent of the mares (n = 310) were scored in both years. Mares descended from 144 sires and 2,554 dams and 26.2% of the dams (n = 669) had more than 1 offspring in the data set (range: 2 to 6). Insect bite hypersensitivity was analyzed as a binary trait with a threshold animal model with and without a maternal effect, using a Bayesian approach. Observed IBH prevalence in Dutch Friesian broodmare population was 18.2%. Heritability on the liability scale was 0.16 (SD = 0.06); heritability on the observed scale was 0.07; and repeatability was 0.89 (SD = 0.03). Maternal effect was 0.17 (SD = 0.06) and significantly differed from zero, although the animal model without a maternal effect fitted the data better. These results show that genetic and permanent environmental factors affect IBH in Dutch Friesian horses. The dam affected the IBH development of her offspring through an additive genetic influence but also by being part of their rearing environment.     

What veterinarians need to know about communication to optimise their role as advisors on udder health in dairy herds

The veterinary practitioner is one of the most important advisors for farmers in the field of udder health. He or she has the tools to improve udder health if farmers are motivated to do so. Many farmers think that udder health is important, but this does not always mean that management of mastitis is up to standard. Many veterinarians are of the opinion that they are unable to convince their clients of the possible profits to be gained from investing in management of mastitis. Something is required to bridge this gap. This article, based on data and experiences from The Netherlands, describes the communication issues that can be considered in order to improve the role of the veterinarian as advisor, to achieve better udder health. The outcome is beneficial for both farmers and veterinarians, the former for reasons of economics, welfare and ease of work; the latter because it creates extra, challenging work. It is concluded that the veterinary practitioner is in an ideal situation to advise and motivate farmers to improve udder health but, to do this, the means of communication need to take account of the different learning styles of farmers. The most important aspects of such communication are found to be a pro-active approach, personalisation of messages, providing a realistic frame of reference for the farmer, and use of the farmer's social environment. Importantly, all persons and organisations in a farmer's social environment should articulate the same message.     

Short-and long-term evaluation of surgical treatment of strangulating obstructions of the small intestine in horses: a review of 224 cases

A retrospective study was carried out of 224 horses operated for strangulating small intestine obstructions. Fifty-four horses were euthanized and 5 horses died during surgery which means that 165 (73%) were allowed to recover. Of these, 53 horses were euthanized or died in the clinic and 112 (50%) were discharged from the hospital. Of 90 horses available for follow-up 1 year postoperatively, 76 (84%) were still alive. The most important causes of death or reasons for euthanasia in the direct post-operative period were post-operative paralytic ileus, (adhesive) peritonitis and intra-abdominal haemorrhage. After discharge from the hospital the reasons were (adhesive) peritonitis and (recurrent) colic. Of the horses which survived for at least 1 year, 16% sometimes suffered from colic, 12% experienced problems with incisional woundhealing and 4% suffered from jugular vein thrombosis. All were in good or reasonable condition and 88% performed at (approximately) the same level as before the operation. The type of surgical intervention (i.e. enterotomy, enterectomy) did not significantly influence the outcome of surgery, whereas the type of anastomosis did. End-to-end jejunojejunostomy had a better prognosis than side-to-side jejunocaecostomy. It was concluded that strangulating obstructions of the small intestine still carry a poor to guarded prognosis. Mortality was highest in the direct peri-operative period. Once discharged from hospital, prognosis can be considered to be fair to good. Attempts to improve outcome should be directed at a better handling of the ileal stump during surgery and at the prevention of post-operative ileus and the formation of adhesions.     

Use of the flexion test of the distal forelimb in the sound horse: repeatability and effect of age, gender, weight, height and fetlock joint range of motion

The flexion test of the distal limb is a commonly used clinical tool in both lame and sound horses. In the latter use it is given some predictive value. In recent studies it has been shown that examiner-related factors (force, time) may strongly influence the outcome of the test. In the present study, the possible influences of a number of horse-related factors and short- and long-term repeatability were investigated. Flexion tests were performed by the same researcher in 100 clinically sound horses under standardized conditions. The outcome of the test was scored on a 9-point semiquantitative scale. The maximum flexion angles of the fetlock joints were measured and the range of motion (ROM) of the fetlock joint was calculated. In the second part of the study, flexion tests were repeated, at intervals of 10 min, 30 min, 48 h and 6 months in 23 horses to assess repeatability. Over 60% of the 100 sound horses had a positive flexion test. Of these, about 50% showed a slight lameness, 35% a mild lameness, and 15% a distinct lameness. There was no influence of weight, height or ROM on the score of the flexion test. The outcome of the flexion test increased significantly with age and was significantly higher in mares than in geldings. When repeating the flexion test with short intervals of 10 and 30 min, the score increased significantly after the second test. Repeated flexion after 48 h did not result in a significantly different outcome. Over a 6-month period, the outcome of the test decreased significantly and the ROM increased significantly. It is concluded that most clinically sound horses have a (slightly) positive flexion test of the distal limb. This and the lack of long-term consistency of the test cast doubt on the presumption that a positive flexion test may be an indication for subclinical joint disorders and question the possible value of the test as a predictor of future joint-related problems. There exists a wide individual variation in ROM of the fetlock joint with, in sound horses, no relationship between ROM and the outcome of the flexion test. The factors age and gender should be taken into account when interpreting the results of a flexion test.     

Pharmacokinetics of sulphadimidine in carp (Cyprinus carpio L.) and rainbow trout (Salmo gairdneri Richardson) acclimated at two different temperature levels

The influence of temperature (10 degrees C and 20 degrees C) on pharmacokinetics and metabolism of sulphadimidine (SDM) in carp and trout was studied. At 20 degrees C a significantly lower level of distribution (Vdarea) and a significantly shorter elimination half-life (T(1/2)beta) was achieved in both species compared to the 10 degrees C level. In carp the body clearance parameter (ClB(SDM)) was significantly higher at 20 degrees C compared to the value at 10 degrees C, whereas for trout this parameter was in the same order of magnitude for both temperatures. N4-acetylsulphadimidine (N4-SDM) was the main metabolite of SDM in both species at the two temperature levels. The relative N4-SDM plasma percentage in carp was significantly higher at 20 degrees C than at 10 degrees C, whereas there was in trout no significant difference. In neither species was the peak plasma concentration of N4-SDM (Cmax(N4-SDM)) significantly different at two temperatures. The corresponding peak time of this metabolite (Tmax(N4-SDM)) was significantly shorter at 20 degrees C compared to 10 degrees C in both carp and trout. In carp at both temperatures, acetylation occurs to a greater extent than hydroxylation. Only the 6-hydroxymethyl-metabolite (SCH2OH) was detected in carp, at a significant different level at the two temperatures. Concentrations of hydroxy metabolites in trout were at the detection level of the HPLC-method (0.02-micrograms/ml). The glucuronide metabolite (SOH-gluc.) was not detected in either species at the two temperatures.     

Pathological, ultrastructural, and immunohistochemical changes caused by Lelystad virus in experimentally induced infections of mystery swine disease (synonym: porcine epidemic abortion and respiratory syndrome (PEARS))

The pathogenicity and pathogenesis of Lelystad virus was studied in six 6-day-old SPF piglets. A third passage of the agent was propagated on porcine alveolar macrophages and intranasally inoculated into pigs. Pigs were killed at hours 24, 48, 60, and 72, and on days 6 and 8 after inoculation. From day 2 on pigs developed diffuse interstitial pneumonia with focal areas of catarrhal pneumonia, and from this day on splenic red pulp macrophages were enlarged and vacuolated. Lelystad virus was re-isolated from the lungs of infected pigs from day 2 after inoculation. Lelystad virus antigens were detected by immunohistochemical techniques in bronchiolar epithelium and alveolar cells, and in spleen cells of infected pigs from day 2 after inoculation. Ultrastructural examination of tissues by electron microscopy revealed degenerating alveolar macrophages and epithelial cells in lungs and nasal mucosa, with excessive vacuolation of the endoplasmic reticulum. Although the respiratory tract seems to be the target organ for this virus, macrophages in other organs, such as the spleen, can also be infected. This preference for macrophages may impair immunological defences.     

Evaluation of the usefulness of the portable device Lactate Pro for measurement of lactate concentrations in equine whole blood.

Blood lactate measurements are commonly used in exercising horses to determine the onset of lactate accumulation and in colic patients to assess clinical status and to indicate prognosis. To study the usability of a portable blood lactate meter based on dry chemistry (Lactate Pro), the data from this instrument were compared to data from a laboratory-used lactate meter based on wet chemistry (ABL 605 blood gas analyzer [ABL]). Heparinized blood samples were obtained from horses participating in a jumping experiment (n = 9), from horses cantering at maximal speed on a racetrack (n = 7), and from patients admitted to the Department of Equine Sciences at Utrecht University for severe colic (n = 13). Seventeen of these samples were tested in duplicate on both instruments to determine the repeatability of the measurements. Blood lactate concentrations measured with the Lactate Pro ranged from 0.8-17.6 mmol/liter and with the ABL from 1.0-18.6 mmol/liter. The correlation between lactate concentrations obtained using the Lactate Pro and values from the ABL was 0.90, and the relationship was represented by the following formula: y = 0.90 . x + 0.36, indicating a linear relationship between values produced by the ABL and Lactate Pro. The repeatability for the Lactate Pro was high (0.997), which is comparable to the ABL (0.999).