In horses undergoing volatile anaesthesia, does intraoperative alpha-2-agonist infusion improve recovery?

PICO question In horses undergoing volatile anaesthesia with isoflurane or sevoflurane, does administration of an alpha-2 agonist as a CRI compared to anaesthetic maintenance with volatile alone improve recovery quality? Clinical bottom line Category of research question Treatment The number and type of study designs reviewed Eight papers were critically appraised. All prospective, randomised clinical trials. 7/8 papers were blinded and 4/8 were crossover design Strength of evidence Moderate Outcomes reported One paper investigating detomidine and one on romifidine showed no improvement in recovery quality. 3/3 medetomidine papers and 2/3 dexmedetomidine papers showed a significant improvement in recovery quality in the alpha-2 agonist CRI group Conclusion In a healthy horse undergoing general anaesthesia with isoflurane or sevoflurane maintenance, an intra-operative constant rate of infusion (CRI) of medetomidine and dexmedetomidine can lead to better recovery quality when compared to horses who are maintained on isoflurane or sevoflurane alone How to apply this evidence in practice The application of evidence into practice should take into account multiple factors, not limited to: individual clinical expertise, patient’s circumstances and owners’ values, country, location or clinic where you work, the individual case in front of you, the availability of therapies and resources. Knowledge Summaries are a resource to help reinforce or inform decision making. They do not override the responsibility or judgement of the practitioner to do what is best for the animal in their care.

Evaluation of the Accuracy of Horse Body Weight Estimation Methods

Methods of estimating horse body weight using mathematical formulae have better accuracy than methods of reading body weight from measuring tape. The aim of the study was to evaluate established formulae for estimating horse body weight from data gathered using measurement tape. The research was conducted in a group of 299 adult horses and ponies of selected breeds: ponies (n = 58), Polish Noble Half Breed (n = 150), Silesian Breed (n = 23), Wielkopolski Breed (n = 52), and Thoroughbred (n = 16). Body measurements were performed on each horse using a measuring stick and tape. The actual body weight of the horses was measured with electronic scale. Statistical analysis was carried out separately for individual breeds of horses. In each of the research groups formulae were selected, the results of which were closest to the actual horse body weight readings. The use of formulae for body weight estimation can be useful in determining feed dosages and additives, medicines or deworming agents. Regular weight measurement is important for maintaining a healthy horse.

First Report of Bleeding Canker Caused by Phytophthora cactorum on Horse Chestnut in Turkey

Bleeding canker on horse chestnut (Aesculus sp.), caused by Phytophthora cactorum (Lebert and Cohn) Schröeter previously has been reported from the United States and Europe (1). In August 2000, it was found for the first time in a park in Ankara Province, Turkey. Symptoms included sparse yellowish brown foliage with abnormally small leaves, and dark-stained spots or dark brown necrosis of the bark on the trunk and main branches, with or without a reddish black gummy exudate. P. cactorum was isolated from tissues taken from the margins of necrotic bark. Pure cultures were slightly radiate, fluffy but not dense, and had short aerial hyphae when grown on carrot agar, potato dextrose agar, or V8 agar. Sporangia were ovoid, strongly papillate, and averaged 35.6 μm in length and 26.8 μm in width (range: 24 to 55 μm × 19 to 40 μm). The isolates were homothallic with smooth-walled paragynous oogonia ranging from 23.5 to 34.5 μm in diameter. To satisfy Koch's postulates, mycelium of P. cactorum was placed under the bark of six branches of healthy horse chestnut. Noninoculated wounds served as controls. Four months later a reddish black gummy exudate was observed oozing from the inoculated wounds, and the bark tissue was necrotic for 3 to 4 cm around each infection. P. cactorum was successfully reisolated from the necrotic bark tissue. Control wounds remained healthy. To our knowledge, this is the first report of this disease on horse chestnut in Asia Minor. Reference: (1) D. C. Erwin and O. K. Ribeiro. Phytophthora Diseases Worldwide. The American Phytopathological Society, St. Paul, MN, 1996.

Have trypanosomes an ultra-microscopical stage in their life-history?

By an ultra-microscopical stage in the development of micro-organism is meant a stage in which the parasites are so small as to be invisible to the highest powers of the microscope, and to be capable of passing through the pores of a porcelain filter. For example, a drop of South African horse-sickness blood will give rise to the disease if injected under the skin of a healthy horse. If a similar drop is examined under the highest available powers of the microscope, nothing in the shape of a micro-organism can be seen. If this blood is filtered through a porcelain filter, the virus passes through, and the filtrate is found to be as infective as the original blood. House-sickness is therefore looked upon as a disease caused by an ultra microscopical micro-organism. For some time it has been reported by various workers that an ultra-microscopical stage exists among the trypanosomes. For example, Plimmer informs us that he found the filtered blood of nagana animals to be infective. Salvin Moore and Breinl write that the blood of animals suffering from Trypanosoma gambiense infection, although apparently containing no trypanosomes at all, and even if properly filtered, is still capable of infecting other animals into which it may be introduced. MacNeal also makes a similar statement in regard to Trypanosoma lewisi . He states that “in culture, on blood-agar, T. lewisi may give rise to much smaller forms, and that such cultures, after passage through a Berkefeld filter, still infect rats.” Finally, it may be noted that the late Dr. Fritz Schaudinn, whose too early death we all lament, expressed the belief that trypanosomes may multiply by longitudinal division so rapidly as to become small enough to pass readily through a Camberlain filter.