The cardiorespiratory effects of morphine and butorphanol in horses anaesthetised under clinical conditions

Twenty-five horses admitted for minor orthopaedic or soft tissue surgery were anaesthetised with detomidine, ketamine and halothane. Heart rate, arterial blood pressure, respiratory rate, tidal volume, minute volume, blood gases and occlusion pressures were measured before and for 30 mins after intravenous (iv) injection of saline, butorphanol 0.05 mg/kg bodyweight (bwt) or morphine 0.02 or 0.05 mg/kg bwt. Drug or saline treatment induced no significant changes from pre-treatment values within a group for arterial blood pressure, heart rate, respiratory rate, arterial carbon dioxide tension, arterial oxygen tension and occlusion pressure. In conclusion, both morphine and butorphanol at the stated doses cause no adverse effects on the cardiovascular and respiratory systems of anaesthetised horses.     

Sedative and cardiovascular effects of romifidine, alone and in combination with butorphanol, in the horse

The behavioural and sedative effects of intravenous (iv) romifidine (40 and 80 μg/kg bodyweight [bwt]) alone or in combination with iv butorphanol (50 μg/kg bwt) were investigated in four ponies and one Thoroughbred horse. Apparent sedation, as judged by the lowering of the head, and by the response to imposed touch, visual and sound stimuli was assessed. The combination with butorphanol reduced the animals' response to imposed stimuli when compared with the effect of the same dose of romifidine alone. Following the administration of romifidine/butorphanol combinations muzzle tremor was noted and some animals attempted to walk forward. In a separate series, the cardiopulmonary effects of iv romifidine (80 μg/kg bwt) alone, or in combination with butorphanol (50 μg/kg bwt) were investigated. Romifidine and the romifidine/butorphanol combination caused similar cardiovascular changes, these being bradycardia with heart block, and hypertension followed by hypotension. Romifidine caused a transient decrease in arterial oxygen tensions and arterial carbon dioxide tensions had increased significantly by the end of the 90 min recording period. Romifidine/butorphanol combinations produced significantly higher arterial carbon dioxide tensions during the first 15 mins after drug administration than did romifidine alone. Butorphanol at 50 μg/kg bwt iv reduced the response to imposed stimuli in horses sedated with romifidine. The combination produced no cardiovascular changes beyond those induced by romifidine alone, but did increase the degree of respiratory depression.     

Excitatory phenomena following the use of propofol in dogs

Over a two month period, 148 dogs presented for surgery had general anaesthesia induced and sometimes maintained with propofol. Excitatory phenomena were recorded on 12 occasions. Signs included muscle twitching, opisthotonus and limb hyperextension (nine cases), and panting with associated activity of the brachiocephalicus muscle and tongue retraction (three cases). The records for a similar two month period were examined for data and observations relating to thiopentone. During this period anaesthesia was induced with thiopentone in 71 dogs and no excitatory phenomena were recorded.     

Confirmation of rinderpest in experimentally and naturally infected cattle using microtitre techniques

Summary Virulent rinderpest virus was detected by immunoperoxidase staining of microtitre bovine kidney cell cultures within 24 to 48 hours of inoculation with prescapular lymph node and spleen homogenates from experimentally infected steers. Rinderpest virus specific cytopathic effects were evident from 48 hours in microtitre plates and from 72 hours in rolled tube cultures. Nasal and ocular secretions collected from cattle naturally infected with rinderpest and inoculated into bovine kidney cell cultures did not readily yield cytopathic virus in both tubes and microtitre plates, but immunoperoxidase staining of microtitre cultures on the fourth day of inoculation detected replication of virus in cultures inoculated with ocular and nasal secretions from seven of 17 cattle tested.

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Resumen Se detectó el virus virulente de mediante la tinción con inmunoperoxidasa de cultivos de células de ri?ón bovino en bandejas de microtitulación, después de la inoculación de estos con suspensiones homogenizadas de ganglios linfáticos preescapulares y de bazo provenientes de novillos infectados experimentalmente. El efecto citopático del virus de la peste bovina fue evidente desde las 48 horas en bandejas de microtitulación y desde las 72 horas en tubos de cultivo giratorios. Secreciones oculares y nasales colectadas de ganado infectado en forma natural con la peste bovina e inoculadas en cultivos de células de ri?ón bovino, no mostraron efecto citopático fácilmente en tubos giratorios o bandejas de microtitulación, pero la tinción de las bandejas con inmunoperoxidasa reveló replicación del virus a partir del cuarto día de inoculación con secreciones oculares y nasales en siete de los 17 animales examinados.

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Résumé Un virus bovipestique virulent a été décelé par le test de coloration à l'immunoperoxydase de cellules rénales bovines en culture dans des plaques de microtitrage et infectées 48 heures plus t?t avec des homogénats de ganglions lymphatiques et de rate provenant de bouvillons infectés expérimentalement. Les effets cytopathogènes du virus étaient évidents au bout de 48 h dans les plaques de microtitrage et 72 h dans les tubes en rollers. Les sécrétions nasales et oculaires prélevées sur du bétail infecté naturellement par la peste bovine et inoculées sur des cellules rénales bovines n'ont pas toujours montré d'effet cythopathogène aussi bien dans les tubes que dans les plaques de microtitrage. Cependant, la coloration à la peroxydase au jour 4 après l'inoculation a permis de déceler la présence de virus dans 7 cas sur 17.

     

Additional diagnostic procedures

This article reviews recent diagnostic procedures that have arisen over the last 10 years. Videoendoscopy of horses on a high-speed treadmill allows observation of some of the changes that take place in a horse's airway during exercise. Measurements of upper airway airflows and transupper airway pressure, the use of an esophageal balloon and a Ventigraph to measure changes in pleural pressure, and pulmonary function testing are new techniques that aid the researcher in understanding the mechanics and pathologic characteristics of airway diseases and help the practitioner in assessing the severity of a problem, measuring response to therapy, and accurately determining a prognosis.     

Participation of H1-receptors in histamine-induced contraction and relaxation of horse coronary artery in vitro.

The mechanisms of histamine-induced contraction and relaxation were investigated in rings isolated from a middle part of the left descending coronary arteries of horses. Intact and endothelium-denuded preparations were compared. Rings of horse coronary arteries contracted in response to histamine in a concentration dependent manner, but some of them relaxed with lower concentrations and contracted with higher concentrations. Removal of the endothelium abolished the relaxation and potentiated the contraction. The pD2 values were 4.70 +/- 0.08 in the rings with intact endothelium and 4.95 +/- 0.08 in endothelium-denuded rings. Histamine-induced contractions in intact and denuded preparations were not affected by an H2-antagonist, cimetidine, but were inhibited by an H1-antagonist, diphenhydramine in non-competitive manner in the rings with endothelium and in competitive manner in denuded rings. After precontraction with PGF2 alpha or norepinephrine, histamine relaxed preparations with intact endothelium (pD2 value, 7.80 +/- 0.11), although histamine-induced relaxations were not observed in denuded preparations. The relaxation was competitively inhibited by diphenhydramine. Relaxing response was significantly attenuated by methylene blue, quinacrine, L-nitro-arginine, gossypol and AA861 but not by indomethacin. These results suggest that the histamine-induced contraction and relaxation in horse coronary arteries are mediated mainly by H1-receptors in the smooth muscle and endothelium, respectively, and H1-receptor activation of endothelial cells may liberate vasodilator substances.     

Standing surgical procedures of the foot.

Several surgical conditions affecting the foot can be successfully managed with the horse standing. Many factors affect the clinician's choice of whether to perform surgery with the horse standing or anesthetized. Temperament or pregnancy of the horse and economics may influence the decision to perform surgery with the horse standing. This article discusses several foot conditions that can be treated successfully in the ambulatory horse.     

Deep Freezing of Boar Semen Packaged in Plastic Bags and Straws

For practical reasons, a large volume (i.e. 5 ml) of frozen boar semen per insemination dose is desirable, but successful freezing has not been achieved, since optimal cooling rates have not yet been established. Post-thaw motility and the acrosome intep'ty of semen from four boars frozen with a programmable freezin machine, in mini-(0.25 ml), maxi-(5 ml) plastic straws and in 10 × 5 cm PVC- or Teflon FEP-plastic bags (0.35 – 0.12 mm thick, 5 ml) was studied. The freezing of the semen was monitored using thermocouples placed in the straws and the bags. The freezing curve started from +5°C, at a rate of −3°C/min, to – 6°C, it was held for 1 min at −6°C, and was followed by further drop to −100°C at a rate of −20°C/min, with subsequent storage in LN₂. The bags had a much shorter freezing point plnteau, compared to the maxi-straws. Post-thaw sperm motility was significantly higher when semen was frozen in mini-straws or in bags than in maxi-straws. The freezing procedure did not cause major acrosomal damages, significantly more normal apical ridges being present in the bags and mini-straws than in the maxi-straws. This in vitro evaluation indicates that the freezing method employed is satisfactory for freezing large volumes of boar semen into plastic bags .     

Distributions of extracellular matrix and carbonic anhydrase-III during bovine palatine ridge development.

The present study describes histological alterations and immunohistochemical distributions of extracellular matrices (ECMs) and the carbonic anhydrase isozyme-III (CA-III) during the period of bovine palatine ridge formation. Morphogenesis of bovine palatine ridges was preceded by epidermal placodes and the mesenchymal condensation (MC). During the early stages of less than 44 cm crown rump length (CRL), fibronectin (FN) was distributed densely in the MC. Strong reactions against type I collagen (C-1) were detected outer to the FN positive site. In the stages of more than 44 cm CRL, FN and C-1 were distributed diffusely in subepithelial mesenchyme. Laminin (LN) and type IV collagen were distributed in the epithelial and endothelial basement membranes (BMs) in all of the stages examined, except in the stage of 7 cm CRL, where LN was not detected only in the BM just beneath the epidermal placode. CA-III was detected in basal epithelial cells except for palatine ridge rudiments in the stages of more than 21 cm CRL. It is suggested that the expressions of LN and CA-III might play a role in the spatial determination of rudiments of bovine fetal palatine ridges.