Experiences With Morphine Injected Into the Subarachnoid Space in Sheep

The effects of morphine (M), 0.1 mg/kg, administered into the lumbosacral subarachnoid space of sheep used for experimental stifle surgery, were investigated. In a pilot study, preservative-free morphine was administered to three sheep, morphine containing preservatives to two sheep, and saline (S) to one sheep. After recovery from anesthesia, all five sheep administered M displayed rear limb weakness. One sheep, which had received morphine containing preservatives, also licked and chewed incessantly at its flank and hindquarters during recovery. A group of 24 sheep was used to study the effects of morphine containing preservatives, injected intrathecally, on recovery from general anesthesia and hindlimb orthopedic surgery. Eight sheep received M, eight sheep received S, and eight sheep had a needle placed in the subarachnoid space without any injection (N). Times from end of anesthesia to standing varied greatly and did not differ significantly among groups (P=.73), with M sheep averaging 119 minutes; S sheep, 87 minutes; and N sheep, 83 minutes. One sheep administered M licked and chewed at its hindquarters during recovery. Another group of 24 sheep was used to study the effects of morphine containing preservatives, injected intrathecally, on postoperative lameness. Treatments were as described previously. Sheep were videotaped intermittently for 36 hours after surgery, and each sheep was scored as follows; 0 = not lame; 1 = slightly lame; and 2 = very lame. The average lameness scores, which did not differ significantly among groups (P=.21), were: M sheep, 1.07; S sheep, 0.81; and N sheep, 0.68. One sheep administered M displayed extensor spasms of the hindlimbs, and could not stand until several hours after surgery. We conclude that subarachnoid morphine at the dosage used produces no apparent benefit in sheep which have had stifle surgery, and in fact may cause detrimental side effects, such as hindlimb weakness, and pruritis or irritation of the hindquarters.     

Increased tolerance to annual ryegrass toxicity in sheep given a supplement of cobalt

SUMMARY To determine whether oral cobalt supplements could modify the clinical onset of annual ryegrass toxicity, groups (n = 5) of sheep were dosed orally with 0, 4 or 16 mg cobalt/day. After 3 weeks on this treatment, toxic ryegrass seed was added to their feed to provide 0, 0.15 and 0.30 mg corynetoxins/kg body weight, daily. Sheep receiving cobalt ingested 30% more toxin than did unsupplemented sheep before clinical signs developed (P = 0.03). There was no significant difference between groups receiving 4 and 16 mg cobalt. The results showed that cobalt delayed, but did not prevent, the onset of clinical signs of annual ryegrass toxicity.     

Serotypes of Erysipelothrix rhusiopathiae in Australian pigs, small ruminants, poultry, and captive wild birds and animals

Serotypes of 93 Australian isolates of Erysipelothrix rhusiopathiae from diseased domestic animals and poultry and a variety of captive wild birds and animals were determined by double diffusion gel precipitation. Two isolates, from the faeces of a swallow were also examined. Serotypes 1a, 1b and 2 were isolated from pigs and serotypes 1a, 1b, 2, 5, 15 and 21 from sheep or goats. Erysipelas in poultry was attributed to serotypes 1b, 5, 15 and 16. In captive wild birds serotypes 1b, 5, 6, 8, 14, 21 and an isolate reactive with antiserum to strain Seehecht were associated with septicaemic deaths. Single isolates from tissues of a bilby (Macrotis lagotis), black rat (Rattus rattus), brown snake (Pseudechis australis) and a bandicoot (Isoodon macrouris) were classified as serotypes 4, 4, 7, and 10 respectively. Six isolates were not able to be typed. Serotype 1b was the most widely distributed and most common (28%), being associated with disease in pigs, sheep, poultry and wild birds. Serotypes 1a or 2 were found in a more restricted range of animals, being commonly associated with erysipelas in pigs, less commonly in sheep and infrequently in other species. From diseased pigs, 26 of 33 isolates (79%) were serotypes 1a and 1b.     

Hemodynamic Function during Neurectomy in Halothaneanesthetized Horses with or without Constant Dose Detomidine Infusion

Nine horses were premediated with acepromazine, and anesthesia was induced with guaifenesin and thiamylal. Anesthesia was maintained in four horses with halothane in oxygen, and in five horses with halothane in oxygen plus a constant dose infusion of detomidine. Both maintenance regimens produced a MAC equivalent of 1.4 at the ambient barometric pressure. Hemodynamic and respiratory measurements were made after the horses were anesthetized, during surgical manipulations involving skin or tissues other than nerves, during manipulation and transection of digital nerves, and after surgery while the limbs were being bandaged. Heart rate was significantly higher in horses anesthetized with halothane only than in horses that also received detomidine; there were no other differences in hemodynamic function or recovery characteristics. Respiratory rate was significantly higher than baseline during soft tissue and nerve manipulations; arterial blood pressure was significantly higher after surgery began and highest during neurectomy; cardiac output and cardiac index were significantly decreased during surgery; systemic vascular resistance was significantly increased during neurectomy and bandaging and highest during neurectomy. The data suggest that the increase in blood pressure often associated with surgical stimulation is caused by increased vascular resistance and may be accompanied by a decrease in cardiac output.     

LABORATORY EXPERIMENTS ON 'CUT BARK' TREATMENTS WITH HERBICIDES, USING CUTTINGS OF POPULUS EURO AMERICAN A'I-78'

Summary. A laboratory method is described for studying the effects of introducing herbicides into the vascular tissues oi Populus cuttings. Of sixteen herbicides tested in this way, MCPA and picloram were the most phytotoxic. Ester formulations of growth regulator herbicides were less active than water soluble amine or inorganic salts. The phytotoxic effects of the latter were increased by supplying water to the cuttings before or after treatment or by applying the herbicide in a relatively large volume of water. A non-ionic surfactant did not increase the effects of injected MCPA salt, approximately similar amounts of which moved both upwards and downwards in cuttings from the point of introduction.
Expériences en laboratoire sur des boutures de Populus × euroamericana "I-78" traités avec des herbicides