Sternal Recumbency Research Articles

A krimpsiekte-like syndrome in small stock poisoned by Ornithogalum toxicarium Archer & Archer.

Krimpsiekte (the syndrome associated with chronic cardiac glycoside poisoning) was purportedly induced by Ornithlogalum toxicarium in the Karas mountains area of Keetmanshoop, Namibia. This chinkerinchee species was previously linked to a condition known as 'kwylbek' krimpsiekte in small stock in the Beaufort West district of the Western Cape Province, South Africa. In a dosing trial, respiratory distress, tachycardia and sternal recumbency were observed in 2 sheep drenched with fresh plant material. A fluorescence polarisation immunoassay (FPIA) detected the presence of a substance that cross-reacted with digoxin antibodies in some of the plant material collected at Keetmanshoop and Beaufort West. This is the first time that apparent cardiac glycoside poisoning was induced by a southern African chinkerinchee species. The presence of the cardiac glycoside-like substance in O. toxicarium requires further chemical verification.

Butorphanol/xylazine/ketamine immobilization of free-ranging Baird's tapirs in Costa Rica.

Cardiopulmonary effects and the utility of a butorphanol/xylazine/ketamine combination were evaluated during twenty immobilizations of sixteen Baird's tapirs (Tapirus bairdii) between March 1996 and January of 1998 in Corcovado National Park (Costa Rica). The animals were attracted to a bait site and darted from tree platforms. The tapirs were estimated to weigh between 200 to 300 kg. Actual weights of three tapirs taken at later dates fell within the estimated range. A butorphanol, 48+/-1.84 (x +/- SE) mg/animal IM, and xylazine, 101+/-2.72 mg/animal IM, combination was used to immobilize the animals. In some instances, ketamine was used either IM or IV at 187+/-40.86 mg/animal to prolong the immobilization period in addition to the butorphanol/xylazine combination. Naltrexone was used IM to reverse butorphanol at 257+/-16.19 mg/animal. Either yohimbine, 34+/-0.61 or tolazoline at 12+/-10.27 mg/animal, was used to reverse xylazine. The mean time from dart impact to first visible effect was 4.63+/-0.50 min (x +/- SE). Mean time to sternal recumbency was 12.21+/-1.08 min. Mean time the tapirs were immobilized was 45.63+/-3.6 min. Mean time to return to sternal recumbency and standing in animals that received yohimbine and naltrexone was 3.16+/-1.06 and 5.33+/-1.45 min, respectively. Mean time to return to sternal recumbency and standing in animals that received tolazoline and naltrexone was 1.57+/-0.39 and 3.14+/-0.51 min, respectively. Cardiopulmonary parameters including heart rate, respiratory rate, body temperature, electrocardiogram, percent oxygen satoration, and indirect blood pressure were recorded. Arterial blood gas analysis was performed on four animals. A mild degree of hypoxemia was evidenced by low arterial oxygen saturations. Five of 14 (36%) animals measured had oxygen saturations below 90%. Bradycardia (heart rates <45 BPM) was an expected finding in 11 (55%) immobilizations. Induction, recovery and muscle relaxation of each immobilization was graded. Premature arousal, which occurred in six (30%) animals, was the only problem associated with the immobilizations. Butorphanol/xylazine is a recommended protocol for immobilization of calm, free-ranging tapirs lasting less than 30 min. Supplemental intravenous administration of ketamine is recommended for longer procedures. Nasal insufflation of oxygen is recommended.

Clinical and pathologic findings in donkeys with hypothermia: 10 cases (1988–1998)

To describe clinical signs and clinicopathologic findings in donkeys with hypothermia. Retrospective study. 10 hypothermic donkeys. Information on signalment, history, physical examination findings, results of diagnostic tests, treatments, and necropsy findings was extracted from medical records of all donkeys with hypothermia between 1988 and 1998 and compared with information from medical records of all normothermic donkeys and hypothermic horses admitted to the hospital during the same period. Donkeys were more likely to be hypothermic than horses. The mean age of hypothermic donkeys was 6 years (range, 7 months to 11 years), compared with 4.2 years (range, < 1 month to 15 years) for normothermic donkeys; this difference was not significant. Ten of 12 horses with hypothermia were neonates; there were no hypothermic neonatal donkeys. At admission, 7 of 8 hypothermic donkeys were in good body condition and all hypothermic donkeys were weak. Six hypothermic donkeys were able to maintain sternal recumbency, 1 remained in lateral recumbency, and 3 were able to stand. Of the 10 hypothermic donkeys, 2 survived, 1 died, and 7 were euthanatized. Histologically, the thyroid glands from 4 of 5 hypothermic donkeys appeared abnormal and were similar to those of foals with hypothyroidism. During the months that hypothermic donkeys were admitted, there was not a significant difference in environmental temperatures on days of admission between hypothermic and normothermic donkeys. Hypothermia is a problem in donkeys during cold winter months, and may not be secondary to other disease or related to diet or management.

Cardiopulmonary and Sedative Effects of Intramuscular Medetomidine-Ketamine and Intravenous Propofol in Ostriches (Struthio camelus)

Eight captive ostriches (Struthio camelus), ranging in age from 9 to 11 months, were given a combination of medetomidine and ketamine, administered intramuscularly, and propofol, administered intravenously, for induction and maintenance of anesthesia. Medetomidine (80 μg/kg IM) and ketamine (2 mg/kg IM) resulted in profound sedation and sternal recumbency within a mean time of 14.6 ± 10.0 minutes in 6 birds. Two birds remained standing but were moderately sedated. Propofol, used for induction (3 mg/kg IV) and maintenance (0.2 mg/kg/min constant rate infusion) of anesthesia, enabled intubation and provided muscle relaxation sufficient for restraint lasting 30 minutes. Apnea was observed after propofol administration, but spontaneous ventilation resumed within 60 to 90 seconds. All birds were bradycardic throughout the anesthetic event. Both the heart rate and the cloacal body temperature decreased significantly at 25 and 30 minutes, respectively, after induction. By 5 minutes after induction, the respiratory rate increased significantly and remained high throughout the remainder of the 30-minute evaluation period. During the anesthetic period, systolic, mean, and diastolic blood pressures, as well as arterial pH, arterial oxygen and carbon dioxide partial pressures, and end tidal carbon dioxide partial pressure showed no significant changes. The relative arterial oxygen saturation (SpO2) was significantly elevated at 15, 25, and 30 minutes after induction. The SpO2 was less than 90% at 2, 5, 10, and 20 minutes after induction; however, arterial blood gas analysis indicated adequate arterial oxygenation. Anesthetic reversal with the α2-antagonist atipamezole (400 μg/kg, one half IV and one half SC) was smooth and resulted in a mean recovery time of 21.0 ± 7.3 minutes. The combination of IM medetomidine-ketamine and IV propofol used in this study proved to be effective for sedation as well as the induction and maintenance of anesthesia in captive ostriches.

Anaesthetic potency of isoflurane in cattle: determination of the minimum alveolar concentration

To determine the minimum alveolar concentration (MAC) of isoflurane in cattle. Prospective study. Sixteen healthy adult female Holstein-Friesian cattle weighing 612 ± 17 kg (× ± SEM) and aged 5.7 ± 0.9 years old. The unsedated cattle were restrained in right lateral recumbency using a rope harness technique. Anaesthesia was induced with isoflurane (ISO) in oxygen via a face mask connected to a large-animal, semiclosed anaesthetic circle system. Each cow was intubated with a cuffed orotracheal tube (25 mm ID). Inspired and end-tidal ISO were monitored using a calibrated infra red analyser with a methane filter. The MAC of ISO that prevented gross purposeful movement in response to a tail and dewclaw clamp was determined. The time from the start of ISO administration to intubation, the time interval between discontinuance of ISO and the time the animal regained sternal recumbency, were recorded. Time to standing and quality of recovery were also recorded. The time from the start of ISO administration to tracheal intubation was 18.68 ± 2.77 minutes. The MAC of ISO in these cattle was 1.27 ± 0.03% (1.14 ± 0.01% corrected to sea level). Time to sternal recumbency after 90 ± 16 minutes of anaesthesia from intubation was 4.60 ± 0.58 minutes and time to standing was 6.70 ± 1.02 minutes. All cattle were extubated when they regained sternal recumbency. The MAC of isoflurane in these cattle was 1.27 ± 0.03% (1.14 ± 0.01% corrected to sea level). ISO provided a smooth induction to, and rapid recovery from, anaesthesia. Knowledge of the MAC of ISO in cattle will facilitate its appropriate clinical use.

Sevoflurane anaesthesia in clinical equine cases: maintenance and recovery

A new inhalant anaesthetic, sevoflurane, was used to maintain anaesthesia in 40 animals (2 mules and 38 horses of 9 breeds) presented for various surgical procedures. Eighteen mares, 11 stallions and 11 geldings underwent 6 orthopaedic and 34 soft tissue operations. Induction of anaesthesia was achieved with combinations of xylazine (0.5–1.1 mg/kg), diazepam (0.03–0.1 mg/kg), butorphanol (0.02 mg/kg), guaifenesin (50–84 mg/kg) and ketamine (1.1 mg/kg). Following tracheal intubation, a surgical plane of anaesthesia was maintained with sevoflurane in oxygen delivered from a precision vaporiser. Temperature, ECG, arterial blood pressure and expired gas composition were monitored. Mechanical ventilation was used in most animals (n=37) because of hypoventilation (P a CO 2 > 7.31 kPa [55 mmHg]). Following surgery, horses were moved to a recovery room and allowed to recover alone (n=36) or with assistance (n=4). Time to sternal recumbency, standing, the time when satisfactory coordination was present (after standing) and the number of attempts to stand were recorded. The quality of recovery was scored on a 1 (best) to 6 (worst) scale. Mean blood pressures at 30, 60, 90, 120 and 150 min of anaesthesia were 72, 73, 74, 75 and 72 mmHg, respectively. Systolic and diastolic pressures at 30, 60, 90, 120 and 150 min of anaesthesia were 97, 97, 94, 96, 93 and 59, 63, 64, 68, 67 mmHg, respectively. Dobutamine was used in 23 horses to maintain mean arterial blood pressure > 60 mmHg. Mean heart and respiratory rates at 30, 60, 90, 120 and 150 min of anaesthesia were 36, 38, 39, 38 and 38 beats/min, and 9, 8, 8, 8 and 8 breaths/min. Mean duration of anaesthesia was 121 rnin (sd: 56 min), mean time to sternal recumbency was 27 min (sd: 13 min), average time to standing (all horses) was 33 min (sd: 12 min) and time to satisfactory coordination was 44 min (sd: 13 min). Most horses (n=37) received xylazine during recovery (mean dose 0.18 mg/kg iv). The median number of attempts to sternal recumbency and standing were 1.0 (range; 1–7) and 2.0 (range; 1–20), respectively, while the median recovery score was 1.5 (range; 14). The ‘depth’ of anaesthesia was easy to control and recoveries were generally very satisfactory.

Frustration of goal-directed behaviour in swine

Pigs acquire, through learning and evolution, expectations of their environment. Frustration of expectations results in motivation to change these conditions and is therefore adaptive. Initially, frustration should produce problem solving behaviour. If these responses are unsuccessful, other behaviours, reflecting general frustration should be elicited. Our purpose was to study both types of responses to frustration in grower pigs. Eighteen grower pigs were fasted for 1, 2 or 3 h each morning by removing the feeders. On training days, Monday and Tuesday of each week, full feeders were returned to the pigs. On test days, Wednesday to Friday of each week, nonfunctional feeders were placed in the pens. Pigs were videotaped for 2 h following return of the feeders and behaviour on training and test days was compared. Two types of feeders were utilized, non-lidded (O) and lidded feeders (L). Non-lidded feeders, when placed in the pens were empty while lidded feeders had the lids bolted down to prevent access to feed. Frustration periods were compared to control periods by split-plot-in-time analysis ( p<0.05). A 6×6 Latin Square design incorporated six treatments (two feeder types×three fast periods) over 6 weeks. Both single pigs (S) and pairs (P) were observed. During the period of frustration both S- and P-pigs increased their general activity level. This was reflected in a decrease in lateral recumbency (S: −12.7% and P: −9.9%) with an increase in sternal recumbency (+10.8%) and sitting (+3.0%) in the S-pigs and an increase in sternal recumbency (+5.2%), sitting (+3.5%) and playing (+0.7%) in the P-pigs. Oral manipulation of the feeder by S-pigs was more pronounced during the first hour than the second hour in L-feeders (7.1% vs. 5.2%) but not in O-feeders (6.1% vs. 6.5%) indicating an increase in activities related to problem solving. Frustration increased general oral activity including increased oral manipulation of other pigs (P: 1.9% to 5.6%), and other objects (S: 8.8% to 28.4% and P: 6.9% to 14.9%). Serum cortisol levels were determined prior to, and at the conclusion of the experiment, as an indication of stress during the 6 weeks of on-and-off frustration. Although all pigs were exposed to all treatments, those pigs exposed to L-feeders during the final week had higher cortisol levels (92.3 nmol/l) than those exposed to O-feeders (56.9 nmol/l). Frustration, as expressed in increased oral activity, did not substantially diminish over a 6-week period although general activity levels tended to return to normal.

Intoxicação por Senna occidentalis (Leg. Caesalpinoideae) em bovinos em pastoreio

São descritos três surtos da intoxicação por Senna occidentalis em bovinos em criação extensiva, exclusivamente em pastoreio, durante o outono e início do inverno, em três estabelecimentos do estado do Rio Grande do Sul. Os bovinos afetados tinham acesso a antigas lavouras de soja ou restevas de lavouras de soja e milho altamente infestados por fedegoso (S. occidentalis). No estabelecimento 1, de um total de 34 novilhas (de aprox. 18 meses de idade), 10 morreram (29,1%); no estabelecimento 2, morreram 9 (4,2%) de um total de 212 vacas prenhes e, no estabelecimento 3, morreram 6 (12,0%) de um total de 50 animais. O curso clínico variou de 3 a 6 dias, e os sinais clínicos incluíam urina marrom-escura, fraqueza muscular, tremores, andar cambaleante, decúbito esternal e morte. Os animais, mesmo em decúbito, permaneciam alerta e com reflexos normais, alimentando-se e bebendo água até poucas horas antes da morte. No estabelecimento 2, os bovinos começaram a adoecer 7 dias após terem sido retirados do campo infestado pela planta. As principais alterações observadas na necropsia foram áreas claras na musculatura esquelética, principalmente nos músculos dos membros posteriores e estrias esbranquiçadas na musculatura cardíaca. A principal lesão microscópica era de degeneração e necrose nos músculos esqueléticos (miopatia degenerativa tóxica multifocal multifásica). Os dados epidemiológicos, clínicos, de necropsia e histopatológico permitiram concluir pelo diagnóstico de intoxicação por S. occidentalis, nesses três surtos.

Genetic-diet interactions in the hyperkalemic periodic paralysis syndrome in quarter horses fed varying amounts of potassium: III. The relationship between plasma potassium concentration and HYPP Symptoms

Summary Six broodmares that were DNA tested to be heterozygous (H/N) and six broodmares that were tested to be homozygous negative (N/N) for Equine Hyperkalemic periodic Paralysis (HYPP), that were descendents of the same stallion, were used in a replicated 3x3 Latin square experiment to determine the genetic-diet relationships in the HYPP syndrome. 1 The mares were fed rations consisting of 65% pelleted concentrate and 35% Coastal Bermuda grass hay that provided 1.1 (diet A), 1.9 (diet B) and 2.9% (diet C) potassium in two evenly spaced meals per day. The experimental periods were 14 days long, resulting in 28 meals per period. The HYPP Symptoms Index was greater at meal 1 than meal 27 and greater when the horses were fed diet C than diet B. Plasma K + concentrations at the onset of symptoms were not different by diet or meal and averaged 3.78 mmol/L. The average time of onset of symptoms was two hours and 33 minutes after the beginning of a meal, which was not different by diet or meal. A regression analysis of 204 paired non-zero HYPP Symptoms Index values and their corresponding plasma K + concentrations at the same times, from the HYPP H/N horses, resulted in an R 2 of .449. While fed diet A, the horses' mean plasma K + values remained below 3.5 mmol/L, and no symptoms were observed. Generally, an increase in Symptoms Index followed increased plasma K + concentration when the horses were fed diets B and C at meal 1. At meal 27, the mean HYPP Symptoms Index and average plasma K + values were lower than at meal 1. However, there were increased plasma K + concentrations observed in the later post-prandial hours after meal 27, when the horses were fed diet B, that did not correspond to HYPP symptoms. In a pilot study, one horse collapsed into sternal recumbency after meal 1 when her HYPP Symptoms Index was 10 and her plasma K + concentration was 7.29 mmol/L. This horse spontaneously recovered from the episode. By meal 27, both the peak plasma K + concentration (4.6 mmol/L) and the peak HYPP Symptoms Index (1) were smaller in this horse, but they still occurred simultaneously.

Anesthetic and cardiorespiratory effects of tiletamine-zolazepam-medetomidine in cheetahs

Objective— To evaluate anesthetic and cardiorespiratory effects of an intramuscular injection of a tiletamine-zolazepam-medetomidine combination in cheetahs. Design— Prospective study. Animals— 17 adult captive cheetahs. Procedure— The anesthetic combination was administered intramuscularly via a dart. Induction quality, duration of lateral recumbency, duration of recovery, and quality of anesthetic reversal with atipamezole were assessed. Cardiorespiratory variables (arterial blood gas partial pressures, arterial blood pressure, heart and respiratory rates, end-tidal CO2, oxygen saturation, and rectal temperature) were measured during anesthesia. Results— Sedation and lateral recumbency developed within 1.9 ± 1.0 (mean ± SD) and 4.3 ± 2.0 minutes of drug administration, respectively. Clinically acceptable cardiorespiratory and blood gas values were recorded for at least 87 minutes after drug administration in all but 1 cheetah. Hypoxemia and arrhythmias developed in 1 cheetah breathing room air but resolved after treatment with oxygen. Hypertension developed in all cheetahs. Significant differences in heart and respiratory rates, mean arterial blood pressure, arterial pH, partial pressure of oxygen, and hemoglobin saturation were found between cheetahs that did and did not receive oxygen supplementation. After administration of atipamezole, sternal recumbency and mobility returned within 6.9 ± 5.8 and 47.5 ± 102.2 minutes, respectively. Postreversal sedation, which lasted approximately 4 hours, developed in 4 cheetahs. Clinical Implications— Tiletamine-zolazepam-medetomidine delivered via a dart provided an alternative method for induction and maintenance of anesthesia in cheetahs. Atipamezole at the dose used was effective for reversal of this combination in the initial phase of anesthesia. (J Am Vet Med Assoc 1998:213:1022-1026)

A note on the effect of control of the thermal environment on the well-being of growing pigs

The effects of providing control over heat onset were examined in 36 pigs, aged 28 days at the start of the experiment. Pigs were randomly allocated to one of three treatments, and then housed in pairs. Treatment S provided standard accommodation with continuous heat from an infrared source. Treatment O allowed pigs operant control of an infrared heat source. Treatment Y was yoked to treatment O such that pigs received identical reinforcement non-contingently. Treatments were imposed for two weeks and behaviour recorded daily. Pigs in treatment O were significantly less active ( p<0.05) and showed a tendency to lie more than pigs in treatments Y and S. Pigs in treatment S played more than pigs in the other two treatments ( p<0.05). The proportion of lying time that pairs spent huddled together was significantly greater in treatment O than in treatment Y, and greater in treatment Y than in treatment S ( p<0.002). The proportion of time spent in sternal vs. lateral recumbency was greater for pigs in treatments Y than in treatment S. Individual pigs were tested in an open-field arena before and after treatment imposition. Activity level, defecation, vocalisation, and response to a novel object were all non-significant between treatments. In general, the provision of controllable heat onset had few discernible welfare benefits.

Increasing available space in a farrowing crate does not facilitate postural changes or maternal responses in gilts

A study was designed to test the effects of gestation and farrowing accommodation on the postural behaviour and maternal responsiveness of gilts. It was hypothesized that increasing available space would allow gilts to move more easily, facilitating maternal responses. Twenty-four gilts were allocated to either an individual stall or small group for gestation, followed by either a narrow crate (42.5 cm wide), wide crate (80 cm wide) or pen (2.4 m×2.4 m) for farrowing and lactation. Postural time budget and standing and lying behaviour were observed on seven occasions during farrowing accommodation occupancy. Maternal responsiveness was tested on d 2 after farrowing by observing each gilt's response to a tape recorded piglet distress squeal, played while she was in the process of lying down. Five days before farrowing (d-5) and one day before farrowing (d-1), postural behaviour indicated restlessness: 65% of time was spent lying laterally, compared to over 80% immediately after farrowing (d 1), and gilts spent about twice as much time standing and sitting on d-5 and d-1 as they did on d 1. Gilts changed posture more than four times as often in the prepartum period than postpartum. This prepartum restlessness was more marked in the wide crate than in the narrow crate or pen, particularly when gilts had gestated in groups. On d-1, gilts in the wide crate spent less time lying in lateral recumbency (55% of time vs. 76%, p<0.01) and more time lying in sternal recumbency (20% of time vs. 10.5%, p<0.05) than gilts in the narrow crate or pen. Occupants of the wide crate displayed more bouts of both kinds of lying ( p<0.01) than other gilts, and shorter bouts of lateral lying ( p<0.05) than gilts in the pen on d-1. In the wide crate, gilts that had gestated in groups lay sternally for 30% of time prior to farrowing, compared to 10% of time in previously stalled animals ( p<0.01), and displayed more bouts of sternal lying ( p<0.01). Gilts in the wide crate lay down more slowly (18.2 s) than those in either the narrow crate (13.1 s) or pen (12.0 s), ( p<0.05). Wide crate occupants also used the crate side for support during lying down less than half as often as gilts in the other two kinds of farrowing accommodation (on 35% vs. 72–89% of occasions, p<0.01), but use or non-use of a support did not affect time taken to lie down in the wide crate. Maternal response to the squeal playback was very variable, and was not affected by gestation or farrowing accommodation. The widened farrowing crate appeared less comfortable than either the narrow crate or pen, particularly when it followed gestation in a group. Contrary to expectations, increasing the available space in a crate did not facilitate posture-changing behaviour. The importance of controlling for type of gestation accommodation when examining the effects of farrowing housing on behaviour is emphasized.

Dorsolateral subluxation of hip joints in dogs measured in a weight-bearing position with radiography and computed tomography.

develop a radiographic procedure to measure dorsolateral subluxation (DLS) of the femoral head in canine coxofemoral (hip) joints in a weight-bearing position. DLS measured on a radiographic projection was compared with DLS measured on computed tomography (CT) images of hip joints in a weight-bearing position. A total of 24 dogs of varying ages were examined including Labrador retrievers, greyhounds, and Labrador-greyhound crossbreeds. Anesthetized dogs were placed in sternal recumbency in a kneeling position in a foam rubber mold. The stifles were flexed and adducted with the femora perpendicular to, and in contact with, the table. To test for DLS, dogs were imaged in this weight-bearing position (DLS test) with routine radiography and CT. For each hip, the DLS score was determined by measuring the percentage of the femoral head medial to the lateralmost point of the cranial acetabular rim on the dorsoventral radiographic projection and the lateralmost point of the central, dorsal acetabular rim on the CT image. Higher DLS scores indicated better coverage of the femoral head by the acetabulum. DLS scores were compared with the distraction index (DI) by grouping joints according to their probability of developing osteoarthritis (OA) as predicted by the DI. The DLS score in the new position ranged from 29% to 71% for radiography and 15% to 59% for CT. Joints classified as OA unsusceptible had a mean score of 64% +/- 1.5% for radiography and 55% +/- 0.8% for CT (n = 10); hip joints having a high probability of developing OA had a score of 39% +/- 2.6% for radiography and 26% +/- 1.9% for CT (n = 8). When the DLS test was repeated on the same dogs at a different time, the intraclass correlation coefficient for the DLS score on the radiographs was 0.85 (left hip) and 0.89 (right hip). There was a strong correlation (r = .89 for both hips) between the DLS score measured on the weight-bearing radiograph and the CT image. A strong correlation also was observed between the DLS score and the DI (r = -.87). The DLS scores for OA unsusceptible joints and joints with a high probability of developing OA were significantly different (P < .05). The DLS test can be performed with CT or routine radiography to measure variable amounts of DLS in weight-bearing hip joints oriented similarly to those of a standing dog. After additional long-term follow-up studies evaluating the development of OA and breed effects are performed, the DLS method may prove useful in studies of normal and abnormal hip joint development related to canine hip dysplasia.

Maintenance of anaesthesia with sevoflurane and oxygen in mechanically-ventilated horses subjected to exploratory laparotomy treated with intra- and post operative anaesthetic adjuncts.

Eight healthy horses premedicated with xylazine and induced with ketamine were used to evaluate sevoflurane in oxygen for maintenance of anaesthesia during elective exploratory laparotomy. After orotracheal intubation, horses were hoisted, placed in dorsal recumbency on a padded surgery table, and received sevoflurane in oxygen for maintenance of anaesthesia. The horses were allowed to breathe spontaneously until instrumented; then, they were mechanically ventilated to maintain the PaCO2 between 35 and 45 mmHg. Systolic (SAP), diastolic (DAP), and mean (MAP) arterial blood pressures, heart rate (HR), ECG, respiratory rate, an estimation of the saturation of haemoglobin with oxygen in peripheral arterial blood (S(p)O2), nasal temperature, end-tidal CO2(ET(CO2)), end-tidal sevoflurane (ET(SEVO)), and vaporiser concentration were recorded every 5 min post induction; arterial blood samples were obtained soon after induction, at 30 min after induction, and every hour thereafter until surgery was completed. Recovery data including times from the sevoflurane vaporiser being turned off to first movement, to sternal recumbency, and to standing, number of attempts to stand, and recovery score (between 1 = safe, smooth and 6 = stormy, major injury to horse) were collected. Analysis of variance was performed using physiological data collected over 195 min of anaesthesia, the longest time period during which all 8 horses were instrumented. Time effects (P<0.05) for HR, SAP, DAP, MAP, and nasal temperature were identified. Heart rate peaked at 45 min and declined over the course of the procedure. Arterial blood pressure generally decreased over time. Body temperature decreased over time. From 15 to 195 min mean ET(SEVO)concentration ranged from 2.0 to 3.3%, while mean vaporiser settings ranged from 3.7 to 5.5%. Three horses received intra-operative ketamine; all horses received dobutamine infusions; and 2 horses received intra-operative calcium-dextrose. Total anaesthesia time was 222-316 min (mean+/-s.d.269+/-31 min). Time from turning the sevoflurane vaporiser off to first movement was mean +/-s.d.18+/-15 min; to sternal recumbency was 54+/-22 min; to standing was 65+/-27 min; and to returning the horse to the stall in the ward was 78+/-24 min. Six horses stood on the first attempt; 2 horses stood on the second attempt. The median recovery score was one (1-3). In conclusion, sevoflurane provided a stable, easily controllable anaesthetic plane during prolonged exploratory laparotomies; horses experienced smooth, safe recoveries after maintenance of anaesthesia with sevoflurane following routine anaesthetic induction and post operative xyalzine administration.

Comparison of four regimens for intraoral administration of medication to induce sedation in cats prior to euthanasia

Objective To compare 4 regimens for intraoral administration of medication to induce sedation in cats prior to euthanasia. Design Prospective randomized clinical study. Animals 36 cats. Procedure Cats were assigned to 4 groups (9 cats/group). Cats in each group were given the following medications: group 1, detomidine (0.5 mg/kg [0.23 mg/lb] of body weight); group 2, ketamine hydrochloride (5 mg/kg [2.3 mg/lb]); group 3, detomidine (0.5 mg/kg) and ketamine (5 mg/kg); and group 4, detomidine (0.5 mg/kg) and ketamine (10 mg/kg [4.5 mg/lb]). All medications were administered by squirting the drug or drug combination into the mouth of a cat, using a syringe or, for intractable cats, a remote delivery device. Cats were evaluated for degree of sedation at 3-minute intervals for 60 minutes. Results Of the 9 cats in group 1, 7 assumed lateral recumbency. Mean (± SD) interval from administration of medication to lateral recumbency was 15 ± 3 minutes. For group-2 cats, 1 cat achieved sternal recumbency (sternally recumbent and unable to stand), whereas the remaining 8 cats achieved mild to moderate degrees of sedation. For group 3, 6 of 9 cats assumed lateral recumbency (mean, 16.5 ± 3.7 minutes). For group 4, all 9 cats assumed lateral recumbency (mean, 17 ± 8 minutes). Clinical Implications Analysis of results of this study indicated that a combination of detomidine (0.5 mg/kg) and ketamine (10 mg/kg) administered intraorally provided an effective and reliable method for sedating cats. (J Am Vet Med Assoc 1998;213:243-245)

Observations on the use of midazolam for sedation, and induction of anaesthesia with midazolam in combination with ketamine in the goat.

Midazolam hydrochloride administered intramuscularly at a dosage of 0.4 mg/kg induced sedation and sternal recumbency in goats. Increasing the dosage to 1 mg/kg resulted in rapid onset of ataxia followed by lateral recumbency, and loss of consciousness. Light surgical anaesthesia lasted for a period of 7-15 min and was suitable for non-painful procedures. Heart rate was significantly increased (p < 0.05) at both dosage rates, while respiration rate was only increased after midazolam at 0.4 mg/kg. The combination of midazolam (0.4 mg/kg) and ketamine hydrochloride (4 mg/kg) increased heart and respiration rate significantly (p < 0.05). A light plane of surgical anaesthesia suitable for endotracheal intubation was induced, which lasted for a period of 16-39 min.

The pharmacokinetics of ketamine after a continuous infusion under halothane anaesthesia in horses

The pharmacodynamics and pharmacokinetics of ketamine, when administered by infusion as an adjunct to halothane anaesthesia in horses, were investigated in 5 equine patients presented for routine castration. Anaesthesia was induced with detomidine, 20 μg/kg, followed by ketamine, 2.2 mg/kg bwt, the trachea intubated and the horses allowed to breathe halothane in oxygen. Five minutes later, a constant rate infusion of ketamine, 40 μg/kg min, was commenced and the halothane vaporiser concentration adjusted to maintain a light plane of anaesthesia. The mean infusion duration was 62 min (range 40–103). The ketamine was switched off approximately 15 min before the halothane. Plasma ketamine and norketamine levels, determined by high performance liquid chromatography, ranged from 0.74–2.04 μg/ml and 0.15–0.75 μg/ml, respectively, during the infusion period. The harmonic mean elimination half-life of ketamine was 46.1 min, mean volume of distribution at steady state (Vdss) was 1365 (271) ml/kg, mean body clearance (Cl) was 32.3 (9.1) ml/min.kg, and average mean residence time for the infusion (MRTinf) was 105.9 (20.4) min, respectively. Following termination of halothane, mean times to sternal recumbency and standing were 21.1 (6.9) and 41.6 (17.0) min, respectively. Surgical conditions were considered highly satisfactory, and physiological parameters were well preserved in most animals.

Impaction of the Stomachs in Farmed Ostriches (Struthio camelus) in Botswana

Impaction of the proventriculus, gizzard, and sometimes intestines due to sand was confirmed at postmortem in 25 cases involving ostriches (Struthio camelus). Although there was no age predisposition, impaction was more common in juvenile over 3 mo old. Clinical signs included sternal recumbency, outstretched neck, debility, and inability to stand. Palpation of the impacted stomachs gave a gritty sensation. Depletion of coronary fat was a consistent postmortem finding. The most common material causing impaction was sand. This report highlights impaction as one of the major causes of debility and death in intensively farmed ostriches. High levels of alkaline phosphatase coupled with low levels of plasma glucose, protein, and albumin detected in impacted ostriches may be useful diagnostic antemortem indicators of the syndrome.

Neuroleptic treatment of red deer calves at weaning

Aims. To determine whether neuroleptic drugs could be useful in reducing weaning stress in red deer, two groups of 30 calves were studied following separation from their dams for weaning at 3–4 months of age. Methods. Within each group, on the day of separation (Day 0), 15 calves were given 0.2 mg/kg haloperidol (a short-acting neuroleptic) and 1 mg/kg perphenazine enanthate (a long-acting neuroleptic) by intramuscular injection (the treated calves) and 15 calves were given a 3 ml intramuscular injection of saline (the control calves). The calves were weighed on Days 0, 14 and 28 and the behaviour of eight individuals (four treated and four control calves) within each group was observed for 2 hours on Days 0, 1,2, 3, 7, 8, 14 and 15. Results. No significant effect of the treatment on weight gain to Days 14 or 28 was observed (mean increases for treated and control calves to Day 14 were 3.4 kg and 3.5 kg, respectively (s.e.d. 0.26 kg), and 6.0 kg for both treatments to Day 28 (s.e.d. 0.36)). Behavioural variables (standing, grazing, moving, fenceline pacing, proximity to other deer and proximity to the fenceline) did not differ significantly between treatments, but in one group sitting in sternal recumbency was lower in treated calves compared with control calves (p < 0.05). Disturbed behaviour declined over the observation days with fenceline pacing, being within 2 m of a fence, and being within 1 m of another deer decreasing, and sitting and grazing both increasing (p < 0.01). Conclusions and clinical relevance. It was concluded that we could not provide evidence from the present study that treatment with haloperidol and perphenazine enanthate at these dose rates was beneficial in reducing weaning stress in red deer calves.

Choosing appropriate space allowances for slaughter pigs transported by road: a review

In the United Kingdom pigs can spend up to 11 hours in transit to slaughter but on average travel for two to three hours. In the past, international journeys have...