Malignant hyperthermia in a Greyhound

A rapid rise in rectal temperature (to 45 C) in a young male Greyhound was attributed to the use of halothane and succinylcholine. Circulatory failure and death occurred within approximately 90 minutes of the onset of the hyperthermia.     

Malignant hyperthermia in the pig: Aetiology,therapy and implications

The malignant hyperthermic syndrome occurs in man and the pig, usually following administration of the anaesthetic halothane or the myorelaxant succinylcholine. Mechanisms in skeletal muscle and in the central nervous system appear to be involved in its development. The primary intracellular event may be a loss of energy phosphates from muscle and other tissues while manifestations of sympathetic activation such as tachycardia and hyperthermia develop subsequently. Myorelaxants, adrenergic blocking agents and neuroleptic drugs have been reported to prevent the onset of acute malignant hyperthermia in susceptible animals.

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Kurzfassung Das bösartige hyperthermie Syndrom tritt beim Menschen und beim Schwein auf, und zwar gewöhnlich nach einer Halothannarkose oder nach der Verabreichung les Muskelrelaxans Succinylcholin. An seiner Entwicklung scheinen Vorgänge in der Skelettmuskelstruktur und im zentralen Nervensystem beteiligt zu sein. Die hauptsächliche intrazelluläre Veränderung könnte in einem Verlust von Energie-Phosphaten in Muskeln und anderem Gewebe bestehen, während die Symptome einer Sympathikus-Aktivierung, z.b. Tachikardie und Hyperthermie, folgen. Berichten zufolge sollen Muskelrelaxantien, adrenergische Inhibitoren und Neuroleptika den Ausbruch der akuten bösartigen Hyperthermie bei anfälliren Tieren verhindern.

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Resume Le syndrome d'hyperthermie maligne se manifeste habituellement chez l'Homme et le Porc à la suite de l'administration d'un anesthésique, l'halothane, ou d'un curarisant, la succinylcholine. Certains mécanismes des muscles squelettiques et du système nerveux central semblent impliqués dans son développement. L'événement intracellulaire initial semble être une chute du taux de l'ATP du muscle et d'autres tissus, cependant que des manifestations d'activation sympathique telles que tachycardie et hyperthermie apparaissent ensuite. Les myorelaxants, les agents bloquants adrénergiques et les drogues neuroleptiques sont susceptibles de prévenir l'apparition de l'hyperthermie maligne aiguë chez le Porc.

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Riassunto La sindrome dell'ipertermia maligna si manifesta abitualmente nell'uomo e nel maiale in seguito alla somministrazione di un anestetico, l'allotano o di un miorilassante, la succinilcolina. Processi propri dei muscoli scheletrici e del sistema nervoso centrale sembrano alla base del suo sviluppo. L'evento intracellulare iniziale sembra essere una caduta del tasso di ATP del muscolo e di altri tessuti; mentre manifestazioni di attivazione del simpatico quali tachicardia e ipertemia compaiono in un tempo successivo. I miorilassanti, gli agenti bloccanti adrenergici e le droghe neurolettiche vengono citate quali agenti atti a prevenire l'apparizione dell' ipertermia maligna acuta negli animali che accusano predisposizione alla malattia.

     

Malignant hyperthermia in dogs

Malignant hyperthermia (MH) is an anesthetic agent-induced hypermetabolic state. Human beings and several other animal species, including dogs, have been described to be genetically predisposed to development of MH. The halothane-triggered MH syndrome was characterized in genetically predisposed dogs, and in vitro contracture sensitivity of biopsied gracilis muscle exposed to halothane and caffeine was quantitated. Within 1 hour of halothane administration, each MH-susceptible dog developed rapid increases in CO2 production and rectal temperature. Reversal of the hypermetabolic state was achieved when halothane was discontinued and dantrolene sodium was given i.v. Biopsied gracilis muscle from MH-susceptible dogs had abnormal in vitro contracture responses to halothane and caffeine. These findings were consistent with those observed for MH-susceptible human beings and pigs in which a loss in regulation of muscle cell Ca(+)+ is believed to be the primary etiologic event for induction of MH.     

Malignant hyperthermia in a horse anesthetized with halothane

Ahealthy, 565-kg, 14-year-old Quarter Horse gelding, negative for equine protozoal myelitis on serum Western blot and for hyperkalemic periodic paralysis (HYPP) by polymerase chain reaction, was selected for use in an electrophysiology study performed under inhalation anesthesia. The study was performed by following the guidelines of an Animal Use and Care Committee Protocol of the University of California at Davis (UCD 8578). Anesthesia was induced with halothane delivered via a face-mask. The horse was intubated 17 minutes later with an orotracheal tube and anesthesia was maintained with halo-thane by using a semiclosed, large-animal breathing circuit. Although muscle relaxation was otherwise good, the horse's ears remained tensed in a caudal direction throughout the study     

Malignant lymphoma in a Sinclair miniature pig

Malignant lymphoma was diagnosed in a 3-year-old, male Sinclair(S-1) miniature pig with acute anorexia, depression, fever, and markedly enlarged inguinal lymph nodes. Results of an initial hemogram indicated a leukocyte count of 121,489 cells/mm3. Most of the leukocytes were mononuclear cells of various sizes, nuclear chromatin pattern, number of nucleoli, amount of cytoplasm, and amount of staining. Cytochemical staining and flow cytometric evaluation of the leukocytes indicated a large number of hypodiploid lymphoblasts in the peripheral blood. Gross necropsy findings included enlargement of all lymph nodes, a pale liver, and multifocal pale areas scattered throughout the kidneys. Microscopic examination indicated massive infiltration of abnormal lymphoid cells into most major organs and complete loss of normal morphologic features of all lymph nodes.     

Genetic evaluation combining purebred and crossbred data in a pig breeding scheme

Genetic evaluations using purebred data alone and combined purebred and crossbred information were performed for lean meat percentage in a pig breeding scheme. One purebred (PB) model and 2 crossbred models (CCPS1 and CCPS2) were used in the analyses. Data were obtained from the Selección Batallé S.A. Company (Riudarenes, Spain) and spanned a period of 4 yr (2006 to 2009). The data corresponded to 3 nuclei of purebred populations, Landrace (LD), Duroc (DU), and Pietrain (PI); 1 multiplying farm with animals from a 2-way cross (TB1; DU × LD); and commercial farms with animals from a 3-way cross (TB2; TB1 × PI). Genetic parameters were similar across the models, with the exception of purebred PI. The DU and LD purebreds presented large heritabilities (0.5 to 0.6) for lean meat percentage, whereas the PI purebred showed a lower heritability (approximately 0.1) for the PB model and moderate heritability for the CCPS1 and CCPS2 models (0.2 to 0.3). The mean reliability of the predicted purebred breeding values was clearly increased when the CCPS1 and CCPS2 models were used. Moreover, a reranking of the animals with important changes in the selection decisions was observed in the PI purebred. In a simulation study, the CCPS1 model achieved a greater response to selection than the PB model for the PI purebred. On another hand, between the CCPS1 and CCPS2 models, CCPS1 was slightly superior in terms of predictive ability, exhibiting a greater robustness. These results illustrate the usefulness of using crossbred models to evaluate lean meat percentage in this pig breeding scheme.     

Production traits of litters in 2 crossbred Duroc pig lines

Genetics of different pig lines affects litter size, birth weight, and neonatal losses. Low birth weight has long been associated with neonatal losses, but piglet body mass index is reported to show stronger correlation with stillbirth. The aim of this study was to investigate differences in litter size, number of stillborn piglets, piglet BW gain, and body mass index between 2 different Duroc crossbred lines. Landrace × Yorkshire sows in 2 farms (n = 89) were divided into 2 groups on each farm. One group of sows on each farm was inseminated with semen from Landrace × Duroc boars (boar group LD, n = 48), and the other was inseminated with semen from purebred Duroc boars (boar group DD, n = 41). Piglets were monitored from birth to weaning at the age of 5 wk. Litter size in boar group LD was larger than in boar group DD (P = 0.03). Number of stillborn piglets in boar group LD tended to be greater than in boar group DD (P = 0.07). Piglets in boar group DD had a greater BW at birth (P = 0.02) and at 3 wk (P = 0.01) than those in boar group LD. Body mass index from birth to weaning was greater in piglets in boar group DD vs. LD (P < 0.01), and both BW and body mass index of liveborn piglets at birth for both groups combined showed a positive correlation with survival at weaning (P < 0.01). In conclusion, breeding for larger litter size in boar group DD may be one approach to increase the number of vigorous piglets in production, but the inverse relationship between litter size and birth weight was more pronounced for this group than for boar group LD (P = 0.03). Further studies of the impact of litter size on BW gain are necessary before a final conclusion can be reached.     

Malignant hyperthermia in a dog: case report and review of the syndrome

Malignant hyperthermia occurred in an adult Greyhound 24 hours after narcotic anesthesia and surgery. Stress was considered the most likely cause. Treatment with dantrolene, in conjunction with cooling techniques and other symptomatic and supportive therapy, was successful.     

淮猪杂交育肥及胴体性能测定

分别选取4窝长白猪×淮猪(长淮组)、大约克猪×淮猪(大淮组)和淮猪(淮猪组)进行育肥和胴体性能测定。试验结果表明,试验猪的日增重差异不显著(P>0.05),但大淮猪平均日增重(626.13±76.82)g(65.24%)、长淮猪平均日增重(587.00±59.58)g(54.91%)均有高于淮猪(378.93±67.74)g的趋势。长淮猪料肉比(3.04)比淮猪(4.54)降低了49.34%,大淮猪料肉比(3.27)比淮猪降低了38.84%。试验猪的平均屠宰率都在70%以上,各组差异不显著(P>0.05)。大淮猪的胴体斜长(74.50±1.91)cm显著长于淮猪(68.50±3.70)cm,(P<0.05)。长淮猪的眼肌面积(36.45±4.80)cm2显著大于淮猪(21.02±4.23)cm2,(P<0.01)。大淮猪后腿比例(31.08±1.97)%有高于淮猪(28.74±1.24)%的趋势。瘦肉率长淮猪(56.69±1.79)%和大淮猪(53.13±1.41)%均极显著(P<0.01)高于淮猪(44.89±2.15)%。淮猪皮(14.10±1.55)%比长淮猪(7.81±0.56)%和大淮猪(8.39±0.81)%高出5个百分点以上,且差异极显著(P<0.01)。3组猪的肉质性状指标都在正常值范围内,肉质优良,未发现有PSE或DFD等劣质肉。     

Suspected panosteitis in a crossbred calf

A male crossbred calf developed a limp and pain upon deep pressure on the right hind limb and the right forelimb. The radiographic findings of affected limbs and pathological findings of bone biopsy were similar to those observed in canine panosteitis. This is the first case of suspected panosteitis reported in cattle.