Tramadol Effects on Lameness Score After Inhibition of P-GP by Ivermectin Administration in Horses: Preliminary Results.

This study aimed to evaluate the effects and lameness degree in horses administered tramadol after the P-glycoprotein (P-gp) enteric inhibitor ivermectin. Six horses were randomly distributed into three groups, which received two different doses of tramadol by a nasogastric tube: 1 mg/kg (tramadol group 1(GT1)), 4 mg/kg (tramadol group 4 (GT4)), and tramadol 1 mg/kg combined with ivermectin 0.2 mg/kg PO (ivermectin tramadol group (GT1 + Ive)), with one-week washout interval. Heart rate (HR), respiratory rate (RR), intestinal motility, body temperature, and the degree of lameness were evaluated for 360 minutes. The blood gas parameters were evaluated at 0, 60 minutes, and 120 minutes. There were no differences in HR and the degree of lameness. Hypomotility occurred in GT1 and GT4 only at the end of the evaluation period, and RR increased in all groups. We conclude that inhibition of enteric P-gp by ivermectin did not alter the effects of tramadol, suggesting that tramadol is not a substrate for P-gp. However, future studies should be conducted to assess the interaction between P-gp inhibitors on the pharmacokinetics of tramadol.

Histologic Evaluation of Palmar Digital Nerves after Perineural Injection of 2% Ammonium Chloride in Miniature Horses.

Neurolytic compounds are widely used by equine practitioners for the management of lameness, mostly related to the foot. The present study aimed to evaluate the neurotoxicity of 2% ammonium chloride (2% AC) applied adjacent to the palmar digital nerves in six miniature horses. The 2% AC and 0.9% saline solution were randomly injected into three and one palmar digital nerve of each horse, respectively. Nerve samples were collected by neurectomy performed under general anesthesia at 5, 12, 19, 35, 47, and 62 days after treatment, with one horse per day of surgery. The inflammatory reaction to perineural injection was evaluated by an increase of pastern superficial skin temperature through thermography 24 hours after treatments. Histological lesions were classified as absent, mild, moderate, and severe Wallerian degeneration. An increase of 2.43 ± 0.79°C and 1.69 ± 0.55°C was observed in the 2% AC and control groups, respectively (P > .05). Moreover, histologic lesions were observed after perineural injection of 2% AC (severe, n = 5/18; moderate, n = 4/18; mild, n = 5/18; and absent, n = 4/18) and saline solution (moderate, n = 3/6; mild, n = 1/6; and absent, n = 2/6) (P = .46). The 2% AC demonstrated to be as safe as 0.9% saline solution, producing mild to severe Wallerian degeneration for up to 62 days after injection with no interference in further neurectomy.

Viability of Equine Chondrocytes After Exposure to Mepivacaine and Ropivacaine In Vitro.

Chondrocyte health is altered when exposed to local anesthetics, raising concerns as to the long-term effects of local anesthetics intra-articularly for diagnosis and analgesia. To investigate the drug with the lowest toxic potential, the effect of ropivacaine and mepivacaine on chondrocytes was evaluated. Articular cartilage from normal metacarpophalangeal joints of five equine cadaver specimens was used to establish chondrocyte cultures. Following seven days, chondrocytes were exposed to standard culture medium (DMEM), ropivacaine 7.5 mg/ml (ROP7.5), ropivacaine 10 mg/ml (ROP10), mepivacaine 20 mg/ml (MEP20), mepivacaine 30 mg/ml (MEP 30), and 0.9% saline solution (SAL). Chondrocyte viability was evaluated by trypan blue exclusion, MTT, and flow cytometry via cellular staining with propidium iodide. No differences were observed between treatments following trypan blue exclusion assay. A difference was observed between DMEM and all other treatment groups (P < .0001) with a significant viability drop using the MTT assay. Mepivacaine 20 mg/ml and MEP30 exposure between showed greatest decrease in cellular viability compared to SAL, ROP7.5, and ROP10 (P < .0001). Cellular viability decreased as measured by flow cytometry in all groups compared to DMEM and ROP7.5 (P < .02). Interestingly, the trypan blue, MTT, and flow cytometry assays yielded different results. Although there was no difference using trypan blue, MTT demonstrated that ropivacaine-treated cells had lower viability than DMEM, and cytometry found that ROP7.5 did not differ from DMEM. Results in vitro suggest that short-term exposure to ropivacaine may result in less chondrotoxicity than mepivacaine. In vivo studies are warranted investigating long-term effects of local anesthetics on equine articular cartilage.

Evaluation of Three Methods of Platelet-Rich Plasma for Treatment of Equine Distal Limb Skin Wounds.

Wounds localized on the distal limbs in horses are difficulty healing. No studies have been conducted to evaluate homologous platelet-rich plasma (PRP) in horses. The aim of this study was to evaluate the effect upon applying autologous PRP, homologous PRP, and autologous PRP gel on the wound healing process of wounds on the distal limb of horses. To study a possible correlation between the platelet count and wound healing time, four skin wounds of 4 cm2 were surgically created on the dorsolateral aspect of the third metacarpus in eight healthy adult horses. Each skin wound was randomly treated according to the established treatment groups (G): GI, treated with autologous PRP injection on the wound edges; GII treated topically with autologous PRP gel; and GIII homologous PRP injection on the wound edges and control group treated with saline solution injected on the wound edges. The animals were monitored every fifteen days throughout the wound healing process. The wound size was determined using a tape measure. Skin biopsies were obtained on the 15th and 30th day after the first PRP treatment. Autologous PRP gel treatment reduced the healing time in 15 days compared to the wounds of the control group. Histologically, GII presented a higher frequency of mild inflammation and mild to moderate neovascularization of biopsies 1 and 2. Platelet-rich plasma in gel form showed the best result on wound healing of the distal limb of horses in both clinical and histopathological evaluations. The homologous PRP is recommended for the recovery of animals with compromised hemodynamic conditions.

Cooling and Cryopreservation of Equine Platelet-Rich Plasma With Dimethyl Sulfoxide and Trehalose.

Equine platelet-rich plasma (PRP) has been used in horses to repair bone, articular and tendinous lesions, laminitis, and even endometritis. However, platelets have a very limited lifespan, which makes it difficult to prepare and use PRP, except in loco. With the aim to produce PRP with higher platelet viability for clinical purposes, the effects of the cryoprotectants dimethyl sulfoxide (DMSO) and trehalose were evaluated on cooled (4°C) and cryopreserved (-196°C) equine PRP. The protocols of cooling and cryopreservation were performed independently, comparing the following treatments: fresh PRP, PRP + 6% DMSO, PRP + 300 mM of trehalose, and PRP only. The PRP samples were prepared by double centrifugation of the blood of six ponies, further divided into four aliquots. The cooled or cryopreserved aliquots were stored for 14 days. All samples were evaluated for the platelet count, the mean platelet volume, and the release of transforming growth factor beta 1 (TGF-ß1). The number of platelets in the fresh PRP and cooled samples was similar; however, platelet count was higher in the fresh PRP than in cryopreserved samples. The release of TGF-ß1 was higher in the fresh PRP (105891 ± 52398 pg/mL), but the stored samples still released significant amounts of this growth factor (27291 ± 9625 pg/mL).

Equine acute erythroid leukemia / Leucemia eritroide aguda em equino

Acute erythroid leukemia (AML M6) is a hematopoietic neoplasm frequently described in cats and mice, rarely in other animal species. This report describes a case of AML M6 in a yearling Thoroughbred filly. Clinically the horse presented marked pale mucous membranes and exercise intolerance. In addition, the owner and referring veterinarian reported a 30-day history of progressive weight loss. The CBC revealed severe anemia and leukopenia by neutropenia. Cytology evaluation obtained from bone marrow fine needle aspirates evidenced inversion of the myeloid: erythroid ratio (0.2), with 48% of the nucleated cells corresponding to rubriblasts. In addition to the gross evidence of anemia, necropsy findings consisted of splenomegaly and lymphadenomegaly. The diagnosis of AML M6B was confirmed histologically due to splenomegaly and lymphadenomegaly, secondary to neoplastic metastasization.

Leucemia eritroide aguda (LMA M6) é um neoplasia hematopoiética descrita com frequência em gatos e camundongos, mas raramente nas demais espécies de animais. Esse relato descreve um caso dessa doença em um equino, fêmea, Puro Sangue Inglês de um ano de idade. Clinicamente, o equino apresentou acentuada palidez das mucosas, intolerância ao exercício e o proprietário relatava emagrecimento progressivo. No hemograma, foi observada anemia grave e leucopenia por neutropenia. No mielograma, havia inversão da relação mieloide:eritroide (0,2) e 48% das células nucleadas da medula óssea correspondiam a rubriblastos. Na necropsia, além de evidências de anemia, havia esplenomegalia e linfadenomegalia. O diagnóstico de LMA M6B foi confirmado histologicamente e o aumento do baço e dos linfonodos foi decorrente de metastatização.

Acute myonecrosis in horse caused by Clostridium novyi type A.

The objective of this study was to describe the first report involving a case of equine acute myonecrosis caused by C. novyi type A with an emphasis on clinical signs, the pathological and bacteriological analysis, and molecular identification of the microorganisms as the key of the definitive diagnosis.

Acute myonecrosis in horse caused by Clostridium novyi type A

The objective of this study was to describe the first report involving a case of equine acute myonecrosis caused by C. novyi type A with an emphasis on clinical signs, the pathological and bacteriological analysis, and molecular identification of the microorganisms as the key of the definitive diagnosis.

Claudicação em cavalos Crioulos atletas / Lameness in athletic Criollo horses

O objetivo deste trabalho foi identificar as principais causas de claudicação em cavalos Crioulos em treinamento para a prova do Freio de Ouro e competições de rédeas. Foram avaliados os registros clínicos de 201 cavalos Crioulos, 5,6 2,1 anos de idade, submetidos a exame físico devido à presença de claudicação ou histórico de baixo rendimento atlético entre os anos de 2002 a 2009. A claudicação foi localizada nos membros torácicos e pélvicos em 47,1 por cento (n=105) e 52,9 por cento (n=118), respectivamente. Nos machos, houve uma predominância de claudicação nos membros pélvicos (60,0 por cento) e nas fêmeas nos membros torácicos (57,1 por cento). Nos membros torácicos, 17,1 por cento (18/105) das alterações foram diagnosticadas proximais à articulação metacarpofalangeana, 14,3 por cento (15/105) na articulação metacarpofalangeana e 68,6 por cento (72/105) estavam localizadas distais à articulação metacarpofalangeana. Nos membros pélvicos, 78,8 por cento (93/118) apresentaram a origem da dor na região do tarso, 17,8 por cento (21/118) proximal ao tarso e 3,4 por cento (4/118) distal ao tarso. As articulações interfalangeanas distais e intertarsiana distal/tarsometatarsiana são importantes fontes de dor e inflamação e estiveram mais frequentemente envolvidas em claudicações de membro torácico e pélvico, respectivamente. Os cavalos Crioulos apresentam problemas de claudicação semelhantes aos descritos em outras raças que participam de provas de rodeio.

This study aimed to identify the source of lameness in Criollo horses that are competing in the most important discipline for this breed in Southern Brazil and also in reining competitions. Clinical records of adult Criollo horses (n=201), 5.6 2.1 years of age, that underwent lameness examination due to history of poor performance or lameness between 2002/2009 were analyzed. Lameness was diagnosed in the front limbs in 47.1 percent (n=105) and in the hind limbs 52.9 percent of the cases (n=118). In males 60.0 percent of the lameness cases were located in the hind limbs. In females 57.1 percent of the lameness cases were located in the front limbs. In the front limbs (47.1 percent, n=105/201), problems proximal to the fetlock were diagnosed in 17.1 percent (18/105). Fetlock problems were diagnosed in 14.3 percent (15/105) and lesions located distal to the fetlock level were seen in 68.6 percent (72/105) of the lameness cases diagnosed in the front limbs. In the hind limbs, problems located proximal to the tarsus were seen in 17.8 percent (21/118), 78.8 percent (93/118) in the tarsus and 3.4 percent (4/118) of the cases were seen distal to the tarsus. The distal interfalangeal joint in the front limbs and the distal tarsal joints in the hind limbs were the two most important sources of lameness. Criollo horses presented similar lameness problems as described in other show horses (reining, cutting and roping). This is the first lameness study done in Criollo horses and it will help to better understand the musculoskeletal diseases affecting this breed.

Epidural analgesia with morphine or buprenorphine in ponies with lipopolysaccharide (LPS)-induced carpal synovitis.

This study evaluated the analgesia effects of the epidural administration of 0.1 mg/kg bodyweight (BW) of morphine or 5 µg/kg BW of buprenorphine in ponies with radiocarpal joint synovitis. Six ponies were submitted to 3 epidural treatments: the control group (C) received 0.15 mL/kg BW of a 0.9% sodium chloride (NaCl) solution; group M was administered 0.1 mg/kg BW of morphine; and group B was administered 5 µg/kg BW of buprenorphine, both diluted in 0.9% NaCl to a total volume of 0.15 mL/kg BW administered epidurally at 10 s/mL. The synovitis model was induced by injecting 0.5 ng of lipopolysaccharide (LPS) in the left or right radiocarpal joint. An epidural catheter was later introduced in the lumbosacral space and advanced up to the thoracolumbar level. The treatment started 6 h after synovitis induction. Lameness, maximum angle of carpal flexion, heart rate, systolic arterial pressure, respiratory rate, temperature, and intestinal motility were evaluated before LPS injection (baseline), 6 h after LPS injection (time 0), and 0.5, 1, 2, 4, 6, 8, 10, 12, 16, 20, and 24 h after treatments. Although the model of synovitis produced clear clinical signs of inflammation, the lameness scores in group C were different from the baseline for only up to 12 h. Both morphine and buprenorphine showed a reduction in the degree of lameness starting at 0.5 and 6 h, respectively. Reduced intestinal motility was observed at 0.5 h in group M and at 0.5 to 1 h in group B. Epidural morphine was a more effective analgesic that lasted for more than 12 h and without side effects. It was concluded that morphine would be a valuable analgesic option to alleviate joint pain in the thoracic limbs in ponies.

Cortisol, resposta glicêmica e secreção de insulina em equinos clinicamente sadios submetidos a sessões de hipóxia normobárica / Serum cortisol, glycemic response and insulin secretion in healthy horses exposed to normobaric hypoxia sessions

Os níveis séricos de cortisol, resposta glicêmica e secreção de insulina foram avaliados em equinos não exercitados submetidos a sessões de hipóxia normobárica. Cavalos adultos sadios (n=8) foram selecionados após exame físico e submetidos ao teste de tolerância à glicose intravenosa (0,5g kg-1) (TTGIV). Amostras de sangue (n=11) foram coletadas entre 0 e 180 minutos após a administração de glicose para avaliar a resposta glicêmica e a secreção de insulina. Os animais foram então expostos a sessões de uma hora de hipóxia duas vezes ao dia, totalizando 43 sessões, com concentração decrescente de O2 de 17 a 12 por cento. A frequência cardíaca e as amostras sanguíneas para a determinação do cortisol sérico foram coletadas antes e a cada 15 minutos durante as sessões 1, 4, 6, 8, 10, 14, 22 e 43. A TTGIV foi repetida ao final do estudo. Os níveis de cortisol sérico foram maiores na sessão 1 (S1) (17 por cento O2) quando comparados aos níveis da S10 (13 por cento O2) e da S43 (12 por cento O2)(P<0,05). A curva glicêmica de equinos clinicamente sadios não submetidos a exercício não é alterada pela exposição a 43 sessões de hipóxia normobárica. O aumento na secreção de insulina, acompanhada de diminuição da frequência cardíaca e cortisol sérico sugerem uma adaptação dos cavalos ao modelo de hipóxia utilizado.

The cortisol levels, glycemic response and insulin secretion were evaluated in non-exercised horses submitted to sessions of normobaric hypoxia. Healthy adult horses (n=8) were selected after physical examination and underwent an intravenous glucose tolerance test (0.5g kg-1) (IVGTT). Blood samples (n=11) were collected between 0 and 180 minutes after glucose administration to evaluate glycemic response and insulin secretion. Then, they were exposed to 1-hour hypoxia sessions twice a day, reaching a total of 43 hypoxia sessions, with [O2] decreasing from 17 to 12 percent. Heart rate and serum samples to measure cortisol were collected before and every 15 minutes during the sessions 1, 4, 6, 8, 10, 14, 22 and 43. The IVGTT was repeated at the end of the study. The serum cortisol levels were higher in session 1 (S1) (17 percent O2) when compared to the levels of S10 (13 percent O2) and S43 (12 percent O2) (P<0.05). The glycemic curve in resting healthy horses is not altered by exposure to 43 normobaric hypoxia sessions. The increase in insulin secretion, followed by decreased heart rate and serum cortisol suggest an adaptation of the horses to the hypoxia model used.

Osteocondrose de articulação fêmoro-tíbio-patelar em potro da raça Crioula / Stifle joint osteochondrosis in a Criollo foal

Um potro da raça crioula, com dois anos de idade, foi encaminhado ao Hospital Veterinário da Universidade Federal de Santa Maria (UFSM) apresentando aumento de volume na região da patela esquerda e claudicação manifestada ao trote. Os exames físico e radiográfico identificaram a presença de uma lesão envolvendo o osso subcondral na tróclea lateral do fêmur, característica de uma osteocondrose. Trata-se do primeiro relato de osteocondrose em um potro da raça Crioula.

A two-year-old Criollo foal was referred to the Veterinary Teaching Hospital of the UFSM presenting joint effusion on the left stifle joint. Physical and radiographic examination revealed the presence of osteochondreal fragmentation located at the lateral throclea ridge of the femur characterizing osteochondrosis in the stifle joint.

Harpejamento em eqüinos no Rio Grande do Sul / Stringhalt in horses from the state of Rio Grande do Sul, Brazil

São relatados a epidemiologia, os sinais clínicos e aspectos macro e microscópicos de casos de harpejamento ocorridos de 2000 a 2005 em eqüinos de oito propriedades rurais de seis municípios do Rio Grande do Sul. Pelo menos 10 eqüinos foram afetados, com idades variando entre 1 e 13 anos (média de 6,2 anos) e 1-2 eqüinos foram afetados por propriedade. Dentre os fatores que podem ter influenciado o aparecimento da doença está incluída a escassez de forragem devido à seca. A presença da planta Hypochaeris radicata, freqüentemente implicada como causa de harpejamento em eqüinos, foi observada na pastagem de três entre cinco propriedades onde a ocorrência dessa planta foi investigada; em seis dessas propriedades a forragem era pouca devido à falta de chuva. A morbidade foi estimada em 17,3 por cento e a letalidade foi perto de zero, embora dois eqüinos tenham sido submetidos à eutanásia para serem necropsiados. Os sinais clínicos característicos incluiam hiperflexão dos membros pélvicos, dificuldade de caminhar e andar com saltos tipo pulos de coelho. Foi feita uma graduação da intensidade dos sinais clínicos em um escore de números de 1 a 5, os números mais altos indicando um grau de intensidade maior. Três eqüinos foram graduados como 1, um eqüino como 2, três eqüinos como 3, um eqüino como 4 e dois eqüinos como 5. O tratamento com fenitoína em dois eqüinos e com fenitoína associada a tenectomia em um outro não resultou em melhora do quadro clínico. Quatro dos 10 cavalos com harpejamento examinados clinicamente se recuperaram sem tratamento após uma doença clínica com evolução de 2-4 meses e quatro cavalos não se recuperaram mesmo após 9-17 meses de doença clínica, quando foram examinados pela última vez. Os achados de necropsia incluíam atrofia dos músculos esqueléticos das grandes massas musculares, confirmada histologicamente. A avaliação histológica dos nervos periféricos de um eqüino afetado submetido à eutanásia revelou redução ou ausência ...

The epidemiology, clinical, gross and histological findings of cases of stringhalt occurring in horses from eight farms in six counties in the State of Rio Grande do Sul, Brazil from 2000-2005 are reported. At least 10 horses were affected. Ages of affected horses were 1-13 years (average 6.2 years) and 1-2 horses were affected in each farm. Factors that might have influenced the appearance of the disease included dearth of forage due to insufficient rainfall. The presence of the plant Hypochaeris radicata, often implicated as a cause of stringhalt in horses, was observed in the pasture of three out of five evaluated farms and in six of these farms the pasture was poor due to scarse precipitation. Estimated morbidity was 17.3 percent and lethality was close to zero although two horses were euthanatized for necropsy. Characteristic clinical signs included excessive flexion of the stifle and hock joints, impaired ambulation and bunny hop-type of gait. Clinical disease was graded by number scores from 1-5, higher numbers indicating increasing severity. Three horses were graded as 1, one horse as 2, three horses as 3, one horse as 4 and two horses as 5. Treatment with phenytoin in two horses and with phenytoin and tenectomy in another one did not result in amelioration of the clinical signs. Four out of ten clinical examined horses with stringhalt recovered with no treatment within 2-4 months of clinical disease and four affected horses did not recover even after 9-17 months of clinical disease, when they were lastly examined. Necropsy findings included atrophy of skeletal muscle of the large muscular groups which was confirmed histologically. Histological evaluation of peripheral nerves of one of the euthanatized horses revealed reduction or absence of myelinated fibers. Ultrastructural findings included signs of demyelination, regeneration and remyelination of peripheral nerves.

Exame clínico e radiológico do terceiro metacarpeano em potros Puro Sangue de Corrida em treinamento / Clinical and radiographic evaluation of the third metacarpal bone in 2-year-old thoroughbred horses in raining

A avaliação clínica e radiológica do terceiro metacarpeano (McIII) de 42 potros Puro Sangue de Corrida de dois anos de idade, em treinamento, realizou-se a cada 15 dias. Vinte e cinco potros foram acompanhados durante dois meses e 17 durante os quatro meses anteriores a sua participação na primeira corrida. Nas radiografias (projeção lateromedial), foram avaliadas o córtex dorsal (CD) do McIII e a espessura do CD, do córtex palmar e da zona medular para determinação do índice radiológico (IR). Não foram observadas alterações radiológicas no CD do McIII nos potros que manifestaram periostite metacarpeana dorsal (PM) aguda. O aumento tanto do CD, como do IR, entre as avaliações foi significativo (P<0,05). Porém, apenas a diferença de espessura do CD entre os McIII sem alterações e os que manifestaram PM foi significativa (P<0,05). O aumento mais acentuado do CD foi observado sempre na avaliação anterior àquela em que foram detectados os sinais clínicos de PM. Portanto, especialmente a mensuração do CD pode ser utilizada como um método diagnóstico precoce de PM, permitindo a sua prevenção.

The third metacarpal bones (McIII) of 42 2-year-old thoroughbreds in training were evaluated clinically and radiologically every 15 days. The evaluation was performed during 2 and 4 month, prior to the first race of 25 and17 horses, respectively. X-rays were taken using latero-medial projection. Dorsal cortex (DC) was evaluated on the X-rays and DC, palmar cortex and medular zone were measured in order to determine the radiologic index (RI). No radiographic changes were observed on the DC of the McIII of horses clinically affected by dorsal metacarpal disease (DMD). There was a significant increase (P<0.05) in DC thickness and RI between evaluations of both, healthy and DMD affected McIII. DC thickness also showed a significant increase between affected and not affected McIII. A larger increase in DC thickness was observed at evaluation before the one in which DMD was diagnosed. In conclusion, the increase in DC thickness could be used as a diagnostic tool for early recognition of DMD allowing adoption of preventive measures.

Fechamento das placas epifisárias do metacarpiano principal, do rádio e da tíbia em potros Crioulos / Closure time of the epiphyseal plates in the third metacarpus, radius and tibia in Criollo foals

Com o objetivo de determinar a idade do fechamento das placas de crescimento dos ossos longos, foram usados 92 potros da raça crioula com idades entre 6 a 29 meses, machos e fêmeas, provenientes de cinco criatórios diferentes. Foram radiografadas as placas epifisárias distais do terceiro metacarpiano, do rádio e da tíbia. A imagem radiográfica foi classificada quanto ao fechamento em: visível, parcialmente visível ou não visível. Foram avaliados a influência do sexo, da propriedade e do regime nutricional sobre o fechamento da placa epifisária. Observou-se que, aos sete meses de idade, a placa epifisária do metacarpiano principal já não era visível. A placa epifisária distal da tíbia não foi possível de ser identificada aos 23 meses. Na porção distal do rádio, a placa epifisária esteve visível até os 25 meses de idade. Os resultados deste estudo comprovam que o período de fechamento da placa epifisária dos ossos metacarpiano principal, rádio e tíbia de potros crioulos se assemelha ao descrito em outras raças.

Aiming at documenting the closure of the physeal plates of the long bones, 92 Criollo foals, males and females, between 6 and 29 months of age, were used in this study. Dorsopalmar radiographs were taken from the distal portion of the radius, 3rd metacarpal bone and tibia. The radiographic image of the growth plate was classified as visible, partially visible or not visible. At 7 months of age the growth plate of the 3rd metacarpal bone was no longer visible. In the distal physis of the tibia the growth plate was no longer visible at 23 months and at 25 months of age in the radius. The results of this study show that period of closure of the physeal plates of the main metacaopal bone, the radius and tibia is similar to the some described in other breeds.

Periostite metacarpiana dorsal: incidência e fatores pré-disponentes / Dorsal metacarpal disease: incidence and predisposing factors

Quarenta e dois potros Puro Sangue de Corrida, de 2 anos de idade, foram acompanhados clinicamente a cada 15 dias, durante o treinamento para sua primeira corrida, para determinar a incidência e possíveis fatores pré-disponentes da periostite metacarpiana dorsal. Durante dois meses no primeiro ano (n=25) e quatro meses (n=17) no segundo ano em que foi realizado o acompanhamento dos potros eles foram submetidos a exames físicos para a identificação de sinais clínicos de periostite metacarpiana dorsal. Dados como sexo, velocidade média, distância dos exercícios de velocidade e treinador foram tabulados. No primeiro ano 28% dos potros manifestaram periostite metacarpiana dorsal e no segundo ano este índice foi de 70,6%. Considerando-se todo o periodo de estudo a incidência foi de 45%. Não houve diferença entre os sexos na manifestação de periostite metacarpiana e velocidade média alcançada. A velocidade média desenvolvida pelos potros que permaneceram sadios e dos que apresentaram periostite metacarpiana se manteve entre 16 e 18 m/s. Nos 500 e 700m a velocidade média dos animais com periostite metacarpiana foi maior (p<0,05). A periostite metacarpiana se manifestou em 10 de 19 potros na distância de 700 m. Houve diferença na incidência de periostite metacarpiana e velocidade média atingida pelos potros de acordo com o treinador. Os potros treinados pelos treinadores que apresentaram maior incidência de periostite metacarpiana foram os mais rápidos. Portanto, fatores que favoreceram a manifestação de periostite metacarpiana foram velocidade média elevada sobre distâncias maiores como os 700m e regime de treinamento preconizado pelos diferentes treinadores.

Forty two 2-year-old thoroughbreds were examined clinically at intervals of 15 days during their training for the flrst race to determine the incidence and the predisposing factors of dorsal metacarpal disease. During the flrst year 25 horses were followed during 2 months and in the second year the follow up was done for 4 months in 17. Horses' data like gender, average speed, speed exercise work and trainer were also collected. Dorsal metacarpal disease was diagnosed in 28% and 70,6% of the 2 year-old thoroughbreds in the flrst and second year of the study, respectively. Total incidence was 45%. The incidence and average speed was not affected by gender. The average speed achieved by affected and none affected horses remained between 16 and 18m/ s. On 500 and 700m speed exercise, the average speed of affected horses was higher than of none affected ones (p<0,05). Ten out of 19 horses showed dorsal metacarpal disease signs at the distance of 700m. There was signiflcant difference between trainers regarding the incidence of dorsal metacarpal disease and average speed of their horses. 2-year-olds under care of trainers whose horses had the highest incidence o dorsal metacarpal disease also were the fastest one's. Therefore, fast speed associated with longer distances (700m) and trainer are factors that predispose young horses to dorsal metacarpal disease.

Inheritance of recurrent exertional rhabdomyolysis in thoroughbreds.

OBJECTIVE: To develop a diagnostic test for recurrent exertional rhabdomyolysis (RER) in Thoroughbreds that relied on in vitro contracture of muscle biopsy specimens and determine whether the inheritance pattern of RER diagnosed on the basis of this contracture test was consistent with an autosomal dominant trait. DESIGN: Clinical trial. ANIMALS: 8 adult horses with RER and 16 control adult horses for development of the contracture test; 23 foals for inheritance of RER. PROCEDURE: External intercostal muscle biopsy specimens from the 24 adult horses were tested for contracture in response to halothane and caffeine, and criteria for a positive test result were determined. These criteria were then applied to results for the 23 foals to determine whether they had RER. Simple segregation analysis was performed to determine whether results were consistent with a dominant pattern of inheritance. RESULTS: Results of the contracture test were positive for 5 of the 12 colts and 4 of the 11 fillies. Results of segregation analysis were consistent with an auto-. somal dominant pattern of inheritance. Two sires with RER produced colts with RER, supporting the hypothesis that RER had an autosomal, rather than an X-linked, inheritance pattern. In addition, in 1 instance, an unaffected colt was produced by 2 affected parents, which was not consistent with a recessive mode of inheritance. CONCLUSIONS AND CLINICAL RELEVANCE: Although the expression of the RER trait is influenced by sex, temperament, and diet, among other factors, results from the in vitro muscle contracture test and this breeding trial suggest that RER in Thoroughbreds can be modeled as a genetic trait with an autosomal dominant pattern of inheritance.

Relevância da ultra-sonografia dos tendões flexores em cavalos Puro Sangue de corrida na adaptação ao treinamento / Significance of flexor tendon ultrasonography in training thoroughbred horses

Vinte e quatro potros Puro Sangue de Corrida (PSC), com dois anos de idade foram avaliados ultra-sonograficamente, durante o período final da doma e início de treinamento, através da imagem transversal dos tendões flexor digital superficial (TFDS) e profundo (TFDP). As avaliações foram realizadas com intervalos de 15 dias. A área transversal (AT), a textura dos ecos e a ecogenicidade dos tendões foram avaliadas nas sete zonas da região metacarpiana através de um programa de mensuração de imagens do próprio aparelho de ultra-sonografia. Durante a doma e treinamento, houve diminuição da AT na zona IA e IIIA (P<0,05, f=0,001 e 0,0266 resp.) e aumento da zona IIIC (P< 0,05 f=0,0391) do TFDS. Ao considerar apenas o período do treinamento, o resultado foi semelhante (P<0,05) na zona IA (f=0,010), IIIA (f=0,023) e IIIC (f =0,0391). O TFDP apresentou uma diminuição na AT durante a doma e treinamento nas zonas IA, IIIA e IIIB (P<0,05, f=0,027; f=0,0001 e f=0,0031 resp.) e nas zonas IA e IIIA durante o treinamento (P<0,05, f=0,006 e f=0,006, resp.). No período da doma, a AT do TFDP não variou significativamente. A textura dos ecos se manteve homogênea e não houve variação significativa na ecogenicidade dos tendões entre o período da doma e após quatro meses de treinamento. A avaliação quinzenal da AT indicou uma adaptação diferente entre as zonas ultrasonográficas dos TFDS e TFDP. A textura e ecogenicidade das zonas IA a IIIC dos TFDS e TFDP não apresentaram variações ultra-sonográficas que sugerissem adaptação ao regime de exercício ao qual os potros PSC estavam sendo submetidos. A ultrasonografia não é o método mais indicado para acompanhamento da adaptação dos TFDS e TFDP em potros PSC em treinamento.