Cardiopulmonary effects of xylazine and acepromazine in pregnant cows in late gestation

OBJECTIVE: To determine effects of sedation achieved by xylazine (XYL) or acepromazine (ACE) on cardiopulmonary function and uterine blood flow in cows in late gestation. ANIMALS: 8 cows between 219 and 241 days of gestation. PROCEDURE: Doses of ACE (0.02 mg/kg) or XYL (0.04 mg/kg) were administered IV. Measurements were obtained to determine cardiopulmonary effects and oxygen delivery to the uterus. RESULTS: Heart rate was not significantly affected by administration of ACE, but it decreased markedly after administration of XYL. Uterine artery flow was decreased at all times by XYL and was always less than for ACE. Xylazine increased uterine vascular resistance through 30 minutes and caused reduced PaO2 and increased PaCO2 at all time periods. Acepromazine caused a 5% decrease in PaO2 only at 5 minutes. Xylazine reduced oxygen delivery by 59% at 5 minutes and 32% at 45 minutes. In contrast, ACE caused a nonsignificant reduction of oxygen delivery by 16% at 15 minutes and a return to baseline values by 45 minutes CONCLUSIONS AND CLINICAL RELEVANCE: Xylazine markedly reduces flow and availability of oxygenated blood to the uterus, which may critically impair delivery of oxygen to the fetus at a stressful and important time of development or delivery. Acepromazine was associated with slight reductions of much shorter duration. When XYL is used to sedate pregnant cows, it could impose physiologic distress on the fetus and potentially increase fetal morbidity and mortality. When sedation of the dam is desirable, ACE could be an alternative to XYL.     

Conservative management of minimally displaced radial fractures in three horses

Minimally displaced, spiral, radial fractures were diagnosed in three adult horses. Two horses had open fractures and in one horse the fracture was closed. A diagnosis was made on radiographs taken 24 h, 5, and 9 days after the fracture. There was minimal displacement of the fracture fragments despite the considerable time which had elapsed between fracture and diagnosis and an unfavourable prognosis with internal fixation, so conservative therapy was the preferred method of treatment. One horse developed a sequestrum and draining sinus, which was treated surgically under general anaesthesia 3 months after diagnosis of the fracture. Other complications were minimal and transient. Two horses were being used for pleasure riding 12 months after fracture and one horse was pasture sound at 8 months.     

Granulomatous enteritis in a thoroughbred horse

A case of granulomatous enteritis in a three-year-old thoroughbred horse is described. Onset of clinical signs succeeded pyrexia of unknown aetiology. The horse was emaciated, depressed and inappetent but diarrhoea was not a feature of the condition. There was hypoproteinaemia, anaemia, leucopaenia and abnormal small-intestinal carbohydrate absorption. Rectal biopsy revealed granulomatous changes in the rectal mucosa. As a result of these findings, euthanasia was performed and an autopsy was carried out. Histopathology showed marked villous atrophy in the small intestine with a diffuse mononuclear cellular infiltration involving mainly the submucosa and lamina propria. There were occasional granulomatous foci. The mononuclear cells consisted mainly of lymphocytes and histiocytes. No aetiological agent was isolated.     

Diagnosis of bacterial infections. Part 2: Bacterial cultivation,susceptibility testing and interpretation

Bacterial culture and susceptibility testing are requested frequently in equine medicine. However, there is little value in these tests unless a standardised approach for submission of specimens, pathogen identification and susceptibility testing is utilised. Additionally, appropriate interpretation must be applied when assessing the significance of the isolate and susceptibility testing results if appropriate therapies are to be prescribed. In this paper we briefly outline standard techniques used commonly in veterinary diagnostic laboratories for bacterial isolation, identification and susceptibility testing. Emphasis has been placed on the principles appropriate to ensure the correct interpretation of culture and susceptibility testing results.     

LOW-FIELD MRI AND ARTHROSCOPY OF MENISCAL LESIONS IN TEN DOGS WITH EXPERIMENTALLY INDUCED CRANIAL CRUCIATE LIGAMENT INSUFFICIENCY

Little is known about the magnetic resonance imaging (MRI) appearance of canine meniscal lesions. The aim of this study is to describe the MR appearance of meniscal lesions in dogs with experimentally induced cranial cruciate ligament (CCL) deficiency. The pilot study revealed dogs weighing approximately 10 kg to be too small for meniscal evaluation on low-field MRI. In the main study, dogs weighing approximately 35 kg were used. The left CCL was transected and low-field MRI was performed regularly until 13 months post-surgery. Normal menisci were defined as grade 0. Intrameniscal lesions not reaching any surface corresponded to grade 1 if focal and to grade 2 if linear or diffuse. Grade 3 lesions consisted in linear tears penetrating a meniscal surface. Grade 4 lesions included complex signal changes or meniscal distortion. Between 2 and 13 months post-surgery, all dogs developed grade 4 lesions in the medial meniscus. Most of them corresponded to longitudinal or bucket handle tears on arthroscopy and necropsy. Two dogs showed grade 3 lesions reaching the tibial surface of the lateral meniscus on MRI but not in arthroscopy. Such tears are difficult to evaluate arthroscopically; MRI provides more accurate information about the tibial meniscal surface. Grades 1 and 2 lesions could not be differentiated from presumably normal menisci with our imaging technique. An MRI grading system better adapted to canine lesions has yet to be developed. MRI is a helpful tool for the diagnosis of complete tears in the canine meniscus, especially in larger dogs.