Risk factors for dystocia in farmed red deer (Cervus elaphus).

OBJECTIVE: To analyse data from a study of deer herd health and productivity to identify potential risk factors for the occurrence of dystocia. DESIGN: A 2-year longitudinal observational study of 14 red deer farms was carried out in New Zealand. About 2700 hinds were monitored each year for individual characteristics including body condition score (BCS), and reproductive performance. Grazing and calving management practices were recorded. During calving, farmers recorded calving difficulties (dystocia) that needed human assistance or caused the death of the hind. Risk factors potentially affecting the occurrence of dystocia were identified and analysed by multivariable statistical techniques. RESULTS: The percentage of hinds with dystocia was 0.52% (95% CI 0.32 to 0.78). Hinds with a post-winter BCS over 3.5 were 2.7 times as likely to experience dystocia as hinds scoring 3.5 or less. Given the same BCS class, bodyweight gain in late pregnancy was associated with an increased risk of dystocia. Grazing steep paddocks in the last trimester of pregnancy decreased the risk of dystocia in hinds with a BCS over 3.5. CONCLUSIONS: The risk of dystocia on red deer farms may be reduced if key individual animal, management and environmental factors are optimal.     

Canine lymphoid leukaemia and lymphoma with bone marrow involvement: A review of 24 cases

Eleven cases of canine lymphoid leukaemia (10 acute and one chronic) were compared with 13 cases of canine lymphoma with bone marrow abnormalities, with regard to presentation, treatment and survival. Breed, age, and sex were similar for the two groups of dogs, but there was a marked difference in presenting signs, haematological parameters and bone marrow analysis, with the leukaemic dogs showing more severe changes. The clinicopathological features of these cases are reported in this paper and discussed with regard to prognosis. The mean survival time was significantly lower (43 days) in dogs treated for acute lymphoblastic leukaemia than for dogs treated for lymphoma with bone marrow abnormalities (351 days).     

The use of sports medicine techniques in evaluating the problem equine athlete

Discovering the cause of poor performance in racehorses can often represent a considerable challenge eluding the more common diagnostic techniques available at the racetrack. Application of sports medicine techniques to these problem cases can aid in the diagnosis of poor performance. Central to the development of this capability has been the use of highspeed treadmills, allowing the racehorse to be evaluated in the controlled laboratory setting, at exercise intensities equivalent to those of racing. Video and cinematographic gait analysis can be used in the diagnosis of subtle lameness conditions. Evaluating hoof balance at high speed has also become an important technique for both lameness diagnosis and prevention. Correcting hoof imbalance normalizes the applied stresses on joints, ligaments, and tendons. Abnormal upper airway function resulting in increased resistance to airflow is major cause of poor racing performance. Often this cause of upper airway dysfunction is difficult to evaluate at rest or after exercise. A definitive diagnosis can be made in these cases using treadmill endoscopy to visualize upper airway function during peak exercise. Lower airway function can also affect performance capability. Radiographic and scintigraphic imaging modalities can be used to evaluate both global and regional lung function in cases of suspected pneumonia, EIPH, COPD, or emphysema. Reduced metabolic fitness can be a primary cause of poor performance due to inherent differences in capability, pathologic changes in the major body systems involved in exercise, or inadequate training. Metabolic stress testing can be used to evaluate the level of fitness in these cases. Orthopedic imaging has also become a valuable diagnostic technique for evaluating musculoskeletal injuries. Scintigraphic evaluation of soft tissue and bone and CT scanning are used to localize the source of lameness and to grade the severity of various orthopedic conditions such as arthritis and stress-induced bone disease that are often difficult to categorize with conventional radiography.     

Effect of diet on Heinz body formation in kittens

Heinz body formation was examined in kittens, in response to consumption of a variety of diets. A commercial salmon-based diet containing 16.5 mg of nitrite, 39 mg of histamine, and 210,000 IU of vitamin A/kg of diet (dry-matter basis) was found to induce Heinz body formation. Purified experimental diets--containing nitrite up to 405 mg/kg; histamine, 50 mg/kg; histamine 50 mg/kg plus nitrite, 45 mg/kg; or vitamin A, 250,000 IU/kg--failed to induce Heinz body formation. The effect of propylene glycol (PG) on Heinz body formation was examined by giving groups of 6 kittens purified diets containing 5 or 10% PG for 12 weeks. Two additional kittens were fed a commercial soft-moist diet containing PG for 12 weeks. All kittens fed PG developed Heinz bodies, with peak values for erythrocytes containing Heinz bodies being: 28% for kittens of the 10% PG group; 20% for kittens of the 5% PG group; and 36% for kittens of the soft-moist diet group. Kittens did not develop anemia or methemoglobinemia. Heinz body percentage required 6 to 8 weeks to decrease to the pretreatment value of less than 1% after diets containing PG were discontinued. 51Chromium-labeled erythrocytes were used to evaluate erythrocyte survival in 4 kittens of the 10% PG-fed group and in 4 control kittens. Kittens with Heinz body formation induced by 10% PG had significantly (P less than 0.001) decreased erythrocyte-survival, compared with that for controls, with half-life of 8.3 days for kittens of the PG group, compared with 12.6 days for kittens of the control group.     

Experiments with the Cornell intermittent lighting system for laying hens

1. Two experiments were conducted to provide further evidence about rate of lay under the Cornell lighting system (2L:4D:8L:10D). Each used 1728 hens of each of 2 brown-egg stocks in 12 light-proof rooms. 2. In the first the Cornell system was compared at 2 light intensities (average values 2 and 10 lux) with a conventional step up lighting programme. In the second, Cornell lighting was introduced at 18, 21 or 24 weeks of age and compared with a step up programme. 3. Total egg output was essentially the same from the Cornell lighting system, using 10 h light/d, as from the step up programme using 16 h/d. When the Cornell system was applied abruptly at 18 weeks to pullets which had been reared on short days (8L:16D) sexual maturity was advanced, resulting in an increase in mean rate of lay to 72 weeks of age and a reduction in mean egg size. Application of the Cornell system from 21 or 24 weeks gave the same egg numbers and the same egg size as the step up programme. 4. Food intake was about 2% lower with the Cornell treatment in both experiments. Although this difference was not quite significant in either, it probably reflects a real effect of the reduced hours of light. It represents a greater potential cost saving than the reduced electricity consumption. 5. Birds in rooms with an average light intensity of 2 lux laid slightly fewer eggs but their eggs were 0.5 g heavier than those laid in rooms maintained at 10 lux. There were no interactions between light intensity and light pattern or between stocks and light pattern.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of diet on struvite activity product in feline urine

Groups of male specific-pathogen-free cats were fed a basal, purified diet (A), with or without 0.45% added magnesium (MgCl2, diet B; MgO, diet C) or 1 of 2 commercial diets (D,E). Urine samples collected for 48 hours after 2 weeks of feeding were analyzed for calcium, magnesium, sodium, potassium, ammonium, sulfate, phosphate, oxalate, and citrate content. Concentrations were used to calculate the negative logarithm of the struvite activity product (pSAP), using a microcomputer-based program for calculation of supersaturation of the urine with crystal solutes. The pSAP value for all samples also was hand-calculated by use of an equation. Consumption of diet B caused a significant (P less than 0.05) increase in urine calcium concentration. Total urine phosphate concentration was lower in urine from cats fed diets A, B, or C than in urine from cats fed diets D or E. For the various diets, urine PO4(-3) was: 5.3 microM for diet A; 6.3 microM for diet C; 0.9 microM for diet E; 36 nM for diet D, and 0.5 nM for diet B. Consumption of diets B and C caused significant increases in urine magnesium concentration (53.1 nM and 49.1 mM, respectively). Ammonium ion concentration was highest in urine from cats fed diets B and D, 116.2 mM and 100.3 mM, respectively. When the pSAP, hand-calculated assuming ionic strength u = 0.2, was regressed on that calculated by use of the microcomputer program, the coefficient of determination was 0.96 (P less than or equal to 0.01).     

Dexamethasone reduces endotoxin-induced tumor necrosis factor activity production in vitro by equine peritoneal macrophages

This study evaluated the effect of dexamethasone on endotoxin-induced production of tumor necrosis factor (TNF) activity in vitro by equine peritoneal macrophages. Peritoneal macrophages from adult horses were cultured in the presence of dexamethasone (1-100 microM) for various time periods (2 hour, 0.5 hour, 0 hour) prior to the addition of endotoxin (5 ng/ml), then the secretion of TNF activity was evaluated. Macrophage supernatant concentrations of TNF activity were estimated by a modified in vitro cytotoxicity bioassay using the murine fibrosarcoma cell line, WEHI 164 clone 13. An experiment was performed to determine whether dexamethasone interfered with the cytolytic bioassay's ability to detect TNF activity. The endotoxin-induced TNF activity production by equine peritoneal macrophages was significantly reduced by co-incubation with 100 microM dexamethasone, but not by tested concentrations of dexamethasone less than 100 microM. This concentration of dexamethasone greatly exceeds those generally attained by therapeutic use of dexamethasone in horses. Preincubation time did not affect the ability of 100 microM dexamethasone to reduce TNF production by equine macrophages. The quantitation of equine TNF activity by its cytolytic bioassay was not altered by dexamethasone.     

Eosinophilic myeloproliferative disorder in a horse

An eosinophilic myeloproliferative disorder resulted in edema and hemorrhagic diathesis in a 10-month-old Standardbred colt. Laboratory abnormalities included severe thrombocytopenia, anemia, mild hypoproteinemia, and marked eosinophilia. Circulating eosinophils were immature or atypical with variation in granule size, disproportionate nuclear to cytoplasmic maturation, and abnormal nuclear size and shape. Bone marrow aspirate had mainly atypical eosinophil precursors, few erythroid precursors, and no megakaryocytes. A blood transfusion and dexamethasone therapy resulted in some improvement; however, the horse was euthanatized due to poor prognosis. Postmortem examination showed gastrointestinal parasitism; histologically the spleen was infiltrated by atypical eosinophils and there were sites of eosinophilopoiesis. The disease was broadly similar to idiopathic hypereosinophilic syndrome in people, but typical cardiac and neurologic involvement of hypereosinophilic syndrome were absent. Progressive myelophthesis and marked eosinophil atypia suggested malignancy.