Osteosarcoma in the proximal humerus of a mare

A 15‐year‐old Quarter Horse mare was examined for significant and progressive lameness in the right front limb. On physical examination, muscle atrophy over the scapular and pectoral regions were noted. A pain response was elicited on palpation of the scapulohumeral joint. No other abnormalities were noted on examination of the limb. Diagnostic nerve blocks ruled out a source of lameness in the distal limb. Arthrocentesis of the scapulohumeral joint was performed and results were within normal limits. Radiographs of the right scapulohumeral joint revealed an extensive, aggressive bone lesion in the proximal humerus, suspected to be an osteosarcoma. After a course of nonsteroidal anti‐inflammatory therapy, minimal improvement to the lameness was noted. The owner elected to subject the horse to euthanasia due to the lack of significant response to treatment. Post mortem radiographic and histological examinations determined a definitive diagnosis of an osteosarcoma in the proximal humerus.     

Paranasal sinus cyst as a cause of stridor in a standardbred colt.

Sinus cysts are epithelium-lined, fluid-filled cavities that can occur in the paranasal sinuses of horses. Extensive damage to the permanent tooth buds was a significant feature in this case. The sequellae of these abnormalities, although not apparent at the time of presentation, remain an important consideration for prognosis.     

肉用仔公鸡饲料中甜菜碱对DL-蛋氨酸取代效应的研究

本试验用2400只肉用仔公鸡研究了DL-蛋氨酸和甜菜碱对1到38日龄期间生长性能和对384只肉用仔公鸡胴体的影响。三个剂量水平(0,0.05％和0.10％)的DL-蛋氨酸和两个剂量水平(0和0.04％)的甜菜碱分别组合,添加到在无蛋氨酸日粮中。雏鸡和生长鸡饲喂玉米-豆粕型日粮或具有荷兰肉鸡工业特点的试验饲粮。所有饲粮都添加胆碱,以避免缺乏含硫氨基酸。 提高蛋氨酸的添加量能显著提高肉用仔公鸡的日增重和饲粮转化率。添加甜菜碱没有影响肉用仔公鸡的生长。甜菜碱明显地提高了没有添加DL-蛋氨酸饲粮的转化率,但对添加DL-蛋氨酸饲粮的转化率效率却没有影响。添加0.05％DL-蛋氨酸的饲粮将胸肉产量提高了大约1.5个百分点,然而,0 04％的甜菜碱添加量只能将胸肉产量提高约0_3到0.6个百分点。饲粮类型对肉用仔公鸡没有影响。总之,在肉用仔公鸡饲粮中,甜菜碱不能完全取代蛋氨酸作为必需氨基酸的添加作用。     

Airway hypersensitivity induced by Ascaris suum extract in New Zealand Romney sheep

Sheep from local farms with and without previous exposure to pigs were tested for their skin and airway responses to a commercial Ascaris suum antigen. There was an immediate reaction to intradermal injection of the antigen in 90% of 101 sheep. A bronchial provocation test by aerosol of the same antigen was undertaken on 43 of the sheep with a positive skin reaction. About 70% of sheep showed an immediate airway response to the antigen as an aerosol, reflected as a significant increase in airway resistance and/or decrease of dynamic lung compliance. The mean peak airway resistance and mean lowest dynamic lung compliance were 165% above and 61% below their baselines, respectively. No significant changes were recorded when the same animals were given an aerosol of phosphate buffered saline. Similarly, no correlation was found between the degree of skin reaction and the magnitude of bronchoconstriction (p>30.05). The sheep with previous exposure to pigs showed no significant differences in airway responses to antigen challenge, although they showed significantly greater skin reactions than those without exposure to pigs. These results indicate that the majority of Romney sheep in the Manawatu have a natural skin and airway sensitivity to A. suum antigen and may therefore be used as an animal model to study human airway hypersensitivity. The origin of this sensitivity has yet to be determined.     

Secretion of luteinizing hormone into pituitary venous effluent of the follicular and luteal phase mare: novel acceleration of episodic release during constant infusion of gonadotropin-releasing hormone

We tested the hypothesis that continuous infusion of native GnRH into mares during the estrous cycle, at a dose of 100 μg/h, would elevate circulating concentrations of LH without disrupting the endogenous, episodic pattern of LH release. Ten cyclic mares were assigned to one of two groups (n = 5/group): (1) Control (saline) and (2) GnRH in saline (100 μg/h). On experimental day 0 (3 to 6 d after ovulation), osmotic pumps containing saline or GnRH were placed subcutaneously and connected to a jugular infusion catheter. Blood samples were collected from jugular catheters daily and at 5-min intervals from catheters placed in the intercavernous sinus (ICS) for 8 h on experimental day 4 (luteal phase; 7 to 10 d after ovulation), followed by an additional 6-h intensive sampling period 36 h after PGF(2α)-induced luteal regression (experimental day 6; follicular phase). Treatment with GnRH increased (P < 0.001) concentrations of LH by 3- to 4-fold in the peripheral circulation and 4- to 5-fold in the ICS. Continuous GnRH treatment accelerated (P < 0.01) the frequency of LH release and decreased the interepisodic interval during both luteal and follicular phases. Treatment with GnRH during the luteal phase eliminated the low-frequency, long-duration pattern of episodic LH release and converted it to a high-frequency, short-duration pattern reminiscent of the follicular phase. These observations appear to be unique to the horse. Further studies that exploit this experimental model are likely to reveal novel mechanisms regulating the control of gonadotrope function in this species.     

Investigation of an emulsifiable oil adjuvant and its components on the activity of a new grass herbicide by factorial experimentation

The herbicidal activity of a new compound [(±)-(EZ}-2-[1-allyloxy-imino)propyr]-3-hydroxy-6-(4-cyanophenyl)cyclohex-2-ene-1-one] (I) , selective to broad-leaf plants, and partially selective in some cereal crops was enhanced by an emulsifiable paraffinic oil (HVI 60E). In order to determine the amount of HVI 60E to be applied with an emulsifiable concentrate of I (IE) a factorial herbicidal assay involving six concentrations of I and five concentrations of HVI 60E (both sets including zero concentration) was conducted to obtain response surfaces of herbicidal activity. The total selectivity of IE in broad-leaf species remained for all HVI 60E concentrations. The activity against grass weeds, except Poa annua L., increased markedly with increasing HVI 60E concentration and enhancement of performance of IE by HVI 60E in broad-leaf crops could be pursued without fear of crop phytotoxicity. However, the increases in activity against grass weeds were accompanied by increases in phytotoxicity against cereal crops. The response surfaces of Echinochloa crus-galli(L.) Beauv. and Zea mays L. were coincident and this result terminated further testing in this outlet. However, the response surfaces of Avena fatua L. and Triticum aestivum L. were reasonably well separated. Further tests in this outlet and in broad-leaf crops are planned around optimum cost-performance ratios derived from combinations with cost-response surfaces. The results of a further lest showed that both components (oil and emulsifier) of HVI 60E were approximately equivalent in adjuvant enhancement activity and so, on cost grounds, a crop oil (low emulsifier content) would be preferred over a crop oil concentrate (high emulsifier content).     

Ideal amino acid profile and dietary lysine specification for broiler chickens of 20 to 40 days of age.

1. The aim of the study was to determine the ideal ratio of the essential amino acids lysine (Lys), methionine (Met), threonine (Thr), tryptophan (Trp), arginine (Arg), valine (Val) and isoleucine (Ile) and to assess the required dietary lysine concentration for optimum performance in broiler chickens of 2 commercial strains from 20 to 40 d of age. 2. An identical basal diet was used throughout all experiments. It consisted mainly of maize and soyabean meal and contained 172 g crude protein and 13.2 MJ AME(N) per kg. For each experiment, the basal diet was adequately supplemented with all essential amino acids except the one to be tested, which was supplemented in 6 graded concentrations in exchange for maize starch. One (Met, Trp, Arg, Val, Ile) or 2 (Lys, Thr) growth trials were conducted per amino acid tested and the response in weight gain, food: gain ratio, breast meat yield and abdominal fat were examined. 3. The ideal amino acid ratio relative to Lys (expressed as a percentage) was calculated to be 75% Met+Cys, 63% Thr, 19% Trp, 112% Arg, 71% Ile and 81% Val on a true faecal digestible basis when the data were subjected to broken-line regression analysis. From both lysine studies the concentration for optimum food: gain ratio was calculated, by exponential regression analysis, to be 11.5 g true faecal digestible lys per kg diet.     

Progressive myelopathy and neuropathy in New Zealand Huntaway dogs

Aim: To investigate the nature and cause of a progressive ataxia in three 20-month-old Huntaway dogs that were litter mates.

Methods: Affected dogs were examined before they were humanely killed and submitted to necropsy. Selected formalin-fixed tissues were examined by light and electron microscopy.

Results: The lesions were those of axon and myelin degeneration within sensory, proprioceptive and motor tracts of the spinal cord and to a lesser degree some peripheral nerves.

Conclusion: A progressive myelopathy and neuropathy, tentatively described as a central-peripheral distal axonopathy, was present in all 3 dogs.The cause was not determined but was likely to be either genetic or nutritional.

Clinical relevance: In the early stages of this disease, careful examination maybe necessary to distinguish the signs of ataxia from orthopaedic disease such as hip dysplasia. Affected animals are unlikely to be of use as working dogs.     

Sudden death in racing Thoroughbred horses: an international multicentre study of post mortem findings

Reasons for performing study: To improve the understanding of exercise related sudden death in Thoroughbred racehorses. Objectives: To describe the post mortem findings in cases of sudden death associated with exercise in 268 Thoroughbred racehorses. Methods: Gross and histological post mortem findings of 268 cases of sudden death were collated and reviewed. Cases originated from 6 racing jurisdictions around the world. Sudden death was defined as acute collapse and death in a closely observed and previously apparently healthy Thoroughbred racehorse, during, or within one hour after, exercise. Cause of death as determined by the attending pathologist was categorised as definitive, presumptive or unexplained and compared between the different populations. Cardiopulmonary lesions recorded at post mortem examination were compared between different populations. Results: Pathologists recorded a definitive cause of death in 53% (143/268) of cases. Major definitive causes of sudden death included cardiac failure, apparent pulmonary failure, pulmonary haemorrhage, haemorrhage associated with pelvic fractures or with idiopathic blood vessel rupture, and spinal cord injury. A presumptive cause of death was made in 25% (67/268) of cases and death remained unexplained in 22% (58/268) of cases. There were several statistically significant inter‐population differences in the cause of death and in reporting of cardiopulmonary lesions. Conclusions: Sudden death can be attributed to a variety of causes. Causes of sudden death and the lesions found in cases of exercise‐related sudden death are similar in different racing jurisdictions. However, the lesions are often not specific for the cause of death and determination of the cause of death is therefore affected by interpretation by the individual pathologist.