A computer model study of light interception by orchards in relation to mechanised harvesting and management

The introduction of mechanised harvesting often results in a redesign of the crop canopy. Computer models have been used to predict light interception, and hence potential yield, by a range of hedgerow tree forms and spacings as a guide to the design of orchard systems for mechanical harvesting. Light interception is increased by increasing tree height, thickness and leaf-area density, and by reducing the clear alleyway. Narrow hedgerows less than 2 m high will need straddle harvesting to avoid loss of light interception and yield.     

Serological study of leptospiral infections and endogenous uveitis among horses and ponies in the United Kingdom

The prevalence of antibody titres to a range of 20 leptospira antigens in the serum of horses and ponies with no ophthalmic abnormalities and with ophthalmoscopic evidence of endogenous uveal inflammatory disease was determined using a microscopic agglutination technique. Titres against leptospira antigens were observed in 13 out of 138 (9.1 per cent) animals with no ophthalmic abnormalities, and in three out of 27 (11.1 per cent) animals with anterior uveitis. Serovar sejroe was common to all seropositive animals with anterior uveitis. The results show that leptospira infection is not a major factor in the aetiology of equine anterior uveitis in the UK, but suggests that the organism may be associated with some cases of recurrent anterior uveitis.     

Use of carbenicillin in two species of tortoise (Testudo graeca and T hermanni)

A preliminary investigation of the blood levels of carbenicillin, after the administration of a single intramuscular injection, suggests that the tortoise's bladder may act as a reservoir of antibiotic that is available for resorption. This phenomenon could confound the establishment of a safe, effective dose regime for antibiotics, in tortoises, which are excreted in an unchanged active form in urine.     

Equine ehrlichial colitis (Potomac horse fever): recognition of the disease in Pennsylvania, New Jersey, New York, Ohio, Idaho, and Connecticut

Equine ehrlichial colitis (Potomac horse fever), a newly identified colitis of the horse, was first recognized in Maryland. In this report, we document occurrence of the disease in Pennsylvania, New Jersey, New York, Ohio, Idaho, and Connecticut. Enzootic areas were recognized by a characteristic pattern. Frequently there was a seasonal pattern and high prevalence of sporadic colitis in unstressed horses. The attack rate per farm generally was low. Horses on pasture, as well as those stabled, were affected. Clinical signs varied from fever and depression to severe diarrhea and laminitis. Occasionally horses developed profound ileus and severe colic. Diagnosis was based on detection of an increase or decrease in serum antibody titers to Ehrlichia risticii, using an indirect fluorescent antibody technique.     

Analysis of post mortem aqueous humour chemistry in the horse, with particular reference to urea nitrogen and creatinine

The concentrations of several post mortem aqueous humour chemical constituents were compared with ante mortem serum chemical values in the horse. Urea nitrogen and creatinine values in post mortem aqueous humour were good predictors of ante mortem serum values. Aqueous humour urea nitrogen increased only slightly and creatinine did not change significantly for up to 24 h after death. Formulae were derived for calculating estimated ante mortem serum urea nitrogen and creatinine from aqueous humour values obtained after death. These results from normal horses identify analytes that are accurate predictors of ante mortem serum values. Determination of post mortem aqueous humour urea nitrogen of creatinine may assist in interpretation of the functional significance of equivocal histological lesions in the kidney.     

Canine ceroid-lipofuscinoses: A review and classification

The ceroid-lipofuscinoses are a group of inherited neurodegenerative diseases of humans and animals characterised by the accumulation of a fluorescent lipopigment in neurons and other cells within the body. Syndromes occurring in dogs are classified, on the basis of the age of onset and, to a lesser degree, the course of the disease, as prepubertal-protracted, early adult acute and adult onset. Clinical signs are generally those of progressive loss of vision, motor disturbances such as ataxia, tremors, seizures and proprioceptive deficits together with behavioural changes including loss of learned behaviour, fearfulness and aggression. The various syndromes can be expected to reflect different mutations, at least some of which affect the catabolism of subunit c of mitochondrial adenosine triphosphate (ATP) synthase. Confirmation of diagnosis depends on the demonstration of lipopigment in brain or skin biopsies by histochemistry, fluorescence or electron microscopy.     

Thrombocytopenia in Horses: 35 Cases (1989–1994)

The records of 3,952 equine patients presenting to the Veterinary Teaching Hospital at North Carolina State University College of Veterinary Medicine were evaluated to determine risk factors associated with thrombocytopenia. Of 2,346 horses from which a CBC was obtained, 35 (1.49%) were thrombocytopenic (platelet count < 75,000/μL). A reference population of 189 horses with normal platelet counts (75,000 to 300,000/μL) was also studied. Standardbred horses were at increased risk for thrombocytopenia. but age and gender were not identified as significant risk factors. Horses with infectious or inflammatory diseases were at increased risk for thrombocytopenia. The potential association of clinical and clinicopathologic factors with thrombocytopenia were assessed by reviewing a series of multiple logistic regression models. Clinical and clinicopathologic variables significantly associated with thrombocytopenia in the final model included increased PCV, increased band neutrophil count, increased total WBC, and decreased plasma protein concentration. Increased mature neutrophil count was associated with normal platelet counts. Thrombocytopenic horses were significantly more likely to die or be euthanized than were horses with normal platelet counts. J Vet Intern Med 1996;10:127–132. Copyright © 1996 by the American College of Veterinary Internal Medicine .