A Clostridium botulinum type B vaccine for prevention of shaker foal syndrome

A toxoid was prepared from type B toxin of Clostridium botulinum by treatment with 0.6% formalin for 6 weeks. The toxoid was adsorbed to aluminium hydroxide and this vaccine was evaluated for safety in guinea pigs, mice and horses, and for immunogenicity in guinea pigs and horses. Neutralising antitoxin was demonstrated in adult horses receiving two 2 ml subcutaneous doses 6 weeks apart, and in a foal which suckled its vaccinated dam. Another vaccinated mare and the passively immunised foal were protected against subcutaneous injection of 1600 and 2000 mouse lethal doses of toxin per kg respectively.     

Clearance of penicillin G in the newborn calf

Sodium penicillin G was administered intravenously (4545 IU/kg) to calves on the day of birth (12-24 h old) and at 5, 10, and 15 days of age. Serum was collected at varying intervals for 120 min after injection and analysed for penicillin G. The mean total body clearance (ClB) of penicillin G on the day of birth was 2.98 ml/min/kg compared to 4.83 ml/min/kg at 5 days, 3.11 ml/min/kg at 10 days and 4.65 ml/min/kg at 15 days of age. Clearances at 5 and 15 days were significantly (P less than or equal to 0.05) higher than on the day of birth. The half-life (t1/2 beta), however, did not change significantly over the 15-day period of the study. These results indicate that the newborn calf has an appreciable ability to excrete penicillin G before it is 24 h old, and that total body clearance of the antibiotic increases rapidly in the immediate postnatal period.     

A rapid method of counting spores of fungal pathogens by infra-red reflectance analysis

A method of counting freshly harvested spores of powdery mildew ( Erysiphe graminis f.sp. hordei ), yellow rust ( Puccinia striiformis ) and brown rust ( P. hordei ) of barley as well as brown rust ( P. recondita ) of wheat, using infra-red reflectance spectrophotometry was investigated. A Neotec 6350 Research Composition Analyser was used to scan spore samples on glass-fibre filter disks in the near infra-red region of the spectrum (1100–2500 nm) and the amount of energy reflected at 1400 different wavelengths recorded. Three wavelengths (1900, 2252 and 2308 nm) that together gave the best multiple correlation with spore populations counted on a haemocytometer slide were selected. Partial regression coefficients for each fungal species were derived by relating reflectance energy values to direct spore counts. Utilizing these and the energy reflected at the three selected wavelengths, it was possible to count spore samples with high precision. Correlations >0.9 between numbers estimated by the instrument and those obtained using a haemocytometer slide (within the range 0–30000 spores) were achieved with all the fungi examined. Application of the technique to smaller, fixed-filter instruments as a routine method of counting spores is discussed.     

MAGNETIC RESONANCE IMAGING OF THE NORMAL EQUINE DIGIT AND METACARPOPHALANGEAL JOINT

Magnetic resonance (MR) images were made in sagittal and transverse planes through the metacarpophalangeal joint and digit of a horse. The images accurately depicted gross anatomic structures in the leg. Soft tissue structures were defined as separate entities on the images. Histologic varlation in tissues correlated with signal intensity differences on the MR images. Magnetic resonance imaging appears to be a promising imaging modality for evaluating musculoskeletal structures in equine limbs.     

Significance of the Heineke-Mikulicz Pyloroplasty in the Treatment of Gastric Dilatation-Volvulus A Prospective Clinical Study

Twenty-six dogs with gastric dilatation-volvulus (GDV) were stabilized medically, followed by tube gastrostomy and gastropexy. In 13 dogs, a Heineke-Mikulicz pyloroplasty was also performed. Complications and recurrences were monitored during the immediate postoperative period and for 5 to 31 months thereafter. Barium gastrograms and contrast radiographs of the stomach were evaluated at week 1 and months 5 to 31. Significantly fewer dogs without pyloroplasty had complications during the immediate postoperative period. There were no differences in the long-term complication rates. Radiographic evaluations of the width of the pylorus, the size of the stomach, and the rate of gastric emptying showed no differences between dogs with and without pyloroplasty at any evaluation period. The Heineke-Mikulicz pyloroplasty increased the immediate postoperative complication rate after surgical fixation of the stomach for the treatment of GDV. It did not appear to influence the long-term outcome of the surgical treatment of this disease. The Heineke-Mikulicz pyloroplasty is not recommended in the treatment of GDV unless pyloric outflow obstruction can be demonstrated.     

Tissue distribution of tetraethylammonium (TEA) in dogs and goats

The tissue distribution of tetraethylammonium (TEA), a highly polar drug which does not undergo biotransformation, was studied in intact and nephrectomized dogs and goats. Values for β, the overall elimination rate constant, were significantly reduced by nephrectomy but species differences were not significant. Values for apparent specific volume of distribution (V'_d) were unexpectedly large and tissue to plasma ratios were 4.0 and 5.0 in the nephrectomized goat and dog, respectively. The distribution of TEA to various tissues followed closely the expected pattern of regional blood flow, although TEA attained concentrations in liver, heart, lungs and viscera in excess of the concentration in the plasma.     

Effect of defoliation on flower initiation in white clover in summer

Flowering behaviour of plants of six cultivars of Trifolium repens (Kent Wild White, Grasslands Huia, S100, Blanca, Olwen and Milkanova) growing in field plots at the Grassland Research Institute, Hurley, was recorded in mid-July. Half of each plot had been defoliated in early May, the other half in mid-June. In all cultivars defoliated in May, inflorescence initiation had stopped even though the natural photoperiod at that time was well above the critical daylength for initiation Defoliation in mid-June had led to a renewal of inflorescence initiation in all cultivars.
The results confirm that the stimulatory effect of defoliation on inflorescence initiation in plants that have stopped initiation in long days, which has previously been observed in Grasslands Huia in controlled environments, also occurs in the field and in other cultivars.