Efficacy of avermectin B1 given orally against equine intestinal strongyles and Onchocera microfilaria

Three groups of horses and ponies (N = 13, 13 and 12) were treated with ivermectin paste (0.2 mg/kg p.o.), avermectin B1 solution (0.2 mg/kg p.o.), or fenbendazole suspension (10 mg/kg via nasogastric tube). The avermectin B1 was a 1% solution in a propylene glycolglycerol formal base. Faecal strongyle egg counts were performed before, and 14, 28, 42, 56 and 70 d, after treatment. Full-thickness skin biopsies from the neck, pectoral and umbilical regions were examined for Onchocera microfilaria before treatment, and again 14 and 70 d later. Ivermectin therapy produced a significant (P less than 0.01) decrease in mean strongyle egg counts 14, 28, 42 and 56 d after treatment. Avermectin B1 therapy resulted in significant (P less than 0.01) decreases in mean strongyle egg counts 14, 28 and 42 d after treatment. All horses given ivermectin or avermectin B1 had zero strongyle egg counts 14 and 28 d after treatment. Fenbendazole failed to significantly decrease strongyle egg counts. Both ivermectin and avermectin B1 resulted in zero microfilaria counts in all horses 14 d after treatment. On day 70 the percentage decrease in microfilaria counts were 100% and 99.6% respectively. Fenbendazole failed to significantly decrease microfilaria counts. The oral administration of this formulation of avermectin B1 appeared to be highly efficacious against intestinal strongyles and Onchocera microfilaria. The duration of anti-strongyle activity was, however, significantly (P less than 0.01) shorter than that of ivermectin paste.     

Resistance to Sappaphis devecta (Wlk.) in apple

Summary Simple methods of selection for resistance to Sappaphis devecta (Wlk.), the rosy leaf-curling aphid, are described. Cox's Orange Pippin was shown to carry a single dominant resistance gene, for which the symbol Sd is suggested. There was clear evidence that the apple varieties James Grieve, Northern Spy and Ashmead's Kernel also provide monogenic sources of resistance, and there were similar indications for Gascoyne's Scarlet and ST 14/20.     

Flavonoids from the moss Mnium affine Bland

Eight different flavone C-glycosides from Mnium affine were tentatively identified by chromatography and spectroscopy. Quercetin-3-diglycoside and other unidentified flavonoids were found in M. arizonicum. The fiavonoid chemistry standing of its systematics.     

Surgical resection of a dysgerminoma in a mare

A mare was referred for further evaluation of a mass found in the left caudal abdomen during a routine postpartum reproductive palpation. The mare was clinically normal with no history of health problems. Ultrasonographic examination of the mass confirmed its presence, but the origin of the mass could not be accurately determined. Routine haematology and serum biochemistry results were within normal limits. The mare was initially treated conservatively with antibiotics, but the mass continued to increase in size, so it was surgically excised. The mass involved the left ovary. The mare showed transient abdominal pain after surgery, but developed no other complications and was in foal 7 months later. On histology, the mass was diagnosed as a dysgerminoma, a rare ovarian tumour of germ cell origin.     

Prolonged suppression of the innate immune system in the horse following an 80 km endurance race

REASONS FOR PERFORMING STUDY: An increased susceptibility to bacterial and viral infections of the respiratory tract, which results in a loss of performance, has been reported in racehorses. Much research has focused on the influence of high-intensity exercise of a short duration on immune system function in horses, but scant attention has been given to prolonged endurance exercise as an immune modulator. OBJECTIVES: The objective of this study was to evaluate the effect of an 80 km endurance race on the monocyte and neutrophil oxidative burst, serum cortisol, glutamine and plasma glucose concentrations in 8 endurance-trained horses (mean +/- s.d. age 9.4 +/- 2.2 years). METHODS: Blood samples were drawn from the horses prior to and following an 80 km ride. RESULTS: Mean time for completion of the 80 km race was 306 +/- 40 mins. Immediately post race mean serum cortisol concentration, blood monocyte and neutrophil counts were higher and blood lymphocyte counts and plasma glucose concentration were lower compared with prerace values (P < 0.05). Neutrophil and monocyte oxidative burst activity decreased following the race and had not regained prerace values after 3 days of rest (P < 0.05). CONCLUSIONS: The present study indicates that long duration exercise in horses has a negative impact on the function of the innate immune system that lasts several days post race. Precise mechanisms instigating the fall in innate immune system function are unclear and multifactorial, but may be attributed, at least in part, to a high serum cortisol response during very prolonged exercise. POTENTIAL CLINICAL RELEVANCE: A prolonged bout of exercise results in a long-term suppression of the innate immune system function in horses which may, in part, account for the observed increase of infectious episodes in horses during training.     

Genetic markers in apple breeding

Efficient early selection techniques are being sought which can be applied within 2 years of germination. Molecular markers can provide a higher level of precision than preselection criteria based on seedling/mature tree correlations. Isoenzymic genes show promise as markers for a limited number of specific characters but there is insufficient polymorphism amongst cultivated apples for their wide use in breeding programmes. An apple Genome Mapping Project utilising DNA RFLP analysis and related techniques has been established. Such techniques have the potential to provide an unlimited range of markers.