Influence of high dietary vitamin E supplementation on egg production and plasma characteristics in hens subjected to heat stress

1. The effects of different dietary concentrations of vitamin E (alpha-tocopherol acetate) were investigated in 2 experiments on laying hens exposed to chronic heat stress at 32C. 2. In the first experiment, egg production and plasma concentrations of calcium and egg yolk precursors were measured in 24 hens before, during and after a stress period of one week and fed on diets containing 10 or 500 mg vitamin E/kg. 3. In the second, larger experiment, egg production and food intake were measured in 300 hens housed in 2 temperature-controlled rooms and fed on diets containing 10, 125 or 500 mg vitamin E/kg. Birds in room 1 were stressed from 24 to 28 weeks of age and those in room 2 from 32 to 36 weeks. 4. In experiment 1, egg production and egg weight were significantly higher (72.6 vs 51.2%, P < 0.05 and 66.6 vs 63.1 g, P < 0.005 respectively) during and after the period of stress in the group given 500 mg vitamin E/kg. Plasma concentrations of calcium, vitellogenin (zinc) and VLDL (triglyceride) were also higher in this group. 5. In experiment 2, egg production was significantly higher (65.4 vs 56.2%, P < 0.05) during and after the period of heat stress in birds in room 1 fed on the diet containing 500 mg vitamin E/kg. Egg production was also higher (49.9% vs 44.7%) on this treatment during the stress period in room 2, though the difference was not significant (P < 0.10). Egg weight and food intake were unaffected by treatment in either room. 6. It is concluded that dietary supplementation with extra vitamin E can, at least in part, alleviate the adverse effects of chronic heat stress in laying hens, perhaps by maintaining the supply of egg precursors in plasma.     

Model field study of Sumithion 50 EC and Fusilade S on pheasants.

Toxicological studies on wild animals play an important role in the ecotoxicological examination of pesticides. The applied model tests enable the assessment of toxicological consequences with particular regard to the life and nutrition of wild animals in the ploughed field among plants treated with pesticides. The application of different pesticide formulations on plough-land may pose a simultaneous chemical burden to wild birds. In this model study, manifestations of the interaction between an insecticide and a herbicide were studied in pheasants. The birds were placed on lucerne in cages (48 m2) and sprayed once. The applied doses were: Sumithion 50 EC 1 litre/ha + Fusilade S 6 litres/ha (practical doses) and Sumithion 50 EC 5 litres/ha + Fusilade S 30 litres/ha. The analytically determined pesticide concentration of the lucerne was taken as a basis in the further treatment of fodder. The fodder of pheasants contained the following chemicals: 85 mg/kg Sumithion 50 EC + 510 mg/kg Fusilade S and 425 mg/kg Sumithion 50 EC + 2250 mg/kg Fusilade S. Sporadic deaths observed among the pheasants were of traumatic origin and not due to a toxic effect. The decrease of body weight was significant only at the higher dose levels. Acetylcholinesterase (AChE) activity of the blood decreased significantly in both dose groups. On the basis of the results obtained it can be established that at the dose level used in the practice the pesticides studied do not give rise to a toxic interaction in pheasants.     

Epidemiological observations on stomach worms of donkeys in Morocco

Over two consecutive years, weekly examinations for the presence of nematodes were conducted on 185 stomachs from donkeys originating mainly from the Rabat, Casablanca and Settat regions of Morocco. All the animals, except one, were infected by at least one of four helminth species.Trichostrongylus axei was found in 93.5%,Habronema muscae in 89.7%,H. majus in 85.4% andDraschia megastoma in 1.1% of donkeys. Most animals were infected by two (23.8%) or three (71.9%) species. High burdens ofT. axei were observed in the winter of both years and in the mid-summer of the second year. Peak burdens ofHabronema were found at various times throughout both years. There were more adultH. majus thanH. muscae. The periods of peak levels of infection by these parasites were related to environmental conditions suitable for the development and survival of infective larvae ofT. axei and for the build-up of muscid fly vectors ofHabronema andDraschia spp.     

Idiopathic, aseptic, effusive, fibrinous, nonconstrictive pericarditis with tamponade in a standardbred filly.

A Standardbred filly was admitted for evaluation of pleuritis and pneumonia. Heart rate was 80 to 120 beats/min, and the pulse was barely palpable. Thoracic and abdominal ultrasonography and echocardiography revealed substantial pericardial effusion with cardiac tamponade, fibrinous pericarditis, pleural effusion, and ascites. Initial electrocardiography revealed normal sinus rhythm with decreased amplitude of the QRS complexes consistent with pericardial effusion. Following thoracentesis, echocardiogram-guided pericardiocentesis was performed. Bacterial culture yielded no growth from any of the fluids, and bacteria were not seen on cytologic examination. Initial treatment included broad-spectrum antibiotic treatments, IV fluid therapy, and anti-inflammatory agent administration. On the basis of negative culture results, an immune-mediated cause was considered, and dexamethasone was instituted in a decreasing dosage regimen. Pericardial effusion, ventral edema, and ascites began to resolve within 3 days after beginning dexamethasone treatment. Thirty days following discharge, the filly was reexamined, and at that time, the prognosis for athletic performance was considered good so the horse was returned to race training. The final diagnosis in this case was idiopathic, effusive, nonconstrictive pericarditis with tamponade. Early identification, clinical understanding, and application of knowledge of the pathophysiologic mechanisms of pericarditis in horses, combined with use of diagnostic aids such as ultrasonography and aggressive therapy consisting of effusion drainage, pericardial lavage, antibiotics that penetrate the pericardium, and corticosteroids when indicated are critical for a successful outcome in horses with pericarditis.     

Impact of a sustained-release ivermectin bolus on weight gain in breeding age Holstein heifers under commercial pasture conditions in southern Québec.

This field trial was designed to test the effect of treatment with a sustained-release ivermectin bolus on average daily and total weight gain in breeding age Holstein heifers under commercial pasture conditions in southern Quebec. One hundred and twelve heifers from 12 herds were randomly assigned at turnout either to treatment with a commercially-available ivermectin bolus or to remain as untreated controls. Ninety-six heifers, 49 treated animals and 47 controls, completed the trial. Animals were weighed at turnout, midseason, and at the end of the grazing season. Fecal samples were collected at each of these times and nematode eggs counted. Nematode egg excretion was relatively low throughout the pasture season, which was abnormally warm and dry until midsummer. Over the entire pasture season, average daily weight gain was higher in treated than in control animals (difference = 0.08 kg/day, P = 0.010). Total weight gain was also higher in treated animals than in control animals (difference = 12.82 kg, P = 0.013). The results of this study suggest that preventive treatment of breeding age, grazing dairy heifers with a sustained-release ivermectin bolus provides a significant weight gain advantage, in situations with moderate utilization of moderately contaminated pastures.