Experimental transmission of bovine anaplasmosis (caused by Anaplasma marginale) by means of Dermacentor variabilis and D. andersoni (Ixodidae) collected in western Canada

Canadian cattle are free of bovine anaplasmosis, with the exception of 4 isolated incursions since 1968, which were eradicated. It is not known why the disease has not become established in regions of Canada adjacent to the United States where it is endemic. To assess the vector competence of wild-caught ticks in cattle-rearing regions, Dermacentor variabilis and D. andersoni were collected in western Canada and fed on calves experimentally infected with Anaplasma marginale (St. Maries strain). The 2 tick species were equally competent in transmitting A. marginale to splenectomized calves, all 15 tick-exposed calves becoming infected. The prepatent periods in 13 calves ranged from 18 to 26 d and did not vary in relation to the numbers of ticks fed or the duration of transmission feedings. The unusually long prepatent periods in 2 calves (45 and 55 d) were probably due to concomitant Eperythrozoon infection. This study clearly demonstrated that tick species present in western Canada are competent vectors of bovine anaplasmosis. Potential barriers, including climate, must be considered in developing strategies to prevent A. marginale from becoming established in anaplasmosis-free regions.     

Effect of Foliar Fertilizers on the Growth of Soybean Cultivars1

Foliar fertilizers (FF) applied at the reproductive growth stage was reported to increase soybean (Glycine max L. Merr.) yield in field trials. But yield increases have not been consistent. Field experiments were conducted on Calloway silt loam soil in 1981—1982 to determine the effect of two foliar fertilizer (FF) formulations, 16N + 4P + 4K + 1 S (Hanway) and 12 N + 4 P + 4 K + 0.5 S (Folian), and time of application, 0800- and 1900-h, on the growth of seven soybean cultivars from maturity groups V, VI, and VII. Foliar fertilizers were applied at a rate of 187 L/ha^?1 in water by a backpack CO₂ pressure sprayer at R5 to R6 growth stages. Foliar fertilizers caused no crop injury (leaf burn) when applied at 1900-h but caused moderate injury at 0800-h, which caused a yield reduction. The most significant crop injury was caused by Hanway formulation when applied at 0800-h. Yields were significantly reduced by FF in 1981 but not in 1982. Generally, Folian formulation treatments had higher yields than Hanway formulation treatments, but neither formulation increased yield above that of the untreated plants. The Bragg cultivar exhibited the least amount of crop injury and the most positive yield response to FF. Plant height, 100-seed weight and lodging rates were not adversely affected by the foliar applications. Due to the general lack of consistent yield increases or in some instances yield reduction from FF applications, the formulations used cannot be recommended for use by soybean producers.     

Studies on canine pregnancy using B-mode ultrasound: Development of the conceptus and determination of gestational age

Development of the conceptus was characterised using B-mode ultrasound in a standard size of dog (labrador retrievers, golden retrievers and their crosses; weight range 22 to 30 kg). Growth curves were established for various measurements of the conceptuses. Regression equations allowed the prediction of the expected time of parturition. Multiple regression analysis of two measurements (biparietal diameter and trunk diameter) resulted in an increase in the confidence of prediction.     

The increasing risk of Lyme disease in Canada

There is an increasing risk of Lyme disease in Canada due to range expansion of the tick vector, Ixodes scapularis. The objectives of this article are to i) raise public awareness with the help of veterinarians on the emerging and expanding risk of Lyme disease across Canada, ii) review the key clinical features of Lyme disease in dogs, and iii) provide recommendations for veterinarians on the management of Lyme disease in dogs.     

Early introduction of water and complementary feeding and nutritional status of children in northern Senegal

OBJECTIVE: Malnutrition is responsible globally for 60% of deaths among children under 5 years and is often attributed to suboptimal feeding practices. In response, the World Health Organization recommends exclusive breast-feeding for the first 6 months of life. The objective of this study was to determine if an association exists between the early introduction of water and complementary foods (CFs) and the nutritional status of children in northern Senegal. DESIGN/SETTING/SUBJECTS: A cross-sectional study of 374 children in the Podor Health District between the ages of 6 and 23 months was conducted. Knowledge and behaviours of mothers regarding introduction of water and CFs were assessed via individual interviews. RESULTS: Water was introduced to about 85% of the children in the first 3 months of life and 62% were fed CFs before 6 months. Overall, 16% had clinically significant wasting (weight-for-length Z-score (WHZ) less than - 2) and 20% had stunting (height-for-age Z-score (HAZ) less than - 2). There was no significant association between wasting or stunting and introduction of water before 3 months (WHZ: odds ratio = 0.99, 95% confidence interval 0.46-2.14, P = 0.97; HAZ: 0.68, 0.34-1.36, P = 0.3) or introduction of CFs before 6 months (WHZ: 0.81, 0.46-1.42, P = 0.5; HAZ: 0.79, 0.46-1.35, P = 0.4). A significant association was found between wasting and male sex, age, living in Guede community, drinking river/pond water and large family size, while stunting was associated with age and drinking tap water. CONCLUSION: The results of the present study suggest that early introduction of water and CFs is frequent and is not associated with increased risk for malnutrition among children from this region of northern Senegal, but the possibility of reverse causality cannot be excluded.