Abstract: Toxocariosis due to Toxocara (Neoascaris) vitulorum is the predominant if not the primary helminthosis of neonatal calves in both Zebu and Taurine cattle. It is of major economic importance in the cattle industry due to it significant impact on replacement stocks (the calves) in both the dairy and beef aspects of cattle production. There have been reported cases of intra-uterine sources of infection but report on colostrums/milk as sources of infection is very scanty. In this study nursing white Fulani Zebu cows and their calves were used as experimental pairs. Faecal and colostrums/milk samples were collected from calves and cows, respectively at weekly intervals from day 0- 30 post calving. The faecal samples were analysed using the floatation technique and the eggs identified by their characteristic ovoid shapes. Colostrums/milk samples were centrifuged at 5000 g for 15 min and smears from the resultant sediments made on microscopic slides and examined microscopically with ×10 magnification for larvae. In all, 71 pairs (cow and calf) were sampled. Twenty seven (38.03%) calves were positive for T. (N) vitullorum eggs in their faeces in the ranges of 4 (5.63%), 2 (2.82%), 10 (14.09%) and 11 (15.92%) by week 1, 2, 3 and 4 of age, respectively. This finding is an indication of pre-natal (in-utero) infection of the calves with the mature helminthes shed their eggs in the faeces. Also, an L2 larva was isolated from the milk of one of the nursing cows by day 14 post calving, with the corresponding calf shedding T. (N) vitullorum eggs in its faeces at 28 days of age. This also confirms the scarcely reported post-natal route of infection of calves by T. (N) vitullorum. This study has shown that both pre and post natal stages of infection of Zebu calves occur. Significantly, the isolation of helminth eggs from the faeces of 7 days old calves is a great pointer to the fact that mature stages of the helminth are present in the calves at very early age. Therefore, there is need for early deworming of these calves to prevent impaired growth and development and in some cases fatality which can have drastic consequences on cattle production and resultant economic loss in terms of foreign exchange earnings as well as loss of vital source of animal protein for the ever-growing human population in developing countries particularly in Africa.
A. K. B. Sackey , T.A. Ojongmboh , J.S. Neils and U. Sale , 2007. The Possible Sources of Toxocara (Neoascaris) vitullorum Infection in Neonatal Zebu Calves in Northern Nigeria . Journal of Animal and Veterinary Advances, 6: 1314-1316.