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Studies of parasitic helminths of sheep and goats in Ghana.

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    ABSTRACT: West African Dwarf (WAD) goats are extremely important in the rural village economy of West Africa, but still little is known about their biology, ecology and capacity to cope with gastrointestinal nematode (GIN) infections. Here, we summarise the history of this breed and explain its economic importance in rural West Africa. We review recent work showing that Nigerian WAD goats are highly trypanotolerant and resist infections with Haemonchus contortus more effectively than other breeds of domestic goat (haemonchotolerance). We believe that haemonchotolerance is largely responsible for the generally low level GIN infections and absence of clinical haemonchosis in WADs under field conditions, and has contributed to the relatively successful and sustainable, anthelmintics-free, small-scale system of goat husbandry in Nigeria's humid zone, and is immunologically based and genetically controlled. If haemonchotolerance can be shown to be genetically controlled, it should be possible to exploit the underlying genes to improve GIN resistance among productive fibre and milk producing breeds of goats, most of which are highly susceptible to nematode infections. Genetic resistance to GIN and trypanosome infections would obviate the need for expensive chemotherapy, mostly unaffordable to small-holder farmers in Africa, and a significant cost of goat husbandry in more developed countries. Either introgression of resistance alleles into susceptible breeds by conventional breeding, or transgenesis could be used to develop novel parasite-resistant, but highly productive breeds, or to improve the resistance of existing breeds, benefitting the local West African rural economy as well as global caprine livestock agriculture. © S.N. Chiejina et al., published by EDP Sciences, 2015.
    Parasite 02/2015; 22(7). DOI:10.1051/parasite/2015006 · 0.82 Impact Factor
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    ABSTRACT: A study was conducted to determine the prevalence and types of coccidia species in slaughter goats and sheep in Tanzania. A total of 91% (191210) of goats and 93% (4043) of sheep were infected with coccidia. The mean coccidia oocyst counts were 3200 g −1 faeces (range 100–46000) in goats and 2900 g−1 faeces (range 100–11400) in sheep. Eimeria species found in goats were Eimeria alijevi (63%). Eimeria arloingi (55%), Eimeria caprina (26%), Eimeria ninakohlyakimouae (26%), Eimeria caprovina (16%), Eimeria hirci (5%), Eimeria jolchijeui (5%) and Eimeria christenseni (3%). Eimeria crandallis (96%), Eimeria parva (92%), Eimeria ovinoidalis (29%), Eimeria bakuensis (29%), Eimeria faurei (29%), Eimeria ahsata (21%) and Eimeria granulosa (8%) infected the sheep. This is the first report on coccidia infecting goats in Tanzania. The presence of pathogenic species of Eimeria in goats (Eimeria alijevi, E. arloingi, E. ninakohlyakimovae and E. christenseni) and in sheep (E. ovinoidalis and E. ahsata) suggests that coccidiosis may be contributing to the enteric syndromes affecting small ruminants in the country.
    Small Ruminant Research 06/1996; 21(2):127-131. DOI:10.1016/0921-4488(96)00860-7 · 1.10 Impact Factor
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    ABSTRACT: The levels and causes of losses, in connection with weight groups from birth to natural weaning, have been discussed in detail. These include morality rates at neonatal (1-14 days), preweaning (14-60 days), and natural weaning (60-105 days) periods. The birth-weight group above 1.5 kg showed no incidence of twin losses in the neonatal period. During the preweaning period, the parity number of dam-related mortality rate followed the expected course, particularly under the free-range system with higher losses within the first-parity-group-born lambs, being lowest at the fifth parity, before increasing again thereafter. The situation under the semi-tethered system was, however, different, with lambs of more than the seventh-parity dam groups suffering the greatest preweaning losses. In both zones, lambs born during the dryspell-minor wet season (H = 12.5%; SH = 11.9%) had much higher losses than those born in the other seasons. In the post-preweaning to natural weaning period (60-105 days), slightly more losses to single (12.1%) than twin (11.5%) lambs were recorded in the humid zone, while in the subhumid zone, the mortality incidence in twins (14.3%) was highly significantly greater than in singles (7.7%). Although lambs' mortality rate varied seasonally, much higher losses occurred in the major-wet season (H = 19.1%; SH = 15.6%) at 105 days in both zones. The losses of weaned (>105 days) to adult sheep (>365 days) over the study period from the first to the second year showed higher significant losses in males (H = 17.3%; SH = 30.4%) than in females (H = 16.0%; SH = 17.2%). Over the study period, weaned to yearling stock (>105-365 days) suffered significantly higher losses (H = 30.9%; SH = 32.5%) than the adults over 365 days old (H = 7.1%; SH = 9.6%). The distribution of the mortality rates over the months was distinctly seasonal (bi-modal), rising steadily from May to June and July of the major-wet season and followed by a drop in August (dryspell month), and then rising again September, peaking in October (months of the minor-wet season), with minimum values in February and April (in the transitional dry-wet season). A higher percentage of the classified main causes of losses was attributable to the category endoparasite-diarrhoea-loss of weight complex among younger stock (H = 37.8%; SH = 35.7%) than among adult stock (H = 6.3%; SH = 3.7%). Losses in orphans, weak, and low-birth-weight lambs, and losses through drowning, ranked second (H = 21.0%; SH = 19.7%).
    Journal of Animal Breeding and Genetics 01/1996; 113(1‐6). DOI:10.1111/j.1439-0388.1996.tb00595.x · 2.06 Impact Factor