Resistance and resilience of traditionally managed West African Dwarf goats from the savanna zone of northern Nigeria to naturally acquired trypanosome and gastrointestinal nematode infections

Abstract

A survey was conducted of gastrointestinal nematode infections and trypanosomosis in Nigerian West African Dwarf (WAD) goats from the savanna region of the country. Animals were screened at two markets, Gboko and Akpagher, from the beginning of April until the end of September, coinciding with the end of the dry season and the first 5 months of the wet season. Of 1054 goats that were examined, 80.5% carried gastrointestinal (GI) nematodes belonging to the genera Haemonchus (61.0%), Oesophagostomum (21.0%) and Trichostrongylus (17.9%). Faecal egg counts (FEC) increased very slowly but significantly from April to maximum levels in September, and varied marginally between the two market sources. The majority of goats (68.8 and 70.1% at the two markets) had low FEC not exceeding 50 eggs/g (epg). FEC did not differ significantly between the sexes or between age classes. Packed cell volume (PCV) also declined significantly with month of the study, but was affected by host sex (a significant month x sex interaction) being generally higher in male animals throughout the period. There was a highly significant negative correlation between log₁₀(FEC+1) and PCV, when all other factors had been taken into account. Body condition scores (BCS) also declined with month of the study, but there was a marked difference between the two sexes, with male animals generally showing a greater stability of BCS across the months compared with females. Trypanosome infections were found in only 4% of the goats and only during the rainy season. Most infections (92.86%) were caused by Trypanosoma brucei alone although T. vivax and T. congolense were occasionally detected. Overall, the majority of goats sampled each month maintained generally good body condition (BCS 3.0-5.0), normal or slightly reduced PCV, even when concurrently infected with trypanosomes and GI nematodes. However, four concurrently infected goats showed signs of overt anaemia during periods of peak infection, during the late rainy season, with marked reductions in PCV (< 15%). Two of the infected goats were also in poor body condition with BCS of < 2.0. There was no evidence of additive or synergistic pathogenic effects of the two parasites. These results are discussed in the context of the unexpectedly strong resistance and resilience of the savanna WAD ecotype to its native strains of GI nematode and trypanosome parasites.

The unique resistance and resilience of the Nigerian West African Dwarf goat to gastrointestinal nematode infections

“…These studies were later extended to include naturally acquired GI nematode infections in these contrasting geo-climatic zones [34,35]. Our data do not support the generally held view about the high susceptibility of goats to GI nematodes and especially to H. contortus , and their inability to control the pathophysiological consequencies of these infections.…”

Responses of the humid zone ecotype of the Nigerian West African Dwarf sheep to mixed infections with Haemonchus contortus and Trichostrongylus colubriformis

“…Such variability in worm burden was described by Chiejina et al (2002Chiejina et al ( , 2005Chiejina et al ( , 2009) and Fakae et al (2004) in humid zone ecotype of Nigerian WAD goats and Chiejina et al (2009Chiejina et al ( , 2010 in savanna ecotype of the Nigerian WAD goats experimentally infected with their native strains of H. contortus. Behnke et al (2006Behnke et al ( , 2011 confirmed that this pattern of responsiveness also occur under natural acquired field infections with mixed GI nematodes. Although information is currently available on the responses of the Nigerian WAD goats experimentally infected with H. contortus, there is little published research data on the responses of their sheep counterpart to either H. contortus alone or mixed GI nematode infection.…”

Comparative Response of the Nigerian Indigenous and Broiler Chickens to a Field Caecal Isolate of Eimeria Oocysts

“…No such documented evidence exists or is known to the authors about the Nigerian indigenous (local) chicken in comparison to their exotic counterparts such as the broilers and layers where some studies have already been conducted. However, like some indigenous breeds of animals such as the West African Dwarf (WAD) goat and Muturu and N'dama cattle that have been shown to be more resistant to helminth and trypanosome infections than their exotic counterparts [26–28], it is hoped that the Nigerian indigenous chicken will be more resistant to Eimeria infections than broilers and layers which are exotic. Such information if available can be exploited in the control of parasitic diseases of chickens particularly coccidiosis if one of the breeds of chickens is found to be more resistant to Eimeria infections than the other.…”