Breed and Environmental Effects on Faecal Egg Counts in Sheep of Nigeria

This study was conducted on the Jos Plateau to investigate the influence of genotype and some non genetic factors on resistance of Nigerian sheep to helminthosis. The study sheep included initial stock of 64 yearlings (12 each of Balami, and Uda, and 20 each of Yankasa, and West African Dwarf, WAD, in a sex ratio of 1:1 per breed) and later their 156 offspring were included. Faecal samples were collected 6-weekly according to breed, sex, age, date, parity, birth type, and body condition score (BCS), and analysed for worm faecal egg counts (FEC) in eggs per gramme of faeces (epg) over a period of three years using modified McMaster method. Gastrointestinal helminths observed were Strongyles, Strongyloides, Trichuris, Nematodirus and Moniezia among which effect of investigated factors varied accordingly. Based on mean total helminths faecal egg counts (THFEC), rankings were: WAD (693.1 epg) > Yankasa (633.2) > Balami (494.5) = Uda (484.5); p<0.001, for breeds; late rainy (620.1) > early rainy(561.4) = early dry(556.4) > late dry(525.5), p<0.05 season. Females and adults had higher THFEC than males and lambs respectively. Higher FEC were associated generally with lower body condition scores (BCS). Year, birth type and parity did not affect FEC Generally.

Conclusion: Nigerian sheep breeds vary in resistance and tolerance to helminthosis and this suggests that there is a genetic basis for FEC. This could be exploited through selective breeding for improvement.