Effect of trace elements profile of different soil and forages on gastrointestinal Helminthiasis in sheep

Abstract

Helminths especially gastrointestinal (GI) nematodes impose severe threat to sheep in terms of mortality, morbidity, treatment cost and control measures. In parasitized sheep, reduction in immunity to fight against GI parasites may occur due to trace element deficiencies. The rangelands of Punjab province have diversified forages used for small ruminants grazing. These forages are a natural source of trace elements for animals. This study was executed at Chakwal district of Punjab, Pakistan for the qualitative and quantitative determination of GI parasitic fauna; estimation of zinc (Zn), copper (Cu), manganese (Mn), cobalt (Co), molybdenum (Mo) and selenium (Se) of sheep, forages and soils of rangelands. A correlation was established between trace element profile and GI parasitic burden in sheep. Microscopically scanned faecal samples of sheep (n=384) revealed an overall prevalence of 65.62 % of GI helminths. The prevalence was significantly higher at Kalar Kahar (77.22 %) followed by Talagang (74.51 %), Choa Saidan Shah (70.97 %) and Chakwal (44.55 %) tehsils (administrative sub divisions of district). The identified parasitic fauna included Haemonchus contortus (60.94%), Ostertagia trifurcata (21.88%), Trichostrongylus spp. (6.25%), Strongyloides papillosus (7.03%), Marshallagia marshalli (6.25%), Avitellina centripunctata (9.64%), Fasciola (F.) gigantica (4.43%) and F. hepatica (1.56%). Nematodes represented higher level of infection than cestodes and trematodes. Rangeland forages reflected higher levels of Zn, Cu and Co than the recommended critical dietary levels for animals; whereas, Se level was within the normal limit. The forage levels of Mn and Mo were below the critical dietary limit. Grazing site soils showed relatively higher levels of Zn, Cu, Mn and Co than the critical levels. Selenium level in soils was below the critical limit; while, Mo level was within the recommended critical limit. Rangeland sheep sera had normal levels of Cu, Mo and Se; while, higher and marginally deficient levels of Mn, Co and Zn, respectively were noted in sheep. Sheep flocks at tehsil Kalar Kahar revealed the highest magnitude (660.21) of egg per gram (EPG) of faeces followed by those of Talagang (610.16), Choa Saidan Shah (506.36) and Chakwal (467.47). Nevertheless, trace elements seem to have no correlation with EPG magnitude in naturally parasitized sheep flocks of the study area. In conclusion, trace elements profile of naturally infected sheep flocks exhibited no significant role in reducing GI parasitic burdens, despite of the fact that rangeland forages and soils contained sufficient levels of most trace elements to cater the requirements of sheep flocks.