The total number of sheep examined, number positive, per cent prevalence is depicted in table 1. The results revealed an overall prevalence of 83.24% with prevalence of Strongyle spp. (80.93%), Strongyloides spp. (28.24%), Trichuris spp. (7.31%) and Moniezia spp. (1.02%).

The prevalence of gastrointestinal parasites in sheep has been reported by many workers earlier. It has been reported by Muraleedharan, 2005; Kaur and Kaur, 2008; Pant et al.,2009; Sutar and Khan, 2011; Choubisa and Jaroli, 2013; Singh et al., 2013 and Vohra et al., 2018).

In the present study, among helminths, the prevalence of strongyles was maximum followed by Strongyloides spp., Trichuris spp. and Moniezia spp. Almost similar observations for helminths have been recorded earlier by (Varadharajan and Vijayalakshmi, 2015; Vohra et al.,2018; Sultan et al, 2016). Lower prevalence of cestode in the study might be due to less dissemination of eggs in the faeces from the gravid segments as reported by Radostits et al, (1994). There were no trematodes observed in the present study. Absence of trematodes might be due to dry area of aeolian plains, absence of natural water bodies as well as snails which act as intermediate host of the trematodes. Therefore, no snail borne disease was observed in the study area.

The number of sheep positive for different GI parasites and their prevalence in relation to age and sex is depicted in table 2. The results in term of age revealed an overall prevalence of 76.67% and 83.84% infection in young and adult animals, respectively. Sex wise, the prevalence was 89.79% and 82.59% in male and female, respectively. The results in relation to age showed a significantly higher infection of strongyle (p<0.01) in adults as compared to young animals. The coprological results in relation to sex revealed a non significantly higher value in male as compared to female for strongyle, Strongyloides, Trichuris and Moniezia infection. Significantly higher infection in adults as compared to young small ruminants was reported by Dabasa et al. (2017) in Bale zone, South Eastern Ethiopia as well as by Rahman et al. (2017) in Tangail, Bangladesh. Almost similar percentage of infection in both male and female might be due to similar management practices and same area visited by these animals during grazing.

During the present study, higher infection of strongyle and Strongyloides was observed in adult as compared to young animals. It may be due to consumption of higher amount of vegetation and grazing on larger area of pastures being contaminated with various flocks and different stress conditions such as climate, long daily traveling and gestation. On the other hand, young animals are less affected by parasitic infections due to consumption of less amount of vegetation and less exposure for grazing as they mainly depend upon milk feeding. Our findings were in concordance with Singh et al. (2017); Yadav et al. (2006); and Emiru et al, (2013) who recorded a higher prevalence of infection in adults than young ones.

The prevalence of various GI parasites in sheep during different seasons is depicted in table 3. The overall prevalence shows 78.88%, 82.72%, 98.88% and 74.17% infection during spring, summer, monsoon and winter, respectively. The examination of infection in sheep showed maximum infection of strongyle and Strongyloides during monsoon season. Similar were the findings of Gupta et al. (2013) and Sutar and Khan (2011). Environmental conditions are usually favourable for the development, survival and translocation of pre-parasitic stages during the rainy season. Therefore, there is a gradual build-up of adult worm populations in grazing animals, consequently, higher prevalence of helminths was recorded during the rainy season.

The prevalence of various GI parasites infection in sheep in different months from March, 2018 to February, 2019 is depicted in table 4. The results revealed that maximum (100%) animals were having parasitic infection during August and September months. Minimum infections (56.67%) were observed during November month. Al- Shaibani et al. (2008) also reported maximum number of sheep positive for GI nematodes during the month of July to October at Hyderabad district of Pakistan.

The results of coproculture studies of GI nematodes in sheep are presented in table 5. The faecal culture showed that the larvae of Haemonchus contortus, Trichostrongylus spp., Oesophagostomum spp. and Strongyloides sp. were present. The larvae of H. contortus were the main contributor throughout the study period among all the four species identified in coproculture. Gupta et al. (1987) also demonstrated infective larvae of Haemonchus spp. and Trichostrongylus spp. throughout the year in goats and sheep of eastern Haryana. Other workers who reported the predominance of Haemonchus were Al-Shaibani et al. (2008); Varadharajan and Vijayalakshmi (2015); Rajaranjan et al. (2017) and Vohra et al. (2018).

The month wise mean epg of strongyles in sheep belonging to aeolian plains of Haryana is depicted in figure 1. The results revealed that the mean epg of animals was maximum (2087.78) during the month of September and minimum (232.22) during the month of February. Al-Shaibani et al., (2008) also reported maximum mean faecal egg count in sheep during August and minimum during February in Pakistan.

The prevalence of GI parasites in sheep of aeolian plains in Haryana was 83.24%. The highest prevalence of strongyle, followed by Strongyloides, Trichuris and Moniezia was observed. Maximum prevalence was recorded in monsoon season during August and September months and highest epg of strongyles was observed during September. The coproculture study revealed the predominance of Haemoncus contortus throughout the study period.