FACTORS AFFECTING VARIABILITY OF RESISTANCE IN GAROLE SHEEP NATURALLY INFECTED WITH HAEMONCHUS CONTORTUS

Resistance status against natural infection to Haemonchus contortus as well as influence of season, sex, body weight, and haemoglobin type on resistance levels were evaluated in 309 numbers of Garole sheep. In adult Garole sheep, egg per gram(EPG) of faeces for Haemonchus contortus was varied from 300 to 1600, but overall EPG in Garole have been recorded as 829.96 ± 20.60. The effects of season, sex, and body weight and haemoglobin type on EPG were all found to be highly significant (P < 0.01). EPG count was highest during monsoon (986.27 ± 28.26), followed by summer (832.88 ± 28.26) and lowest during winter (670.74 ± 28.26) which indicated the existence of a seasonal variation of EPG. Rams had higher EPG (954.32 ± 57.93) than ewes (705.60 ± 45.79) which reflected that males appeared to be more susceptible to Haemonchus contortus infection compared to females. Animals with lower body weight (upto 10 kg) showed higher EPG (1017.20 ± 54.82), then the infection level decreased as body weight increased (886.79 ± 56.23 for 10 kg to 12 kg and 737.18 ± 50.29 for 12 kg to 14 kg) and lowest EPG was recorded in animals with above 14 kg body weight (678.68 ± 54.49). This study reveals Hb-BB type animals had higher EPG count (983.81 ± 18.22) in comparison to Hb-AB type animals (676.12 ± 33.96) indicating that Haemoglobin-A locus has some relation with resistance. From our study it can be concluded that resistant level of Garole sheep against Haemonchus contortus is influenced by some intrinsic factors like sex, body weight, and haemoglobin type of the sheep and also by extrinsic factor like season.