Genetic Studies on Faecal Egg Counts and Packed Cell Volume Following Natural Haemonchus contortus Infection and Their Relationships with Liveweight in Muzaffarnagari Sheep

  • Yadav, N.K. (Genetics and Breeding Division, Central Institute for Research on Goats) ;
  • Mandal, Ajoy (Genetics and Breeding Division, Central Institute for Research on Goats) ;
  • Sharma, D.K. (Genetics and Breeding Division, Central Institute for Research on Goats) ;
  • Rout, P.K. (Genetics and Breeding Division, Central Institute for Research on Goats) ;
  • Roy, R. (Genetics and Breeding Division, Central Institute for Research on Goats)
  • Received : 2005.11.18
  • Accepted : 2006.02.20
  • Published : 2006.11.01


A total of 437 animals, comprising lambs aged between 3 and 12 months and adults of either sex of Muzaffarnagari sheep maintained at the Central Institute for Research on Goats, Makhdoom, Farah, Mathura, India were screened to assess the prevalence of Haemonchus contortus infection following natural infection and to identify the various factors affecting faecal egg count (FEC) and packed cell volume (PCV) of ewes and their genetic control. The relationships between FEC, PCV and body weight were also estimated. The prevalence rate for H. contortus infection in the flock under study was 15.7% indicating much lower occurrence of worm infection in lambs up to one year of age. On the other hand, a large proportion i.e., 67.7% of sheep was refractive to natural H. contortus infection. The random effect of sire significantly contributed (p<0.01) variation in log-transformed FEC (LFEC) of ewes. The season of birth had a significant (p<0.01) effect on LFEC of ewes. The lactating ewes had significantly (p<0.01) higher faecal egg counts compared to dry and pregnant ewes. The linear regression effects of the age of ewes on LFEC of animals were significant (p<0.01) in the present study. The heritabilities of LFEC, PCV and body weights of ewes during the course of infection were moderate to high in magnitude and ranged from 0.24 to 0.47. The LFEC of ewes was significantly (p<0.05) and negatively correlated with PCV at both genetic and phenotypic level. The genetic and phenotypic relationships between LFEC and body weights of ewes were -0.26 and -0.06 for this breed. The genetic correlation of PCV and body weight of ewes was positive and high (0.58) and statistically significant (p<0.05) but it was negatively correlated (-0.01) with body weight at the phenotypic level.


  1. Baker, R. L. 1999. Genetic resistance to endoparasites in sheep and goats. Animal Genetic Resources Information, Rome, Food and Agricultural Organization 24:13-30
  2. Baker, R. L., D. M. Mwamachi, J. O. Audho, E. O. Aduda and W. Thorpe. 1999. Genetic resistance to gastro-intestinal nematode parasites in Red Massai, Dorper and Red MaasaiXDorper ewes in sub-humid tropics. Anim. Sci. 69:335-334
  3. Barger, I. A. 1993. Influence of sex and reproductive status on susceptibility of ruminants to nematode parasitism. Int. J. Parasitol. 23:463-469
  4. Roberts, J. and R. A. Swan. 1982. Quantitative studies of ovine haemonchosis. The interpretation and diagnostic significance of the changes in serial egg counts of Haemonchus contortus in a sheep flock. Vet. Parasitol. 9:211-216
  5. Tembely, S., A. Lahlou-Kassi, J. E. O. Rege, E. Mukasa-Mugerwa, A. Anindo, S. Sovani and R. L. Baker. 1998. Breed and season effect on the peri-parturient rise in nematode egg output in indigenous ewes in a cool tropical environment. Vet. Parasitol. 77:123-132
  6. Harvey, W. R. 1990. User's guide for LSMLMW PC-2 Version mixed model least squares maximum likelihood computer program. Minneograph Columbus, Ohio, USA
  7. Woolaston, R. R. and R. G. Windon. 2001. Selection of sheep for response to Trichostrongylus colubriformis larvae: genetic parameters. Anim. Sci. 73:41-48
  8. Bisset, S. A., A. Vlassof, C. A. Morris, B. R. Sothey, R. L. Baker and A. G. H. Parker. 1992. Heritability of and genetic correlations among faecal egg counts and productivity traits in Romney sheep. N. J. Agric. Res. 35:51-58
  9. Kramer, C. Y. 1957. Extension of multiple range tests to group correlated adjusted means. Biomet. 13:13
  10. Wilson, D. E., M. F. Rothschild, M. V. Boggess and D. G. Morrical. 1996. Adjustment factors for birth weight and 30-day, 60-day and 90-day weaning weight in sheep. J. Anim. Breed. Genet. 113:29-41
  11. Vanimisetti, H. B., S. L. Andrew, A. M. Zajac and D. R. Notter. 2004. Inheritance of faecal egg count and packed cell volume and their relationship with production traits in sheep infected with Haemonchus contortus. J. Anim. Sci. 82:1602-1611
  12. Chauhan, K. K., P. K. Rout, P. K. Singh, A. Mandal, S. K. Singh and R. Roy. 2003. Genetic resistance of Barbari and Jamunapari kids to natural infection with gastrointestinal nematodes. Trop. Anim. Hlth. Prod. 35:397-408
  13. Gauly, M. and G. Erhardt. 2001. Genetic resistance to gastrointestinal nematode parasites in Rhon sheep following natural infection. Vet. Parasitol. 102:253-259
  14. Gauly, M., M. Krasus, L. Vervelde, M. A. W. Van Leeuwen and G. Erhardt. 2002. Estimating genetic differences in natural resistance in Rhon sheep following experimental Haemonchus contortus infection. Vet. Parasitol. 106:55-67
  15. Mandal, Ajoy, K. P. Pant, D. R. Notter, P. K. Rout, R. Roy, N. K. Sinha and N. Sharma. 2005. Studies on inbreeding and its effects on growth and fleece traits of Muzaffarnagari sheep. Asian-Aust. J. Anim. Sci. 18:1363-1367
  16. McKenna, P. B. 1981. The diagnostic value and interpretation of faecal egg counts in sheep. N. Z. Vet. J. 29:129-132
  17. Eady, S. J. 1995. Phenotypic traits associated with resistance to internal parasites. In: (Ed. G. D. Gray) breeding for small ruminants, A.C.I.A.R. Canberra, Australia, pp. 219-236
  18. Yazdi, M. H., F. Eftekhari-Shahroudi, M. Hejazi and L. E. Liljedahl. 1998. Environmental effects on growth traits and fleece weights in Baluchi sheep. J. Anim. Breed Genet. 115:455-465
  19. Bishop, S. C., K. Bairden, Q. A. McKellar, M. Park and M. J. Stear. 1996. Genetic parameters for faecal egg count following mixed, natural, predominantly Ostertagia circumcincta infection and relationships with liveweight in young lambs. Anim. Sci. 63:423-428
  20. MAFF. 1977. Manual of Veterinary Parasitology Laboratory Technique. Technical Bulletin No. 18. Her Majesty's Stationery Office, Ministry of Agriculture, Fisheries and Food, London, p. 160
  21. Mandal, A., L. B. Singh and P. K. Rout. 2000. The Muzaffarnagari sheep, a mutton breed in India. Animal Genetic Resources Information, Rome, Food and Agricultural Organization. 28:19-25
  22. Morris, C. A., A. Vlassof, S. A. Bisset, R. L. Baker, C. J. West and A. P. Hurford. 1997. Responses of Romney sheep to selection for resistance or susceptibility to nematode infection. Anim. Sci. 64:319-329
  23. Gopal, R. M., W. E. Pomroy and D. M. West. 1999. Resistance of field isolates of Trichostrongylus colubriformis and Ostertagia circumcincta to ivermectin. Int. J. Parasitol. 29:781-786
  24. Romjali, E. R., V. S. Pandey, R. M. Gatenby, M. Doloksaribu, H. Sakul, A. Wilson and A. Verhulst. 1997. Genetic resistance in different genotypes of sheep to natural infection with gastrointestinal nematode. Anim. Sci. 64:97-104
  25. Larsen, J. W., A. L. Vizard and N. Anderson. 1995. Production losses in Merino ewes and financial penalties caused by trichostrongylid infections during winter and spring. Aust. Vet. J. 72:58-63
  26. Woolaston, R. R. and R. L. Piper. 1996. Selection of merino sheep for resistance to Haemonchus contortus: genetic variation. Anim. Sci. 62(3):451-460
  27. Preston, J. M. and E. W. Allonby. 1978. The influence of breed on the susceptibility of sheep and goats to a single experimental infection with Haemonchus contortus. Vet. Rec. 103:509-512

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