Skip to main content Accessibility help
×
Home

Survival of Red Maasai, Dorper and crossbred lambs in the sub-humid tropics

  • R. Nguti (a1), P. Janssen (a2), G.J. Rowlands (a3), J.O. Audho (a3) and R.L. Baker (a3)...

Abstract

The survival rates of Dorper, Red Maasai and crossbred lambs born over a period of 6 years at Diani Estate, Coast Province, Kenya were compared using the Cox mixed proportional hazards model with a random (frailty) term for sire. Of the 1785 lambs born, proportionately 0·44 died before they were 1 year old. Almost half of these deaths occurred before weaning; a third were associated with mis-mothering and a fifth with gastro-intestinal nematode parasite (endoparasite) infections. Half of the deaths post weaning were associated with endoparasite infections, predominantly Haemonchus contortus. The Red Maasai lambs had a lower risk of death than the Dorper lambs with a relative hazard of 0·27 pre-weaning and 0·25 post weaning. Other crosses and back crosses had relative hazards in between these values and 1; there was no evidence of heterosis. Survival rates were different among years and appeared to be associated to some degree with variations in rainfall. There were highly significant effects of both birth weight and weaning weight on survival. Body weight, together with packed red cell volume and faecal egg count, were also introduced into the proportional hazard model as time-varying covariates. All three variables had major influences on survival. The risk of death over the following month in animals individually treated with an anthelmintic drug pre weaning was reduced by 0·61 compared with those not treated. The sire frailty variance estimate was similar to its standard error pre-weaning but larger post weaning. When adjusted for lamb body weight the sire variance post weaning increased to three times its standard error.

Copyright

Corresponding author

Email: L.Baker@cgiar.org

References

Hide All
Baker, R.L. 1998. A review of genetic resistance to gastrointestinal nematode parasites in sheep and goats in the tropics and evidence for resistance in some sheep and goat breeds in sub-humid coastal Kenya. Animal Genetics Resources Information Bulletin 24: 1330.
Baker, R.L., Mugambi, J.M., Audho, J.O., Carles, A.B. and Thorpe, W. 2002. Comparison of Red Maasai and Dorper sheep for resistance to gastro-intestinal nematode parasites, productivity and efficiency in a humid and a semi-arid environment in Kenya. Proceedings of the seventh world congress on genetics applied to livestock production, Montpellier, France, vol 31, pp. 639642.
Baker, R.L., Mwamachi, D.M., Audho, J.O., Aduda, E.O. and Thorpe, W. 1999. Genetic resistance to gastro-intestinal nematode parasites in Red Maasai, Dorper and Red Maasai ✕ Dorper ewes in the sub-humid tropics. Animal Science 69: 335344.
Baker, R.L., Nagda, S., Rodriguez-Zas, S.L, Southey, B.R., Audho, J.O., Aduda, E.O. and Thorpe, W. 2003. Resistance and resilience to gastro-intestinal nematode parasites and relationships with productivity of Red Maasai, Dorper and Red Maasai ✕ Dorper crossbred lambs in the sub-humid tropics. Animal Science 76: 119136.
Cloete, S.W.P., Snyman, M.A. and Herselman, M.J. 2000. Productive performance of Dorper sheep. Small Ruminant Research 36: 119135.
Collett, D. 1994. Modelling survival data in medical research. Chapman and Hall, London.
Ducrocq, V. 2000. Genetic improvement of laying hens viability using survival analysis. Genetics Selection, Evolution 32: 2340.
Ducrocq, V., Quaas, R.L., Pollak, E.J. and Casella, G. 1988. Length of productive life of dairy cows. II. Variance component estimation and sire evaluation. Journal of Dairy Science 71: 30713079.
Gatenby, R.M. 1986. Sheep production in the tropics and sub-tropics. Tropical Agricultural Series, Longman Group Ltd, Essex.
Gray, G.D., Woolaston, R.R. and Eaton, B.T. 1995. Breeding for resistance to infectious diseases of small ruminants. Australian Centre for International Agricultural Research monograph no. 34. ACIAR, Canberra, Australia.
Henryon, M., Berg, P., Jensen, J. and Andersen, S. 2001. Genetic variation for resistance to clinical and subclinical diseases exists in growing pigs. Animal Science 73: 375387.
Klein, J.P. and Moeschberger, M.L. 1997. Survival analysis: techniques for censored and truncated data. Springer, New York.
Lawless, J.F. 1982. Statistical models and methods for lifetime data. Wiley, New York.
McGilchrist, C.A. 1993. REML estimation for survival models with frailty. Biometrics 49: 221225.
Mathsoft, . 1999. S-Plus 2000 user’s guide: statistics, 1999 edition. Mathsoft, Seattle, Washington.
Milne, C. 2000. The history of the Dorper sheep. Small Ruminant Research 36: 99102.
Mukasa-Mugerwa, E., Lahlou-Kassi, A., Anindo, D., Rege, J.E.O., Tembely, S., Markos, Tibbo and Baker, R.L. 2000. Between and within breed variation in lamb survival and the risk factors associated with major causes of mortality in indigenous Horro and Menz sheep in Ethiopia. Small Ruminant Research 37: 112.
Muller, H.G. and Wang, J.L. 1994. Hazard rate estimation under random censoring with varying kernels and bandwidths. Biometrics 50: 6176.
Over, H.J., Jansen, J., Von Olm, P.W. 1992. Distribution and impact of helminth diseases of livestock in developing countries. Food and Agricultural Organization of the United Nations animal production and health paper no. 96. FAO, Rome.
Rege, J.E.O., Tembely, S., Mukasa-Mugerwa, E., Sovani, S., Anindo, D., Lahlou-Kassi, A., Nagda, S. and Baker, R.L. 2002. The effect of breed and season on production and response to infections with gastro-intestinal nematode parasites in sheep in the highlands of Ethiopia. Livestock Production Science In press.
Southey, B.R., Rodriguez-Zas, S.L. and Leymaster, K.A. 2001. Survival analysis of lamb mortality in a terminal sire composite population. Journal of Animal Science 79: 22982306.
Therneau, T.M. and Grambsch, P.M. 2000. Modelling survival data. Extending the Cox model. Springer, New York.
Traore, A., Peacock, C.P., Mack, S. and Agyemang, K. 1985. Mortality of lambs in African traditional livestock production systems. Veterinary Research Communications 9: 295301.
Wallin, L., Strandberg, E., Philipsson, J. and Dalin, G. 2000. Estimates of longevity and causes of culling and death in Swedish warm blood and cold blood horses. Livestock Production Science 63: 275289.
Wilson, R.T. 1991. Small ruminant production and the small ruminant genetic resource in tropical Africa. Food and Agriculture Organisation animal production and health paper no. 88. FAO, Rome.
Wilson,, R.T., Traore, A. and Mukasa-Mugerwa, E. 1993. Mortality and morbidity of African small ruminants under various management systems. Études et Synthèses de 1’IEMVT 42: 208236.
Yazdi, M.H., Rydhmer, L., Cederberg, E.R., Lundeheim, N. and Johansson, K. 2000. Genetic study of longevity in Swedish Landrace sows. Livestock Production Science 63: 255264.
Yazdi, M.H., Visscher, P.M., Ducrocq, V. and Thompson, R. 2002. Heritability, reliability of genetic evaluations and response to selection in proportional hazards models. Journal of Dairy Science 85: 15631577.

Keywords

Survival of Red Maasai, Dorper and crossbred lambs in the sub-humid tropics

  • R. Nguti (a1), P. Janssen (a2), G.J. Rowlands (a3), J.O. Audho (a3) and R.L. Baker (a3)...

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed