Springer Nature is making SARS-CoV-2 and COVID-19 research free. View research | View latest news | Sign up for updates

The effect of weather on the occurrence and magnitude of periparturient rise in trichostronglyid nematode egg output in Dorper ewes in a semi-arid area of Kajiado District of Kenya


An investigation was carried out to assess the effects of weather on the occurrence and magnitude of the periparturient rise (PPR) in trichostrongylid nematode egg output in breeding Dorper ewes. The study was conducted over three breeding seasons on a ranch in the semi-arid area of Kajiado District in Kenya between June 1999 and December 2001. During each breeding season 20 ewes randomly selected from the breeding stock and 20 others selected from the unmated yearlings were monitored for faecal strongyle egg counts every 3 weeks. The lambing seasons were timed to coincide with the onset of the short rains (October–November 1999), the mid-short rains (November–December 2000) and the end of the dry season (September–October 2001). In each season higher egg outputs were recorded in the peri-parturient ewes compared to the unmated yearlings. The highest PPR occurred in September 2001, when lambing coincided with the end of the dry season, possibly as a result of maturation of hypobiotic larvae. The lowest PPR occurred in November 2000 when the onset of lambing coincided with the mid-short rains, possibly owing to low pasture infectivity associated with a long dry spell between January and October of the same year. The results of this study indicate that PPR occurred when lambing coincided with both the wet and the dry seasons. However, the magnitude was greatly influenced by the season when lambing occurred. It was also influenced by resumption of development of hypobiotic larvae and the nutritional status of the ewes. Not only should control of gastrointestinal nematode parasites in this area aim at preventing the occurrence of PPR by treating ewes 2–3 weeks before they are to lamb and during lactation, but the anthelmintic used must also eliminate hypobiotic larvae. In addition, the animals must be given supplementary feeding during this period.

This is a preview of subscription content, log in to check access.



periparturient rise


  1. Agyei, A.D., Sapong, D. and Probert, A.J., 1991. Peri-parturient rise in faecal egg counts in West African Dwarf Sheep in Southern Ghana in the absence of arrested strongyle larvae. Veterinary Parasitology, 39, 79–88

  2. 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 Maasai × Dorper ewes in the sub-humid tropics. Animal Science, 69, 335–344

  3. Barger, I.A., 1993. Influence of sex and reproductive status on susceptibility of ruminants to nematode parasitism. International Journal for Parasitology, 23, 463–469

  4. Connan, R.M., 1968. The post-parturient rise in faecal nematode egg counts of ewes. Its aetiology and epidemiological significance. World Reviews in Animal Production, 4, 53–58

  5. Connan, R.M., 1976. Effects of lactation on the immune response to gastrointestinal nematodes. Veterinary Record, 99, 476–477

  6. Coop, R.L. and Kyriazakis. I., 1999. Nutrition-Parasite interaction. Veterinary Parasitology, 84, 187–204

  7. Hansen, J. and Perry, B., 1994. The Epidemiology, Diagnosis and Control of Gastrointestinal Parasites of Ruminants in Africa, (ILRAD, Nairobi, Kenya)

  8. Houdijk, J.M.G, Kyriazakis, I., Coop, R.L. and Jackson, F., 2001. The expression of immunity to Teladorsagia circumcincta in ewes and its relationship to protein nutrition depends on body protein reserves. Parasitology, 122, 661–672

  9. Reynolds, L. and Adediran, S.O., 1987. The effects of browse supplementation on the productivity of West African Dwarf Sheep over two reproductive cycles: In: Goat Production in the Humid Tropics, Proceedings of a workshop, University of Ife, Nigeria, 83–91

  10. Romjali, E., Dorney, P., Batubara, A., Pandey, V.S. and Gatenby, R.M., 1997. Peri-parturient rise in faecal strongyle egg counts of different genotypes of sheep in North Sumatra, Indonesia. Veterinary Parasitology, 68, 191–196

  11. Schillhorn van Veen, T.S. and Ogunsusi, R.A., 1978. Peri-parturient and seasonal rise in the trichostrongylid egg output in infected ewes during the dry season in Northern Nigeria. Veterinary Parasitology, 4, 377–383

  12. Tembely, S., Lahlou-Kassi, A., Rege, J.E.O., Mukasa-Mugerwa, E., Anindo, D., Sovani, S., Baker, R.L., 1998. Breed and seasonal effects on the peri-parturient rise in nematode egg output in indigenous ewes in a cool tropical environment. Veterinary Parasitology, 77, 123–132

  13. Wanyangu, S.W., Mugambi, J.M., Bain, R.K., Duncan, J.L., Murray, M., Stear, M.J., 1997. Response to artificial and subsequent natural infection with Haemonchus contortus in Red Maasai and Dorper ewes. Veterinary Parasitology, 69, 275–282

  14. Whitlock, H.V., 1948. Some modifications of the McMaster helminth egg counting technique and apparatus. Journal of the Council of Science and Industrial Research of Australia, 51, 177–180

Download references

Author information

Correspondence to C. J. Ng’ang’a.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Ng’ang’a, C.J., Kanyari, P.W.N., Maingi, N. et al. The effect of weather on the occurrence and magnitude of periparturient rise in trichostronglyid nematode egg output in Dorper ewes in a semi-arid area of Kajiado District of Kenya. Trop Anim Health Prod 38, 389–395 (2006).

Download citation


  • Trichostrongylid nematodes
  • Periparturient rise
  • Weather
  • Hypobiosis
  • Semi-arid region
  • Kenya