Effects of helminths and nutrition on sheep production in northern China

• Chinese Academy of Agricultural Sciences, China

Helminth infections and poor nutrition are well known to reduce the production of wool and meat in grazing sheep. Surveys conducted in the northern provinces of China show that the common gastrointestinal helminths of sheep such as Haemonchus, Ostertagia and Trichostrongylus spp. are abundant and widely distributed and outbreaks of disease indicate that parasitism is severe in winter and spring when the availability of forage is limited and the nutritional status of sheep is low. Data describing the nutritional value of herbage grazed in different seasons and of the supplements fed in winter will be valuable for this region of the world.

This project aims to determine the significance of helminths in the family Trichostrongylidae infections and poor nutrition as causes of reduced wool production, both in quantity and quality, and to assess changes in sheep management designed to increase production from Merino sheep in northern China. The nutritive value of pastures and supplements are to be determined for the purpose of assessing the productivity of the present sheep production system.

Sites in Gansu Province and the Autonomous Regions of Xinjiang and Inner Mongolia will be used in collaboration with Projects No. 8454, 8464 and 8456. The seasonal rate of wool growth, liveweight gain and total fleeceweight will be measured on groups of sheep which graze together although treated in different ways, to allow comparisons to be made between sheep with naturally acquired infections of Trichostrongylidae, those treated according to current practice and those maintained worm-free. It is proposed that observations be conducted on two age groups of sheep, namely, weaners and young breeding ewes, in each of 3 successive years to measure the variation between wool types, seasons and years. At the same time forage and when appropriate, supplement also, will be collected for detailed analysis. It is expected that data from these analyses will be used in a simulation model to aid in the development of management systems. Experiments have been designed to measure the interaction between trichostrongylid infections of sheep and nutrition by measuring the effects of a graded series of infections of either Osteragia or Trichostrongylus spp. on both the amount and quality of wool produced by Merino sheep grazing typical pastures at times when nutritive stress occurs.

The project has a high probability of providing essential information on the effects of helminth epidemiology and the supply of nutrients for sheep grazing in three northern provinces of China.

The project will be carried out in the major fine wool growing areas of Northern China at 3 locations, Xinjiang, Inner Mongolia and Gansu. The Bureau of Animal Husbandry, and the National and Provincial extension groups will be fully involved in the project. Extension results will be fed into the Bureau of Animal Husbandry to facilitate dissemination of the results. In addition, annual consultations are proposed to be held in China to facilitate extension of the results to the State and Provincial farms and between provinces.

If a suitable management system is developed, Provincial Workshops will be held under the auspices of the Bureau of Animal Husbandry to assist in the extension of the results. In addition each site will have on-farm demonstrations for other farm managers.