Impact of grazing on parasites

Results:

There is little evidence to support changing the current sward height recommendations based on the findings of this report. Rotational grazing systems do not generally offer greater parasite control over set stocking. Mixed grazing systems can improve pasture utilisation and improve the growth rates of lambs through dilution of parasites and differences in grazing behaviour and grazing height between cattle and sheep.

Planned activity:

The report will be converted into a BRP+ booklet.

The Problem:

Grazing management is a key focus for EBLEX activity in 2009 and 2010.  A key message from our activity is sward height management, e.g. 4 cm being ideal for set stocked ewes and lambs, and 8 cm being ideal for set stocked cows and calves.  When this concept is discussed at on-farm events, questions are raised about the consequences for parasite control when animals are grazing tight pastures.

Project Aims:

• To understand where parasites are within the sward profile, and how this changes with sward heights and plant type.
• To establish how the risk changes with different grazing strategies, e.g. set stocking, rotational grazing, strip grazing (with and without back fence), block grazing and forward creep grazing, and how this changes with time of year, parasites and climate.
• To appreciate the benefit of tight grazing taking into consideration feed quality versus risk of parasite ingestion.
• To consider the difference in risk between lowland, upland and hill grazing, with thought given to the impact of environmental grazing.
• To highlight the potential on bioactive forages, and the likelihood of them being successful grown, e.g. chicory vs lotus.
• To identify if new research is needed.

Approach:

A review of literature relating to the impact of grazing management on cattle and sheep parasites will be undertaken.