Evaluation of a sward sampling technique for estimating herbage intake by grazing sheep


Mr R. J. K. Walters, Welsh Plant Breeding Station, Plas Gogerddan, Aberystwyth, SY23 3EB, UK.


A sampling procedure for estimating herbage intake by the ‘Difference’ method over short grazing periods using an electrically powered sheep-shearing head to cut long narrow sample strips, was compared with several indirect animal techniques on single-variety grass swards. The method provided intake estimates in good general agreement with those obtained by animal methods but discrepancies arose when used on a semi-prostrate variety due, probably, to incomplete recovery of sampled herbage cut from post-grazing residues.

It was concluded that the method might be usefully adopted for the preliminary assessment of the intake characteristics of herbage varieties in routine evaluation programmes, provided that care is taken to ensure the efficient collection of herbage sampled post-grazing and that a reduction in the land requirement can be achieved without undue loss of accuracy or precision. Confirmation of results should be sought using animal methods when possible.