The effect of winter and early spring grazing by sheep on subsequent sward production

Abstract

SummaryThe effect on sward production of grazing by sheep during different periods of the winter and the effect of different dates of ceasing grazing in late winter-early spring were measured in field experiments by cuts during the spring and summer and by botanical analysis.Winter and early spring grazing reduced herbage yield in April, May and June, but not subsequently. Nitrogenous fertilizer applied when grazing ceased approximately counterbalanced the reduction in yield due to grazing. The grazing treatments had little or no effect on botanical composition. The size of the reduction in yield due to grazing was such that it might reasonably be explained in terms of the date on which grazing ceased and the amount of photosynthetic tissue left at that date. The amount of yield added during a given period in the spring appeared to be very greatly affected by the amount of photosynthetic tissue present at the beginning of that period and it is suggested that this is a partially hidden cost of winter and early spring grazing which should be more fully researched.