Grazing down process: The implications of sheep's ingestive behavior for sward management

Abstract

Foraging behavior studies have supported innovations in sward management, making pastoral systems more sustainable and competitive. Based on this, we evaluated the sheep's ingestive behavior responses and the changes in sward structure during four stages of grazing down in rotational stocking, indicating the threshold level of grazing down for sheep grazing in the reproductive stage of annual ryegrass (Lolium multiflorum Lam.) managed under two grazing intensities (low and moderate). We found evidence that the two grazing intensities each promoted a grazing down at approximately 45% of the non-limiting pre-grazing sward height. However, during grazing down at the end of the sward reproductive stage, the leaves frequency remained lower than that of inflorescences, indicating a restrictive situation for animals in each of the two grazing intensities evaluated. The sheep's ingestive behavior patterns were constrained by the modifications in sward structure. There was observed a decrease in grazing time and bite rate, and a gradual increase in the number of steps between feeding stations during the grazing down stages. Therefore, sheep's behavioral responses during the grazing down of annual ryegrass depend on: (i) grazing intensity, (ii) period of the sward reproductive stage, and (iii) forage structural and chemical composition during grazing down.