Herbage intake by Churra ewes grazing at two different sward heights

Abstract

Herbage intake and some characteristics of diet selected by grazing Churra ewes were studied on two plots of a Lolium-Festuca- Trifolium pasture maintained at two different sward heights (sward heights (SH): 4 cm (SSH) and 8 cm (HSH) in two periods (PE): summer and autumn. Herbage intake was estimated from measurements of faecal output and of digestibility of extrusa samples. With the exception of crude protein content, no significant (P≤0.05) effects of PE nor SH were detected in the chemical composition and digestibility of herbage on offer. Daily herbage intake (g OM/kg live weight) was greater (P≤0.10) on HSH than on SSH and was also greater (P≤0.05) in autumn than in summer. Significant effects of PE (P≤0.01) and SH (P≤0.05) were obtained in the selection ratios (calculated as the content of each considerate component in extrusa samples divided by its content in the herbage on offer) for alI chemical fractions and for digestibility. Except for cellulose, interaction between main factors had a significant (P≤0.001) effect on the selection ratios.