This study testedthe hypothesis that variation of herbage allowance during the growing seasoninfluences pasture dynamics and grazing behaviour. Treatments consisted of fourfixed herbage allowances during the entire year (4.0, 8.0, 12.0, and 16.0%,expressed as kg DM/100 kg live weight/day) and three variable herbage allowances(8% in spring and 12% along the rest of the grazing season; 12% spring and 8%along the rest of the grazing season; 16% in spring and 12% along the rest ofthe grazing season). A randomized complete block design was used, with two replicates.It was used a variable continuous stocking method, using the "put-and-take"technique. Primary and secondary productions were measured, as well as steergrazing behaviour. Results showed that low herbage allowance, as in 4% treatment,jeopardize animal performance. Herbage allowance of 8% in spring and 12% alongthe rest of the grazing season promoted good animal performance, suggestingthis management could be interesting when manipulating sward structure. Concerninggrazing behaviour, results indicated that differently from what occurs in cultivatedpastures, herbage allowance or herbage mass did not explain sufficiently thegrazing time observed. It was concluded that in heterogeneous vegetation, itmust be considered the structural diversity on pasture characterization in orderto link that with grazing behaviour.
