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Sward structure management for a maximum short-term intake rate in annual ryegrass

Authors


Correspondence to: J. C. Mezzalira, Grazing Ecology Research Group, Federal University of Rio Grande do Sul, Av. Bento Gonçalves, 7712, CEP 91540000, Porto Alegre, RS, Brazil.

E-mail: mezzalirajc@gmail.com

Abstract

This study tested the hypothesis that different sward structures, which were constructed by varying the pre- and post-grazing sward heights of annual ryegrass pasture (Lolium multiflorum Lam.) in southern Brazil, affect the short-term intake rate (STIR) by dairy cows. Treatments consisted of four sward-management strategies defined by a combination of two pre- (25 and 15 cm) and two post-grazing sward heights (10 and 5 cm): 15-05, 15-10, 25-05 and 25-10. A completely randomized block design with four replicates was used for the experimental design. The STIR was determined by the double-weighing technique. Jaw movements were evaluated using automatic recorders (IGER Behaviour Recorder). The results showed that treatment 25-10 allowed the animals to collect more herbage with a greater bite mass and thus resulted in a greater STIR. Treatments in which sward height was reduced to 10 cm generally favoured the ingestion process than treatments with a post-grazing sward height of 5 cm.

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