Publication Date
1997
Description
Two studies involving the sequential grazing of sets of patches on a perennial ryegrass (Lolium perenne) sward were carried out to investigate the effects of patch characteristics on the selective behaviour of grazing cattle. Experiment 1 involved a range of combinations of sward height (8.9 - 19.6 cm) and bulk density (1.33 - 1.67 mg DM/cm3). Distribution of grazing activity (number of bites or residence time) was strongly and positively related to patch height, but additional effects of variation in bulk density were limited. In Experiment 2 patches were manipulated to offer contrasts in both height (13.4 and 21.8 cm) and maturity (leaf to stem ratio, 2.53 and 0.74). In this case animals concentrated grazing bites and time on the shorter, more leafy patches. Behaviour at a patch was not significantly affected by the characteristics of the preceding or the succeeding patch in either study. These results indicate that under short term observations decision rules are largely influenced by the factors influencing ease of ingestion of herbage.
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Influence of Vegetation Patch Characteristics on Discriminatory Grazing by Dairy Cows
Two studies involving the sequential grazing of sets of patches on a perennial ryegrass (Lolium perenne) sward were carried out to investigate the effects of patch characteristics on the selective behaviour of grazing cattle. Experiment 1 involved a range of combinations of sward height (8.9 - 19.6 cm) and bulk density (1.33 - 1.67 mg DM/cm3). Distribution of grazing activity (number of bites or residence time) was strongly and positively related to patch height, but additional effects of variation in bulk density were limited. In Experiment 2 patches were manipulated to offer contrasts in both height (13.4 and 21.8 cm) and maturity (leaf to stem ratio, 2.53 and 0.74). In this case animals concentrated grazing bites and time on the shorter, more leafy patches. Behaviour at a patch was not significantly affected by the characteristics of the preceding or the succeeding patch in either study. These results indicate that under short term observations decision rules are largely influenced by the factors influencing ease of ingestion of herbage.
