Publication Date
1985
Location
Kyoto Japan
Description
The impacts of brief periods of intense grazing in multipasture-single herd grazing systems on critical plant and animal parameters in natural mixed swards are not well understood. It was our objective to determine the interrelationship and nutritional consequence of tiller defoliation intensity, selection ratio and diet composition of two codominant species with contrasting phenology and growth habit as stocking rate was increased. A 16-pasture, 1-herd short-duration grazing regime was simulated at four stocking rates on a little bluestem (Schizachyrium scoparium)-brownseed paspalum (Paspalum plicatulum) savannah. Variables measured included morphology and defoliation intensity of marked tillers, diet composition and quality of esophageally fistulated steers, and intake using ytterbium as an external marker on non-cannulated steers. Regression models were developed to isolate factors affecting defoliation and selection. The data support the hypothesis that increasing stocking rate reduces the morphological variation in plant populations while minimizing the negative effects of plant structure on the selection process. Selection pressure was disproportionally greater on species with an erect growth habit (little bluestem) as stocking rate increased. Animals stabilized protein intake by switching to dicot species during the growing season as the more preferred grass species declined in stature and abundance and matured phenologically. This strategy was only effective for energy intake during the first half of the growing season.
Citation
Stuth, J W.; Brown, J R.; Olson, P D.; and Araujo, M R., "Influence of Stocking Rate on the Plant-Animal Interface in Rotational Grazed Mixed Swards" (1985). IGC Proceedings (1985-2023). 32.
(URL: https://uknowledge.uky.edu/igc/1985/ses11/32)
Included in
Agricultural Science Commons, Agronomy and Crop Sciences Commons, Plant Biology Commons, Plant Pathology Commons, Soil Science Commons, Weed Science Commons
Influence of Stocking Rate on the Plant-Animal Interface in Rotational Grazed Mixed Swards
Kyoto Japan
The impacts of brief periods of intense grazing in multipasture-single herd grazing systems on critical plant and animal parameters in natural mixed swards are not well understood. It was our objective to determine the interrelationship and nutritional consequence of tiller defoliation intensity, selection ratio and diet composition of two codominant species with contrasting phenology and growth habit as stocking rate was increased. A 16-pasture, 1-herd short-duration grazing regime was simulated at four stocking rates on a little bluestem (Schizachyrium scoparium)-brownseed paspalum (Paspalum plicatulum) savannah. Variables measured included morphology and defoliation intensity of marked tillers, diet composition and quality of esophageally fistulated steers, and intake using ytterbium as an external marker on non-cannulated steers. Regression models were developed to isolate factors affecting defoliation and selection. The data support the hypothesis that increasing stocking rate reduces the morphological variation in plant populations while minimizing the negative effects of plant structure on the selection process. Selection pressure was disproportionally greater on species with an erect growth habit (little bluestem) as stocking rate increased. Animals stabilized protein intake by switching to dicot species during the growing season as the more preferred grass species declined in stature and abundance and matured phenologically. This strategy was only effective for energy intake during the first half of the growing season.
