Influence of structure and composition of ryegrass and prairie grass‐white clover swards on the grazed horizon and diet harvested by sheep

Abstract

Influence of structure and composition of ryegrass and prairie grass-white clover swards on the grazed horizon and diet harvested hy sheep Abstract Diet selection from ryegass-and prairie grasswhite clover swards, vertically stratified into three horizons (A>6 cm, B 3-6 cm, C>3 cm), was studied using oesophageally fistulated sheep during summer and autumn. Animals grazed for 3-day periods. Apparent herbage intake was calculated from total herbage disappearance. The composition of each horizon and of the diet selected was measured daily.Herbage mass (DM ha"') and sward height (cm) prior to grazing were not significantly different between swards in each season, and were 20 and 20 in summer and 1-6 and 10 in autumn. In summer. 36% and 5% of the green grass leaf (GGL) for prairie grass and ryegrass, respyectively, was distributed in horizons A and B. In autumn 39% and 29% of GGL occurred above 3 cm for prairie grass and ryegrass, respectively. GGL distribution determined which sward horizons were grazed. Sheep grazed horizon C (0-3 cm) of summer ryegrass pasture, and the surface canopy (>3 cm) of all other swards.In summer, apparent intake achieved by sheep grazing prairie grass swards was 87% higher than that achieved on ryegrass swards. In autumn a greater GGL distribution above 3 cm with prairie Correspondence; P. J. L'Huillier, Ruakura Agricultural Research Centre, Private Bag, Hamilton, New Zealand. grass (39%) than with ryegrass (29%) was associated with 36% higher apparent intake.

Allelopathic effects of endophyte‐infected perennial ryegrass extracts on white clover seedlings

“…The current study, however, used only the pseudostem of the ryegrass shoot where concentrations of endophyte mycelium and endophyte alkaloids are greatest. Pseudostem represents a large proportion of the green shoot biomass of grass in a sward and a site of accumulation of dead material (e.g., Parsons et al 1984;L'Huillier et al 1986). Allelochemicals can be leached from this plant material or released by decomposition of the dead residues (Rice 1984).…”

Microhistological Estimation of Grass Leaf Blade Percentages in Pastures and Diets

“…One of these procedures quantifies the percentages of the different plant parts in esophageal fistula samples (Arnold 1960;Chacon and Stobbs 1976;L'Huillier et al 1986;Del Pozo et al 1997). The other one quantifies the percentages of blade and those of the other plant parts together in vegetation of monospecific swards by near-infrared reflectance spectroscopy (NIRS) (Smart et al 1998).…”

“…However, studies that have evaluated blade selection by herbivores are scarce (Arnold 1960;Chacon and Stobbs 1976;L'Huillier et al 1986;Del Pozo et al 1997;Smart et al 1998). This can be related to the fact that the methodology usually used to determine plant part percentages in herbivore diets requires the use of esophageal fistulated animals or expensive equipment.…”

Intake and milk production of suckling ewes reared at pasture in humid tropics according to the post-grazing residue management

“…In fact, the protein supplies represented 95% and 77% of the total protein requirements in the RM and the RR systems, respectively. Probably the animals were not subjected to a too severe restriction, since they could have exerted their selective foraging behaviour and could have eaten the more leafy part of the sward [7,20]. As a matter of fact, taking into account the daily DM intake comparatively to the amount of forage on offer, the refusal rate was 16% and 46% in the RM and RR groups, respectively.…”