<b>eaf tissue flows in ryegrass managed under different stocking rates

Abstract

ABSTRACT. Morphogenetic, structural variables and leaf biomass flows of Italian ryegrass (Lolium multiflorum Lam.) were evaluated under two stocking rates: 'Low' and 'High'. These rates were determined by heifers exclusively on pasture or on pasture and supplemented with corn grain. The experimental design was completely randomized following a repeated measure arrangement, two stocking rates, two and four replications of area for the stocking rates 'low' and 'high', respectively. The morphogenetic variables, the number of green leaves and tiller density were similar in both stocking rates. Leaf senescence rate was higher with low stocking rate. Heifers grazed with similar intensity and frequency in both stocking rates. The increase by 33.6% in the stocking rate caused by the use of supplement does not change the leaf biomass flow of Italian ryegrass, but alters its potential efficiency of use near the reproductive stage of the plant.

Effect of herbage allowances on biomass flows in Italian ryegrass

“…In a study on ryegrass managed under three forage disappearance intensities, CONFORTIN et al (2009) observed that in grazing, the 43.3% disappearance intensity of pre-grazing forage mass allowed a greater flow of leaf blades intake, with intermediate growth and senescence flows. SILVA et al (2015), observed that when ryegrass is managed under different stocking rates, the leaf biomass flow is not altered.…”

<b>Efficiency of the use of ryegrass by heifers in response to the receival of supplement

“…The forage mass values indicate that there was no restriction on DM intake for grazing heifers (Roman et al, 2007) and also the sward height did not restricted the consumption (Silva et al, 2015). The leaf mass (736.4 ± 29.8 kg DM ha ; p = 0.2449) were similar, regardless of the evaluated feeding system.…”

“…The intensity of defoliation, with values between 50 and 55%, tends to be relatively constant, regardless of the adopted management (Lemaire et al, 2009). Silva et al (2015), when providing corn grain to grazing heifers on ryegrass, observed that the intensity of defoliation was 60.9%.…”

“…Considering the importance of ryegrass on production systems in the southern region of Brazil, there are few studies on intensity and frequency of defoliation, when grazing animals are supplemented (Silva et al, 2015). This study was conducted aiming to characterize the grazing efficiency of beef heifers exclusively on ryegrass pasture or grazing and receiving supplement (corn grain or extruded commercial supplement with added fat).…”

<b>Patterns of use of time by heifers with or without supplementation at different phenological stages of winter grasses

“…Evaluation of ingestive behavior comprised grazing and rumination time in minutes/hours of the day; forage intake, using chromium oxide as external marker (Rosa et al, 2013); leaf lamina intake (Silva et al, 2015) and forage ingestion rate (g DM min -1 ) (Benvenutti, Gordon & Poppi, 2006). Ingestive behavior was calculated by visual observations during 18-hour periods.…”