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The barley culture has been conquering space in Southern Brazil, being an option for rotation with wheat. One of the main constraints for the increased productivity is the race against weed, especially ryegrass. Therefore, this study aimed to evaluate the barley competitive ability (Hordeum vulgare) against the ryegrass (Lolium multiflorum), in relation to the nitrogen absorption and to measure the density in which the culture is negatively affected. For this, a field experiment was conducted using experimental designs of randomized blocks, where the barley coexisted with different ryegrass densities (0, 4, 16, 32, 64 and 128 m-2). The analyzed varieties were plant height, chlorophyll, number of barley and ryegrass stems, barley and ryegrass dry mass, leaf area, number of spikes, number of grains per spike, the weight of a thousand grains and yield. The ryegrass interferes negatively on the barley's development and productivity, even in low densities, being necessary its control to four plants m-2. [ABSTRACT FROM AUTHOR]

Forage breeding is key to improving livestock management and the objective of this study was to evaluate Pearson's simple correlation between the yield components of forage dry matter and grain in ryegrass. Five ryegrass genotypes, planted on five dates and cut from one to four times, were set out in a complete randomized block design. Ryegrass forage with a lower dry matter production, but with more leaves, fewer culms, higher protein and less fiber content, produces a higher grain yield, spike length, thousand grain weight and lower spike number. The association between the yields of dry matter and grain components is an important criterion for selecting ryegrass genotypes, since grain yield is positively correlated with leaf dry matter, gross protein content, spike length and thousand grain weight. [ABSTRACT FROM AUTHOR]

Leaf tissue flow in Italian ryegrass (Lolium multiflorum Lam.) was quantified in three grazing intensities. The intensities corresponded to the disappearance of 21.1 ('Low'), 43.3 ('Mean') and 61.0% ('High') of the initial forage mass on each grazing cycle. The experimental animals were ewe lambs and the thermal sum of 313 degree-days determined the interval among grazing. The experimental design was completely randomized with three treatments and four replicates. In intensity 'Low' the highest growth and senescence flows were registered, respectively, 85.6 and 54.6kg ha day-1 of DM. In 'Mean' and 'High' intensities the growth and intake flows were higher in the beginning of pasture utilization and the senescence flow increased with the development of the Italian ryegrass cycle. It is recommended the use of the 43.3% grazing intensity which allowed greater values of intake flow, with mean growth and senescence flows. [ABSTRACT FROM AUTHOR]

The aim of this research was to evaluate the effect of undegradable protein supplementation to dairy cows grazing Italian ryegrass. Twelve Holstein cows in the mid lactation were used and treatments were 0 (zero) and a mixture (60:40) of ground corn + corn gluten meal (4.0kg cow day-1) evaluated along three periods of fifteen days. Cows were distributed in four groups (two per treatment) and assigned to Italian ryegrass plots submitted to intermittent grazing with a herbage allowance of 24kg of DM cow day-1. Pre-grazing herbage mass (2325kg of DM ha-1) and sward surface height (15.8cm) were similar on plots and crude protein and NDF of ingested forage were 18.9 and 53,0%, respectively. Supplementation did not affect herbage DM intake (mean=8.5kg cow day-1) but, both, total DM intake and metabolisable energy increased 3.0kg and 42MJ cow day-1, respectively. Supplementation increased milk production (4.0 kg.cow.day-1) but did not change protein and fat milk content (32.8 and 29.2g kg-1). At low herbage allowance, supplementation with corn ground meal (22% of crude protein) increase milk production on proportion of 1:1 and studies should be done at conditions of non- limitant herbage allowance. [ABSTRACT FROM AUTHOR]

Body development of beef heifers grazing Italian ryegrass pasture (Lolium multiflorum Lam.) was evaluated. The animals received different alternatives of mineral supplement: associated or not to ionophore addition and the treatments were: 'Common salt': mineralization with sodium chloride; '40P salt': mineralization with mineral salt plus 40g of phosphorus per kilo of product; 40P salt + ionophore: mineralization with 40g of phosphorus plus 2000mg of lasalocid per kg of product. The values of crude protein, neutral detergent fiber and Ca and P of the apparently consumed forage, salt intake, body condition and body weight:height relation were similar (P>0.05) between animals receiving 'common salt', '40P salt' and '40P salt+ionophor'. For beef heifers grazing ryegrass pasture without intake restriction, the lasalocid associated to mineral salt provides a greater body weight at twelve months age and a positive financial. [ABSTRACT FROM AUTHOR]

This study had the objective to evaluate Pampa Corte Model's reliability in predicting beef cattle performance in grazing systems. For this purpose, model's predicted values were compared to available data base of published papers. Correlation coefficients above 90 % were obtained between simulated and real data in all tested alternatives. Model's data base should be enlarged by forage productivity data in different climatic conditions. Mixtures of Italian ryegrass and oat need more studies to obtain qualitative parameters (crude protein degradability and neutral detergent fiber), as well, animal performance in the single pastures of oat or Italian ryegrass. [ABSTRACT FROM AUTHOR]