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The inclusion of legumes in pasture reduces the need for mineral nitrogen applications and the pollution of groundwater; however, the agronomic and animal husbandry advantages with tropical legumes are still little known. The objective of this study was to quantify the effect of the use of forage peanut (Arachis pintoi cv. Amarillo) in dwarf elephant grass pastures (Pennisetum purpureum cv. BRS Kurumi) on forage intake and animal performance. The experimental treatments were dwarf elephant grass fertilized with 200 kg N/ha, and dwarf elephant grass mixed with forage peanut without mineral fertilizers. The animals used for the experiment were 12 Charolais steers (body weight (BW) = 288 ± 5.2 kg) divided into four lots (two per treatment). Pastures were managed under intermittent stocking with an herbage allowance of 5.4 kg dry matter of green leaves/100 kg BW. Dry matter intake (mean = 2.44 % BW), the average daily gain (mean = 0.76 kg), and the stocking rate (mean = 3.8 AU/ha) were similar between the studied pastures, but decreased drastically in last grazing cycle with the same herbage allowance. The presence of peanut in dwarf elephant grass pastures was enough to sustain the stocking rate, but did not allow increasing forage intake and animal performance.

-The objective of this work was to assess the effects of the sward structure of Italian ryegrass (Lolium multiflorum), during the first grazing cycle, on its morphological and bromatological characteristics throughout the growing season, and on the performance of dairy cows. The treatments consisted of two structures obtained as a function of canopy-light interception: high-light interception (HLI) and low-light interception (LLI), with different pre-grazing heights in the first grazing cycle. Pasture was managed under rotational grazing with a herbage allowance not below 30 kg dry matter (DM) per cow per day. Three grazing cycles, with a grazing interval of 30 days, were evaluated. Pre-grazing herbage mass was greater (2,240 vs. 1,656 kg ha -1 DM), but the proportion of leaf blades was smaller (0.35 vs. 0.43) for HLI swards. Neutral detergent fiber (NDF) content and organic matter digestibility (OMD) were similar between treatments in the first grazing cycle, but in the second and third ones NDF was greater, and OMD lower, for the HLI swards. Milk yields were greater for cows grazing LLI swards (19.4 vs. 21.1 kg per day). Initial grazing with 90% of light interception promotes greater nutritional value in the subsequent cycles.

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The aim of this study was to evaluate the effects of shading on structural characteristics and herbage accumulation of palisade grass (Brachiaria brizantha cv. Piatã), in a crop–livestock–forest integration area. Three shade regimes were evaluated: no shade (NS), moderate shade (MS, 338 trees ha–1), and intense shade (IS, 714 trees ha–1). The effects of shade regime on soil-water content and nitrogen nutrition index were also evaluated. Grazing management was established based on sward light interception targets (95% LI pre-gazing). The MS and IS regimes were divided into two shade strips (central and lateral) in order to describe the variation in light availability within the paddocks. Two methods for taking the reference readings of LI were tested in IS paddocks: LI reading inside (under the tree canopy) and outside (under full sunlight) the experimental area. Increased tree density reduced photosynthetically active radiation on lateral and central shade strips by 37% and 12% for MS, and 52% and 50% for IS, respectively. For NS, MS, IS (outside) and IS (inside), grazing intervals were 23, 26, 28 and 35 days, pre-grazing heights corresponded to 33, 35, 43 and 52 cm, and pre-grazing herbage mass to 5.37, 4.44, 2.96 and 3.23 t ha–1, respectively. Leaf percentage remained relatively stable across shade regimes, but stem percentage was greater and dead material percentage was smaller for IS than for NS and MS. Soil water content was lower near the trees, especially during the dry season. Relative to NS, herbage accumulation decreased by 39% and 68% for MS and IS, respectively. Under natural shade, small variations in light availability affect sward structure and herbage production. The use of the 95% LI target developed under full sunlight conditions is not suitable for use under trees, emphasising the need to generate specific grazing-management targets for pastures cultivated under trees.

Ruminants vary their walking trajectory according to the positioning of the trees in integrated systems, which can determine the concentration of dung deposition at certain locations. The aim of this study was to map the distribution of feces and the behavior of dairy heifers in sunny and shaded areas. This experiment was carried out in Mato Grosso, Brazil, where the main grazing conditioner is shade due to the presence of trees in the pastures. Shading levels used were: full sunlight (control), moderate shade (338 trees ha−1) and intensive shade (714 trees ha−1) in randomized complete blocks. The experimental period was divided into three evaluation periods based on rainfall distribution: rainy period = December 2012; transition period = March 2013 and dry period = June 2013. Animal behavior assessments and dung distribution mapping were performed. The full sunlight system displayed a higher concentration of feces patches at sites near the gate, cow drinkers and fences opposite the gate. Heifers picked shaded places for ruminating and idleness. The major concentration was reported in the central area and under trees, in shaded systems. There were places with greater feces concentrations, but when the pasture had trees, deposition did not only happen underneath trees but also in places under their influence. The distribution was more homogeneous when trees were present in large quantities. The shaded area available in pastures affects spatial distribution of dung, stimulating uniformity.

No abstract

I Farelo de glúten de milho para vacas leiteiras em pastos de azevém anualCorn gluten meal to dairy cows grazing italian ryegrass RESUMO Neste trabalho, foi avaliado o efeito da suplementação com proteína de baixa degradabilidade ruminal (PNDR) para vacas leiteiras em pastos de azevém anual (Lolium multiflorum Lam.). Foram utilizadas 12 vacas da raça