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Among the various sources with a potential negative impact on the environment, methane (CH 4 ) emissions from livestock origin have been highlighted as important for the agricultural sector. Research to mitigate CH 4 emissions and understand how integrated crop and livestock production systems may contribute to the reduction of greenhouse gases, is essential for the development of public policies for environmental preservation. We hypothesized that combinations of stocking methods and grazing intensities provokes differences in the quantity and quality of herbage ingested, thus altering animal production and CH 4 emissions by the grazing animal. Experiments were carried out in 2011 (Experiment 1) and 2012 (Experiment 2), when the production of pasture and CH 4 emissions from sheep were studied in a system that integrates soybean (Glycine max. (L.) Merr.) and maize (Zea mays L.) in the summer/autumn, in rotation with Italian ryegrass (Lolium multiflorum Lam.) in winter/spring. Two stocking methods (continuous or rotational) and two grazing intensities (herbage allowance: moderate and low, 2.5 and 5 times the potential daily dry matter intake, respectively) in a randomized complete block design with three replicates were studied. Lambs were used in the first experiment, while lactating ewes (all with a single lamb) were used in the second experiment. Average daily gain (ADG) of lambs was greater (P < 0.05) in continuous than in rotational stocking, regardless of grazing intensity (150 vs. 89 g day −1 and 241 vs. 209 g day −1 in Experiments 1 and 2, respectively). Ewe ADG did not differ (P > 0.05) between treatments. Live weight gain per hectare (LWGHA) showed the same response in both experiments, with greater LWGHA in moderate grazing intensity (P < 0.05). In Experiment 1, the dry matter intake (DMI) was on average 21% greater (P < 0.05) for continuous stocking than rotational stocking (1345 g day −1 vs. 1075 g day −1 , respectively), while in Experiment 2, no differences (P > 0.05) between stocking methods and grazing intensities were observed (1673 ± 83 g day −1 ). The CH 4 emissions per animal did not differ (P > 0.05) among treatments in both experiments (22.7 ± 1.0 and 39.9 ± 1.3 g day −1 , Experiments 1 and 2, respectively), but when expressed in g CH 4 kg ADG −1 emissions were on average 35 and 15% greater (Experiments 1 and 2, respectively) (P < 0.05) under rotational than continuous stocking, independent of grazing intensity (171 vs. 263 g CH 4 kg ADG −1

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An understanding of the processes involved in grazing behaviour is a prerequisite for the design of efficient grassland management systems. The purpose of managing the grazing process is to identify sward structures that can maximize animal forage daily intake and optimize grazing time. Our aim was to evaluate the effect of different grazing management strategies on foraging behaviour and herbage intake by sheep grazing Italian ryegrass under rotational stocking. The experiment was carried out in 2015 in southern Brazil. The experimental design was a randomized complete block with two grazing management strategies and four replicates. The grazing management treatments were a traditional rotational stocking (RT), with pre- and post-grazing sward heights of 25 and 5 cm, respectively, and a ‘Rotatinuous’ stocking (RN) with pre- and post-grazing sward heights of 18 and 11 cm, respectively. Male sheep with an average live weight of 32 ± 2.3 kg were used. As intended, the pre- and post-grazing sward heights were according to the treatments. The pre-grazing leaf/stem ratio of the Italian ryegrass pasture did not differ between treatments (P > 0.05) (~2.87), but the post-grazing leaf/stem ratio was greater (P < 0.001) in the RN than in the RT treatment (1.59 and 0.76, respectively). The percentage of the non-grazed area was greater (P < 0.01) in post-grazing for RN compared with RT treatment, with an average of 29.7% and 3.49%, respectively. Herbage nutritive value was greater for the RN than for the RT treatment, with greater CP and lower ADF and NDF contents. The total time spent grazing, ruminating and resting did not differ between treatments (P > 0.05), with averages of 439, 167 and 85 min, respectively. The bite rate, feeding stations per min and steps per min by sheep were greater (P < 0.05) in the RN than in the RT treatment. The grazing time per hour and the bite rate were greater (P < 0.05) in the afternoon than in the morning in both treatments. The daily herbage intake by sheep grazing Italian ryegrass was greater (P < 0.05) in the RN than in the RT treatment (843.7 and 707.8 g organic matter/sheep, respectively). Our study supports the idea that even though the grazing time was not affected by the grazing management strategies when the animal behaviour responses drive management targets, such as in ‘Rotatinuous’ stocking, the sheep herbage intake is maximized, and the grazing time is optimized.

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We aimed to evaluate the effect of different grazing management strategies on carcass characteristics traits, meat quality and CH4 intensity and yield of lambs grazing Italian ryegrass pastures in Southern Brazil. A grazing trial was performed (2014 and 2015) in a randomized complete block design with two grazing management targets and four replicates. Treatments were traditional rotational stocking (RT), with pre-and post-grazing sward heights of 25 and 5 cm, respectively, and 'Rotatinuous' stocking (RN), with pre-and post-grazing sward heights of 18 and 11 cm, respectively. Castrated crossbred Texel and Polwarth lambs were used.Results indicated that diet cost per kg of dry matter (p = 0.001) and per hectare (p < 0.001) were lower for RN than for RT treatment. Final live weight (p = 0.022) and hot and cold carcass weight (p = 0.006) were greater for the RN treatment. All commercial cuts were greater for RN than for RT treatment. The RN treatment presented greater (p < 0.001) production of carcass, edible food and crude protein.Feed efficiency and feed cost conversion were better for RN than for RT treatment.CH4 intensity per kg of carcass, edible food and crude protein gain were 2.6, 2.7 and 2.1 times lower (p < 0.001) for RN. Moreover, CH4 yield was lower (p = 0.014) for RN than for RT treatment, with an average of 7.6 and 8.3% of the gross energy intake, respectively. We conclude that the 'Rotatinuous' stocking results in a greater carcass production, carcass quality and lower diet cost, and CH4 intensity and yield of grazing lambs. Adopting this grazing management strategy could enhance both lamb production and mitigation of CH4 intensity and yield in grazing ecosystems, which could be considered a good example of climate-smart livestock production.

reSUmO Busca-se nos Sistemas Integrados de produção agropecuária (SIpa) maior ciclagem do nitrogênio (n). este trabalho objetivou avaliar a adubação antecipada em azevém pastejado por ovinos no índice de nutrição nitrogenada (Inn) das culturas de verão em SIpa. O estudo foi realizado em um protocolo de longa duração manejado, no período de inverno, sob dois métodos de pastoreio, contínuo e rotativo, e duas intensidades de pastejo, moderada e baixa, com quatro repetições. no verão, a área foi subdividida em dois sistemas de cultivos, soja e rotação soja/milho. a fertilização foi feita na fase pastagem, com 75 kg de n e 60 kg de p 2 O 5 e K 2 O ha -1 . avaliaram-se a massa de forragem residual (mFr) da pastagem e o rendimento, o teor de N e o INN da fitomassa das culturas de verão. No milho, houve efeito das intensidades de pastejo para Inn, ao contrário da soja. não houve efeito dos métodos de pastoreio. a mFr é importante fonte de n para a cultura de verão subsequente. menores intensidades de pastejo Recebido para publicação em 2 de maio de 2015 e aprovado em 21 de junho de 2015.