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Integrated crop-livestock systems (ICLS) can be an alternative to increase the productivity of agroecosystems by enhancing nutrient cycling via grazing animals. Despite the holistic approach that bears the designing of ICLS, fertilization practices are proceeded in a conventional crop basis, disregarding nutrient fluxes at the appropriate spatial and temporal dynamics. We argue that fertilization practices in ICLS must follow the same integrated approach. To test this, we compared a conventional crop fertilization strategy versus a system fertilization approach applied to two production systems being a conventional cropping system and ICLS. The conventional cropping system consisted of a soybean crop succeeded by a non-grazed Italian ryegrass cover crop. The ICLS model consisted of a soybean-Italian ryegrass rotation grazed by sheep. In the conventional crop fertilization strategy phosphorus and potassium were applied at soybean sowing and nitrogen at the Italian ryegrass establishment. The system fertilization consisted of the application of all nutrients during the Italian ryegrass establishment. Accordingly, treatments were fertilization strategies in a factorial framework with production systems randomly distributed in a complete block design with four replicates. Results indicated for the first time greater daily herbage accumulation rate (24%; P < 0.01) and total herbage production (18%; P < 0.05) in the system fertilization compared with conventional crop fertilization. Consequently, system fertilization allowed for greater stocking rates in the pasture phase (17%; P < 0.05). The ICLS presented greater equivalent soybean yield (P < 0.001), energy production (P < 0.01), and system productivity (P < 0.05) compared with the cropping system, regardless of fertilization strategies. Soybean yield was not affected by fertilization strategies or grazing. In conclusion, the adoption of system fertilization strategy and crop-livestock integration enhance the production without jeopardizing soybean grain yields, so that land use is optimized by a greater energy production per unit of nutrient applied. [ABSTRACT FROM AUTHOR]

• Rotatinuous stocking is a grazing management innovation based on animal behaviour. • Grazing management affects faecal N excretion and GHG emissions by sheep. • Faecal N excretion by grazing sheep is greater under Rotatinuous stocking. • Faecal CH 4 and N 2 O emissions by grazing sheep are greater under Rotatinuous stocking. Rotatinuous stocking (RN) management is based on animal ingestive behaviour responses, where optimal pre- and post-grazing sward heights are defined to increase nutrient intake per unit of grazing time. We hypothesized that the optimal sward structure and consequently, a high herbage nutritive value in RN treatment results in a greater faecal nitrogen (N) excretion by sheep and consequently, a greater faecal greenhouse gas (GHG) emissions compared with the traditional rotational stocking (RT) management, which is based on a maximum herbage accumulation and harvest. Therefore, the aim of this study was to evaluate the effect of two grazing management strategies (RN and RT) on the amount of dry matter (DM) faecal excretion, faecal N excretion and faecal GHG (CH 4 and N 2 O) emissions from growing sheep grazing Italian ryegrass pastures. In order to evaluate faecal production and N excretion per animal and per ha, a first experiment (1) was carried out: RT - pre and post-grazing sward heights of 25 and 5 cm, respectively and, RN - pre and post-grazing sward heights of 18 and 11 cm, respectively. A second experiment (2) was carried out to measure the CH 4 and N 2 O fluxes from faeces, using the static chamber method. Daily DM faecal and N excretion per animal were higher (P < 0.001) in RN compared with RT treatment. However, when considered daily DM faecal and N excretion per ha, results were lower (P < 0.001) for the RN than the RT treatment. CH 4 and N 2 O emissions from faeces were higher (P < 0.001) in RN compared with RT treatment, both per animal and per hectare. In conclusion, our study showed that the RN grazing management, based on animal behaviour, resulted in a higher daily N excretion per animal and higher CH 4 and N 2 O emissions from faeces of sheep grazing Italian ryegrass pastures. This study contributes to improve GHG national inventories for the subtropical Brazilian climatic conditions, where estimations from CH 4 and N 2 O emissions factors for faeces from growing sheep grazing Italian ryegrass are markedly lower than the values reported by IPCC Default Tier 1. [ABSTRACT FROM AUTHOR]

To test the hypothesis that the best sward structure in the grazing management strategy based on animal behaviour, called “Rotatinuous” stocking, results in higher nutrient intake and lower methane emission and intensity by sheep grazing Italian ryegrass pastures, two grazing management strategies were studied: the traditional rotational stocking (RT) with pre- and post-grazing sward target heights of 25 and 5 cm, respectively and, “Rotatinuous” stocking (RN) with pre- and post-grazing sward target heights of 18 and 11 cm, respectively. Male castrated sheep were used. The experiment was carried out in 2014 and 2015 in southern Brazil. The experimental design was a randomized complete block with four replicates. The RN treatment had better herbage chemical composition in terms of quality than that of the RT treatment, with greater (P < 0.05) crude protein and lower neutral and acidic detergent fibre. The ideal sward structure and greater chemical composition of Italian ryegrass pastures found under RN treatment resulted in greater herbage digestibility and intake of organic matter and metabolizable energy by grazing sheep than under the RT treatment. Our study highlights that management is the key strategy to reduce the environmental impact of grazing through lower CH 4 emissions in livestock grazing systems. “Rotatinuous” stocking was the more efficient grazing management strategy for mitigation of CH 4 emissions and intensity by grazing sheep, with 64% less CH 4 production per area and 170% less CH 4 emission per unit of animal product when compared to the RT treatment. [ABSTRACT FROM AUTHOR]

• External markers are important in sheep nutritional studies. • The purified and enriched lignin (LIPE®) is a potential marker to estimate faecal output. • LIPE® was evaluated in sheep fed with temperate and tropical grasses. • LIPE® marker has low accuracy to estimate faecal output in sheep. A series of trials were conducted in different experimental and feeding conditions to evaluate a purified and enriched lignin extracted from Eucalyptus grandis (LIPE®) as a marker to estimate faecal output in sheep fed temperate and tropical grasses. Two indoor trials were conducted in metabolism cages: the first one (Trial I) was conducted with sheep fed Italian ryegrass (Lolium multiflorum Lam.) pastures, which was evaluated in two different periods [Period I (n = 14), and Period II (n = 15)], and the second one (Trial II) was performed with sheep fed pearl millet [ Pennisetum americanum (L.) Leeke] pastures (n = 16). Grazing trials were performed with sheep grazing Italian ryegrass [Trial III (n = 62)] and pearl millet [Trial IV (n = 34)]. According to the manufacturer's statements, sheep were dosed once a day with capsules containing 250 mg of LIPE® for a period of seven days, beginning two days before total faecal collections started and finishing on the last faecal collection day. To measure the observed daily faecal output, sheep were harnessed with faecal bags that were emptied once a day at 0800 h for five days. Faecal subsamples from indoor and grazing trials were taken to determine the LIPE® content by infrared spectroscopy. Regression analyses performed between estimated and observed faecal output (g DM/kg LW/day) by sheep were not significant (p > 0.05) in three of the four evaluated trials. Faecal LIPE® recovery from the total data of the four trials showed a statistical difference when compared to the reference value (100%). In conclusion, our results show that the LIPE® marker presents low accuracy to estimate the daily faecal output of sheep fed temperate (Italian ryegrass) and tropical (pearl millet) grasses. [ABSTRACT FROM AUTHOR]