Low-intensity, high-frequency grazing positively affects defoliating behavior, nutrient intake and blood indicators of nutrition and stress in sheep

The intensity and frequency of grazing affect the defoliating strategy of ruminants, their daily nutrient intake, thus nutrition and physiological status. Italian ryegrass (Lolium multiflorum Lam.) pastures were grazed by sheep either under a low-intensity/high-frequency grazing strategy (Rotatinuous stocking; RN) with nominal pre- and post-grazing sward heights of 18 and 11 cm, respectively, or under a high-intensity/low-frequency strategy (traditional rotational stocking; RT) with nominal pre- and post-grazing sward heights of 25 and 5 cm, respectively. Treatments were arranged under a complete randomized design and evaluated over two periods, in different years. In 2017, the aim was to depict the type of bites that sheep perform during the grazing-down and associate them to the grazing management strategy according to their relative contribution to the diet ingested. In 2018 we estimated the total nutrient intake and evaluated blood indicators of the nutritional status and immune response to stress of sheep. The bite types accounting the most for the diet ingested by RN sheep were those performed on the “top stratum” of plants with around 20, 15, and 25 cm, whereas the type of bites accounting the most for the diet of RT sheep were those performed on “grazed plants” with around 10, 5, and ≤ 3 cm. In 2018, the RN sheep increased by 18% the total organic matter (OM) intake and by 20–25% the intake of soluble nutrients (i.e., crude protein, total soluble sugars, crude fat), digestible OM and of metabolizable energy, and had 17.5, 18, and 6.1% greater blood concentration of glucose, urea nitrogen (BUN) and albumin, respectively, but 17% lower blood neutrophil-to-lymphocyte (N:L) ratio. Sheep grazing vegetative Italian ryegrass pastures under the low-intensity/high-frequency grazing strategy (RN) ingested a diet of better quality from bites allocated on the top stratum of plants, had greater intake of soluble nutrients and blood parameters positively associated with nutritional status and immune response to stress

Land-use intensification trends in the rio de La Plata region of South America : toward specialization or recoupling crop and livestock production

The Rio de la Plata region comprises central Argentina, Uruguay, and southern Brazil. Modern agriculture developed around 1900 with recent decades being characterized by the advance of cropping areas over native grasslands. Highly specialized agriculture has decoupled crop and livestock production but has succeeded in intensifying yields. However, significant losses of ecosystem services have been reported. Thus, questions have been raised on the sustainability of this pathway. A glance at world regions that have experienced similar trends suggests that an urgent course correction is needed. A major concern has been the lack of diversity in regions with highly specialized agriculture, promoting renewed interest in integrated crop-livestock systems (ICLS), not only because ICLS are more diverse than specialized systems, but also because they are rare examples of reconciliation between agroecosystem intensification and environmental quality. Consequently, this paper discusses alternatives to redesign multifunctional landscapes based on ICLS. Recent data provide evidence that recoupling crop and animal production increases the resilience of nutrient cycling functions and economic indicators to external stressors, enabling these systems to face climate-market uncertainty and reconcile food production with the provision of diverse ecosystem services. Finally, these concepts are exemplified in case studies where this perspective has been successfully applied

Tillering in Italian ryegrass established after soybean or corn, under different stockings and grazing intensities

O objetivo deste trabalho foi avaliar a densidade populacional de perfilhos, a massa de forragem, o padrão populacional de perfilhamento e o índice de estabilidade de pastagens de azevém anual (Lolium multiflorum) estabelecidas após os cultivos de soja ou milho, submetidas a diferentes métodos e intensidades de pastejo por cordeiros. Foram avaliados os métodos de pastejo rotativo e contínuo, sob as intensidades moderada (oferta de forragem correspondente a 2,5 vezes o potencial de consumo de cordeiros) e baixa (correspondente a 5,0 vezes). Utilizou-se o delineamento experimental de blocos ao acaso, em arranjo fatorial 2x2x2, com quatro repetições. As avaliações foram feitas mensalmente, entre agosto e outubro de 2010, durante a fase de pastejo. A densidade populacional de perfilhos apresentou diferenças significativas para métodos e intensidades de pastejo, e foi maior na área previamente cultivada com soja. As maiores massas de forragem foram observadas em pastagens subsequentes à soja e com baixa intensidade de pastejo, enquanto as menores, nas pastagens subsequentes ao milho e com moderada intensidade de pastejo. No período de florescimento, a densidade de perfilhos reduziu-se e suas massas individuais aumentaram. A intensidade de pastejo moderada reduz o percentual de perfilhos florescidos. A redução da densidade de perfilhos durante o florescimento não compromete o índice de estabilidade do pasto.The objective of this work was to evaluate tiller density, herbage mass, pattern of tiller population, and sward stability index in Italian ryegrass (Lolium multiflorum) pastures established after soybean or corn, subjected to different stocking methods and grazing intensities by sheep. Rotational or continuous stockings were evaluated under moderate (forage allowance equivalent to 2.5 times the potential consumption of lambs) and low grazing intensities (equivalent to 5.0 times). It was used a completely randomized block design, with a 2x2x2 factorial arrangement with four replicates. Evaluations were done monthly, between August and October 2010, during the pasture period. The tiller population density differed significantly with stocking methods and grazing intensities and was higher in the area previously cultivated with soybean, in the evaluation performed in August. The highest herbage masses were observed in pastures established after soybean at low‑grazing intensity, whereas the lowest were observed in pastures established after corn with moderate grazing intensity. During the reproductive period, tillering density reduced, and the individual tiller mass increased. Moderate grazing intensity reduces the percentage of fertile tillers. Reduction in tiller density during flowering does not affect the sward stability index

Methane emissions and forage intake by sheep on integrated croplivestock system: effect of stocking method and grazing intensity

Objetivou-se avaliar como diferentes estratégias de manejo do pasto de azevém anual interferem na produção animal, no consumo de forragem e na emissão de metano por ovinos em sistema de integração lavoura-pecuária (SILP) (Capítulo II). Já no Capítulo III objetivou-se avaliar as técnicas dos nalcanos e do nitrogênio fecal na estimativa do consumo de forragem por ovinos em pastos de azevém anual. Os experimentos foram conduzidos nos anos de 2011 e 2012 na Estação Experimental da UFRGS. Foram utilizados ovinos em um SILP de soja e milho no verão, em rotação com azevém anual no inverno. Para ambos os Capítulos (II e III) foram estudados dois métodos de pastoreio (contínuo e rotativo) e duas intensidades de pastejo (moderada e baixa; 2,5 e 5 vezes o potencial de consumo de matéria seca, respectivamente) em um delineamento de blocos casualizados com 3 repetições. Para o Capítulo II, no primeiro experimento os animais experimentais eram cordeiros, enquanto no segundo foram ovelhas em lactação. Os resultados indicaram que o ganho médio diário (GMD) dos cordeiros foi maior (P0,05), porém, quando expressas em g CH4 kg GPV-1 as emissões foram em média 15,33% maiores (P0.05), but when expressed in g CH4 kg-1 LWG emissions were, on average, 15.33% higher (P<0.05) for rotational grazing method, regardless of grazing intensity. Methane emissions per animal were not affected by the treatments applied. However, from system point of view, the continuous grazing method is more efficient, since lower methane emissions per kg of LWG, regardless of grazing intensity, were obtained. In Chapter III, were used only lambs. The methodologies of n-alkanes and fecal nitrogen, were applied through total collection with dung bags. In relation to n-alkanes, better results were obtained when using the pair C31:C32. For the methodology of fecal nitrogen, the equations proposed by Wang et al. (2009) and Azevedo (2011) were the best (P<0.05). The technique of fecal nitrogen proved to be more accurate than the use of n-alkanes, which overestimated the intake

Rotatinuous stocking : an innovation in grazing management based on animal behaviour and implications to pasture production, foraging behaviour, herbage intake and methane emission by grazing sheep

The aim of this thesis was to investigate contrasting pasture management strategies on the foraging behaviour, pasture production, carcass characteristics, herbage intake, faecal gas emissions and methane emission by sheep grazing Italian ryegrass (Lolium multiflorum) pastures. The experiment was carried out in 2014 and 2015. The experimental design was a randomized complete block with four replicates and two grazing strategy treatments (traditional rotational stocking method – RT meaning pre- and post-grazing target heights of 25 and 5 cm, respectively and, “rotatinuous stocking” – RN with pre- and post-grazing target heights of 18 and 11 cm, respectively). The grazing management was based on a 1-day strip-grazing regime. Male castrated sheep were used. The actual average sward heights for the RN treatment were 17.9 and 11.1 cm (pre- and post-grazing, respectively) and 27.1 and 7.8 cm for the RT (pre- and post-grazing, respectively). The stocking period in 2014 was 146 and 140 days (RN and RT, respectively) and in 2015 it was 155 and 146 days (RN and RT, respectively). The diurnal animal activities (grazing, ruminating and resting time) did not differ between treatments, with average of 439.6, 166.9 and 85.0 minutes, respectively. The bite rate, feeding station per min and steps per min were greater at the RN than the RT treatment. Grazing time and bite rate were greater in the afternoon than morning in both treatments. Therefore, the daily herbage intake by sheep grazing Italian ryegrass was greater for the RN than the RT treatment (CHAPTER II). The herbage production in the RN was 28% higher than the RT treatment. Individual average daily gain and live weight gain per hectare were greater in the RN than the RT treatment (CHAPTER III). RN treatment presented greater final live weight, carcass and commercial cut weights from grazing sheep than RT treatment (CHAPTER IV). RN treatment had a faecal chemical quality greater than RT treatment, resulting in a greater daily nitrogen excretion per animal and greater faecal CH4 and N2O emissions (CHAPTER VI). The “rotatinuous stocking” (RN) was the better grazing management strategy for mitigation of CH4 emissions by sheep grazing Italian ryegrass, emitting 64% less CH4 per unit area and 170% less CH4 per unit of animal product than the traditional rotational stocking method (RT) (CHAPTER V)

Las Provincias : diario de Valencia: Año XLVI Número 16343 - 1911 Junio 18

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Urinary creatinine as a nutritional and urinary volume marker in sheep fed with tropical or temperate forages

To test the accuracy of creatinine as a marker for estimating urinary volume and its use as a nutritional index, the possible interference of forage intake and forage quality over creatinine excretion was evaluated. For this, sheep were fed different levels of pearl millet (Pennisetum americanum (L) Leeke) or Italian ryegrass (Lolium multiflorum Lam). The experiment consisted of a compilation of digestibility trials (n=6) with pearl millet or Italian ryegrass in completely randomized designs with four replications and four forage levels: 1.5, 2.0, 2.5% (kg dry matter (DM)/ 100 kg of live weight (LW)). The trials were repeated at different periods to evaluate how stable the average metabolic excretion of creatinine is. In each trial, total urine collection was performed individually during a period of 24 hours for five consecutive days and subsequently analyzed by colorimetry for creatinine and purine derivatives. The creatinine excretion was not affected (P>0.05) by forage offer or forage type, but there were period effects (P=0.0001). The average creatinine excretion for both forages was 0.21mmol/kg PV0,75. Linear regressions between the purine derivatives:creatinine index with total excretion of purine derivatives were detected for pearl millet (P0,05) pelo consumo de forragem ou pelo tipo de forragem, mas foi influenciada pelo período (P=0,0001). A excreção média de creatinina para ambas as forragens foi 0,21mmol/kg PV0,75. Regressões lineares entre os índices derivados de purina:creatinina com a excreção total de derivados de purina foram detectadas para milheto (P<0,0001; R²=0,64) e azevém (P=0,02; R²=0,20). Os resultados demonstraram que a excreção de creatinina é independente do tipo e do consumo de forragem e pode ser usada como marcador preditivo do volume urinário e do status nutricional em sistemas de pastejo

Estimativa de emissão de metano por ruminantes em ambientes pastoris

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Urinary creatinine as a nutritional and urinary volume marker in sheep fed with tropical or temperate forages

To test the accuracy of creatinine as a marker for estimating urinary volume and its use as a nutritional index, the possible interference of forage intake and forage quality over creatinine excretion was evaluated. For this, sheep were fed different levels of pearl millet (Pennisetum americanum (L) Leeke) or Italian ryegrass (Lolium multiflorum Lam). The experiment consisted of a compilation of digestibility trials (n=6) with pearl millet or Italian ryegrass in completely randomized designs with four replications and four forage levels: 1.5, 2.0, 2.5% (kg dry matter (DM)/ 100 kg of live weight (LW)). The trials were repeated at different periods to evaluate how stable the average metabolic excretion of creatinine is. In each trial, total urine collection was performed individually during a period of 24 hours for five consecutive days and subsequently analyzed by colorimetry for creatinine and purine derivatives. The creatinine excretion was not affected (P>0.05) by forage offer or forage type, but there were period effects (P=0.0001). The average creatinine excretion for both forages was 0.21mmol/kg PV0,75. Linear regressions between the purine derivatives:creatinine index with total excretion of purine derivatives were detected for pearl millet (P0,05) pelo consumo de forragem ou pelo tipo de forragem, mas foi influenciada pelo período (P=0,0001). A excreção média de creatinina para ambas as forragens foi 0,21mmol/kg PV0,75. Regressões lineares entre os índices derivados de purina:creatinina com a excreção total de derivados de purina foram detectadas para milheto (P<0,0001; R²=0,64) e azevém (P=0,02; R²=0,20). Os resultados demonstraram que a excreção de creatinina é independente do tipo e do consumo de forragem e pode ser usada como marcador preditivo do volume urinário e do status nutricional em sistemas de pastejo