Steers production in integrated crop-livestock systems: pasture management under different sward heights

Abstract

-The aim of this study was to evaluate the effects of different grazing intensities on forage production and animal performance of yearling steers kept under permanent grazing in an integrated crop-livestock system. The treatments consisted of areas with sward heights of 10; 20; 30 and 40 cm, and one treatment with no grazing. The pastures were of bristle oat (Avena strigosa Schreb.) and annual ryegrass (Lolium multiflorum Lam.) following soybean (Glycine max (L.) Merr.). The variables forage mass, forage allowance and residual straw showed a positive and linear fit to the increasing sward height (P 0.0001). Average daily gain of steers displayed a quadratic response (P = 0.0017), being optimal with increases in grazing height up to values of near 30 cm, showing a weight gain per animal of approximately 1.0 kg day -1. A similar response was seen for live weight at slaughter and carcass characteristics (P 0.0305). The results suggest that sward heights close to 30 cm provide greater individual gains, due to the increase in forage available to each animal and the better quality of the consumed forage without compromising the residual straw destined for the following crop. RESUMO -O objetivo deste trabalho foi avaliar o efeito de diferentes intensidades de pastejo sob a produção de forragem e o desempenho animal de novilhos superprecoces mantidos sob pastejo contínuo em sistema integrado de produção agropecuária. Os tratamentos consistiram das alturas de manejo de pasto de 10; 20; 30 e 40 cm; e de um tratamento sem pastejo. Os pastos eram constituídos de aveia-preta (Avena strigosa Schreb.) e azevém anual (Lolium multiflorum Lam.) em sucessão a cultura da soja (Glycine max (L.) Merr.). As variáveis massa de forragem, oferta de forragem e palhada residual se ajustaram de forma positiva e linear ao incremento da altura do pasto (P 0,0001). O desempenho individual de novilhos apresentou resposta quadrática (P = 0,0017) e foi otimizado com o incremento na altura do pasto até valores próximos a 30 cm, com ganho de peso por animal de aproximadamente 1,0 kg dia -1. O mesmo foi observado para o peso vivo ao abate e as características de carcaça (P 0,0305). Os resultados sugerem que alturas próximas a 30 cm permitem maiores ganhos individuais, devido ao aumento da quantidade de forragem disponível por animal e a melhor qualidade da forragem consumida, não havendo comprometimento da palhada residual destinada à cultura subsequente. Palavras-chave:Novilhos. Pastagem-manejo. Carga animal. Ganho médio diário. Peso de carcaça.

Grazing intensity determines pasture spatial heterogeneity and productivity in an integrated crop‐livestock system

“…Pasture productivity is affected by grazing intensity (Figure ). Increased grazing intensities reduced sward surface heights and average herbage masses, corroborating previous research (Carvalho et al., ; Wesp et al., ). These authors suggested the sward height as a practical management tool in establishing goals for pasture structure and animal production.…”

“…This should result in higher animal performance when compared to intensive grazing, as reported by Wesp et al. (), who observed higher animal weight gains in pastures managed between 20 and 30 cm of sward height.…”

“…The higher spatial structuring revealed by the stronger DSD in G30 and G40 probably allowed animals to explore pasture heterogeneity with a maximum efficiency for a short period of time, although the more stable pattern observed in G20 throughout the stocking period enabled them to graze efficiently for a longer time. This should result in higher animal performance when compared to intensive grazing, as reported by Wesp et al (2016), who observed higher animal weight gains in pastures managed between 20 and 30 cm of sward height.…”

Herbage production, botanical and plant-part composition of mixed black oat (Avena strigosa Scherb.) annual ryegrass (Lolium multiflorum Lam.) pastures under different management strategies

“…These authors recommended a constant of approximately 2,000 kg ha -1 of cover crop biomass for no-till systems. In contrast, the values found in our study were lower (3,800 kg of DM ha -1 ) than those recommended by Wesp et al (2016) to overcome the effect of animal trampling on soil physical characteristics. The greatest herbage mass in the final period (159-187 DAS) of pasture usage was the result of the prolonged vegetative cycle of these species; however, this was associated with an increase in the stem and dead material proportions ( Figure 3).…”

Tree legume enhances livestock performance in a silvopasture system

“…Benefits of SPS include the delivery of more ecosystem services from different categories, such as provisioning, regulating, supporting, and cultural services (Dubeux et al., 2017a). Grazing animals in SPSs improve nutrient cycling because of faster nutrient turnover and soil organic C (Wesp et al., 2016), increasing soil C stock (Aryal, Gómez‐Gonzalez, Hernández‐Nuriasmú, & Morales‐Ruiz, 2019), and leading to a more efficient land use (Dubeux et al., 2017b). Further benefits include decreased greenhouse gas emissions, such as nitrous oxide and methane (Foley et al., 2011; Gibbs et al., 2010), and the additional source of income to producers coming from livestock (Esperschuetz et al., 2017).…”