Sward characteristics and performance of dairy cows in organic grass–legume pastures shaded by tropical trees

Abstract

The silvopastoral system (SPS) has been suggested to ensure sustainability in animal production systems in tropical ecosystems. The objective of this study was to evaluate pasture characteristics, herbage intake, grazing activity and milk yield of Holstein × Zebu cows managed in two grazing systems (treatments): SPS dominated by a graminaceous forage (Brachiaria decumbens) intercropped with different leguminous herbaceous forages (Stylosanthes spp., Pueraria phaseoloides and Calopogonium mucunoides) and legume trees (Acacia mangium, Gliricidia sepium and Leucaena leucocephala), and open pasture (OP) of B. decumbens intercropped only with Stylosanthes spp. Pastures were managed according to the rules for organic cattle production. The study was carried out by following a switch back format with 12 cows, 6 for each treatment, over 3 experimental years. Herbage mass was similar ( P > 0.05) for both treatments, supporting an average stocking rate of 1.23 AU/ha. Daily dry matter intake did not vary ( P > 0.05) between treatments (average of 11.3 ± 1.02 kg/cow per day, corresponding to 2.23 ± 0.2% BW). Milk yield was higher ( P < 0.05; 10.4 ± 0.06 kg/cow per day) in the SPS than in the OP (9.5 ± 0.06 kg/cow per day) during the 1 st year, but did not significantly differ ( P > 0.05) in subsequent years. The highest ( P < 0.05) values for herbage mass and milk yield were observed during the 3 rd year. In the SPS, with moderate shade (19% shade relative to a full-sun condition), the grass CP was higher ( P < 0.05) than in the OP, although the NDF content and digestibility coefficient were not modified. The animals spent more time ( P < 0.05) idling in the SPS than in OP. The higher legume proportion in the SPS was associated with the higher CP level in B. decumbens relative to the OP, which could explain the better ( P < 0.05) performance of the cows in silvopastoral areas during the 1 st year. However, during the 2 nd and 3 rd years, similarities in the legume percentages of both systems resulted in similar ( P > 0.05) milk yields. Low persistence of Stylosanthes guianensis was observed over the experimental period, indicating that the persistence of forage legumes under grazing could be improved using adapted cultivars that have higher annual seed production. The SPS and a diversified botanical composition of the pasture using legume species mixed with grasses are recommended for organic milk production.

Intensification of cattle ranching production systems: socioeconomic and environmental synergies and risks in Brazil

“…In Brazil up to 40 million hectares of pastures are planted with Brachiaria brizanhta cultivar Marandu (Food and Agriculture Organization of the United Nations (FAO), 2013), followed by over 11 million hectares with Panicum Maximum that was introduced from Africa (Jank et al, 2005). Tropical grasses, having lower nutritional value than the temperate species, particularly benefit from the introduction of legumes that increase nitrogen availability in tropical soils and can thus increase herbage mass, protein content of the ruminants diet and milk yield (Shelton et al, 2005;Paciullo et al, 2014). The use of legumes may diminish or entirely replace the need for synthetic nitrogen fertilizer and thus not only increase productivity but also reduce production costs and environmental footprint (e.g.…”

“…It has been demonstrated that silvopastoral systems, where trees are included within pastures, can increase meat and milk yield, and provide shade for cows thus improving animal welfare (Porfírio-da-Silva, 2004;Embrapa, 2011b;Paciullo et al, 2014). For instance, Paciullo et al (2014) showed that milk yield could be higher by 1 kg/cow per day in agrosilvopastoral systems compared with open pastures, but discussed that the effect was not always persistent over successive years.…”

“…It has been demonstrated that silvopastoral systems, where trees are included within pastures, can increase meat and milk yield, and provide shade for cows thus improving animal welfare (Porfírio-da-Silva, 2004;Embrapa, 2011b;Paciullo et al, 2014). For instance, Paciullo et al (2014) showed that milk yield could be higher by 1 kg/cow per day in agrosilvopastoral systems compared with open pastures, but discussed that the effect was not always persistent over successive years. Transition of extensive pastoralism to agroforestry may also result in a range of socioeconomic benefits (Tilman et al, 2002;Murgueitio et al, 2011), such as risk reduction due to supply of alternative market products and higher incomes.…”

Review: Make ruminants green again – how can sustainable intensification and agroecology converge for a better future?

“…In a Colombian dairy system, a tree-rich matrix allowed an increased stocking rate and increased milk production by 130% (Murgueitio et al, 2011) while completely eliminating the use of chemical fertilisers and contributing to climate regulation via the maintenance of soil organic matter and complex soil food webs. In tropical silvopastoral systems, the presence of trees within pastures benefits cattle welfare through less exposure to stressful climatic conditions and might increase milk yield (Paciullo et al, 2014). Observations in Latin America have emphasised that enhancing tree species diversity and structural complexity could increase system resilience after a hurricane (Altieri et al, 2017).…”

Editorial: Agroecology for producing goods and services in sustainable animal farming systems

“…Technical assistance is however essential, particularly for small-and medium-scale farmers. An example also in Brazil is presented by Paciullo et al (2014), who illustrate how organic dairy production that incorporates several herbaceous (legumes and grasses) and tree species in a silvopastoral system can improve animal nutrition, helping to reconcile animal production and environmental conservation. Accatino et al (2014) present a dynamic model of rangelands to which they apply the mathematical framework of viability theory to quantify the management adaptability of the system.…”