Prediction of the nutritional values by INRA (2018) feed evaluation system of Megathyrsus maximus subjected to different grazing strategies
Santiago Alexander Guamán Rivera, Escuela Superior Politècnica de Chimborazo (ESPOCH)
Angela Edith Guerrero-Pincay, Escuela Superior Politècnica de Chimborazo (ESPOCH)
Nelson Rene Ortiz-Naveda, Escuela Superior Politècnica de Chimborazo (ESPOCH)
Raúl Lorenzo González-Marcillo, Escuela Superior Politècnica de Chimborazo (ESPOCH)
Livestock playsan important role in the livelihoods of rural households and the economies of developing countries (McDermott, Staal, Freeman, Herrero, & Van de Steeg, 2010; Herrero et al., 2013; Thornton & Gerber, 2010; Do-Lam, Trung-Thanh, & Grote, 2019; Torres, Heredia-r, Toulkeridis, & Estupiñ, 2022). Nevertheless, meat and dairy production in arid, equatorial and tropical regions is often lower than productive in temperate regions due to the lower nutritional quality of forage grasses, infertile soils and adverse climatic conditions (Lee, Davis, Chagunda, & Manning, 2017; B, Heredia-r, Valencia, & Torres, 2021; Meister et al., 2021). Sustainable intensification as a form of production wherein yield increase without adverse environmental impact and without the cultivation of more land, are being largely considered (Barreto-álvarez, Heredia-rengifo, Padilla-almeida, & Toulkeridis, 2020; Nicolás et al., 2018). In tropical regions, forages are the main food source for ruminants, however, the environmental conditions and the management of grasslands directly affect the yield and quality of the pastures, impacting its growth, animal performance, and the functioning of the pastoral ecosystem (Schons et al., 2021; Szymczak et al., 2021). In this sense, higher cut intervals increase total forage mass, but tend to reduce the nutritional value (Macdonald, Penno, Lancaster, & Roche, 2008; De Sousa, Alexandrino, Dos Santos, & Freitas, 2019). Since, maximum herbage accumulation is set as the optimal to start grazing, while intense grazing (i.e., low residual sward height) is usually imposed as the limit of sward depletion (Szymczak et al., 2021). Therefore, grazing management strategies that optimize herbage utilization and digestible dry matter intake (DMI) by grazing cows might improve land use and mitigate key environmental issues of pasture-based livestock systems (Lascano & Cárdenas, 2010; Souza et al., 2019).Megathyrsus maximusis the main grass used in tropical livestock systems as it contains high forage production potential, nutritional value and adaptation to different climatic conditions and in poor soils (Carnevalli et al., 2006; de Lima Veras et al., 2020). This leads to the assumption that the grasses of Poaceae are ecologically dominant and by far the most economically important family in the world (Stromberg, 2011; Benabderrahim & Elfalleh, 2021). The Orellana Province, with a total population estimate 157,520 habitants, form part the Amazonian Region (RA) and represent 18.6% of a total 45.47%. Besides, thiszone has showed a social composition many complexes, experimenting deep changes since the decade of 1960 as effect of several laws of agrarian reform and colonization and the begin the hydrocarbon production. In this sense, GADPO (2015) has mentioned thatmain activities for generate income producers in the RA are concentrated in the agriculture (56.5%), livestock (10%), while 30% are under mix production system (agriculture-livestock) however, all these actions employ extensive pasture-based systems with very low productivity and rentability level. In fact, although Megathyrsus maximusis the most relevant grass adapted for raising cattle in the RA, the use of continuous stocking combined with minimum rest periods, and high defoliation intensities are management practices that contribute to low availability and quality of forage, with negative effects on animal performance (Cedeño-Aristega, Luna Murillo, Espinoza Coronel, & Romero Garaicoa, 2021; Gómez Villalva, Pérez, Vásconez Galarza, & Moran Salazar, 2021). Subsequently, for a better forage utilization, it is fundamental to understand the adequate timing of harvest from the point of view of the yield, quality and persistence of the plants (Fulkerson & Donaghy, 2001; Parsons et al., 2011; Ben & Toulkeridis, 2022). Since, maintaining high rates of forages intake, and high animal performance for tropical forages, require pastures with adequate canopy structures (Rao, 2001; Euclides et al., 2018). Therefore, the recent research with tropical forage grasses hasbeen focused on identifying grazing management strategies that harmonize with and optimize the natural growth cycle of plants, favouring their growth and production (S. Da Silva, Sbrissia, & Pereira, 2015). Furthermore, considering that tropical grasses are of lower nutritional value compared to those from temperate areas, it is essential to identify tropical grass varieties with the highest nutritive value (Batistoti et al., 2012).Forage quality is a central consideration in the design and implementationof grazing systems, as it is influenced by the length of both the grazing and the rest periods between subsequent grazing events (Briske et al., 2008). Whereas, nutritional values of forages is crucial in livestock nutrition, because effective livestock production is related to the amount of nutrients in the forages (Amiri, Rashid, & Shariff, 2012). Numerous feed evaluation systems among them those of the National Research Council, (NRC, 2001), the Cornell Net Carbohydrate and Protein System (Fox et al., 2004), the DVE/OEB system NorFor (Volden, 2011), and the Institut National de la Recherche Agronomique (INRA, 2018) have been developed and are regularly being updated in order to offer the possibility to formulate rations by matching nutrient supply with animal requirements (Daniel, Van Laar, Dijkstra, & Sauvant, 2020).In Ecuador, there is very little research information available on the forage quality and feeding values of Tanzania grass (Megathyrsus maximus). Considering this, through the recently updated INRA (2018) feed evaluation system, our study aimed to do an accurate estimation of nutrient partitioning of Tanzania grass (Megathyrsus maximus) subjected at different grazing strategies.
DOI: https://doi.org/10.36253/jaeid-14203
Read Full Text: https://www.jaeid.it/index.php/jaeid/article/view/14203
