Wilting whole crop black oat with glyphosate for ensiling: effects on nutritive, fermentative, and aerobic stability characteristics

Abstract

Black oat (Avena strigosa Schreb) is one of the most important small grain cereals for animal feeding in southern Brazil. Despite grain yield, black oat is also cultivated for ensiling; however, it is not an easy forage to be stored in anaerobic conditions, compared with maize, for example. According to Haigh (1990), a content of water-soluble carbohydrates (WSC) over 37 g kg −1 DM in herbage is necessary for an adequate fermentation. Whole crop black oat WSC content ranges from 139 g to 79 g kg −1 DM, for milky and dough grain stages, respectively.However, black oat herbage has a high buffer capacity, demanding a larger quantity of water-soluble carbohydrates ABSTRACT -We aimed to evaluate the effects of glyphosate as a chemical desiccant on the nutritional quality, fermentation pattern, and aerobic stability of wilted black oat (Avena strigosa Schreb) silage. Black oat sowing occurred in the first fortnight of May 2013. Desiccant application took place when oat reached milky/dough grain stage (96 days after planting). Glyphosate dosages evaluated were 0, 500, 750, 1000, and 1250 mL ha −1 . Three days after desiccation, all treatments were ensiled, and the silos were kept stored for 150 days. A completely randomized design was used, and all statistical procedures were performed by means of Bayesian Inference. Treating herbage prior to ensiling from 500 mL ha −1 glyphosate increased dry matter and organic matter contents compared with control. On the other hand, fiber content decreased linearly for desiccated silages, as shown by the negative slopes for neutral detergent fiber, acid detergent fiber, and cellulose. The highest concentrations of hemicellulose and neutral detergent insoluble nitrogen occurred for the dosages of 729.96 mL ha −1 and 759.52 mL ha −1 glyphosate, respectively. Wilted silage had less concentration of acetic acid and isovaleric acid and presented a higher amount of 2,3-butanediol. Due to the lack of beneficial short-chain fatty acids, treated silages had a higher organic matter loss (0.1 g mL −1 ) and reached a maximum pH (0.009 h mL −1 ) more quickly than control silage, after aerobic exposure. In this way, for wilted black oat silage production, harvested at milky/dough grain stage, the application of 500 mL ha −1 glyphosate is recommended.

Chemical composition, aerobic stability, and fermentation pattern of white oat silage wilted with glyphosate

“…However, when glyphosate was applied at 500 mL ha -1 , 750 mL ha -1 , and 1000 mL ha -1 , DM contents were higher than control. Chemical desiccation prior to ensiling normally increases DM content because glyphosate affects stomatal conductance, cellular membrane selective permeability, and aquaporin functionality, thus reducing water absorption by plants (Zobiole et al, 2010;Carneiro et al, 2017;Bueno et al, 2018). Nevertheless, glyphosate doses above 1000 mL ha -1 may induce stomatal closure, which could reduce transpiration and carbon dioxide assimilation, decreasing the DM accumulation by plants (Brecke & Duke, 1980;Yannicari, Tambussi, Istilart, & Castro, 2012).…”

Producción, calidad y utilización de ensilajes de gramíneas tropicales en la dieta de rumiantes

“…Para maiores detalhamentos acerca dos processos produtivos, fermentativos e tecnológicos da silagem recomenda-se leitura de outras bases literárias (Bueno et al, 2018;Daniel et al, 2019;Jobim et al, 2007;Wilkinson & Davies, 2013;Wilkinson & Muck, 2019), pois essa revisão tem como objetivo discutir os principais entraves da produção de silagens a partir de capins tropicais, os fatores que podem alterar a qualidade da silagem e as implicações ao inserir esse tipo de volumoso na dieta de ruminantes, portanto não dará enfoque para cada etapa do processo produtivo e fermentativo.…”

In vitro digestion characteristics of various combinations of elephant grass hay, gliricidia hay or silage, soybean meal and corn meal in rations for sheep

“…Pasture-based production systems are limited primarily by variations in climatic conditions, which directly interfere with plant growth (Euclides et al 2019), resulting in negative impacts on animal performance, especially during the dry season (Emerenciano Neto 2018; Braga et al 2019). One possible solution is to conserve forage in periods of high availability to be used during times of scarcity (Bueno et al 2018), along with feeding of protein supplements.…”