Quality Changes in Alfalfa Hay During Storage in Bales

Effects of spontaneous heating on fiber composition, fiber digestibility, and in situ disappearance kinetics of neutral detergent fiber for alfalfa-orchardgrass hays

“…Declining concentrations of NDF suggest that portions of the NDF matrix, such as hemicellulose, may become reactive and lose their normal analytical properties (Van Soest, 1982). Previously, concentrations of NDF, ADF, and lignin have been related linearly to HDD, MAX, and average internal bale temperature for bermudagrass hays (Coblentz et al, 2000), and similar linear relationships have been established for NDF and ADF regressed on HDD for alfalfa hays (Coblentz et al, 1996). As observed in the present studies, these regressions were characterized by high r 2 statistics, which ranged up to 0.952 for a linear relationship between NDF and HDD within heated bermudagrass hays (Coblentz et al, 2000).…”

“…Within the present study, the curvilinear nature for many of our regression relationships is most likely a function of greater spontaneous heating incurred in large-round bales. Accumulations of HDD for interactive treatments in the present study ranged as high as 1,997 HDD (Coblentz and Hoffman, 2009), which was approximately 5 and 6 times the maximum accumulations reported for small rectangular bales of bermudagrass packaged at 32.5% moisture (Coblentz et al, 2000) and alfalfa packaged at 29.7% moisture (Coblentz et al, 1996), respectively. Because concentrations of fiber components increase primarily by indirect mechanisms during bale storage, the asymptotic nature of ΔNDF, ΔADF, ΔCELL, and ΔLIG within regressions on HDD may also indicate near exhaustion of substrate pools for microbial respiration, thereby limiting the indirect concentrating effect on fiber components.…”

“…In previous studies (Coblentz et al, 1996(Coblentz et al, , 2000, concentrations of NDF, ADF, cellulose, and lignin have been related to various indicators of spontaneous heating in positive linear relationships that are often characterized by relatively high coefficients of determination (r 2 ). Positive relationships between concentrations of fiber components and measures of spontaneous heating are assumed to occur primarily by indirect mechanisms; the respiratory activity of microorganisms has a concentrating effect on fiber constituents by oxidizing nonfiber compounds (Rotz and Muck, 1994), rather than actually creating additional forage fiber.…”

“…Although the threshold moisture for acceptable storage for small (~45-kg) rectangular bales is approximately 20% (Collins et al, 1987), thresholds for larger hay packages are assumed generally to be lower, but they vary with the size and density of bales, as well as other factors. In addition to oxidation of nonstructural carbohydrates (Coblentz et al, 1997a), the phenomenon of spontaneous heating is associated with mold growth (Roberts, 1995), deleterious changes in forage nutritive value (Collins et al, 1987;Coblentz et al, 1996Coblentz et al, , 2000Turner et al, 2002), alteration of ruminal disappearance kinetics of N, fiber, and DM (Coblentz et al, 1997b;McBeth et al, 2003;Turner et al, 2004), and less desirable measures of in vivo disappearance of DM (Montgomery et al, 1986;McBeth et al, 2001;Turner et al, 2004).…”

Curva de desidratação e composição químico-bromatológica do feno de grama-estrela (Cynodon nlemfuensis Vanderyst) em função do teor de umidade no enfardamento

“…Geralmente, o conteúdo de FDA e FDN aumentam e a digestibilidade da MS diminui com o aquecimento dos fenos (COLLINS et al, 1987;COBLENTZ et al, 1996). Também Coblentz et al (1996) encontraram aquecimento de feno nos primeiros 5 dias de armazenagem, valores máximos de 50 e 33ºC para os fenos com alta umidade (30%) e baixa umidade (20%) no enfardamento, respectivamente.…”