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Os processos de conservação de volumosos têm como objetivo fundamental manter a qualidade nutritiva das forrageiras, para que essas possam suprir a baixa disponibilidade e qualidade de alimento volumoso em épocas desfavoráveis. O objetivo do presente trabalho foi avaliar o efeito de número de camadas de filme de polietileno e tempos de armazenamento sobre o valor nutricional do pré-secado de capim Tifton 85 (Cynodon spp cv. Tifton 85). Foram utilizadas quatro e seis camadas de filme de polietileno branco leitoso no revestimento de silos-fardos com capacidade de 400 kg (100 e 150 um de espessura no total, respectivamente) e quatro diferentes tempos de armazenamento (enfardamento, 30, 60 e 90 dias). Utilizou-se o delineamento experimental em blocos casualizados, com quatro repetições, em esquema de parcelas subdivididas no tempo, sendo que o número de camadas de filme de polietileno que revestiram os fardos do pré-secado constituiu as parcelas e os tempos de armazenamento as subparcelas. Os teores de proteína insolúvel em detergente neutro (PIDN) foram superiores no pré-secado revestido com quatro camadas de filme de polietileno (35,8 g kg-1 PB). Houve efeito de tempo de armazenamento sobre os teores de fibra em detergente neutro (FDN), fibra em detergente ácido (FDA), matéria mineral (MM), PIDN, lignina e digestibilidade in vitro da matéria seca (DIVMS). Constatou-se acréscimo linear para os teores de FDA e lignina, e decréscimo linear para o teor de DIVMS. A MM apresentou comportamento quadrático negativo. Observou-se comportamento quadrático positivo sobre os teores de PIDN e FDN. Para os teores de matéria seca (550,3 g kg-1), proteína bruta (102,3 g kg-1 MS), proteína insolúvel em detergente ácido (28,9 g kg-1 PB) e digestibilidade in vitro da fibra em detergente neutro (582,1 g kg-1 MS) não houve influência de tempo de armazenamento. Coclui-se que o número de camadas de filme de polietileno não influenciou o valor nutricional do pré-secado de capim Tifton 85. O armazenamento durante 90 dias reduz o valor nutricional do pré-secado de capim Tifton 85.

This study evaluated the variations in temperature and dry matter content in Tifton 85 bermudagrass and Wrangler grass hay stored under different environmental conditions. The fungal and mycotoxin populations in the hay production area were also evaluated. Fifty samples (30 hay bales, ten samples of organic matter [OM], and ten samples of grass [G] before baling) were used in a completely randomized design and factorial scheme with ten treatments (a combination of two classes of G: Tifton 85 bermudagrass and Wrangler grass) and three storage systems: a covered shed without side walls, covered with a clear tarp; an open environment covered with a double-sided tarp; and a ventilated closed shed. Four additional treatments, five replications, and one sample per experimental unit completed the study design. The environment influenced the temperature of the Tifton 85 bermudagrass and Wrangler grass bales, and the dry matter content of the bales during the evaluated period was above the recommended limit (800 g kg-1). The genus Penicillium occurred with the highest frequency in the Wrangler grass stored under a double-sided tarp (6.13 log CFU g-1). In the additional treatment, the OM deposited in the soil of the Wrangler grass production area exhibited a greater occurrence of the fungus Fusarium (4.66 log CFU g-1) and of the mycotoxin zearalenone (ZEA; 594.2 μg kg-1). The hay stored in the shed with a clear tarp exhibited more aflatoxin (AFLA) and deoxynivalenol (DON). The concentration of mycotoxins varied across the storage environments and between the stored species; however, the shed storage system used in hay production might also be a source of hay contamination via the incorporation of decomposing OM with mycotoxins in the hay.

This study evaluated the variations in temperature and dry matter content in Tifton 85 bermudagrass and Wrangler grass hay stored under different environmental conditions. The fungal and mycotoxin populations in the hay production area were also evaluated. Fifty samples (30 hay bales, ten samples of organic matter [OM], and ten samples of grass [G] before baling) were used in a completely randomized design and factorial scheme with ten treatments (a combination of two classes of G: Tifton 85 bermudagrass and Wrangler grass) and three storage systems: a covered shed without side walls, covered with a clear tarp; an open environment covered with a double-sided tarp; and a ventilated closed shed. Four additional treatments, five replications, and one sample per experimental unit completed the study design. The environment influenced the temperature of the Tifton 85 bermudagrass and Wrangler grass bales, and the dry matter content of the bales during the evaluated period was above the recommended limit (800 g kg-1). The genus Penicillium occurred with the highest frequency in the Wrangler grass stored under a double-sided tarp (6.13 log CFU g-1). In the additional treatment, the OM deposited in the soil of the Wrangler grass production area exhibited a greater occurrence of the fungus Fusarium (4.66 log CFU g-1) and of the mycotoxin zearalenone (ZEA; 594.2 μg kg-1). The hay stored in the shed with a clear tarp exhibited more aflatoxin (AFLA) and deoxynivalenol (DON). The concentration of mycotoxins varied across the storage environments and between the stored species; however, the shed storage system used in hay production might also be a source of hay contamination via the incorporation of decomposing OM with mycotoxins in the hay.