Evaluating carbohydrate fractions and degradation kinetics of maize silages on different storage periods and the estimates of milk production

Abstract

The objective of this study was to evaluate the effect of maize (Zea mays L.) carbohydrate contents and the estimates of milk production on different storage periods. The experimental design was completely randomised, with four treatments (storage time), each replicated four times. We observed a reduction in non-fibrous carbohydrates and an increase in the fibrous fraction, whereas starch plus soluble fibres (B1) showed a quadratic behaviour. As for the degradation kinetic parameters of the silages, an increase in gas production and degradation rate (B) was observed, whereas the fraction (A) decreased; the other parameters were not affected by the lengthening of storage time. The dietary simulation showed a reduction in protein, metabolisable energy and average daily gain (ADG), requiring more storage time to gain a point in the body condition score. The in vitro digestibility of dry matter (IVDMD) and total digestible nutrients (TDN) showed quadratic responses, whereas the digestibility of neutral detergent fibre and the milk production estimates were not affected by the storage time of maize silages. It is recommended to store maize silages for up to 221 days, because after this period there is a reduction in the digestibility of silages.