Degradation of starch and crude protein in dent and dent x flint maize hybrids in different stages of maturity

Abstract

In situ experiment was conducted to determine degradation of starch and crude protein in maize hybrids with dent and dent x flint type of grains. The samples of grains were harvested in four stages of maturity. The first harvesting was done in milk-waxy stage and than fornightly at intervals until full grain ripeness. Used dent x flint hybrids were Mesnil, Chambord, Queen, while Aude, Meridien, KX 13 93, Omero belonged to dent. In sacco experiment was carried out on three rumen canullated cows of live weight 630 kg. The cows were fed a ration at maintenance level twice daily. The effective degradability of crude protein and starch of maize grains have decreasing tendency with increasing maturity stage. The maize hybrids of dent type had higher effective starch degradability (60.2 %) than hybrids dent x flint (59.6 %). The degree of maturity had a significant (P <0.01) effect on effective degradability of starch and crude protein. The maize hybrids KX 1393 and Meridien had the highest rate of starch degradability (parameter c: 0.075 %.h-1 and 0.074.h-1, respectively). Protein and starch in the hybrids dent x flint were less rapidly degraded than dent hybrids. This means that the starch and crude protein of these hybrids are more efficiently used by ruminants.