Comparison of crude protein and starch degradability parameters of dent/flint and dent maize grain
2006
Mlyneková, Z.,Slovak Centre of Agricultural Research, Nitra (Slovak Republic) | Čerešňáková, Z.,Slovak Centre of Agricultural Research, Nitra (Slovak Republic)
The aim of the experiment was comparison of degradability parameters and effective degradability of starch and crude protein in grain of seven maize hybrids (three with dent/flint - floury/vitreous type of corn and four with dent - floury type of corn) in different time of corn maturity. Monitored was the corn from milk-wax maturity till harvesting maturity (four samplings in two-week intervals). Degradability of starch and crude protein was determined by standard in sacco method in three fistulated non-lactating cows. The incubation in the rumen took 0-2-3-4-6-9-16-24-48 hours. Cows were fed twice daily. Feeding ration consisted of maize silage, alfalfa hay, wheat, barley grist and Vitamix-Sl. Water was available ad libitum. The results show that the effective degradability of crude protein in all hybrids has decreased in process of maturity. Significantly lowest value was found in the 4th sample (except KX-1393 hybrid with dent corn type). In mature corn, the highest effective degradability of crude protein was found in hybrid Meridien (53.6% with dent corn type), the lowest in Mesnil (42.2%, dent/ flint corn type). In all hybrids the part of rapidly soluble and degradable fraction (parameter a) significantly decreased with maturity of corn, however, the tendency of rate change was not definite. Considerable differences were found in the starch effective degradability between hybrids (except second sample), however, it was not tendency of decrease from the first till the fourth sampling. Significantly lowest effective degradability was in hybrids with floury/ vitreous endosperm (dent/flint corn type).
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