Influence of endosperm vitreousness and kernel moisture at harvest on site and extent of digestion of high-moisture corn by feedlot steers

Abstract

Six ruminally and duodenally cannulated Angus-Jersey crossbred steers (450 kg of BW) were used in a 6 x 6 Latin square to evaluate the effect of kernel vitreousness and moisture on intake and digestibility of high-moisture corn. Arranged in a 2 x 3 factorial, diets included a floury (FLO) or a vitreous (VIT) endosperm corn hybrid harvested at 28.1% (DRY), 31.2% (MID), or 35.7% (WET) kernel moisture content. Diet DM consisted of 88.25% high-moisture corn, 6% chopped alfalfa hay, 2% corn gluten meal, 0.75% urea, and 3% supplement. Supplement was included to ensure that the diets contained a minimum (DM basis) of 0.6% Ca, 0.6% K, 0.2% S, 33 mg/kg of monensin, and 11 mg/kg of tylosin. Geometric mean diameter of lyophilized high-moisture corn tended to be less (P = 0.06) for VIT than for FLO, and the calculated particle surface area was 15.8% greater (P = 0.03). An interaction of vitreousness with the quadratic effect of moisture was noted (P < 0.001), such that fraction a and effective degradation for starch tended to be greater for the vitreous hybrid at the least and greatest moisture content but lower for the vitreous hybrid at the intermediate moisture content. Intake and ruminal disappearance of DM, OM, and starch were not influenced by vitreousness or moisture, with ruminal starch disappearance averaging 90.9%. Intestinal starch digestion measured as a percentage of starch entering the intestines averaged 91% and was greater (P < 0.05) for VIT than FLO corn. Averaged across moisture levels, total tract starch digestibility was greater (P < 0.003) for VIT than FLO. Compared with FLO kernels, VIT kernels appeared to be more brittle and therefore shattered more readily when rolled, particularly at the driest kernel moisture level. Furthermore, increased surface area of smaller particles may have been responsible for the greater starch utilization from VIT corn. In contrast with the results from other in situ and in vivo trials with dry-rolled corn grain, in which the starch from vitreous hybrids was less rapidly or completely digested, hybrids with more vitreous starch, when fed as high-moisture corn, had greater total tract starch digestibility, primarily due to greater postruminal starch digestion.

Influence of corn hybrid and processing method on nutrient digestibility, finishing performance, and carcass characteristics1

“…They found that flaking hybrids eliminated differences between harder and softer hybrids observed within DRC. Utilizing only HMC, Szasz et al (2007) found that more vitreous hybrids were more digestible than less vitreous hybrids, due mostly to an increase in postruminal starch digestibility, which is in disagreement with previous research utilizing DRC (Corona et al, 2006).…”

Effect of grain and forage fractions of corn silage on milk production and composition in dairy cows

“…Differences of DM concentration in HMC (74.0%) and corn grain in WCS (56.6%) could also have had a significant impact on organic matter and starch digestibility, and therefore on the energy supply for milk production. In feedlot steers, Szasz et al (2007) reported a linear increase in effective degradability of DM and starch with decreasing levels in DM concentration from 72% to 64% in HMC using the in sacco technique. However, total tract digestibility of starch was not different between treatments (Szasz et al, 2007).…”

“…In feedlot steers, Szasz et al (2007) reported a linear increase in effective degradability of DM and starch with decreasing levels in DM concentration from 72% to 64% in HMC using the in sacco technique. However, total tract digestibility of starch was not different between treatments (Szasz et al, 2007). This may explain why the 4% fat-corrected milk (FCM) and efficiency of milk production was not different between WCS and RCS in the current experiment (Table 5).…”

<b>Bromatological characteristics and ruminal digestibility of grain corn hybrids with different vitreousness in silage maturity

“…These results show that for the protein matrix, a component which complicates the ruminal starch digestion, hybrids with dent endosperm must be chosen to make silage because they have a lower vitreous proportion in the grain. Vitreousness is highlighted as an important parameter to be considered from the inferences of Szasz et al (2007), who claimed that corn hybrids differ minimally in starch content in the grains while there are large differences in vitreousness. Corona et al (2006) and Cantarelli et al (2007) verified the higher digestibility coefficient of grain dry matter in dent genotypes compared with flint grains in corn hybrids.…”