Description
The objective of this study was to determine the influence of stage of maturity on the intake and digestibility of P. maximum (cv. Gatton) during the active growing season. Low DM content at the young and medium growth stages (24.9 and 25.2%) did not hamper DOMI (48.8 and 44.1 g/kg W0.75/d) respectively. The N concentration of the three stages were well within the limit required for optimal rumen microbial production (1.8 - 2.0%). The high NDF value of the adult stage (59.5%) resulted in a significantly lower IVDOM value (62.3%) but the IVDOM values of all stages were on the higher side (average 66.4%) of the spectrum for C4-grasses. Significantly higher NH3-N and VFA levels in the rumen fluid were obtained for the young and medium growth stages and the same trend was observed for DOMI and N-intake. The higher DOMI resulted in a higher digesta flow rate in the abomasum and ileum. The lower DOMI of the adult stage was most probably due to the taller growing sward. Differences in the proportionally OM disappearance in the stomach didn’t differ (average 0.63) but was higher in the small intestine for the younger growth stages. The very high proportional disappearance of non- NH3-N in the small intestine, indicates that ± 30% OM which disappeared in the small intestine, must have consisted primarily of protein matter. The fact that about 70% of N intake was apparently digested in the small intestine, may be the function of a lower soluble N content.
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Intake and Partial Digestibility of Panicum Maximum (CV. Gatton) at Three Stages of Maturity During Summer
The objective of this study was to determine the influence of stage of maturity on the intake and digestibility of P. maximum (cv. Gatton) during the active growing season. Low DM content at the young and medium growth stages (24.9 and 25.2%) did not hamper DOMI (48.8 and 44.1 g/kg W0.75/d) respectively. The N concentration of the three stages were well within the limit required for optimal rumen microbial production (1.8 - 2.0%). The high NDF value of the adult stage (59.5%) resulted in a significantly lower IVDOM value (62.3%) but the IVDOM values of all stages were on the higher side (average 66.4%) of the spectrum for C4-grasses. Significantly higher NH3-N and VFA levels in the rumen fluid were obtained for the young and medium growth stages and the same trend was observed for DOMI and N-intake. The higher DOMI resulted in a higher digesta flow rate in the abomasum and ileum. The lower DOMI of the adult stage was most probably due to the taller growing sward. Differences in the proportionally OM disappearance in the stomach didn’t differ (average 0.63) but was higher in the small intestine for the younger growth stages. The very high proportional disappearance of non- NH3-N in the small intestine, indicates that ± 30% OM which disappeared in the small intestine, must have consisted primarily of protein matter. The fact that about 70% of N intake was apparently digested in the small intestine, may be the function of a lower soluble N content.
