An evaluation of Panicum maximum cv. Gatton: 3. The partial digestion by sheep of organic matter, nitrogen and neutral detergent fibre of herbage at three stages of maturity during summer, autumn or winter

Abstract

The aim of this study was to quantify the partial digestion of organic matter (OM), nitrogen (N) and neutral detergent fibre (NDF) in sheep grazing Panicum maximum cv. Gatton pastures at three stages of pasture maturity during summer, autumn or winter. As pasture progressed from the young to the mature stage, OM digestibility decreased for all seasons, but OM disappearance in the rumen was unaffected. OM disappearance from the small intestine decreased with increasing pasture maturity during summer, and OM disappearance from the large intestine decreased with increasing pasture maturity during winter. N disappearance from the small intestine decreased with increasing pasture maturity during all seasons and N disappearance from the large intestine decreased with increasing pasture maturity in summer. Non ammonia nitrogen disappearance from the small intestine was decreased with increasing pasture maturity only for mature autumn pasture. Total tract N disappearance decreased with increasing pasture maturity during summer and autumn. NDF disappearance from the rumen decreased with increasing pasture maturity during autumn and winter, while NDF disappearance from the large intestine was unaffected. NDF disappearance from the total tract decreased with increasing pasture maturity during all seasons. It was concluded that P. maximum cv. Gatton pasture would best be utilized at the younger stages of development and that nutritional value would be higher in summer followed by younger autumn and winter pastures.

Influence of grass species and stage of maturity at ensiling on intake and partial digestibility by sheep

“…Growth stage had also no effect on true N digested (%) in the GIT by sheep fed the two grass silages (Table 2). In contrast, Relling et al (2001) found lower total tract N disappearance with increasing stage of maturity for P. maximum pasture during summer and autumn, but not during the winter period.…”

“…Grass species had no significant effect on intake, digesta flow and OM disappearance, both in the abomasum and ileum of sheep fed on the silages ( -reviewed paper: 10 th World Conference on Animal Production 236 disappearance in the rumen and GIT recorded in our study is within the range reported by Relling et al (2001) while the OM disappearance values in the small intestine were generally low compared to values reported for P. maximum pasture during summer. The partial digestibility of N of the two grass silages is presented in Table 2.…”

“…Generally growth stage had no effect on the total N flow (g/d) and NAN flow (g/d) in both the abomasum and ileum. In contrast, Relling et al (2001) found a lower abomasal N flow with increasing stage of maturity mainly associated to N, which is present in the fibre component. However, for D. eriantha the ileum NH 3 -N flow (g/d) was higher in boot stage than full bloom stage silage.…”

“…However, the total N flow (g/d), non-ammonia nitrogen (NAN) flow (g/d) and NAN flow per N intake in the abomasum for D. eriantha were higher than P. maximum silage when compared at the full bloom stage. The high level of disappearance of NAN for D. eriantha is an indication that more amino acids (of microbial protein origin) were available for absorption from this species (Relling et al, 2001). The NH 3 -N flow (g/d) in the abomasum as well as the total N-flow (g/d) and NAN flow (g/d) recorded in the ileum did not differ among the two grass species.…”

“…In contrast, Relling et al (2001) (Table 2). This was due to a higher N concentration of P. maximum silage that was recorded at full bloom than boot stage (Hassen et al, 2009).…”