**Methods:** Eight ruminally fistulated Wether sheep (57.4 ± 2.4 kg) were fed a basal diet (45% soybean stem, 25% wheat straw, 18.56% corn, 4.95% soybean meal, 4.95% wheat bran, plus minerals and premix). Twenty-five feedstuffs were collected: six protein feeds, nine energy feeds, and ten roughages. Samples were dried at 65°C for 48 h, milled through a 2.5 mm sieve for in situ degradation, and analyzed for DM, OM, CP (N × 6.25, Kjeldahl), NDF, and ADF. Nylon bags (48 μm pore size, 6×10 cm) were filled with 3 g (protein/energy feeds) or 5 g (roughages) and incubated in duplicate per sheep. Protein and energy feeds were incubated for 2, 4, 8, 16, 24, 36, 48 h; roughages for 4, 8, 16, 24, 36, 48, 72 h. After removal, bags were washed until clear, dried at 65°C for 48 h, and residues analyzed. Degradation kinetics were modeled using Y = a + b(1 − e^(−ct)), and effective degradability (ED) was calculated as ED = a + bc/(c + k) with outflow rates of 3.14%/h (roughages), 3.99%/h (DDGS), 2.53%/h (silage), and 5%/h (oil-seed-meals). Three five-point combinations were tested for protein/energy feeds (① 2,16,24,36,48 h; ② 2,8,16,24,48 h; ③ 2,8,16,36,48 h) and six for roughages (① 4,16,36,48,72 h; ② 4,16,24,48,72 h; ③ 4,16,24,36,72 h; ④ 4,8,16,24,72 h; ⑤ 4,8,16,36,72 h; ⑥ 4,8,16,48,72 h). Selection criteria kept the shortest, longest, and 16 h time points. Statistical analysis used SAS GLM and SPSS; significance at p < 0.05.
**Key Results:** For protein feeds, only a few parameters differed significantly between five and seven time points: the 'a' of CP and OM of CSM, 'b' of CP and 'a' of OM of CGM, 'a' of DM of DDGS, and 'b' of CP of SOM (p < 0.05). ED of CP for CGM and ES was significantly different at all five-point combinations (p < 0.05). For energy feeds, significant differences in 'a' and 'b' of DM, CP, and OM were found for BY and WT; 'b' of DM for HS; 'a' and 'b' of DM for HY9 and GWC; 'a' of DM for YC; and 'b' of DM for YWB (p < 0.05). ED of DM, CP, and OM for CBS, and ED of DM for YWB and GWC, were significantly different (p < 0.05). For roughages, significant differences were observed for 'a' and 'b' of CP of RG; 'a' and 'b' of DM of RSW; 'a', 'b', and 'c' of OM of RSW and TP; 'b' of DM of OG and CS; 'c' of OM of CS; 'a' of DM of TP; and 'a', 'b', 'c' of CP of TP (p < 0.05). ED of DM and OM of RSW and ED of DM, CP, and OM of TP were significantly different (p < 0.05). Critically, R² values for all fitted curves exceeded 0.9. For protein and energy feeds, combination ① (2, 16, 24, 36, 48 h) yielded R² closest to 1; for roughages, combination ⑥ (4, 8, 16, 48, 72 h) yielded R² closest to 1. In both cases, five-point R² values were closer to 1 than those from seven points.
**Clinical Implications:** Reducing incubation time points from seven to five is feasible for determining rumen degradation characteristics of feedstuffs using the nylon bag technique, with minimal impact on effective degradability and improved curve fit (R² closer to 1). The optimal five-point sets are 2, 16, 24, 36, 48 h for protein and energy feeds, and 4, 8, 16, 48, 72 h for roughages. This simplification reduces labor, cost, and animal stress from repeated rumen access, improving animal welfare without compromising data quality. However, caution is warranted for certain feeds (e.g., TP—tall fescue pasture) where five-point estimates differed significantly from seven-point values, suggesting that feed-specific validation may be needed before adopting reduced protocols.