Measurement of yield and in situ dry matter degradability of maize varieties harvested at two stages of maturity in sheep

Yield and in situ dry matter degradability (DMD) of six varieties of maize harvested at two maturity stages were compared. At both dates of harvest, the variety Boss yielded highest total DM (16.9 and 19.9 t ha−1) and cob (9.4 and 11.0 t DM ha−1) as well as cob percentage (55.6 and 55.4) while Bezemara ranked the lowest (13.5 and 12.9 t DM ha−1 6.8 and 4.6 t cob DM ha−1, 50.1 and 35.9%). Total DM yield did not vary significantly with the maturity except that in Boss, where it was higher (P<0.05) at late maturity stage. The stover of Carlos and Bezemara varieties had higher (P<0.05) DMD after 8–96 h of incubation than of Boss whereas all other varieties exhibited intermediate degradability. The DMD of all varieties of stover decreased with increasing maturity. Potential degradability and degradation rate of stover of all varieties did not vary significantly. Based on index value/degradability of maize stover showed the following ranking order: Carlos>Pirat>Bezemara>Diva>Aura>Boss in early stage and Bezemara>Diva>Carlos>Pirat>Aura>Boss in late stage of maturity. The highest potential degradability of cobs was in the late harvested Bezemara and Pirat (97.4 and 97.3%) and the lowest at the early harvested Pirat (92.7%). The rate of degradation varied between 5.5% (Aura, Stage II) and 7.9% (Boss, Stage I). The correlation between yield and index value was negative but did not attain statistical significance. erall results showed differences in cob and stover yield and quality among varieties as well as between maturity, and indicated that the maize varieties Boss and Aura had the highest yields but the lowest stover degradabilities.