Study On In Vitro Fermentation Characteristics And In Situ Degradability Of Different Varieties And Maturity Stages For Maize Stover

Three experiments were conducted to study the effect of different varietiesand maturity stages on the in vitro rumen fermentation characteristics for maizestover. Six Liu-yang black goats, average initial body weight of 20±1kg, fittedwith ruminal cannulas for the experiments of fermentation in vitro anddegradation in situ.In Exp. 1, Effects of different varieties and maturity stages on the nutritivevalues of maize stover. Four especial varieties maize stover were selected (HOC115, HQ 1, KXT 1, KXN 1), and conventional corn (KX 11) was used as thecontrol. Whole plant of all varieties was collected at the day of 65 and 80respectively, after emerging at spring and autumn sowing. The result showed thatthe nutritive value of maize stover, except for content of P, were significantlyaffected by interaction among variety, stage of maturity and sowing season.The nutritivevalue of KX 11 showed an increasing trend with increasing stage of maturity,whereas those four especial varieties showed a decreasing trend from milk stageto dough stage, and the dough stage of autumn sowing was the best stage, onlythe quality of KXN 1 decreased most quickly, the nutritive value of KXN 1 inthis stage was better than that for other three especial varieties. The nutritivevalue of every stage of HOC 115, HQ 1 and KXT 1 was better than KX 11.In Exp.2, Study on the in vitro rumen fermentation characteristics ofdifferent varieties and maturity stages for maize stover. Three Liu-yang blackgoats which fitted ruminanl cannulas provided the rumen fluid which was usedfor fermentation in vitro. The result of in vitro gas production showed that: thehighest values of the cumulative gas production of 72h and theoretical maximumgas production during those four stages occurred in KXN 1, correlation analysesindicated that both two kinds of gas production were negatively related to thecontent of NDE Furthermore, the IVDMD of KXN 1 was also the highest onebesides dough stage of spring sowing. The IVDMD of HOC 115 in four stages orHQ 1 and KXT 1 in all stages except for dough stage of autumn sowing werehigher than conventional variety. It was concluded that IVDMD was constantwith chemical composition of corn stalks, the nutritive value of KXN 1 was thebest, following HOC 115, HQ 1 and KXT 1 as for the IVDMD of maize stover,moreover, the digestibility of milk stage in autumn sowing of these four varieties was the best.In Exp.3, Study on the in situ DM degradability of different varieties andmaturity stages for maize stover. The result showed that EDp was significantlyaffected by varities, sowing seasons, intereaction between varieties and sowingseason, intereaction among varieties, maturities and sowing season but not bymaturities, there was an increasing trend in in situ DM degradability withincreasing stage of maturity of HOC 115, HQ 1 and KXT 1 in spring sowing,whereas opposite trend was observed in autumn sowing, DM degradability ofKXN 1 and KX 11 trended to decline with increasing stage of maturity in springand autumn. The DM degradability value of milk stage in autumn sowing was thehighest among all stages, HQ 1 was higher (76.80%) than that of other varietiesin this stage, and it was significantly higher (p＜0.05) than HOC 115, KXT 1 andKX 11, but similar with (p＞0.05) KXN 1.