Effects Of Different Harvesting Period And Concentrate To Forage Ratio On Ruminal In Situ Disappearance Of Nutritients In Sheep

Three healthy Inner Mongolia semi-fine wool wethers (1.5-2 years old, BW 32 kg) fitted with the ruminal permanent fistula were used by a self-control test design to investigate the change of the degradability rule of forage nutrients by rumen nylon bag method in sheep fed three diets of different concentrate-to-forage ratio (dietâ… , 2:8; dietâ…¡, 3:7; dietâ…¢, 4:6) and forages at different harvesting periods (Aug 4th,Aug 27th,Sept 15th). Ruminal environmental fermentation parameters and degradability of nutrients were determined during the treatment period.The results showed: Daily average ruminal pH value of sheep fed three diets of different concentrate-to-forage ratio was 6.35, 6.38 and 6.28(p>0.05), respectively; Ruminal pH value was between 6.07 and 6.55 for one day. The amount of rumen ciliate was no difference with three diets (p>0.05). Daily average NH3-N concentrations (mg/100mL) were 7.12, 10.70 and 10.20, and the range of NH3-N concentrations was 5.44-14.72 mg/100mL, NH3-N concentrations of dietâ… were very significantly lower than dietâ…¡and dietâ…¢(p<0.01). Ruminal bacterial protein concentrations of dietâ…¡and dietâ…¢were very significantly higher than dietâ… (p<0.01), but there was no difference between dietâ…¡and dietâ…¢. The total VFA concentration was no change (p<0.05). Nutrients of forage at three different harvesting periods were the same. The degradability of DM, NDF, ADF, CP at the same sampling time(0h, 2h, 6h, 12h, 24h, 36h, 48h, 72h) in forages at three different harvesting periods in the same dietary concentrate-to-forage ratio were no significant different (p>0.05), but the degradability of them was lower with increasing harvesting periods. The degradability of DM,NDF,ADF,CP in the same forage at the different dietary concentrate-to-forage ratio was no significant different too(p>0.05), but dietâ…¡and dietâ…¢slightly higher than dietâ… .The results also showed that forages have already been matured before August 2007 on the Huitengxile grassland in Xilinguole, Inner Mongolia. The contents of nutrients of forage after August and their degradability did not change. Forages should harvest before August considering their nutritive value.