Study On The Biological Yield And Feeding Value Of Different Varieties Of Maize

The purpose of this experiment was to investigate the biological yield of different varieties of maize when were harvested for whole plant corn,and to discuss the ruminal degradation of the whole plant corn before and after it was ensiled.The biological yield of different varieties of maize was measured by field plot experiment with randomized block.Four Dorper sheep fitted with permanent ruminal fistula were chosen for this study.Nylon bags technique was used to evaluate the ruminal degradation characteristics of the whole plant corn before and after it was ensiled.The tested maize varieties include zhengdan 958,dedan NO.5,luqing NO.1,Henan silage 23,yayu NO.9,dedan 121,jingke 968 and zea Mexicana.The results of field test showed that maize varieties in the same planting area,due to the difference of their own quality,when were harvested at the same growth time,the plant height,ear height,initial moisture content,fresh matter yield,dry matter yield and nutrient yield were significantly different(P<0.05).The plant height,ear height,initial moisture content,fresh matter yield,dry matter yield and nutrient yield of the same varieties were significantly different(P<0.05)due to the geographical differences,management level and growth time in different planting areas.The seedling emergence rates in Tai’an,Tengzhou and Guangrao are higher than that in Jiaozhou.There was no significant difference in seedling emergence rate among different varieties of maize,except for LuQing NO.1.Plant height,ear height,fresh yield and dry yield are positively related.The results of whole plant corn ruminal degradation test showed that the ruminal degradabilities of DM,OM,CP and NDF of all maize varieties were significantly increased with the increase of the incubation time in the rumen(P<0.05).The rumen degradabilities ofDM,OM,CP and NDF of different maize varieties were significantly different at 0 to 72 h(P<0.05).The degradation parameters(a,b,c)and effective degradabilities(ED)of DM,OM,CP and NDF of different maize varieties were significantly different(P<0.05).The results of whole plant corn silage ruminal degradation test showed that the ruminal degradabilities of DM,OM,CP and NDF of all maize varieties were significantly increased with the increase of the incubation time in the rumen(P<0.05).The whole plant corn silage ruminal degradabilities of DM,OM,CP and NDF of different maize varieties were significantly different at 0 to 72 h(P<0.05).The whole plant corn silage degradation parameters(a,b,c)and effective degradabilities(ED)of DM,OM,CP and NDF of different maize varieties were significantly different(P<0.05).The content of initial moisture,dry matter and organic matter were measured on the basis of fresh samples,the CP,EE,NDF,ADF content were determined on the basis of air dried samples.The results of comparison of nutritional value of the whole plant corn before and after ensiled showed that,compared with whole plant corn,the initial moisture content of whole plant corn silage is 2%-6% lower,DM content is 3%-6% higher,OM content is 1%-6%higher,the CP content is 0.1%-1% higher,NDF content is 2%-5% lower,but there was no significant difference in ADF content.The nutritional value of whole plant corn can be maintained by ensiling.The results of the degradation characteristics of nutrients in the whole plant corn before and after ensiled showed that,compared with whole plant corn,the fractions of rapidly degraded on DM,OM,CP and NDF of whole plant corn silage were higher(P<0.05),but the fractions of slowly degraded were lower(P<0.05),and the degradation rates of slow degradation component were higher.Besides,the effective degradabilities on DM and OM of whole plant corn silage were slightly lower(P<0.05),the effective degradabilities on CP and NDF were slightly higher(P<0.05).