| Additives added to alfalfa hay at high moisture for storing is an effective way for solving several problems which are large nutritive losses of hay during baling at low moisture,storing troubles in rain and humid places.The studies on several additives for storing high moisture alfalfa hay at northern region of China were conducted which included several experiments as follows:1.According to Orthogonal Test Design L16(45) experimental design with five factors and four levels,the experiment was conducted to investigate the compound additive prescriptions of five kinds of additives and their adding levels on the quality of alfalfa hay.After analyzing chemical composition of alfalfa hay which had stored 60 days with different compound additive prescriptions at high moisture, the best compound additive prescription was selected.2.Further study was conducted to investigate treatments of the best compound additive which was obtained with Orthogonal Test Design,the similar additive of SG(water content 27%-28%),high moisture hay with no additive(27%-28%,CKg) and low moisture hay(17%,CKd) on the tendency of changes of temperature,water content,nutrient contents in hay during preservation.At the same time,the difference of nutritional quality between alfalfa hay treated with high moisture and low moisture was also analyzed and compared after preservation.3.Taking SG,CKg and CKd as the comparisons,the digestive rates of the CP,NDF,ADF and DM of hay which was treated with additives were studied by using in vitro method to contrast the difference of digestive rates of high moisture and low moisture hay after storing 60 days. The results indicated:1.The best compound additive prescription obtained by the way of Orthogonal Test Design was:NaSO4 35.51%,K2SO3 32.78%,K2SO4 1.64%,a-amylase 0.03%,Bentonite at the base of sodium 21.85%,glucose 8.19%.The quantity of the compound additive added to hay is 1.15kg/t.The effect of various factors influence on quality of alfalfa hay after preservation was:NaSO4 was the main influencing factor on nutrient content of hay after preservation in the five factors.K2SO4 had the best effects on enhancing DM,WSC and reducing NDF,ADF in alfalfa hay.Bentonite at the base of sodium which was the major effecting factor on CP,NPN,Asp of hay and improved CP content of hay obviously after being added to hay to preservation.Both of the K2SO3 and amylase improved nutrient content of the hay after preservation.2.Compound additive could rapidly reduce the temperature and moisture in the hay bales at its early stage of preservation,and also could reduce the highest temperature value during the preservation period of alfalfa hay.At the same time,it could postpone the reaching time of the highest temperature in the alfalfa hay bale.It was concluded in the present study that the temperature climax reached at day 4,the temperature value were 47.438℃and 48.2℃respectively in the CKg and SG alfalfa hay bales.In the compound additive treated alfalfa hay bale,the highest temperature reached at day 7,the temperature was 41.76℃.The contents of WSC,DM,Asp and CP were improved and the proteolysis in alfalfa was inhibited in the compound additive treated alfalfa hay bale.The content of WSC(25.42 g/kg) in the compound additive treated alfalfa hay bale,in which the NPN,NDF,ADF was reduced,was higher than that in the other treatments alfalfa hay.The contents of WSC,DM and Asp in the alfalfa hay treated with the compound additive were significantly higher(P＜0.05) than that in the SG treated hay,but the NPN and NDF content with the opposite way.According to the evaluation standards of hay,the ranges of CP,ADF and DMD in the alfalfa hay treated with the compound additive ranked to the special class, and the rest indexes detected in the present study were also ranked to the first class. Therefore,the comprehensive quality of alfalfa hay treated with the compound additive was better than the SG treated alfalfa hay.3.The contents of DM,ADF and the digestion rate of CP of alfalfa hay treated with the compound additive were higher than that of CKg and SG treatments.Digestion of NDF in all of the high moisture treated hay was increased compared with alfalfa hay before treatments,but the lowest increasing rate of digestion of NDF was observed in compound additive treated hay.No difference(P＞0.05) was observed on in vitro NDF digestion of alfalfa hay treated with compound additive,SG or with out additive treatment(CKg), which may resulted from the inhibition of microorganism to degrade crude fiber by compound additive.All these results suggested that the effectiveness of inhibiting microbe and improving in vitro digestion rate of DM and CP by the compound additive was better than SG,but no significant difference was observed(P＞0.05).4.Before the preservation of alfalfa hay,contents of CP and WSC in the low moisture hay was lower than that in the high moisture hay,which were 18.60%and 21.06%in CP respectively;39.32 g/kg and 46.50g/kg in WSC respectively.When at the time of baling, NPN content in the low moisture hay was also lower than that in high moisture hay,but the difference was not significant and also there were relatively higher content of NDF,ADF and DM in the low moisture hay.After 60 days of preservation,the nutrients in the hay decline especially in the hay of CKg,but the change trend of chemical nutrients in the hay of CKd was steady-going.Significant difference(P＜0.05) was observed in the chemical nutrients of alfalfa hay with different moisture content except for ADF.Content of CP in the alfalfa hay of CKg was significantly higher than that in the CKd(P＜0.05),but the content of WSC was relatively lower than that in the hay of CKd,which only 17.80g/kg was detected.It maybe caused by microbe that using the WSC as substrate for their growing.Changes of in vitro digestion rate of chemical nutrients in low moisture hay were not obvious before and after preservation.For the high moisture hay it was opposite,the digestion of NDF was obviously increased and the digestion of DM and CP were obviously decreased,but changes of ADF was not obvious.After 60 days preservation,no difference of in vitro digestion rate of DM,NDF and ADF was observed between low moisture hay and high moisture hay(P＞0.05). |
