| Guangxi is a big province of buffalo farming.Meanwhile,Guangxi possesses abundant available roughage resources.Previous studies have shown that buffalo has better roughage-resistance than other cattle breeds,but the reason why the roughage-resistance of buffalo is better than other cattle breeds has not been fully elucidated.The study on the growth performance and changes in rumen bacterial population of young buffalo after feeding on roughage is the basis for further understanding the rumen development of buffalo.At the same time,the local Pennisetum purpureum and different cutting length of roughage were used to provide a reference for local buffalo farming,roughage and length selection in Guangxi.In this experiment,2*2 group design was adopted,and the different roughage quality and the roughage length were taken as two-factor,among which Pennisetum purpureum hay and Avena sativa hay were selected as roughage,and the length of roughage was between 3 ± 0.5cm and 6 ± 0.5cm,which were divided into short Pennisetum purpureum group,long Pennisetum purpureum group,short Avena sativa group and long Avena sativa group(E1,E2,T1,T2).In the experiment,32 buffalo calves with 1 month old(30 days old)with similar body weight and good health were randomly divided into 4 groups according to their body weight,with 8 in each group.During the pre-feeding period of the experiment,only the milk replacer was fed for 3 days;the formal period was 56 days,which was divided into two stages: 35 days before weaning and 21 days after weaning(3 weeks).Milk replacer was fed twice a day.For buffalo calves with 30-50 days old,there were 4 L / head in the morning and 2 L/ head in the afternoon;for buffalo calves with 50-60 days old,there were 2 L /head in the morning and 1 L / head in the afternoon;for buffalo calves with60-63 days old,there were 1.5L/head per day;for buffalo calves with 63-65 days old,1L / head per day;weaning was carried out for buffalo calves with 65 days old.Concentrate and roughage could be freely fed.In the third week after weaning,the total collection method was used to carry out a 7-day digestion experiment,2 days for the pre-feeding period and 5 days for the formal period.The experimental results are as follows:(1)The period from before weaning to weaning.Feed intake: 31-65 days old,the rough oat grass intake of the short oat grass group was significantly higher than that of the elephant grass group and the long oat grass group(P<0.05,the same below),and the concentrate feed intake of the long oat grass group was significant Higher than the elephant grass group and short oat grass group.In terms of growth performance: the daily weight gain of the long oat grass group was significantly higher than that of the long elephant grass group,but the length of roughage had no significant effect on the daily weight gain;the total average daily dry matter intake of the oat grass group was higher than that of the elephant grass group;The material-to-weight ratio of the long elephant grass group was significantly higher than that of the oat grass group and short elephant grass group.In the rumen bacterial flora: after quality control and dehosting,the data volume of group T2 is significantly higher than that of the other three groups;at the gate level,Firmicutes,Actinobacteria,Bacteroides phylum is the predominant phylum at the phylum level of each treatment group;at the genus level,the genus Selenomonas,Acidaminococcus,and Prevotella are the dominant genus;in At the species level,the dominant strains are Acidaminococcus Fermentans,Selenomonas Bovis,Acidaminococcus Intestini.(2)The period from weaning to three weeks after weaning.In terms of feed intake: three weeks after weaning,the rough oatmeal intake of the short oat grass group was significantly highest.During the entire three weeks after weaning,the concentrate intake of the long oat grass group was significantly higher than that of the long grass group.In terms of production performance: the daily weight gain of the long oat grass group is significantly higher than that of the elephant grass group,but the length of roughage has no significant effect on the daily weight gain;the total average daily dry matter intake of the oat grass group is higher than that of the elephant grass group,However,the length of roughage has no significant effect on the total average dry matter intake.The feed-weight ratio of the short elephant grass group and long oat grass group was significantly lower than that of the long elephant grass group and short oat grass group.In terms of apparent nutrient digestibility: the apparent digestibility of dry matter,the apparent digestibility of neutral detergent fiber,and the apparent digestibility of acid detergent fiber of the oat grass group were significantly better than the elephant grass group.In the rumen p H: three weeks after weaning,the long elephant grass group was significantly higher than the short elephant grass group,and the p H value of the long roughage group was higher than that of the short roughage group.(3)Looking at the growth performance and economic benefits of the entire test period: the roughage intake of oat grass is significantly higher than that of the elephant grass group,and the short oat grass group is the largest;the concentrate feed intake of the long oat grass group is significantly the highest;In terms of weight gain,the long oat grass group was significantly higher than the elephant grass group;the feed weight ratio of the short elephant grass group and the long oat grass group was significantly higher than that of the long elephant grass group and the short oat grass group;the net income of the oat grass group was significantly higher Long Elephant Grass Group.In conclusion,during the period before weaning: the source and length of roughage will affect the feed intake of roughage.The long Avena sativa group can promote the buffalo calves to take in more concentrates,but the short Avena sativa group has the greatest advantage in general.Short roughage can significantly increase the relative abundance of Lactobacillus.The relative abundance of Ruminococcus Flavefaciens and Selenomonas Bovis were affected by the source of roughage.During three weeks after weaning,the weaning stress in Pennisetum purpureum group was less.After weaning,the intake of Avena sativa by buffalo calves was much higher than that of Pennisetum purpureum,with an average increase of 58.18%.The advantage of long Avena sativa hay was obvious after weaning.Compared with Pennisetum purpureum group,NDF and ADF digestibility of long Avena sativa group were significantly increased by15.09% and 13.13%;during three weeks after weaning,the p H of the long roughage group was significantly increased by 6.89%.During the whole experiment period: the ADG of buffalo calves fed with Avena sativa was86.31g/d more than that of Pennisetum purpureum,which showed that there was a certain gap in growth.However,in terms of economic benefits,the difference in net income between Pennisetum purpureum group with 3cm in length and3 cm and 6cm Avena sativa group with 3cm and 6cm in length was not significant.If the local Pennisetum purpureum is more easily available,Pennisetum purpureum group with 3cm can completely replace Avena sativa with 3cm in length as feed during three weeks after weaning. |
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