Effects Of Feed Patterns Of Different Solid And Liquid Feed Ratio On Growth And Gastrointestinal Development In Calves

In this research,pre-and post-weaning calves were used to investigate the effects of feeding patterns of different solid and liquid feed proportion on growth performance,serum indices,digestion and utilization of energy and nitrogen,and rumen fermentation.Furthermore,the effects of different feeding patterns on gastrointestinal development were also determined.The present research was consisted of three experiments described below.Experiment 1: Effects of Feeding Patterns of Different Solid and Liquid feed proportion on Growth and Serum Indices in Holstein CalvesThe experiment was conducted to evaluate the effects of different feeding patterns(solid and liquid feed ratio)on growth performance and some serum indices of Holstein calves.Thirty six healthy calves aged 7 days were assigned to three groups.Three feeding patterns were adopted,Group with High liquid feed ratio(HL),Control group with low solid feed ratio(LS),Group with high solid feed ratio(HS).Solid and liquid feed were with the same nutrient(milk replacer,solid milk replacer).Calves in group HS were weaned at 42 days old when the total dry matter supply reached 1.1kg per day and the solid feed intake was 1.0 kg/d.Group HL and LS were weaned at 56 days old,when the solid feed intake were 0.5 kg and 1.0 kg respectively and the DMI intake were both 1.5kg.At this time,the ratio of solid to liquid intake in group HL was 1:2 and 2:1 in group LS.During the experiment period,the DMI were kept consistent between the 3 groups.The results showed as follows: 1)the daily gain(ADG)of group HS and group LS were significantly higher than that of group HL(P<0.05)at 70 days of age.During the 50-70 days of age,The F/G of group HS was significantly better than group HL(P<0.05).2)At the age of 70 days,the wither height and heart girth of group HS were significantly higher than group HL(P<0.05).3)The TAOC and the concentration of IGF-1 in group HS was significantly lower than that in group HL and group LS(P<0.05),but it was significantly higher than group HL at the age of 70 days(P<0.05).The concentration of IgG in group HS was significantly lower than that in group HL and group LS(P<0.05)at days of 42 days,but it was significantly higher than group HL at the age of 56 and 70 days(P<0.05),The concentration of NO in group HS was significantly higher than that in group HL(P<0.05)at the age of 56 and 70 days.The apparent digestibility of crude fat in the HS group was higher than that in the other two groups(P=0.095).The results demonstrate that feeding patterns of HS is the best of the three;solid feed intake has a great impact on growth and health of calves.Increasing the intake of solid feed,it is suitable to translate from liquid feed to solid feed at the age of 42 days when the solid intake is up to 1.0 kg/d.Experiment 2: Effects of Feed Patterns of Different Solid and Liquid Feed Ratio on Nutrient Metabolism and Rumen Fermentation of CalvesThe experiment was conducted to search for a new way to wean for calves through evaluating the effects of different feeding patterns(solid and liquid feed ratio)on energy and nitrogen metabolism,rumen microbial protein synthesis and rumen fermentation of pre-and post-weaning calves.Thirty-six Chinese Holstein bull calves aged 7 days were used and assigned to one of the three groups with 12 calves each.The nutritional ingredient in solid and liquid feed was same.Three feeding patterns were adopted,Group with High liquid feed ratio(HL),the feed ratio of solid and liquid feed kept to 1:2 during 28 to 56 days of age,calves weaned at day 56 days of age.Control group(LS),the feed ratio of solid and liquid feed varied from 1:2 to 1:1 during 28 to 56 days of age,calves weaned at 56 days of age.Group with high solid feed ratio(HS),the feed ratio of solid and liquid feed varied from 1:2 to 1:0 during 28 to 42 days of age,calves weaned at 42 days of age.During the experiment period,the feeding scale of dry matter was kept consistent between the 3 groups.The trial lasted 77 days.The rumen fluid was collected at 28,42,56 and 84 days of age,digestion trials were conducted to estimate nutrients metabolism at 35 and 63 days of age,respectively.The results showed as follows: comparing with HS group,metabolizable energy of pre-weaning calves in HL and LS group were higher but not significantly(P>0.05);compared with HL group,the utilization of nitrogen and energy and nitrogen biological value of post-weaning calves in HS group were significantly increased(P<0.05);Compared with HL group,microbial protein content(56 and 84 days of age)in HS group were significantly increased(P<0.05),but the proportion of ammonia nitrogen was not impacted by treatments(P>0.05);total volatile fatty acid concentration and butyrate content in HS group were significantly higher than those in HL group at 84 days of age(P<0.05);and the contents of pentanoic acid was not significantly affected(P>0.05).In conclusion,the high feed ratio of solid feed of group HS can help to improve rumen fermentation and increase microbial protein synthesis and can also increase metabolizable energy of diet and nitrogen biological value for post-weaning calves,decrease fecal energy and total excrete nitrogen.it can ultimately improve digestibility of nutrients.Experiment 3: Effects of Feed Patterns of Different Solid and Liquid Feed Ratio on gastrointestinal development in calvesThis trail aimed to investigate the effects of different solid and liquid feed ratio on gastrointestinal development in calves.The trail was designed as the experiment.Thirty-six Chinese Holstein bull calves aged 7 days were used and assigned to one of the three groups with 12 calves each.The nutritional ingredient in solid and liquid feed was same.Three feeding patterns were adopted,Group with High liquid feed ratio(HL),the feed ratio of solid and liquid feed kept to 1:2 during 28 to 56 days of age,calves weaned at day 56 days of age.Control group(LS),the feed ratio of solid and liquid feed varied from 1:2 to 1:1 during 28 to 56 days of age,calves weaned at 56 days of age.Group with high solid feed ratio(HS),the feed ratio of solid and liquid feed varied from 1:2 to 1:0 during 28 to 42 days of age,calves weaned at 42 days of age.During the experiment period,the feeding scale of dry matter was kept consistent between the 3 groups.The trial lasted 77 days.The growth performence was collected at 28,42,56 and 84 days of age.Six calves were cloected and were slaughtered at d 84.Then,the gastrointestinal development was determined.The results were presented as follows: Compared with group HL and LS,the dressing percentage of calves in group HS was higher but the difference was not significant(P>0.05).The pH of rumen fluid in group HL is significantly higher than the other two group(P<0.05).Compared with the group HL,the fresh weight of stomachus compositus in HS group were significantly increased(P<0.05),the fresh kidney weight in group HS showed a higher trend(P=0.053).In addition,the fresh weight of rumen accounted for complex stomach rates of the HS group were significantly higher than those in group HL(P<0.05),and the fresh weight of gastric abomasum in group HL was significantly higher than that of group HS(P<0.05).Compared with the HL group,the morphology of gastrointestinal tract development,rumen papillae length,muscle thickness in group HSwere significantly increased(P<0.05),However,the abomasal muscle thickness in group HS decreased significantly(P<0.05),duodenal muscle layer thickness increased significantly(P<0.05).The rumen papillae length and duodenal muscle layer thickness difference were not significant in group HS and LS.The results show that the increase in solid feed ratio(group LS and HS)improve calf slaughter performance and promote tissue organ development,significantly improve the development of ruminal and intestinal morphology,and then improve the growth status of weaned calves.In conclusion,the experimental results showed that the high proportion of solid feeding pattern(HS)helps especially after weaning the calf increase growth performance,nutrient digestion and the development of the gastrointestinal tract,and this article arguments and the datas can be used as future calves feeding pattern reform one of the important reference factors.