Effects Of Texturized And Pelleted Starter On Growth Characteristics And Gastrointestinal Development In Holstein Male Calves

Three different experiments were conducted to evaluate the effect of different starters(Texturized andPelleted)on growth characteristics and gastrointestinal development in Holstein male calves. It explored theeffects of different starters on the dry matter intake, average daily gain, feed efficiency, body measurementindexes, serum biochemistry indexes, enzyme activity of small intestine, rumen and duodenal growingdevelopment physiology indexes of Holstein calves.Experiment1sixteen Holstein male calves (average body weight=41.3kg, P>0.05) were selectedand allotted randomly into two groups fed a texturized and pelleted starter respectively. The experimentwere started from birth day and studied for10weeks, all the calves were weaned at8W. After weaning,four calves were selected form each group randomly and kept in the individual hutches, during the last oneweek and feed in a small group. From3d of age, each group had ad libitum access to starters. Dry matterintake of starter was measured and fecal scoring conducted daily. Growth parameter measurements wereconducted weekly. The result indicated that: before weaning, the DMI、ADG and FE of two treatments haveno significant difference (P>0.05); At the last one week after weaning, the dry matter intake (DMI)ofpelleted starter group was significantly higher than that of texturized starter group (P=0.038), but at1-9weeks, feed efficiency of texturized starter group was significantly higher than that of pelleted startergroup（P=0.001）. During the whole trial, diarrhea rate in texturized starter group was lower14.3％thanpelleted starter group.Experiment2sixteen Holstein male calves were selected and allotted randomly into two groups feda texturized and pelleted starter respectively. Feeding methods and trial period were same to theExperiment1. From born to10weeks age, blood samples were collected weekly and stored at-20℃untilanalyzed. The result indicated that: at preweaning period, the serum BUN and TG concentrations oftexturized starter group was significantly higher than those of pelleted starter group (P=0.031, P=0.025);the serum metabolite concentrations of two treatments were significantly increased and the serum AKP,AST and ALT activity of two groups were significantly decreased with the growth of age (P<0.05), theserum BUN and ALB concentrations of of texturized starter group were significantly higher than pelleted starter group (P=0.005, P=0.024). After weaning, the serum TC, GLU, ALB concentrations weresignificantly improved and serum AST and AKP activity of two groups were significantly rising with thegrowth of age (P<0.05), and than the serum LDH activity of texturized starter group were significantlyhigher than that of pelleted starter group (P=0.032).Experiment3Eight male Holstein calves were selected and allotted randomly to two groups.Feeding methodes were same to the Experiment1, and all calves was euthanized at8W of age, and sampledfor rumen epithelial growth measurements. The results showed that: the duodenum and ileum amylaseactivity, jejunum lactase activity, jejunum and duodenum chymotrypsin activity of texturized starter groupwere significantly higher than those of pelleted starter group (P <0.05). In the pelleted starter group, thejejunum and ileum amylase activity was significantly higher than that of the duodenum (P<0.05); duodenalchymotrypsin activity was significantly higher than jejunum (P<0.05); the lactase, trypsin and lipaseactivity of three bowel have significant difference (P<0.05). In the texturized starter group, the amylase,lactase, lipase and trypsin activity of three bowel have significant difference (P<0.05), duodenalchymotrypsin activity was significantly higher than those of the jejunum and ileum (P<0.05). The rumenacetic acid, propionic acid, isovaleric acid and valeric acid concentrations of texturized starter group weresignificantly higher than those of pelleted starter group (P=0.017, P=0.001, P=0.009, P=0.049); Thereticulum, omasum and rumen epithelium mucosae color of texturized starter group significantly deeperthan those of pelleted starter group; The praedorsum caecus, praeabdomen caecus and posterior bellycaecus of texturized starter group were significantly longer than those of pelleted starter group (P=0.028,P=0.014, P=0.001).In summary, two starters have no significant impact on the growth and health of calves. Although theDMI of texturized calf starter was lower than that of pelleted calf starter, but has a greater feedefficiency.The nutrient balance of texturized calf starter was greater than that of pelleted calf starter. Thetexturized calf starter could help to promote its rumen and reticulum development，strengthen the enzymeactivity of intestinum tenue and pancreas, which was beneficial rumen health, enhance the rumendevelopment.