Effect Of Early Weaning By Different Feeding Schemes On Ingestion Ability Of Roughage And Growth Development In Dairy Calves With 2 To 6 Month

The study was based on the former research which was carried out with 36 healthy China Holstein male calves with average age of 1.83 d were divided into 9 groups randomly to take early weaning by different feeding schemes, and it was began when the age of test calves up to 2 month and body weight of 82.00 kg. The L9(34) orthogonal experimental design took different feeding schemes in former stage as basis(aftereffect factor), different energy feedstuff, different add levels in mannan oligosaccharides and probiotic as test factors. Soybean meal as the main protein source, energy feedstuff derived from steam-flaked corn, common corn+4% vegetable oil and common corn. Mannan oligosaccharides and probiotic were set in the three add levels of 0.00%, 0.08%, 0.16% and 0.00%, 0.10%, 0.20% respectively. Three feeding schemes were used by 7+1, 5+3 and 3+5. The objective of this experiment was to ascertain the effect of ingestion ability on roughage and growth development by different feeding schemes in early weaning calves with 2 to 6 month old to select the best optimization solution, and to provide reference for artificial feeding of early weaning China Holstein female calves and beef resources utilization for male calves.The results showed that the factor optimization of early weaning by different feeding schemes was by 0.08% mannan oligosaccharides, former feeding scheme with 7 weeks milk replacer + 1 week transition feedstuff, 0.20% probiotic and common corn+4% vegetable oil during 2 to 4 month old, mannan oligosaccharides as the main effect factor,former feeding scheme and probiotic were secondary effect factor. While at the stage of 4 to 6 month old in the experiment, former feeding scheme with 7 weeks milk replacer + 1 week transition feedstuff, common corn, 0.08% mannan oligosaccharide and 0.10% probiotic were the optimization factors combination for calves, former feeding scheme as the main effect factor, energy feedstuff and mannan oligosaccharide were secondary effect factor. In conclusion, former feeding scheme by 7+1, 0.08% mannan oligosaccharides, 0.10% probiotic and common corn + 4% vegetable oil was the comprehensive combination of factor optimization in the whole experimental stage, former feeding scheme as the main effect factor in general. Which reached average daily gain 1162, 1340 g, dry matter intake of roughage 1.87, 2.73 kg and profit for weight gain 22.37, 23.29 yuan for each calve per day at the stage of 2 to 4 month and 4 to 6 month respectively.The findings indicated that not only the developmental biology process of digestive tract morphology and function but also development of digestive enzyme system at the stage of artificial feeding with early weaning in male calves is closely related to the feeding scheme. Appropriate add level of mannan oligosaccharides can make up for the shortage while the immune function of digestive tract in calves hadn't developed completely yet with the age of 2 to 4 month old. In addition, common corn + 4% vegetable oil as energy source performed better effect at this stage because of its higher energy and better palatability. With the growth of age, the morphology and function of digestive tract and digestive enzyme system developed absolutely. Accordingly, the effect of mannan oligosaccharides and probiotic was reduced with the age of 4 to 6 month. However, rational feeding period of milk replacer in dairy calves can improve its digestive function, and then enhances the ability of roughage ingestion, digestion and absorption. The whole test phase with 2 to 6 month in calves was the special biological stage on synchronous development of forestomach and abomasums, and small intestine digestion transit to forestomach digestion gradually as well, different former feeding schemes as the main effect factor. Mannan oligosaccharides, probiotic and composite enzyme of milk replacer by 7+1 not only has immunomodulatory effects, but also promote the establishment of rumen microbial flora and supplement the deficiency of digestive tract enzyme system, which was better than 5+3 and 3+5. Feeding scheme by 7+1 was more conducive to the development and improvement of the forestomach morphology and function, which has the optimal control effect.