| This thesis was conducted to investigate the effects of feeding levels and mode of milk replacer on growth performance, digestion and absorption of nutrients, serum biochemical indices, feeding and interrelated behavior in pre-ruminant calves, and may be regarded as the reference in practice.Experiment one:effects of feeding levels of milk replacer on growth, digestion, metabolism and serum biochemical indices in pre-ruminant calves. Twenty four new-born Holstein calves with similar body weights were allotted into 3 treatments with 8 replicates each and 1 calf in each replicate, the calves were raised in single cages. Each treatment was fed milk replacer at a level of 9.5%(group 9.5%),11.0%(group 11.0%) or 12.5%(group 12.5%) of the body weight (BW). Body weight and measurement was measured, and blood samples were collected at 0,2,4,6,8 weeks of age. Feed intake and fecal score were record every day. The metabolism trials were conducted during 3 to 4 and 5 to 6 weeks of age, respectively. The results showed that, body weight (BW) and body measurement did not significantly different among the three groups (P=0.5010) during the whole experiment, but the average daily gain (ADG) of calves from either group 11.0% or 12.5% were significantly higher with 107.6 g and 99.3 g than that of group 9.5% (P=0.0019) during 3 to 4 weeks of age. With the weekly age of calf increased, BW and body measuremen were significantly increased (P<0.0001). Calves at 1 to 2 weeks were prone to diarrhea (fecal index>2), but with the age of calf increased, the fecal index of three groups began to decrease under 2 points after 2 weeks. Feed intake was significantly different in three groups of calves (P=0.0011). During 3 to 4 weeks of age, feed efficiency in group 11.0% was lowest and significantly different from group 9.5% or 12.5% (P=0.0239). The results of digestion and metabolism trials showed that, during 3 to 4 weeks of age, feed intake of ether extracts was significantly different among the three groups (P=0.0008). Feed intake of dry matter, organic matter, crude protein, calcium and total phosphorus in group 9.5% were significantly lower than group 11.0% and 12.5%(P=0.0009). The nutritive matter apparent digestibility of group 9.5% was highest, but the apparent digestibility of crude protein and total phosphorus were highest in group 11.0%. Digestible energy and metabolic energy of group 12.5% were highest, and was significantly different from group 9.5% (P=0.0068). The digestibility of energy was significantly different (P=0.0014) among the three groups. During 5 to 6 weeks of age, the feed intake of ether extracts in group 12.5% was highest, and significantly higher than other groups (P=0.0002). The apparent digestibility of nutritive matter in group 11.0%slightly higher than other groups, the calcium apparent digestibility of group 11.0% was significantly higher than that of group 12.5%(P=0.0197), the energy excretion of group 11.0% was significantly lower than that of group 12.5%(P=0.0070). The serum biochemical indices were influenced by the weeks of age, serum total protein, albumin and globulin increased and A/G slightly decrease with the weekly age of calf increased, the serum glucose, triglyceride and blood urea N were stable in a certain range. The conclusions indicate that milk replacer has effects on the body weight gain, digestion and metabolism of nutrients, and serum biochemical indices of calves. It is feasible when milk replacer fed at 11.0% of body weight.Experiment two:effects of feeding mode of milk replacer on growth performance and behavior of calves. Twenty four new-born Holstein calves with similar body weights were allotted into 4 treatments with 6 replicates each, the calves were raised at 11.0% of BW with feeding mode of bucket in single cages (group BS), milk bottle in single cages (group MS), bucket in group cages (group BG), milk bottle in group cages (group MG). BW and body measurement was measured at 0,2,4,6,8 weeks of age. Manual and video recorder recorded the calf of behavioral parameter at 1,3,5,7 weekly ages select one of 3,4,5,6 of days. The results showed that, the BW and ADG of calves did not significantly different among the four groups (P=0.9587). Body length of group MS was significantly longer than group MG (P=0.0358) and group BG (P=0.0330) at 6,8 weeks of age. The fecal index of calves were high before 2 weeks, and descended low after 2 weeks, but the fecal index of group BG or MG increased suddenly, that were significantly different from group BS or MS (P<0.0001). The time of ingesting milk in group MS or MG was significantly longer than group BS or BG (P<0.0001). The rate of ingesting milk in group BS or BG was faster and group BS was significantly faster than other groups (P<0.0001) at 3,5,7 weeks. The more frequency of bunting behaviour with group BS or MS was appeared, the group MS of calf keep more frequency of bunting behaviour at 3,5 weeks. The time of sucking empty bucket or teat of group BS or MS was significantly longer than group BG or MG (P.<0.0001), and group MG was significantly different in group BG at 3 weeks (P<0.0001). Sucking bucket edge or milk bottle of group BS or BG was significantly higher than group MS or MG (P<0.0001) at 1 weeks, and that group BS was significantly higher than other groups (P<0.0001) at 3,5 weeks. The group BS or BG of calf showed a longer time in licking pen during the whole experiment. The dillydally pen, self grooming, sniffing land and lying down of calf, and sniffing the other calf and social grooming of group BG or MG were influenced by feed mode of milk replacer, but the duration was short. The abnormal behaviours of calf were cross-sucking mouth, ear, neck, under belly or body with other calf. The time of cross-sucking neck (P=0.0040) and cross-sucking ear (P=0.0377) in group BG was significantly longer than group MG at 1,5 weeks. The conclusions indicate that feed mode of milk replacer has effects on behaviour of calves. The time of non-nutritive sucking and abnormal behaviours reduced effectively when the calf fed using milk bottle. |
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