Effects Of Different Nutrient Levels Of Milk Replacer And Feeding Methods On Growth Performance And Meat Quality Of Dairy Male Calves Aged 4 Months

In order to investigate the effects of different nutrient levels of milk replacer and feeding methods on growth performance and meat quality of dairy male calves aged 4 months, two experiments were conducted:Experiment 1: Effects of nutrient levels of Milk replacer on growth Performance, Slaughter performance and Meat quality of calves aged from 0 to 4 months40 healthy male calves with close birth date and body weight were selected, and randomly divided into four groups(10 per group), which were fed with milk replacer at different nutrient levels, namely groupâ… (22% CP, 16.00 MJ/kg DE), group â…¡(20% CP, 16.00 MJ/kg DE), group â…¢(22% CP, 15.00 MJ/kg DE), and group â…£(20% CP, 15.00 MJ/kg DE). The experimental period lasted for 120 days. The results showed as follows: Compared with group â…¡, group â…¢ and group â…£, average daily gain(ADG) of groupâ… was the highest respectively increased by 11.63%(P<0.01), 6.67%(P<0.01) and 5.49%(P<0.01). The protein level of milk replacer had a significant effect on final weight and average daily gain, final weight and ADG of calves in the group with the milk replacer containing 22% protein were increased by 3.29%(P<0.05) and 5.62%(P<0.01) compared with the group of the milk replacer containing 20% protein. The digestible energy(DE) levels of milk replacer affected the DMI, that was reduced significantly with the increasing of DE levels, DMI of calves fed with 16 MJ/kg DE milk replacer was increased comparing to that of calves fed with 15 MJ/kg DE milk replacer, the DMI was reduced by 2.90%(P<0.01); The digestibility of CP and EE of 60 d and 120 d calves were affected significantly by protein levels of milk replacer, compared with the calves of 20% protein, the digestibility of CP of 60 d and 120 d of the calves of 22% protein were respectively increased by 3.49%(P<0.05) and 4.57%(P<0.05), the digestibility of EE of 60 d and 120 d calves were respectively increased by6.67%(P<0.05) and 3.80%(P<0.05); The content of BUN, TP and T3 in serum of 120 d calves were respectively increased by 21.61%(P<0.05), 4.36%(P<0.05) and 5.79%(P<0.05) compared with the group of 22% protein. The eye muscle area and live weight before slaughter of calves were significantly affected by protein levels of milk replacer(P<0.05), that were increased with the increasing of protein levels, compared with the group of low protein level, the eye muscle area and live weight before slaughter of calves in the group of high protein level were increased by 4.58% and 1.19%(P<0.05). The net meat weight percentage and carcass meat production rate of calves fed with 16 MJ/kg energy milk replacer were increased comparing to that of calves fed with 15 MJ/kg energy milk replacer. Specifically, the net meat weight was increased by 3.74%(P<0.01), the net meat percentage was increased by 3.25%(P<0.01), and the carcass meat production rate was increased by 2.29%(P>0.05). Feeding 16 MJ/kg had improved the content of crude protein and crude fat(P>0.05), but did not affect on the shear force, meat color and cooking loss of beef. The content of saturated fatty acid(SFA)was reduced by 2.65%(P<0.01), comparing that of the group with 20% protein in the milk replace to the group with 22% protein. The content of polyunsaturated fatty acids(PUFA)and monounsaturated fatty acids(MUFA) was improved significantly by increasing the energy levels. Statistical analysis suggests that the content of PUFA and MUFA of calves fed with16 MJ/kg energy milk replacer was increased by 3.46%(P<0.05) and 5.50%(P<0.05) than that of calves fed with 15 MJ/kg energy milk replacer. In this study, meat percentage, eye muscle area and the content of CP and crude fat of groupâ… was the highest of the four groups. Based on the analysis of all indicators, ADG, nutrient apparent digestibility, Slaughter performance and Meat quality of groupâ… was the best, economic benefits was the highest. the suitable energy and protein level of milk replacer for 0~4 months old fattening dairy bull calves were DE 16.00MJ/kg and CP 22.00%.Experiment 2: Effects of different milk replacer and feeding methods on growth Performance and Meat quality of Holstein Bull CalvesThe study was undertaken to determine the effect of growth performance and meat quality of dairy male calves fed on the liquid milk replacer(containing mainly dairy products), the powdered milk replacer(containing mainly plant diet,etc) and grainy milk replacer. 30 healthy male calves with similar birth date and body weight were selected, and randomly divided into three groups(10 per group), for a period of 120 d white beef production fattening test. Groupâ… fed with milk replacer(commercial, 22% CP, 16% EE), groupâ…¡with milk replacer(formulated, 22% CP, 16.00MJ/kg DE) and group â…¢ with milk replacer(formulated, 22% CP, 16.00MJ/kg DE). The results showed as follows: 0~120 d ADG and 120 d weight of group â…¢ was the highest, compared with groupâ… and groupâ…¡, groupâ…¢ respectively increased by 10.91%(P<0.01) and 11.82%(P<0.01),8.21%(P<0.01)and 10.36%(P<0.01). 0~120 d feed conversion ratio of groupâ…¡was the highest, compared with groupâ… and groupâ…¢, group â…¡ respectively increased by 15.02%(P<0.01)and 7.73%(P<0.01). There were no significant differences in nutrient apparent digestibility of Holstein Bull Calves with different milk replacer and feeding methods(P>0.05). Carcass weight and meat weight of groupâ… calves were significantly higher than those of group â…¡ and group â…¢, compared with group â…¡ and group â…¢, group â… respectively increased by 10.62%(P<0.05)and 12.14%(P<0.05), 11.06%(P<0.01)and 11.27%(P<0.01), but there was no significant difference in carcass meat production rate during three groups(P>0.05). There was no significant difference in shearing force, cooking lose and meat color of longissimus during three groups(P>0.05), but compared with group â…¡and group â…¢, the water losing rate of groupâ… increased by 17.24%(P<0.01)and 21.54%(P<0.05). The content of crude fat of groupâ… was significantly higher than group â…¡and group â…¢(P<0.01),but there were no significant differences in the content of Moisture, CP, Ca, P and Fe of longissimus between two groups(P>0.05). The powdered milk replacer and grainy milk replacer can save the feed costs, were significantly reduced by 45.38% and 40.34%. In summary, the growth performance and meat quality of three groups calves was similar, feeding cost was reduced significantly. Grainy milk replacer is more beneficial for the intake, health and weight gain, reduced the damage of dust to respiratory system, is more conductive to the promotion and application in actual production.