Replacement of dry ground corn with reconstituted corn grain
silage in the starter concentrate of dairy calves

Thirty-six newborn Holstein calves were used in a randomized block design and allocated to the following groups: 1 – starter concentrate based on ground corn grain, soybean meal, wheat bran and premix of minerals and vitamins (Control); and 2 – the same diet composition, but ground corn replaced with reconstituted corn grain silage (RCGS). Calves were fed 6 l/day of whole milk and had free access to water and concentrate. Calves were weaned from day 57 to 63 and fed hay ad libitum until 70 days of age. The period from birth to 56 days of age was called pre-weaning and from day 57 to 70 – the transition period. On day 70, five animals/treatment were slaughtered to assess ruminal development. Dry matter intake (DMI) and health problems were recorded daily, while weight and blood samples were collected weekly. Ruminal fluid was collected at weeks 8 and 10. Replacing corn grain with RCGS resulted in greater feed efficiency (FE) at pre-weaning (0.71 vs 0.66). Concentrate DMI was higher for control during the transition period (303 vs 256 g/day). Control calves presented higher faecal scores throughout the study. The control diet resulted in higher concentrations of isovaleric and isobutyric acids and ammonia-N at week 8. RGCS increased glucose levels, but decreased total protein concentration during the whole evaluation period. Feeding RCGS was efficient during the preweaning period; however, it decreased intake during the transition period. Data from a longer feeding period after weaning are needed to evaluate the effects of a highly digestible starch source in the diet of young calves.

ACKNOWLEDGEMENTS

The authors express their appreciation for the scholarship granted to the first author by the Brazilian National Council for Scientific and Technological Development (CNPq). We would also like to thank the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior‐Brasil (CAPES).

CONFLICT OF INTEREST

The Authors declare that there is no conflict of interest.

METADATA IN OTHER LANGUAGES:

Chinese

重组玉米颗粒青贮料代替干磨碎玉米作为开食精料饲喂乳牛犊效果

摘要：36头新生荷斯坦犊牛采用随机区组设计，分为以下几组：（1）以磨碎玉米、豆粕、麦麸和矿物质和维生素预混料为基础的开食精料饲喂组（对照组）；（2）日粮组成相同，但用重组玉米颗粒青贮饲料（RCGS）代替磨碎玉米。犊牛每天喂食6升全脂牛奶，自由饮水和采食开食精料。犊牛在第56~63天间断奶，期间自由采食干草，饲喂期共70天。从出生到56天为断奶前阶段，从57~70天为过渡阶段。在第70天，每组屠宰5头犊牛评估瘤胃发育。每天记录干物质摄入量（DMI）和犊牛健康问题，每周测定体重和血液样本1次。在第8周和第10周收集瘤胃液。在断奶前阶段，用RCGS替代磨碎玉米饲喂犊牛提高了饲料效率（FE）（0.71 vs 0.66）。在过渡阶段，对照组精料干物质采食量（DMI）较高（303克/天，256克/天）。在整个试验期，对照组犊牛的粪便评分较高。在第8周，对照组犊牛的异戊酸、异丁酸和氨氮浓度升高。在整个试验期，RCGS组葡萄糖水平增加，但总蛋白浓度降低。在断奶前阶段，饲喂RCGS是有效的；然而，在过渡阶段，摄入量减少。因此，仍需要断奶后较长的饲喂期数据来评估犊牛日粮中高消化淀粉来源的效果。

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