Performance of Holstein calves having free access to milk and dosed with Megasphaera elsdenii

ABSTRACT Megasphaera elsdenii converts lactate and glucose into butyrate, the main volatile fatty acid responsible of papillae development and may benefit calf performance. Twenty-six Holstein calves (BW = 34.5 ± 1.65 kg) were randomly assigned at birth to a control group (Meg0) and a group that received an oral dose of M. elsdenii NCIMB 41125 at 14 d of age (Meg14). Calves received colostrum for the first 3 d followed by free choice access to whole milk until weaning at 56 d. From d 4 onward, starter and water were offered ad libitum. Intakes were measured daily and body weights (BW) weekly. Blood samples were collected on day 7, 21, 28, 42, and 56 for β-hydroxybutyrate (BHBA) analysis. Performance was measured for an additional 14 d post-weaning. Pre-weaning milk intake was lower (p = 0.010) and starter DMI (dry matter intake) greater (p = 0.001) for Meg14 than Meg0 calves. Total DMI, metabolisable energy (ME) intake and average daily gain (ADG) were similar (p > 0.05) for both groups, but Meg14 calves had greater weaning BW (p = 0.012) and feed efficiency (p < 0.029). The average BHBA between d 21 and 56 was greater for Meg14 (p = 0.03) compared to Meg0 calves. After weaning, Meg14 calves had greater DMI (p = 0.027), ME intake (p = 0.023) and ADG (p = 0.002) and tended to have better feed efficiencies (p = 0.07) than Meg0 calves. Administering M. elsdenii NCIMB 41125 improved starter intake and feed efficiency, which was associated with high blood BHBA.摘要：埃氏巨球形菌（Megasphaera elsdenii）可将乳酸与葡萄糖转化为丁酸——这是调控瘤胃乳头发育的核心挥发性脂肪酸，且可改善犊牛生产性能。本试验选取26头初始体重为34.5±1.65 kg的荷斯坦犊牛，于出生时随机分为对照组（Meg0）与14日龄口服灌服埃氏巨球形菌NCIMB 41125组（Meg14）。犊牛出生前3d饲喂初乳，随后自由采食全乳直至56日龄断奶；自第4日起，不限量供给开食料与饮用水。每日记录采食量，每周测量体重。分别于第7、21、28、42和56日采集血样，用于β-羟丁酸（β-hydroxybutyrate）检测。试验在断奶后额外监测14d的生产性能。结果显示，与Meg0组犊牛相比，Meg14组的断奶前乳采食量更低（p=0.010），而开食料干物质摄入量（dry matter intake, DMI）更高（p=0.001）。两组的总干物质摄入量、代谢能（metabolisable energy, ME）摄入量与平均日增重（average daily gain, ADG）均无显著差异（p>0.05），但Meg14组的断奶体重（p=0.012）与饲料转化率更高（p<0.029）。Meg14组在第21至56日的平均血液β-羟丁酸水平显著高于Meg0组（p=0.03）。断奶后，Meg14组的干物质摄入量（p=0.027）、代谢能摄入量（p=0.023）与平均日增重（p=0.002）均显著高于Meg0组，且饲料转化率有优于Meg0组的趋势（p=0.07）。综上，灌服埃氏巨球形菌NCIMB 41125可改善犊牛的开食料采食量与饲料转化率，该效果与血液高浓度β-羟丁酸水平密切相关。