PDF(Pubmed)
Abstract：
Young calves are more susceptible to cold than older animals due to their limited ability to regulate body temperature and lack of fat reserves and may have difficulty consuming the energy needed to cope with the cold by maintaining body temperature and meeting their metabolic needs, especially when fed constant levels of waste milk (WM) with less solids, which can be detrimental to health and future performance. An alternative to overcome this problem is increasing the milk\'s solids content to the existing volume by using different sources [milk replacer powder (MR) or transition milk (TM)]. Thus, we aimed to evaluate the effects of increasing the total solids of WM via MR (WM+MR) or TM (WM+TM) on the performance, feeding behavior, and health-related variables of cold-stressed dairy calves during pre- and post-weaning. We hypothesized that feeding WM supplemented with MR or TM as potential liquid feed enhancers would improve milk dry matter and energy intake of the calves with a positive impact on body development and have no negative impact on feeding behavior and health. Additionally, we hypothesized that MR would not differ from TM. As a sample size calculation at 80% power using power analysis (PROC POWER) in SAS 9.4, a total of 51 Holstein-Friesian vigorous male calves [vigor score 21-27; 17 per treatment; 4-d old; body weight (BW) = 40.0 ± 0.63 kg (mean ± SD)] were selected, assigned randomly to treatments, and housed in individual pens in an outdoor barn. Irrespective of the type of treatment, all calves were fed 6 kg/d liquid feed from d 1 to d 53 of the experiment. In a step-down weaning program, calves received 0.5 kg liquid feed from d 54 to d 60. All calves were weaned on d 61 and remained in the study until d 101 as post-weaning evaluation. The calves had ad libitum access to starter feed and fresh drinking water across the experiment. Intake, growth, and behavior data were analyzed using a general linear mixed model and health data were analyzed using mixed logistic regression, mixed linear regression, and survival analysis models in SAS. We found that supplementation was responsible for a greater dry matter intake (DMI; P = 0.004), superior average BW (P = 0.037), and increased crude protein (CP; P = 0.001) and crude fat (CF; P = 0.001) intakes, with the most favorable outcomes observed for the WM+TM group when compared with WM+MR. Animals fed WM (control group; CON) showed a smaller average daily gain during the first 40-d of life (P = 0.026), showing slight changes during the whole period of evaluation when compared with the supplemented groups (SUP; WM+MR and WM+TM). No difference between MR- and TM-SUP groups, probability of having abnormal appearance (P = 0.032) and pneumonia occurrence (P = 0.022) was reduced in the SUP than in CON animals, with no effect on diarrhea among treatment groups (P = 0.461). Using milk supplements added to WM is an alternative to improve the intake, performance, and health of young calves under cold stress. Our findings showed that SUP animals outperformed the CON group in terms of DMI, average BW, and intake of CP and CF, with the TM-SUP group displaying the most favorable outcomes. Moreover, the SUP groups demonstrated reduced odds of experiencing abnormal appearance and pneumonia, highlighting the positive impact of supplementation on calf health.
摘要：
幼牛比老年动物更容易受寒，因为它们调节体温的能力有限，缺乏脂肪储备，并且可能难以通过维持体温和满足代谢需求来消耗应对寒冷所需的能量，特别是当喂恒定水平的废奶(WM)和较少的固体时，这可能对健康和未来的表现有害。克服此问题的替代方法是通过使用不同来源[牛奶替代品粉末（MR）或过渡牛奶（TM）]将牛奶的固体含量增加到现有体积。因此，我们旨在评估通过MR（WM+MR）或TM（WM+TM）增加WM总固体对性能的影响，喂养行为，断奶前后冷应激乳牛的健康相关变量。我们假设饲喂补充有MR或TM作为潜在液体饲料增强剂的WM将改善小牛的乳干物质和能量摄入，对身体发育有积极影响，对喂养行为和健康没有负面影响。此外,我们假设MR与TM没有差异。作为SAS9.4中使用功率分析（PROCPOWER）在80％功率下的样本量计算，总共选择了51只荷斯坦-弗里斯健壮的雄性小牛[活力评分21-27；每次治疗17；4天；体重（BW）=40.0±0.63kg（平均值±SD）]，随机分配给治疗，并安置在户外谷仓的单独围栏中。不管治疗的类型，从实验的第1天到第53天，所有小牛都喂6kg/d的液体饲料。在一个逐步下降的断奶计划中，从第54天到第60天，小牛接受0.5公斤液体饲料。所有小牛在第61天断奶，并保留在研究中，直到第101天作为断奶后评估。在整个实验过程中，小牛可以随意获得起始饲料和新鲜饮用水。Intake,增长,和行为数据使用一般线性混合模型分析，健康数据使用混合逻辑回归分析，混合线性回归，和SAS中的生存分析模型。我们发现，补充是导致更多的干物质摄入量的原因（dmi;P=0.004），优越的平均BW(P=0.037)，和增加粗蛋白（CP;P=0.001）和粗脂肪（CF;P=0.001）的摄入量，与WM+MR相比，WM+TM组观察到最有利的结果。饲喂WM（对照组；CON）的动物在生命的前40天显示出较小的平均日增重（P=0.026），与补充组（SUP；WMMR和WMTM）相比，在整个评估期间显示轻微变化。MR-和TM-SUP组之间没有差异，与CON动物相比，SUP的异常外观（P=0.032）和肺炎发生（P=0.022）的概率降低，对治疗组的腹泻无影响（P=0.461）。使用添加到WM中的牛奶补充剂是提高摄入量的替代方法，性能，和寒冷压力下小牛的健康。我们的发现表明，SUP动物在MDI方面优于CON组，平均BW,以及CP和CF的摄入量，TM-SUP组显示出最有利的结果。此外，SUP组出现异常外观和肺炎的几率降低，强调补充剂对小腿健康的积极影响。
