Does the use of corn and soybean hulls affect calf performance in the preweaning period?

ABSTRACT The objective of this study was to assess the effects of two levels of soybean hulls (0 and 400.1 g/kg) and whole or ground corn in the diet of newborn crossbred dairy male calves on intake, performance, blood indicators, and feeding cost. Twenty-eight calves with an average weight of 33.0±6.2 kg and four days of age were distributed into four treatment groups in a completely randomized design (n = 7) for 56 days. Weekly samples of feed, diets, and leftovers were collected to determine dry matter and nutrient intakes. To evaluate apparent digestibility, samples were taken using titanium dioxide as a maker. Blood samples were also collected to evaluate blood indicators. The inclusion of soybean hulls resulted in greater neutral detergent fiber intake by the calves, but reduced their non-fibrous carbohydrates intake, which was also reduced by the use of whole corn in the diet. Although the total digestible nutrients content of diets decreased with the use of whole corn and inclusion of soybean hulls, its intake did not vary (0.75 kg/d), regardless of the factors analyzed. The apparent digestibilities of dry matter (0.87 kg/kg) and crude protein (0.89 kg/kg) were similar, resulting in similar performance between the animals, regardless of the factors analyzed. In the quantities evaluated, the use of soybean hulls or whole corn did not affect blood indicators and was insufficient to reduce feed costs; the cost of daily feed was $2.06, while the cost per kilogram of gain was $3.74. The inclusion of up to 400.1 g/kg of soybean hulls or the replacement of ground corn with whole corn does not affect the performance of crossbred dairy calves during the preweaning period, demonstrating that both can be used in animal feed during this phase of production.

摘要
本研究旨在评估日粮中添加两种水平的大豆壳（soybean hulls）与整粒/粉碎玉米对新生杂交奶用公犊牛采食量、生产性能、血液指标及饲养成本的影响。选取28头平均体重33.0±6.2 kg、日龄4天的杂交奶用公犊牛，采用完全随机试验设计（completely randomized design）分为4个处理组（每组n=7），试验期共计56天。每周采集饲料、日粮及剩料样本，以测定干物质与养分采食量。以二氧化钛（titanium dioxide）为指示剂采集样本，用以评估表观消化率。同时采集血液样本以检测血液相关指标。日粮中添加大豆壳可提升犊牛的中性洗涤纤维（neutral detergent fiber）采食量，但会降低其非纤维性碳水化合物（non-fibrous carbohydrates）采食量；而日粮中使用整粒玉米同样会降低非纤维性碳水化合物采食量。尽管日粮中添加整粒玉米与大豆壳会降低总可消化养分含量，但犊牛的总可消化养分采食量并未发生变化（0.75 kg/d），与各试验因素无关。干物质（0.87 kg/kg）与粗蛋白质（0.89 kg/kg）的表观消化率无显著差异，因此各试验组犊牛的生产性能无显著区别，与各分析因素无关。在本试验所评估的添加量范围内，使用大豆壳或整粒玉米均不会对血液指标产生影响，且无法降低饲养成本；试验期间日均饲料成本为2.06美元，每千克增重成本为3.74美元。在断奶前阶段，日粮中添加最高400.1 g/kg的大豆壳，或用整粒玉米替代粉碎玉米，均不会影响杂交奶用公犊牛的生产性能，表明二者均可应用于该生产阶段的动物日粮中。