Caqueta, Colombia, has a bovine population of 1,809,702 head, of which 88% are in dual purpose livestock systems; it ranks fifth in milk production at the national level. The aim of this study was to evaluate the effect of different levels of tree cover on milk production in dual-purpose livestock systems in the humid tropics of Colombia’s Amazon region. The work was carried out in the Centro de Investigaciones Amazonicas CIMAZ Macagual. It is within the tropical humid forest life zone. Nine pastures of one hectare each were selected, covered by improved pastures (Brachiaria decumbes) and dispersed trees. Treatments were defined by the percentage of tree cover: (1) high (20.43 ± 0.47), (2) medium (14.83 ± 0.58) and (3) low (4.20 ± 0.85). The spatial distribution of the dispersed trees was obtained using the SexI-FS simulator. Nine milking cows with similar characteristics were selected and managed following a 3 × 3 Latin square experimental design (Cross Over), repeated three times. The ANOVA using the general linear mixed model revealed that milk production varied with the levels of tree cover (p < 0.05), getting the highest milk production with the medium and high level of tree cover, (4.43 ± 0.21 and 4.39 ± 0.21 kg cow− 1 day− 1 respectively), followed by the low levels of tree cover (4.13 ± 0.21 kg cow− 1 day− 1).

中文翻译：

---

哥伦比亚亚马逊地区潮湿热带地区不同树木覆盖水平对两用畜牧系统产奶量的影响

哥伦比亚的卡克塔拥有 1,809,702 头牛，其中 88% 处于双重目的的畜牧系统中；牛奶产量居全国第五位。本研究的目的是评估不同水平的树木覆盖对哥伦比亚亚马逊地区潮湿热带地区两用畜牧系统产奶量的影响。这项工作是在 Centro de Investigaciones Amazonicas CIMAZ Macagual 进行的。它位于热带潮湿的森林生活区内。选择了 9 个牧场，每个牧场占地 1 公顷，覆盖了改良牧场（Brachiaria decumbes）和分散的树木。处理由树木覆盖的百分比定义：（1）高（20.43±0.47），（2）中（14.83±0.58）和（3）低（4.20±0.85）。使用 SexI-FS 模拟器获得分散树木的空间分布。按照 3 × 3 拉丁方实验设计（Cross Over）选择和管理具有相似特征的 9 头奶牛，重复 3 次。使用一般线性混合模型的方差分析显示，牛奶产量随树木覆盖水平而变化（p < 0.05），在中等和高水平树木覆盖下（4.43 ± 0.21 和 4.39 ± 0.21 kg 母牛）获得最高的牛奶产量− 1 天− 1），其次是低水平的树木覆盖（4.13 ± 0.21 kg 牛− 1 天− 1）。