Neonate calves are usually handled a day after birth for navel care and identification. During this procedure the newly calved cows usually become agitated and, in some cases, exhibit aggressive behavior toward humans, increasing the risk of accidents for both, humans and animals. In order to understand the dynamic relationships between cow, calf, and cowhand's behavior expressed in this particular situation, a conceptual model was built by using the system dynamics methodology. Three dynamic hypotheses were formulated regarding the cause-effect relationship between: i) livestock-handling quality and maternal aggressiveness; ii) livestock-handling quality and newborn calf reactivity, and; iii) newborn calf reactivity and maternal aggressiveness. The first two hypotheses indicated that the improvement (increase) in handling quality will cause an effect in the opposite direction, decreasing cow's aggressiveness and calf's reactivity towards the cowhands. The third hypothesis indicated that the greater the calf's reactivity, the greater will be the cow's aggressiveness, interconnecting cow-calf behaviors. Moreover, the cow, calf, and cowhand subsystems are also comprised of other variables such as human and animal welfare and the occurrence of labor accidents. The combination of these three subsystems constituted a complex general dynamic model highlighting the connection among all agents involved in newborn handling procedure. Despite the complexity it is possible to identify components that promote, simultaneously, human and animal welfare when carrying out newborn calves handling procedures, offering opportunities to develop and adopt system management strategies. In this way, to reduce the risks of labor accidents and the impoverishment of overall welfare it is necessary to focus on three different factors, as follow: i) human behavior, ii) animal behavior, and iii) handling facilities. Thus, it is recommended to implement human capacity-building courses, the culling of aggressive cows and the use of appropriate facilities for the handling of newborn calves.

新生儿犊牛通常在出生后一天进行处理，以进行肚脐护理和鉴定。在此过程中，新犊牛通常会变得烦躁不安，在某些情况下，它们会表现出对人类的攻击行为，从而增加了人畜事故的风险。为了了解在这种特殊情况下表达的牛，小腿和牛手行为之间的动态关系，使用系统动力学方法建立了一个概念模型。三个动态假设被有关之间的因果关系制定：我）牲畜处理的质量和产妇侵略性; ii）牲畜的处理质量和新生小牛的反应性；以及 iii）新生小牛的反应性和产妇的攻击性。前两个假设表明，处理质量的提高（增加）将在相反的方向产生影响，从而降低母牛的攻击性和犊牛对母牛的反应性。第三个假设表明，小牛的反应性越强，母牛的侵略性就越强，它们相互联系，会影响小牛的行为。此外，母牛，小牛和母牛的子系统还包括其他变量，例如人类和动物的福利以及工伤事故的发生。这三个子系统的组合构成了一个复杂的通用动态模型，突出了涉及新生儿处理程序的所有代理之间的联系。尽管很复杂，但仍可以识别出可同时促进以下方面的成分：在执行新生犊牛处理程序时，为人类和动物带来福利，为开发和采用系统管理策略提供了机会。以这种方式，为了减少劳动事故的风险和整体福利的贫困，有必要集中注意三个不同的因素，这些因素包括：i）人类行为，ii）动物行为，和iii）处理设施。因此，建议实施人员能力建设课程，挑衅好斗的母牛并使用适当的设施处理新生小牛。如下：i）人类行为，ii）动物行为，和iii）处理设施。因此，建议实施人员能力建设课程，挑衅好斗的母牛并使用适当的设施处理新生小牛。如下：i）人类行为，ii）动物行为，和iii）处理设施。因此，建议实施人员能力建设课程，挑衅好斗的母牛并使用适当的设施处理新生小牛。