Managing social dynamics to improve dairy cow health and welfare

现代奶牛生产系统包括根据泌乳阶段、产奶量和胎次对奶牛进行频繁的重新分组。然而，重新分组使组内攻击率加倍，导致采食量和反刍时间减少10%，导致产奶量减少9%。重组也减少了14%的躺卧时间，导致跛行的风险显着增加。增加奶牛社会群体的稳定性，减少侵略，但促进社会稳定的因素，在牛群知之甚少。社会网络分析（SNA）允许群体的结构和模式被量化，以定义不同群体结构中个体的位置和角色，以解释群体动态如何运作，以及如何受到与个体属性相关的因素的影响。初步研究表明，少数“关键奶牛”对群体社会结构的组织特别有影响力，并且在维持群体社会结构方面具有不成比例的影响力。特别是重组后的稳定性。尽管迄今为止还没有在牛身上进行过研究，其他物种中的关键个体可以通过优势地位和气质等因素来表征。为了管理动态分组对牛福利和生产力的重大负面影响，更精确地定义占据网络位置以维持稳定性的关键个体的特征和作用在乳制品行业中至关重要。学生将通过以下方式实现这一点：使用直接观察量化奶牛互动、社会偏好和网络位置，并通过行为记录进行验证。他们将使用SNA的交互数据来量化重组前后的网络结构，并使用经过验证的牛气质测试来定义促进网络稳定性的关键个体的特征。结合SNA数据和个体气质特征，将确定促进网络稳定性的关键个体的特征。基于具有特定气质的个体的网络角色操纵群体组成将允许管理优化以促进群体稳定性，从而最大限度地减少已知的对奶牛健康，福利和生产力产生负面影响的压力因素。

Modern dairy cattle production systems involve frequent regrouping of cows based on lactation stage, milk yield and parity. However, regrouping doubles the rate of intra-group aggression leading to 10% decreases in feed intake and rumination time resulting in reductions in milk yield of up to 9%. Regrouping also reduces lying time by 14% leading to a significantly increased risk of lameness.Increasing the stability of cow social groups reduces aggression but factors that promote social stability in cattle groups are poorly understood. Social Network Analysis (SNA) allows the structure and patterns of groups to be quantified to define the place and role of individuals within differing group structures to explain how group dynamics operate and are influenced by factors linked to individual attributes.Preliminary studies have shown that a small number of 'key cows' are particularly influential in the organisation of group social structure and have a disproportionate influence in maintaining group stability particularly after regrouping. Although not studied to date in cattle, keystone individuals in other species can be characterised by factors such as dominance status and temperament.More precise definition of characteristics and roles of keystone individuals occupying network positions that maintain stability is critically important in the dairy industry in order to manage the significant negative effects of dynamic grouping on cattle welfare and productivity.The student will achieve this by quantifying cow interactions, social preferences and network positions using direct observation which they will validate by behavioural recording. They will use SNA of interaction data to quantify network structures before and after regrouping and define the characteristics of keystone individuals that promote network stability using validated cattle temperament tests.Combining SNA data and individual temperament profiles will identify characteristics of keystone individuals who promote network stability. Manipulation of group composition based on network roles of individuals with particular temperaments will allow management optimisation to promote group stability thereby minimising the stress factors known to detrimentally influence dairy cow health, welfare and productivity.