Managing social dynamics to improve dairy cow health and welfare

现代奶牛生产系统涉及根据泌乳期、产奶量和胎次频繁重组奶牛。然而，重新分组会使群内攻击率增加一倍，导致采食量和反刍时间减少10%，导致产奶量减少9%。重新组合还能减少14%的躺卧时间，从而显著增加跛行的风险。提高牛的社会群体的稳定性可以减少攻击性，但促进牛群体社会稳定的因素却知之甚少。社会网络分析（SNA）允许对群体的结构和模式进行量化，以定义个人在不同群体结构中的位置和角色，以解释群体动态如何运作并受到与个人属性相关的因素的影响。初步研究表明，少数“关键奶牛”在群体社会结构的组织中特别有影响力，在维持群体稳定方面具有不成比例的影响力，特别是在重组之后。尽管迄今为止还没有对牛进行研究，但其他物种的关键个体可以通过统治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显著负面影响，更精确地定义占据网络位置的关键个体的特征和角色对乳制品行业至关重要。学生将通过直接观察来量化奶牛的互动、社会偏好和网络位置，并通过行为记录来验证。他们将使用交互数据的SNA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数据和个人气质特征，可以识别促进网络稳定的关键个体的特征。根据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，从而最大限度地减少已知的有害影响奶牛健康，福利和生产力的压力因素。

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.