Managing social dynamics to improve dairy cow health and welfare

点击翻译按钮获取中文摘要

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.