The Impact of Dystocia on Stress Indicators and Health Outcomes in Beef Calves: A Literature Review

Objectives: To assess the impact of dystocia in beef calves on the dynamic changes in cortisol, and immunoglobulins levels, contributing to health changes in growing calves through a literature review. Neonatal survival and development heavily depend on the physiological progression of birth. However, dystocia, or difficulty during calving can result in less vigorous offspring, leading to impaired general health due to exhaustion, pain, and human intervention. One of the primary consequences of dystocia is an elevated neonatal stress response, negatively impacting health through reduced appetite, impaired non­ specific immunity, slowed growth, and increased morbidity. Unlike in dairy cattle, in reviewed literature research on the effects of dystocia in beef calves is limited, highlighting the relevance and need for further investigation. Dystocia is painful and challenging process for both dam and calf. Non­ physiological calving induces pain and significantly increases cortisol levels in neonatal blood serum during the first two days of life. High levels of stress lead to exhaustion and generalized weakness, affecting critical neonatal behaviours such as early colostrum intake. Since beef calves typically remain with the dam, their colostrum intake depends on a functioning natural suckling reflex. Weakness from dystocia­ induced stress delays suckling, which, when combined with lower intake volumes, often results in a high incidence of passive transfer failure. General weakness of the body requires time of recovery resulting in delayed suckling. Reduced and delayed colostrum intake is linked to reduced serum Immunoglobulin G concentrations and significantly higher rates of morbidity and mortality in growing calves. In conclusion, findings from the reviewed literature emphasize the need for improved dystocia management strategies to enhance passive immunity transfer and calf health outcomes in beef production systems. A deeper understanding of the dynamic relationship between stress biomarkers, passive immunity, and health outcomes could contribute to better management practices aimed at improving calf survival and growth.