Factors influencing fertility
Cow comfort, health status and energy balance are crucial for good fertility. Most problems are linked to the peripartum period when cows are faced with high stress, alongside the risk of infectious and metabolic diseases. Problems during the transition period, such as negative energy balance, subclinical and clinical ketosis, systemic inflammation, and loss of body condition, are directly associated with reproductive performance. Good fertility is achieved with good quality, healthy oocytes that are able to ovulate at the right moment and produce strong enough signals to provoke estrus. Poor quality dominant follicles, however, are unable to send strong enough signals to provoke estrus and fertilisation. Even if they become fertilised by using estrus synchronisation protocols, embryo quality will be poor and invariably result in embryonic mortality.