Weaning and beyond: using data to engage farmers in post-weaning heifer management

The post-weaning period in dairy heifer rearing is often underappreciated; however, it is a crucial phase in developing future productive dairy cows. It begins around 8–10 weeks of age, when calves fully transition from a milk-based diet to solid feed, and, as this author refers to it, extends until the first calving. Insufficient management during this period can lead to stunted growth, delayed puberty and ultimately, an increase in the age at first calving (AFC) beyond the desired 23–24 months. Conversely, effective post-weaning management enables producers to meet key growth benchmarks, positioning heifers to calve on schedule and perform optimally as dairy cows. Veterinary engagement in heifer rearing frequently declines post-weaning because of the reduced ease of handling and because animals may potentially reside in locations that are harder to access. As a result, implementing timely interventions to optimise AFC becomes more challenging. However, by leveraging data readily available through milk recording systems, a targeted report has been developed to appraise and enhance the efficiency of on-farm heifer rearing, focusing on three primary key performance indicators (KPIs): AFC, survivability and first-lactation productivity.