A farrowing-rate comparison with changing definitions

A breeding unit reports a lower farrowing rate this month and asks the veterinarian to identify the infectious cause immediately. The two reports use different denominators: one follows a defined service cohort and the other divides current litters by all breeding females present. Animals have also moved between groups, and records of repeat services are incomplete. Piglet survival is being discussed in the same percentage without separating stillbirths from deaths after live birth. The veterinarian needs to reconcile the definitions before deciding which biological investigation is justified. The actual sows still require care, but a changed spreadsheet formula is not itself evidence of a new reproductive pathogen or a reason for one universal hormonal programme.