Evaluating the efficacy of visual assessment of gilt vulva size prior to puberty on subsequent reproductive performance *

Abstract

Objective: This study's objective was to assess the relationship between visually assigned prepubertal vulva score and subsequent sow productivity in a commercial production system. Materials and Methods: The study was conducted at a genetic nucleus herd, where farm personnel visually classified prepubertal gilts into categories: vulva score 1 (VS1; below average size), VS2 (average vulva size), and VS3 (above average vulva size), at approximately 15 wk of age. Reproductive performance from gilts incorporated into the breeding herd were tracked through 2 parities of production. Results and Discussion: Age at parity 1 (P1) was greatest (P ≤ 0.01) in gilts assigned a VS1 score compared with those receiving a VS2 or VS3 score. The P1 total pigs born for gilts categorized as VS2, VS3, and VS2/3 (VS2 and VS3 combined into one group) was greater (P ≤ 0.05) compared with gilts receiving a score of VS1. The number of pigs born alive was also lower (P ≤ 0.05) for gilts assigned a VS1 compared with those assigned VS2 or VS3 and the combined group (VS2/3). Second parity litter performance was not affected (P > 0.18) by prepubertal vulva score assignment, although total pigs born and pigs born alive through 2 parities combined tended to be greater (P ≤ 0.08) for gilts in the combined VS2/VS3 group compared with those assigned a score of VS1. Implications and Applications: These data suggest visually assessing prepubertal vulva development may identify females more likely to farrow at a younger age with improved P1 litter performance.