Lifetime and removal reasons for Pietrain boars in European AI centers: a retrospective analysis.

Abstract

Currently, artificial insemination (AI) is the most common reproductive method used in swine production. The economic profitability of AI centers is closely linked to a boar's retention rate and the purchase of replacement boars. The objectives of this study were to examine data of selection process and lifetime of a total of 6,496 purebred Pietrain AI boars and to analyze the frequency and reasons of removal in eight European countries. Data were obtained from two German boar multiplication farms as well as 53 AI centers from 2018 to 2022. The retention time was analyzed from the selection process until replacement and to the end of the examination, respectively. The selection process of the boars took place at 168 ± 5 (mean ± SD) days of age. For further calculations, the removal reasons were divided into nine groups: breeding (BR), died (DI), euthanasia (EU), health (HE), genetics (GE), low libido (LI), sperm quality (SQ), structure (ST), and other (OT). Overall, 56.1% of the examined boars were removed, with 17.5% being removed within the same year they entered the AI center. The annual removal rate for the 53 AI centers averaged 42.4%. The most frequent removal reason was low SQ (45.1%), followed by genetics (28.6%) and low libido (10.6%). The highest relative frequency of removals was observed for an age of 2 yr (34.0%). The highest removal risk was calculated for boars in Czech AI centers (P < 0.001), while the lowest removal risk occurred in Dutch (P = 0.006) and Portuguese AI centers (P = 0.01). The comparison of removal groups revealed, inter alia, higher body weight at selection process for the BR group (117.9 ± 9.0 kg) and longer quarantine periods for LI group (45.9 ± 17.6 d). Boars in the GE group were characterized by the oldest age at removal (934.0 ± 272.8 d) and longest period of exploitation (672.5 ± 266.8 d). The results could be helpful to detect the most common reasons for production failure of AI Pietrain boars and beneficial for establishing an economical removal policy in AI centers and for improving boar management through problem-based selection in boar multiplication farms.