Poor welfare compromises testicle physiology in breeding boars

In commercial pig breeding farms, boars are often exposed to stressful situations, such as confined housing conditions, inadequate environmental temperature, food restriction, lameness, diseases, among other challenges. Confined housing conditions, such as crates, are reported as a major source of stress for pregnant sows, and were banned in the UK and in Europe, however there is limited information about the impact of this housing system for boars. The goal of this study was to investigate the impact of three different housing conditions for boars and the consequence on the testicles. We studied 27 crossbred boars (F1 large white and landrace), housed in crates (n = 9), pens (n = 9), or enriched pens (n = 9), during 10 weeks. We collected data of scrotal superficies mean temperature (SSMT) with a thermal camera; we measured testicular parenchyma perfusion (ultrasound evaluation); and we measured sperm characteristics. We found that boars housed in crates had a higher SSMT (p < 0.05) and higher testicular parenchyma perfusion than boars housed in pens and enriched pens (p = 0.01). Regarding the semen features, we found that boars housed in crates showed more agglutinated semen, and higher values of linear curved linear velocity (VCL) than boars housed in pens and enriched pens, both indicators of reduced fertility. These results indicates that boars housed in pens and in enriched pens showed better indicators of testicular health, better sperm motility features (VCL, p = 0.046), and less agglutinated sperm (p < 0;05) than that observed in boars kept in crates.