A total of 952 multiparous sows from five commercial breeding units across the United Kingdom, Ireland and South Africa were evaluated to determine whether Brix classification of sow colostrum could be used as a predictor of reproductive performance. Fresh colostrum samples were collected within three hours of farrowing and analysed using a Brix refractometer to estimate immunoglobulin (IgG) content. Results showed that 36.8% of sows produced suboptimal colostrum. Sows producing optimal colostrum tended to have more piglets born alive (17.1 vs. 16.4 piglets per litter) and significantly lower stillbirth rates (8.1% vs. 9.4%) compared to sows producing suboptimal colostrum. These findings demonstrate that colostrum quality may be an indicator of both passive immunity transfer and sow reproductive performance. Brix refractometry provides producers with a simple, rapid and cost-effective on-farm tool to assess herd status, identify opportunities to improve colostrum quality and support improved productivity and economic returns.