Magnesium Administration in Preslaughter Drinking Water Reduces Spinal Fractures in Pigs during Stunning

Spinal fractures in pigs during electrical stunning are frequent and compromise animal welfare, meat quality, and generate economic losses. Despite the relevance of the problem, specific preventive strategies are still little explored. This research evaluated, in an unprecedented way, the effect of magnesium supplementation in drinking water during preslaughter fasting on the occurrence of these fractures. A total of 2,080 pigs were evaluated, divided into a control group (CT) with 964 animals, not supplemented and a treatment group (TG) with 1,116 animals, supplemented with magnesium in drinking water, at a concentration of 300 mg/L. The supplementation reduced the proportion of fractures from 39.4% (380/964) to 30.0% (335/1,116), with an odds ratio of 0.66, suggesting a protective effect associated with muscle relaxation. Pigs with fractures had lower water holding capacity (WHC: 0.338 vs 0.351; <i>p</i> = 0.0076), especially in the supplemented group (0.333 vs 0.357; <i>p</i> = 0.0002), confirming the relationship between skeletal injuries and meat quality. In conclusion, preslaughter supplementation with magnesium is practical and effective to reduce fractures and improve pork quality.