Potentially hazardous sulfur conditions on beef cattle ranches in the United States

Objective: To analyse the sulfur content of water and forage samples from a geographically diverse sample of beef cow-calf operations in the United States and to estimate frequency and distribution of premises where forage and water resources could result in consumption of hazardous amounts of sulfur by cattle. Design: Cross-sectional study. Sample Population: 709 forage samples (lucerne (n=196), brome (Bromus; n=20), bermuda (Cynadon dactylon; n=112), fescue (Festuca; n=73), sudan (Sorghum sudanese; n=61), cereal (n=46), native grass (38), grass (n=70), silage (n=31), orchard grass (Dactylis glomerata; n=34) and others (n=28)) from 678 beef cow-calf operations and individual water samples from 498 operations in 23 states (Arkansas, Illinois, Iowa, Missouri, Kansas, Nebraska, North Dakota, South Dakota, Oklahoma, Texas, Alabama, Florida, Georgia, Kentucky, California, Colorado, Montana, New Mexico, Oregon and Wyoming). Procedure: Sulfur content of forage samples and sulfate concentration of water samples were measured. Total sulfur intake was estimated for pairs of forage and water samples. Results: Total sulfur intake was estimated for 454 pairs of forage and water samples. In general, highest forage sulfur contents did not coincide with highest water sulfate concentrations. Overall, 52 of the 454 (11.5%) sample pairs were estimated to yield total sulfur intake (as a percentage of dry matter) ≥0.4%, assuming water intake during conditions of high ambient temperature. Most of these premises were in north-central (n=19) or western (19) states. Conclusions and Clinical Relevance: Results suggest that on numerous beef cow-calf operations throughout the United States, consumption of forage and water could result in excessively high sulfur intake. All water sources and dietary components should be evaluated when assessing total sulfur intake. Knowledge of total sulfur intake may be useful in reducing the risk of sulfur-associated health and performance problems in beef cattle.