The effect of nitrogen use efficiency on productivity in tropical beef

Seasonal conditions can result in periods of poor nutrition, and nitrogen (N) has been reported as a limiting nutrient during these periods. Some cattle can consistently put on more weight during these harsh conditions, than others. Cantalapiedra-Hijar et al. (2015) demonstrated that the ratio of 15N to 14N stable isotopes enrichment (δ¹⁵N) of ruminant plasma proteins was correlated with Nitrogen use efficiency (NUE) in cattle. Silva et al. (2022) reported a variation in δ¹⁵N in cattle, and that δ¹⁵N influenced reproductive performance. This paper presents preliminary results examining if δ¹⁵N influences winter live weight change measured in tropically adapted beef breeds.