The effect of incremental levels of dietary nitrate on methane emissions in Holstein steers and performance in Nelore bulls

• Published in: Journal of animal science Vol. 92; no. 11; pp. 5032 - 5040
• Main Authors: Newbold, J R, van Zijderveld, S M, Hulshof, R B A, Fokkink, W B, Leng, R A, Terencio, P, Powers, W J, van Adrichem, P S J, Paton, N D, Perdok, H B
• Format: Journal Article
• Language: English
• Published: United States 01.11.2014
• Subjects: Animal Nutritional Physiological Phenomena; Animals; Cattle - growth & development; Cattle - physiology; Diet - veterinary; Male; Methane - metabolism; Nitrates - administration & dosage; Nitrates - pharmacology; Silage - analysis; feedlot; beef cattle; enteric methane; dietary nitrate; methemoglobinemia
• ISSN: 1525-3163
• DOI: 10.2527/jas.2014-7677

Two experiments were conducted to study effects of dietary nitrate on enteric methane production, blood methemoglobin concentration, and growth rate in cattle. In Exp. 1, 36 Holstein steers (288 ± 25 kg BW) were fed increasing levels of dietary nitrate (6 levels; 0 to 3.0% of feed DM) in corn silage-based total mixed rations. Nitrate was introduced gradually in a 25-d adaptation period before methane production was determined in environmentally controlled rooms. In the rooms, feed intake was restricted and similar among all treatments. Methane production (g/d) decreased linearly as dietary nitrate concentration increased (P < 0.01). The apparent efficiency (measured methane reduction divided by potential methane reduction) with which enteric methane was mitigated was 49%. Blood methemoglobin levels increased with increasing nitrate dose. In Exp. 2, 300 Nelore bulls (392 ± 28 kg) were fed increasing levels of nitrate (6 levels; 0 to 2.4% of feed DM) in high-concentrate total mixed rations offered ad libitum. Feed intake decreased linearly with increasing level of dietary nitrate (P < 0.01). However, ADG was not affected by nitrate dose (P = 0.54), resulting in a linear improvement in G:F (P = 0.03) as dietary nitrate level increased. Carcass dressing percentage showed a quadratic response to incremental dietary nitrate, reaching the highest value at 0.96% of NO3/kg DM (P = 0.04).