title: The effect of incremental levels of dietary nitrate on methane emissions in Holstein steers and performance in Nelore bulls.
abstract: 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).
authors.affiliation: Cargill Animal Nutrition, Veilingweg 23, 5334 LD, Velddriel, The Netherlands john_newbold@cargill.com.
authors.forename: J R
authors.initials: JR
authors.lastname: Newbold
authors.affiliation: Cargill Animal Nutrition, Veilingweg 23, 5334 LD, Velddriel, The Netherlands.
authors.forename: S M
authors.initials: SM
authors.lastname: van Zijderveld
authors.affiliation: Cargill Animal Nutrition, Veilingweg 23, 5334 LD, Velddriel, The Netherlands.
authors.forename: R B A
authors.initials: RB
authors.lastname: Hulshof
authors.affiliation: Cargill Animal Nutrition, P.O. Box 69, Brookville, OH 45309.
authors.forename: W B
authors.initials: WB
authors.lastname: Fokkink
authors.affiliation: University of New England, Armidale, NSW 2351, Australia.
authors.forename: R A
authors.initials: RA
authors.lastname: Leng
authors.affiliation: Nutron Alimentos Ltda, Av. Jose Bonifacio Coutinho Nogueira 150, Jardim Madalena, Campinas, SP. 13091-611, Brazil.
authors.forename: P
authors.initials: P
authors.lastname: Terencio
authors.affiliation: Michigan State University, East Lansing 48824.
authors.forename: W J
authors.initials: WJ
authors.lastname: Powers
authors.affiliation: Cargill Animal Nutrition, Veilingweg 23, 5334 LD, Velddriel, The Netherlands.
authors.forename: P S J
authors.initials: PS
authors.lastname: van Adrichem
authors.affiliation: Cargill Animal Nutrition, P.O. Box 69, Brookville, OH 45309.
authors.forename: N D
authors.initials: ND
authors.lastname: Paton
authors.affiliation: Cargill Animal Nutrition, Veilingweg 23, 5334 LD, Velddriel, The Netherlands.
authors.forename: H B
authors.initials: HB
authors.lastname: Perdok
mesh_terms: D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002417:Cattle / Q000254:growth & development / Q000502:physiology*; D004032:Diet / Q000662:veterinary*; D008297:Male; D008697:Methane / Q000378:metabolism*; D009566:Nitrates / Q000008:administration & dosage / Q000494:pharmacology*; D012820:Silage / Q000032:analysis*
chemical_list: D009566:Nitrates; D008697:Methane
keywords: beef cattle; dietary nitrate; enteric methane; feedlot; methemoglobinemia