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Nitrate (NO 3 ¯ ) is an effective non-protein nitrogen source for gut microbes and reduces enteric methane (CH 4 ) production in ruminants. Nitrate is reduced to ammonia by rumen bacteria with nitrite (NO 2 ¯ ) produced as an intermediate. The absorption of NO 2 ¯ can cause methaemoglobinaemia in ruminants. Metabolism of NO 3 ¯ and NO 2 ¯ , on insulin and glucose dynamics. A glucose tolerance test using an intravenous bolus of 1 ml/kg LW of 24% (w/v) glucose was conducted in twenty sheep, with 10 sheep receiving 1.8% supplementary NO 2 ¯ resulting from a low-risk dose of dietary NO 3 ¯ will increase insulin sensitivity (S I ) and glucose uptake in sheep. We evaluated the effect of feeding sheep with a diet supplemented with 18 g NO 3 ¯ /kg DM or urea (Ur) isonitrogenously to NO 3 ¯ , on insulin and glucose dynamics. A glucose tolerance test using an intravenous bolus of 1 ml/kg LW of 24% (w/v) glucose was conducted in twenty sheep, with 10 sheep receiving 1.8% supplementary NO 3 ¯ and 10 receiving supplementary urea isonitrogenously to NO 3 ¯ . The MINMOD model used plasma glucose and insulin concentrations to estimate basal plasma insulin (I b ) and basal glucose concentration (G b ), insulin sensitivity (S I ), glucose effectiveness (S G ), acute insulin response (AIRg) and disposition index (DI). Nitrate supplementation had no effect on I b (p > .05). The decrease in blood glucose occurred at the same rate in both dietary treatments (S G ; p = .60), and there was no effect of NO 3 ¯ on either G b , S I , AIRg or DI. This experiment found that the insulin dynamics assessed using the MINMOD model were not affected by NO 3 ¯ administered to fasted sheep at a low dose of 1.8% NO 3 ¯ in the diet., (© 2019 Blackwell Verlag GmbH.)