The use of co-products as an alternative feed source is a common practice when formulating dairy rations. A study using 12 multiparous (79 ± 16 DIM; mean ± SD) lactating Jersey cows, was conducted to evaluate the feeding effects of dried distillers grains with solubles (DDGS) or canola meal on energy utilization. A replicated 4 × 4 Latin square design was used to compare 4 different dietary treatments. Treatments were composed of a control (CON) containing no co-products, a treatment diet containing 10% (DM basis) reduced fat DDGS (RFDDGS), 10% high fat DDGS (HFDDGS), and a 10% canola meal (CAN). The crude fat content of the RFDDGS, HFDDGS, and canola meal was 6.05 ± 0.379%, 10.0 ± 0.134%, and 3.46 ± 0.085%. Co-products were included in partial replacement for corn and soybean meal. Indirect headbox-style calorimeters were used to estimate heat production. Daily dry matter intake and milk yield were similar (P > 0.55) across treatments averaging 17.5 ± 0.78 kg/d and 24.1 ± 0.80 kg. Heat production per unit of metabolic body weight tended (P = 0.058) to be affected by treatment and was lowest for CON and diets containing co-products were similar (192, 200, 215, and 204 ± 5.91 kcal per kg of metabolic body weight for CON, LFDDGS, CAN, and HFDDGS respectively). The ME concentration of the diet was affected (P = 0.034) by dietary treatment specifically, HFDDGS did not differ from CON, but was higher than RFDDGS and CAN (2.58, 2.46, 2.29, and 2.27 ± 0.089 Mcal/kg for HFDDGS, CON, RFDDGS and CAN respectively). Lastly, the NEL concentration of the diet tended to be affected (P = 0.062) by dietary treatment. Although HFDDGS did not differ from CON and RFDDGS, it was higher than CAN (1.38, 1.36, 1.14, and 1.06 ± 0.111 Mcal/kg for HFDDGS, CON, RFDDGS, and CAN respectively). Results of this study suggest that the energy content of co-products is influenced by the crude fat content and that RFDDGS and canola meal have a similar energy content when consumed by lactating dairy cattle.