This study, aimed to compare the performance of sows offered a diet containing a high level of co-products during gestation (d5–112). A control (cereal/soy) gestating diet was compared with one containing 50% of a co product (a blend of potato skins, whey permeate, and residual grains and effluent from the production of an alcoholic beverage). A total of 176 sows (88/treatment), penned in groups of 8, were group fed over 11 time periods (each group was balanced for weight, parity and condition score). Individual sows were used as the experimental unit when assessing effects on litter performance. Lactation feed intake was measured for 10 pairs of sows per treatment. The DE, CP, lysine and CF content of the diets were formulated to be 2.77 and 2.96 Mcal/kg, 17.7 and 14.4%, 0.7 and 0.7%, 9.1 and 7.4% for the co product and control diets respectively. Sows were offered feed once a day during gestation using a feed curve that offered sows 8.60 Mcal/d from d 7–34, 6.69 Mcal/d from d 35–83 and 8.60 Mcal/d from d 84–112 of gestation. Sows were fed ad lib during lactation they farrowed. Changes in sow condition score and weight and litter performance were measured. Sow dirtiness was scored on a 0–3 point scale. Statistical analysis used ANOVA with period as a blocking factor. There was no difference in sow parity (3.85), weight (204 kg) or condition scoring (2.9) on d 5 of gestation. Due to the lower energy content of the co product diet, total sow intake was numerically higher when it was offered (245 vs. 229 kg). There was no effect of diet on sow weight at farrowing (266 kg), condition score (3.2), litter size (13.6), number born alive (12.7), dead (0.73) or mummified (0.17). When the co-product diet was offered, sows were dirtier (P < 0.001) (2.09) compared with when the control diet was offered (1.03). The average daily lactation feed intake of sows was statistically similar when the co product diet (5.97 kg/d) was offered compared with when the control diet was offered (6.62 kg/d). In conclusion, the inclusion of 50% of the blended co product had no significant impact on sow weight, condition score or productivity at farrowing.