Two maize milling by-products (maize gluten feed; MGF and maize by-product feed; MBPF) were compared with shelled maize (SM) and soyabean meal (SBM) for their in situ nutrient disappearance. In situ experiments were conducted in two rumen fistulated Holstein cows to evaluate dry matter (DM), crude protein (CP), neutral detergent fibre (NDF) and starch disappearance of the products. Zero-hour washout (in situ Fraction a) of DM was higher for MBPF (56.9%) than SM (45.0%). The disappearing rate (kd) of DM was higher for MGF (0.054/h) than for SM (0.046/h). Fraction a for CP was higher for MBPF (69.6%) than MGF (55.9%) and lower for SBM (7.8%). Similarly, ruminal CP disappearance was higher for MBPF (83.4%) and MGF (80.1%) than SBM (52.1%). Neither NDF disappearance rate nor ruminal NDF disappearance was different between MGF and MBPF. The disappearance rate of starch was higher for MGF (0.203/h) and MBPF (0.116/h) than for SM (0.051/h). Similarly, ruminal starch disappearance was higher for MGF (82.7%) than for SM (54.2%). Results indicate that the tested maize by-product feeds had greater ruminal CP disappearance when compared to SBM. Both MGF and MBPF may be useful feedstuffs in lactating dairy cows ration due to their higher ruminal starch disappearances.