Abstract:

The experiment was conducted to study the effects of steamflaked corn (SFC) in the diet on the performance and the excretion of nitrogen and phosphorus in dairy cows, using a 4×4 replicated Latin square design. Steamflaked corn contents in the experimental ration were dividedly 0%, 10%, 20% or 30% of the concentrate. There were four 28d experimental periods. The results indicated that dry matter intake was unaffected by diet (P>0.05), but steamflaked rather than dryground corn (DGC) in diets could significantly increase the feed efficiency (4% FCM/DMI) (P<0.05). Milk yield was increased (P<0.05) for cows fed SFC diet compared with cows fed DGC diet. FCM yield for cows fed concentrate diets containing 20% or 30% SFC was separately significantly increased 2.78(P<0.01) and 2.87 kg·d1 (P<0.01) than the control diet. The percentages of milk fat, protein, lactose and nonfat solid (SNF) were unaffected by diet（P>0.05）, but tended to increase except milk fat; The apparent digestibility of nutrients were unaffected by diet（P>0.05）. The MUN were decreased (P<0.05) for cows fed SFC diets. Comparing with the control group (0%SFC), the excretion of nitrogen of the cows fed with the SPC diets w were decreased by 4.23%（P>0.05）,9.37%（P<0.05）and 10.29%（P<0.05）,and the excretion of phosphorus were decreased by 1.93%（P>0.05）,2.59%（P>0.05）and 5.19%（P>0.05）, respectively. In conclusion, compared with DGC diet, SFC diet had decreased the excretion of nitrogen and phosphorus while the performance was significantly increased.