Effects of calcium oxide treated corn stover as a partial replacement for corn silage, Chinese wildrye or concentrate on milk yield and composition of dairy cows

Abstract Text: The utilization of corn stover was limited by its poor digestibility for ruminants. Studies showed that the nutritive value of corn stover can be improved by calcium oxide (CaO) treatment. The objective of this experiment was to determine the effect of replacing a portion of corn silage (CS), Chinese wildrye (CW) or concentrate (CT) in the diets with CaO-treated corn stover on milk yield and milk composition of dairy cows. Sixty four Holstein cows in mid to late lactation were assigned to 1 of the 4 treatments in a randomized block design (16 cows/group): (1) control treatment (CON), diets included 15% Chinese wildrye, 25% corn silage, 10% alfalfa hay, and 50% concentrate; (2) replacing 15% Chinese wildrye with treated stover (RCW); (3) replacing 12.5% corn silage with treated stover (RCS); (4) replacing 7% concentrate with treated stover (RCT). Cows were offered the total mixed ration (TMR) thrice daily and the experiment was lasted for 90 d. The inclusion of treated stover in treatment diets as a substitute for CW, CS, and CT had no effects (P＞0.05) on lactose percentage, 4% fat-corrected milk yield, milk fat yield, and milk protein yield. Cows in RCW and RCT treatments had similar milk yield (P＞0.05) compared with that in CON treatment. Cows in CON treatment had higher (P<0.05) milk protein percentage than that in other treatments. Cows in RCS treatment had higher (P<0.05) milk yield and milk lactose yield than that in CON treatment. Milk fat percentage was decreased (P＞0.05) for the RCW treatment compared with the CON treatment. The CON treatment had higher (P<0.05) total solids percentage and MUN concentration than other treatments. The RCS treatment had lower (P<0.05) somatic cell count than other treatments. These results suggest that a portion of corn silage, Chinese wildrye or concentrate can be replaced by CaO-treated corn stover without negative effects on 4% FCM, milk fat, milk protein, and milk lactose yields of dairy cows.

Keywords:  dairy cow; performance; treated corn stover;