PSVIII-14 - Effect of Certillus, a direct-fed microbial, on milk yield, milk components, and feed intake in primi- and multiparous lactating Holstein cows

To determine the effect of Certillus on milk production, milk components and feed efficiency, primiparous (n = 13) and multiparous (n = 12) Holstein cows were assigned to one of two dietary groups starting from 8 to 120 days of lactation. The controls (n = 13) received regular TMR ration, and treated cows (n =12) received control TMR plus 2 x 10⁹ cfu/head of Certillus (Church & Dwight Co., Inc., Waukesha, WI). Cows were housed in an open-air free-stall barn with 16 Insentec electronic feeders (8 feeders/group) to record daily feed events and intake (DMI). Cows were provided with ad libitum TMR fed twice daily and were milked twice daily. Milk samples were taken weekly during successive a.m./p.m. milkings and analyzed for percentage milk fat, protein, lactose, and milk urea nitrogen (MUN). Data were analyzed using a repeated-measures 2 x 2 factorial ANOVA. Daily milk production (4%FCM) was influenced (P < 0.05) by treatment x parity, week and parity, averaging 11% greater (P < 0.05) in Certillus-fed than control cows. Milk fat percentage increased (P < 0.005) from 4.02 to 4.41 + 0.09% with Certillus feeding. Milk lactose was influenced (P < 0.05) by week and treatment x parity. Milk protein was affected by week (P < 0.001) only. Certillus decreased (P < 0.05) MUN levels such that MUN was 1.0 mg/dL greater (P < 0.001) in Certillus-fed than control cows. Feed intake was reduced by 9% (P < 0.01) and feed efficiency (kg 4%FCM/kg DMI) was improved by 14% (P < 0.05) in Certillus-fed versus control cows. We conclude that Certillus may hold potential as an effective direct-fed microbial to increase feed efficiency and milk production.