Abstract

Eighteen Holstein dairy cows averaging 141 days in milk were used in a complete randomized design to determine the effects of feeding liquid acid whey (LAW) on milk production and composition. Animals received a diet consisting of berseem clover (Trifolium alexandrinum., L), wheat straw and concentrate (Control). Treatments were control and control plus 40 liters/cow/day of LAW. Daily individual Dry Matter Intake (DMI) and milk production were measured. Diet digestibility was determined using the total collection method. Results showed that LAW increased (P<0.05) DMI. However, in vivo dry and organic matter digestibilities were not affected by whey feeding. 4% fat corrected milk (FCM) and milk fat and protein yields were higher (P<0.05) for cows fed the whey (15.4 and 14.6 kg/day and 592 vs. 555 g/day and 486 vs. 462 g/day for milk and yields of milk fat and proteins, respectively). Milk composition was similar (P>0,05) for both treatments. It can be concluded that including LAW in dairy diets, in a partial replacement of the concentrate, significantly improved FCM and milk fat and protein yields without affecting milk composition.

Key words: Dairy cow, whey, milk yield, milk composition.