Short communication: Intake, milk production, and milk fatty acid profile of dairy cows fed diets combining fresh forage with a total mixed ration

摘要

To establish the effects of access time to high-quality temperate fresh forage (FF) on intake and performance of cows fed a total mixed ration (TMR), 9 Holstein cows were assigned to three 3×3 Latin squares with 20-d periods with sampling in the last 10 d. The following treatments were evaluated: 0 (T0), 4 (T4), and 8 (T8) h of daily access to FF. Forage (Lolium multiflorum) was cut daily and offered ad libitum beginning at 0800 h in individual stalls, and a TMR was offered ad libitum during the period when cows had no access to FF. Fresh forage dry matter intake (DMI) increased and TMR DMI decreased with the access time to FF, whereas total DMI was 3.0 kg higher for T4 than for T8; no differences were detected with T0. Compared with T0, 8 h/d of access to FF decreased milk, protein, and casein yields, and tended to decrease fat and lactose yields, but treatment had no effect on milk composition or feed efficiency. The milk fatty acid profile in T8 had a higher content of rumenic, vaccenic, and linolenic acids compared with T0. We concluded that cows with 4 h of access to high-quality FF had similar DMI and milk yields as cows fed only the TMR, but more than 4 h of access reduced DMI and performance without changes in feed efficiency, although milk fat had enhanced levels of beneficial fatty acids.