Effects of Two Sources of Malate on Milk Performance and Feed Efficiency of Dairy Cows

The aim of the study was to evaluate the efficacy of malic acid and sodium and calcium salts of malic acid (Rumalato^®, Norel, Spain) on milk yield and feed efficiency of dairy cows. A total of 60 cows (176±70.3 DIM, 32.3±5.45 kg/d; 33 multiparous; 27 primiparous) were split in three groups (n=20) and exposed for 63 d to 3 treatments following a randomized complete block design. Treatments consisted of no supplementation (CTRL), 40 g/d of Rumalato^® (RUM), and 25 g/d of malic acid (MAL). The daily amount of malic acid provided by RUM and MAL was the same (25 g/d). Cows were fed a TMR (15.3% CP, 31.8% NDF, 1.63 Mcal of NEl/kg; DM basis). On a daily basis, feed intake, milk yield, and milk fat and protein contents were determined individually. Because treatments were applied at the animal level, the experimental unit will was the animal. Data were summarized by week of study and analyzed using a mixed-effects model for repeated measures. Overall, average feed intake (22.9, 24.1, and 22.7±0.76 kg/d), milk yield (30.4, 32.5, and 31.1±1.20 kg/d), milk fat content (5.04, 3.88, and 4.01±0.08%), milk protein content (3.13, 3.10, 3.14±0.02%), and feed efficiency (1.40, 1.42, and 1.46±0.84 kg/kg) did not differ among CTR, RUM, and MAL cows, respectively. However, there was an interaction (P< 0.05) among treatment, week and parity on milk yield, with multiparous cows on RUM producing more milk than multiparous cows on CTRL and MAL after the 2 wk of study, and MAL multiparous cows producing more milk than CTRL multiparous cows between week 2 and 6 of study. But there were no differences among treatments in milk yield in primiparous cows. As a result, feed efficiency (kg of milk/kg of dry matter intake) was also affected by treatment, and multiparous cows on RUM had greater (P< 0.05) feed efficiency during the second and third week of the study than CTRL multiparous cows. It is concluded that sodium and calcium salts of malic acid have the potential to improve milk yield and feed efficiency of multiparous cows in mid lactation.