Effects of feeding rumen-protected methionine pre- and postpartum in multiparous Holstein cows: Lactation performance and plasma amino acid concentrations

Objectives were to evaluate the effect of feeding rumen-protected methionine (RPM) in pre- and postpartum total mix ration (TMR) on lactation performance plasma AA concentrations dairy cows. A 470 multiparous Holstein cows [235 at University Wisconsin (UW) 235 Cornell (CU)] enrolled approximately 4 wk before parturition, housed close-up dry cow replicated pens. Pens randomly assigned treatment diets (pre- postpartum, respectively): UW control (CON) diet = 2.30 2.09% Met as percentage metabolizable protein (MP) RPM 2.83 2.58% MP; CU CON 2.22 2.19% MP, 2.85 2.65% MP. Treatments evaluated until 112 ± 3 d milk (DIM). Milk yield was recorded daily. samples collected 1 2 lactation, then every other week, analyzed for composition. For pens, matter intake (DMI) Body weight body condition score determined from DIM parturition 39 49 DIM, respectively. Plasma within h after during periparturient period [d ?7 (±4), 0, 7 (±1), 14 21 (±1); n 225]. In addition, (every 24 h) 76 8 (n 16) 80 72). The had no DMI (27.9 vs. 28.0 kg/d) or (48.7 49.2 CON, Cows fed increased concentration (3.07 2.95%) (1.48 1.43 kg/d), fat (3.87 3.77%), although did not differ. tended be greater (25.9 22.9 µM), differ (22.0 20.4 (31.0 21.2 µM) remained with consistent (d 14: 30.5 19.0 µM; 21: 31.0 17.8 µM). However, decreased Leu, Val, Asn, Ser 7, 14, 21) Tyr 14). At a later stage (34.4 16.7 consistently throughout day, changes AA. Substantial variation detected (range: 8.9–63.3 7.8–28.8 among [coefficient (CV) > 28%] day (CV: 10.5–27.1%). conclusion, improved via production.