282 Metabolic and Endocrine Changes in Dairy Cows fed Different Diets at dry-off

Abstract Concentrate withdrawal and feed restriction reduce milk production to facilitate dry-off. We investigated the impact of rations providing different amounts nutrients in combination with on performance, endocrine, metabolic responses before after abrupt Forty-three cows were studied from d 12 until 6 dry-off (56 scheduled calving). Cows fed experimental concentrates rich either crude protein (nitrogenic, n=14), glucogenic precursors (glucogenic, or lipids (lipogenic, n=15). On 3 dry-off, total allowance was restricted 50 % one-half animals each dietary group whereas remained unchanged other animals. Statistical analysis (SAS, version 9.4) carried out using a mixed model group, time, diet×time interaction as fixed effects (Significance assumed at P< 0.05). Feed immediately resulted negative energy balance (NEB) decreased (P< Concomitantly, concentrations non-esterified fatty acids (NEFA) increased, insulin, insulin-like growth factor-1 (IGF-1), glucagon After turned positive plasma NEFA again. Plasma glucose, IGF-1 increased all groups Glucose, greater non-restricted compared Milk urea nitrogenic concentrate Overall, endocrine adaptations supporting synthesis continued during first days despite cessation milking. Thus, short-term increase glucose triglyceride concentrations, delayed response re-establish nutrient homeostasis blood.