ABSTRACT: The objective was to evaluate the effects of nutrient restriction on the liver transcriptomic response after 24 h challenge to intramammary lipopolysaccharide (LPS) in early lactation cows. At 24 ± 3 days of lactation, multiparous cows were fed either an ad libitum lactation diet (CON, n = 6), or a ration diluted with barley straw (48% DM) for 4 days (RES, n = 6). On day 3, one healthy rear mammary quarter from each cow was infused with 50 µg of LPS. Blood and liver biopsies were collected on day 4, corresponding to 24 h after LPS challenge. The liver transcriptome was analyzed using 44K bovine microarrays (Agilent Technologies). Blood and transcriptomic data were analyzed using SAS mixed models and GeneSpring (moderate t-test with Westfall-Young correction, P < 0.05), respectively, and data mining was performed using Panther and Pathway Studio software. The energy balance was no different before the diet change. By experimental design, energy intake was 41 and 97 ± 15 % of NEL requirements in RES and CON, respectively. Plasma NEFA and BHBA were higher, and glucose was lower in RES than in CON, which is consistent with a 4-day nutrient deficit in RES. Seventy seven differentially expressed genes (DEGs) between CON and RES were identified, with 29 genes downregulated and 48 upregulated in RES. Genes involved in fatty acid synthesis (ACAT2, FASN, SCD), lactate metabolism (LDHC), and cortisol binding (SERPINA6) were downregulated in RES, while those involved in fatty acid oxidation, detoxification, cholesterol synthesis, lipoprotein lipid secretion, and gluconeogenesis (ACADVL, CPT1A, CPT1B, ANGPTL4, CYP4A11, HMGCSA, APOA1, APOA4, GK, PC and PCK2) were upregulated in RES. Overall, DEGs were in agreement with the negative energy balance and plasma metabolite profile, and reflect a state of intense lipomobilization, glucose deficit and ketogenesis in RES. Preliminary results suggest that nutrient restriction did not alter hepatic expression of genes directly involved in immune function 24 h after an intramammary LPS challenge.