EFFECTS OF BODY CONDITION SCORE IN LIVER INSULIN-SIGNALING OF DAIRY CATTLE DURING THE TRANSITION PERIOD

ANGELI E; REY F; ORTEGA HH; HEIN GJ

Bologna

Congreso; 50° Congresso Nazionale S.I.B./50th SIB National Congress; 2018

Sociedad Italiana de Buiatría

The transition period (TP) is the mostcritical stage in the lactation of a dairy cow, characterized by an increase ofplasma non-esterified fatty acids (NEFA) and beta-hydroxybutyrate (BHB) withlow glucose concentration. Previous studies have descripted the presence ofinsulin resistance during peripartum [1]. The aim of this study was to evaluatethe insulin-signaling pathway and some plasma parameters during the TP in thein cows with different body score condition (BSC).Sixteen grazing dairy cows, belonging to acommercial dairy farm, were classified using the 5-point scale [2] as high BCS (HBCS, ≥ 3.5, n = 8,) and lowBCS (LBCS, < 3.5, n = 8). Blood and liver biopsies were sampled at -14, 4,14 and 28 days relative to parturation. The concentrations of NEFA, BHB, glucose, triglycerides, insulin and liver triglycerides werespectrophotometrically measured. Also, the liver protein expression of relevantinsulin signaling components: insulin receptor (IR), insulin receptor substrate1 (IRS-1), protein kinase B (Akt) and phosphorylated protein kinase B (p-Akt), wasmeasured by western blot.Cows in HBCS had higher NEFA concentrationthan LBCS (p < 0.05). In addition, we detected an interaction (BCS x time, p< 0.05) for glucose; concentration of this parameter increased at day 28postpartum in HBCS group (p < 0.05). On the other hand, we also recorded aninteraction (BCS x time, p < 0.05) for p-Akt; the protein expression was lowerin HBCS than LBCS group at 28 days postpartum (p < 0.05). No differences wererecorded in the other parameters (p > 0.05).These results suggest that an alterationin liver insulin-signaling from cows with HBCS could contribute to the augment ofglycemia. Besides, a lower insulin sensitivity could be associated with higher NEFAconcentrations [3]. This knowledge could represent a usefultool to understand the metabolic behavior to optimize the health and milkproduction of dairy cattle during this period.References:[1]         DeKoster JD, Opsomer G. Insulin resistance in dairy cows. Vet Clin North Am -Food Anim Pract 2013;29:299?322.[2]         Edmonson AJ, Lean IJ, Weaver LD, Farver T, Webster G. A BodyCondition Scoring Chart for Holstein Dairy Cows. J Dairy Sci 1989;72:68?78.[3]         Pires JAA, Pescara JB, Grummer RR. Reduction of Plasma NEFAConcentration by Nicotinic Acid Enhances the Response to Insulin in Feed-RestrictedHolstein Cows. J Dairy Sci 2007;90:4635?42.