Blood metabolites and haematological indices of beef cattle fed rumen-protected methionine

Abstract

In the course of the trial which lasted 94 days, and involved growing beef cattle, a close examination of the nutritive effects of rumen-protected methionine on biochemical and haematological values in the blood (total protein, albumin, triacylglycerols, total cholesterol, glucose, urea, creatinine, alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyltransferase (GGT), red blood cell count (RBC), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), red cell distribution width (RDW), haemoglobin concentration (Hb), haematocrit value (Hct), white blood cell count (WBC) and differential blood count) was carried out. Twenty six beef cattle were divided into two groups of equal number: control (C) and experimental group (E). Cattle were fed with meadow hay, maize grain silage and a 500 g of protein rich concentrate (35% CP). In addition to the fodder mix, animals in group E received 10 g DL-rumen protected methionine per animal daily. Blood samples were collected on the 1st, 34th, 68th and 94th day of the trial. Plasma glucose concentration and the total cholesterol concentration in cattle in group E showed a tendency to increase at the end of the trial (P=0.065 and P=0.064, respectively). Plasma urea concentration had a tendency to decrease in group E (P=0.082) by the end of the trial. The activity of ALT in animals in group E increased on the 68th and 94th day (P=0.127 and P=0.104, respectively). No significant differences were found between the groups in total protein, albumin, triacylglycerols, creatinine plasma concentrations, AST and GGT activities. The results indicate that excessive supplementation of rumen protected methionine might increase the level of plasma glucagon.