Enzymic Activity, Metabolites, and Hematological Responses Changes of Clinical Healthy High-Risk Beef Calves During Their First 56-Days from Arrival.

The objective of this study was to evaluate the changes in enzymic activity, metabolites, and hematological responses during the first 56-d of arrival of newly received calves, which were qualified at reception as high-risk but diagnosed as clinically healthy. A total of 320 blood samples were taken from 64 crossbred bull calves (average initial body weight = 148.3 ± 1.3 kg) at different times from arrival (d 0, 14, 28, 42, and 56 of received). Calves included in the study were received in June ( = 20), November ( = 24), and April ( = 20); thus, experimental treatments were arranged in a generalized complete block design (three blocks = month of arrival). The following parameters were determined: total white blood cells (WBC): lymphocytes (LYM), lymphocytes % (LYM%), monocytes (MON), monocytes % (MON%), granulocytes (GRA), granulocytes % (GRA%), platelets (PLT), and mean platelet volume (MPV); red blood cells (RBC): red blood cell distribution width test % (RDW%), hematocrit (HCT), and mean corpuscular volume (MCV); hemoglobin (HGB): mean corpuscular hemoglobin (MCH) and mean corpuscular hemoglobin concentration (MCHC). The enzymatic activity and metabolites analyzed were alkaline phosphatase (ALP), gamma glutamyltransferase (GGT), aspartate aminotransferase (AST), alanine aminotransferase (ALT), total protein (TP), albumin (ALB), globulin (GLO), ALB/GLO ratio, blood urea nitrogen (BUN), creatinine (CRE), total bilirubin (TBIL), total cholesterol (TCHO), triglycerides (TG); (4) calcium (Ca), glucose (GLU), sodium (Na), potassium (K), and chlorine (Cl). It was observed that ALP, ALT, TP, ALB, GLO, ALB/GLO ratio, TCHO, TG, Ca, and GLU increased as days from reception increased (linear effect, ≤ 0.04), whereas CRE and TBIL were reduced (linear effect, ≤ 0.02). A quadratic response ( ≤ 0.001) was observed to GGT and AST values being maximal on days 1 and 56 after arrival ( ≤ 0.001). Na, K, and Cl concentrations were not affected by prolonged days after arrival. Finally, blood cells of LYM, LYM%, PLT, RBC, HGB, HCT%, MCV, and MCH increased (linear effect, ≤ 0.001) as the number of days after arrival increased. Whereas MON% was linearly decreased ( ≤ 0.05). It was concluded that even when all parameters were within the range of reference intervals (RIs) determined for healthy cattle, during the period of monitoring, as the days after arrival lengthened, blood serum parameters related to health and immunity increased, and metabolites related to tissue injury decreased. In contrast, plasmatic electrolytes (Na, K, and Cl) were slightly reduced as the day after arrival increased. Apparently, at least 42 d is the minimum period after arrival to permit calves to reach more adequate physiological and metabolic conditions before starting the fattening phase.