Abstract
This study evaluated the effects of clove extract and hydrolyzed whey protein supplementation, alone or in combination, on growth performance, physiological responses, hematological and biochemical parameters, antioxidant status, and health indicators of suckling dairy calves during the first 14 days of life. A total of 100 newborn dairy calves were randomly assigned to one of four treatments in a completely randomized design (n = 25 calves per treatment): (1) control (CON), milk without supplementation; (2) clove extract (CL), milk supplemented with 10 mL clove extract per day; (3) hydrolyzed whey protein (W), milk supplemented with 10 mL hydrolyzed whey protein per day; and (4) mixture (MIX), milk supplemented with 10 mL clove extract plus 10 mL hydrolyzed whey protein per day. Daily dry matter intake, body weight at 15 days of age, average daily gain, and feed conversion ratio were not affected by treatment. Rectal temperature did not differ among treatments. Hematological parameters showed no treatment effects on white blood cell count, hemoglobin concentration, hematocrit, platelet count, or differential leukocyte counts. However, red blood cell count differed among treatments, with calves in the control group exhibiting a higher RBC concentration compared with those receiving clove extract, hydrolyzed whey protein, or their combination (P = 0.048). Blood biochemical parameters, including malondialdehyde, total antioxidant capacity, cholesterol, blood urea nitrogen, liver enzymes, minerals, albumin, total protein, and ferritin concentrations, were not influenced by treatment. The incidence and duration of diarrhea and fecal scores were similar among treatments; however, the day of diarrhea onset differed significantly among treatments (P < 0.01), with the latest onset observed in calves receiving clove extract-containing treatments. In conclusion, supplementation of milk with clove extract and/or hydrolyzed whey protein during the early neonatal period had minimal effects on growth performance, physiological status, oxidative balance, and most health-related parameters of dairy calves, with the exception of alterations in red blood cell count and the timing of diarrhea onset.