Clinical, hematological, and biochemical studies on hypozincemia in neonatal calves in Egypt

BACKGROUND AND AIM: Zinc has a wide spectrum of biological activities and its deficiency has been related to various dysfunctions. This study aimed to clarify the clinical, hematological, and biochemical changes in Holstein dairy calves with naturally occurring hypozincemia before and after treatment. MATERIALS AND METHODS: This study was carried out on 25 Holstein dairy calves <1 month of age in the El-Salhya Dairy Farm, Al-Sharqiya Province, Egypt. Calves were born from apparent healthy dams without any clinical signs of zinc deficiency. They were divided into two groups. The first group (G1) included five clinically healthy calves that were used as controls. The second group (G2) included 20 calves suffering from alopecia and skin lesions. The diseased calves were then treated by oral administration of zinc oxide at the rate of 80 mg/day for 10 successive days and then 20 mg/week for 2 weeks (G3). A total of 90 samples, whole blood and serum samples were collected during the study across all groups. Whole blood was evaluated for complete blood count and serum was used to estimate total protein, albumin, globulin, zinc, calcium, magnesium, phosphorus, and the activity of alkaline phosphatase (ALP) and aspartate aminotransferase. RESULTS: The diseased calves had macrocytic normochromic anemia. Total leukocytes, neutrophils, and lymphocytes were significantly reduced in the diseased calves than in the control and treated groups. Biochemical analysis of serum revealed a highly significant decrease in the globulin, zinc, and calcium concentrations in the diseased calves than in the control and treated groups. ALP activity was significantly lower in the diseased and treated calves than in control. There were no differences in any other parameters between the groups. CONCLUSION: Zinc deficiency naturally occurring in calves caused clinical, hematological, and biochemical alterations such as alopecia, skin abnormalities, and macrocytic normochromic anemia. In addition, zinc deficiency altered the cell-mediated immunity as indicated by leukopenia and lymphopenia. These alterations were improved by oral administration of zinc oxide.