Hematological Reference Intervals Milk-Fed Calves During the First Four Weeks upon Arrival to the Farm

The aim of this investigation was to establish the hematological reference intervals of milk-fed calves during the first four weeks of arrival at the farm. 80 dairy Holstein neonates were used (2 to 7 days of age). All calves in the study were fed standard milk replacer twice daily. The blood samples to establish the hematological reference intervals in milk-fed calves were taken 24 hours after arrival, at 7 days, 14 days, 21 days, and 28 days (5 samples in 4 weeks). A complete blood count and total serum protein measurement were performed, in addition, the calves were weighed 24 h and on day 28 after arrival. Parameters expressed in minimum and maximum ranges of WBC 3.5 to 53.6 cellx109/L; segmented neutrophils 46.6 – 0.43 cellx109/L, lymphocytes 13.4 – 1.1 cellsx109/L; monocytes 2.7 – 0.2 cellx109/L; eosinophils 0 - 0.8 cellsx109/L; basophils 0 - 0.5 cellx109/L, RBC 5.2 to 12.1 cellx1012/L; HGB 61 to 153 g/L; HCT 0.18 to 0.45 L/L, MCV 24 to 47 fL, MCH 8 to 15 pg; and MCHC 298 to 354 g/L; were obtained. For these 5 sampling times, the total serum protein was x̅ 5.11 g/100 mL, 4.76 g/100 mL, 4.63 g/100 mL, 4.65 g/100 mL, and 5.14 g/100 mL. Weight gain x̅ 51.82 kg (minimum 31.8 and maximum 72.6 kg). Given the non-existence of reference blood parameters in milk-fed calves, this study provides the bases to support initial reference parameters during the first 4 weeks of arrival in production systems (animals between 30 and 37 days of age).