Hematological changes in anemic dairy calves treated with a hematinic complex.

BACKGROUND AND AIM

Weaning is a critical period in calf development, particularly under tropical conditions where nutritional stress and parasitic infestations can precipitate anemia. Anemia compromises growth and survival; yet, few studies have evaluated the effectiveness of hematinic therapy in anemic calves before weaning in tropical systems. This study aimed to assess hematological responses in anemic dairy calves treated with a hematinic complex and to establish anemia thresholds based on hematological indices in healthy calves raised under tropical conditions.

MATERIALS AND METHODS

A total of 22 Holstein × Zebu calves were studied from January to April 2024 in Tabasco, Mexico. Calves were grouped as healthy (n = 10; hematocrit [HCT] >24%) or anemic (n = 12; HCT <24%). The anemic group received an intramuscular hematinic complex for 5 consecutive days and three additional doses at day 42. Hematological parameters were measured every 21 days using an automated analyzer. Anemia thresholds were defined from the healthy group using mean ± 2 standard deviations. Data were analyzed using a repeated-measures design over time.

RESULTS

Anemia thresholds were determined as HCT <21.3%, hemoglobin (HGB) <7.5 g/dL, and red blood cell (RBC) <5.4 × 10/µL. At baseline, anemic calves exhibited significantly lower HCT (21.4%), HGB (6.9 g/dL), and RBC (5.9 × 10/µL) compared to healthy controls (p < 0.01). Three calves presented with microcytic hypochromic anemia and one with macrocytic anemia. By day 42, hematinic-treated calves surpassed the anemia threshold, reaching an HCT of 25%, and further increased to 30% following the second treatment. HGB and RBC levels also improved, showing no significant differences from healthy calves at study end. Males responded more robustly to treatment than females.

CONCLUSION

The administration of a hematinic complex effectively restored hematological parameters in anemic calves within 42 days, with sustained improvement following a second application. This intervention is recommended as part of pre-weaning health protocols to mitigate anemia-related growth setbacks in tropical cattle systems.