Study of evaluation methods of iron deficiency anemia in newborn calves

Author(s)

Rogerio Batista dos Santos

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Medicina Veterinária e Zootecnia (FMVZ/SBD)
• Defense date: 2013-12-17

Examining board members

Fernando José Benesi; Milton Ricardo Azedo; Marcia Mery Kogika; Fabio Celidonio Pogliani; Juarez Pinto Fernandes Távora

• Advisor: Fernando José Benesi

Abstract

The zinc protoporphyrin (ZPP) is a metabolic originated by zinc addition in the iron site during the synthesis of hemoglobin molecule, when iron is total or partially unavailable. The aim of this study was to standardize the values of zinc protoporphyrin (ZPP) in erythrocyte of healthy calves until one month of life, and to evaluate this determination as a predictor of the occurrence of iron deficiency anemia in newborn calves, compared with other methods. Therefore, 134 Holstein calves were used, aged from birth to 30 days of life, from dairy farms located in the São Paulo State, splitted into two groups, classified as healthies (67 animals), and anemics (67 animals). The animals were monitored by physical examination and laboratory assessments (complete blood cell count and reticulocytes, serum iron (SI) and total iron binding capacity (TIBC), levels of serum bilirubin and urea, and ZPP levels). During the exam standardization, the mean values found were: erythrocyte ZPP of unwashed erythrocytes within 3 hours after blood sampling of 30 healthy animals - 80.9 &#181;mol ZPP/mol heme; erythrocyte ZPP after washing of red blood cells, determined by 3 hours and 12 hours after blood collection, from the same group were 61.40 &#181;mol ZPP/mol heme and 61.03 &#181;mol ZPP/mol heme, respectively. Based on these results, it was concluded that blood samples taken for measurement of ZPP may be stored under refrigeration at 4 °C for up to 12 hours, without significant changes of the values of erythrocyte ZPP, and it is also advisable to wash the red cells before erythrocyte ZPP values measuring, due to the presence of interfering substances in the animal plasma. A significant difference was found in the ZPP levels and in all erythrogram components, as well as on the levels of iron metabolism between anemic and healthy animals. The bilirubin and serum urea levels remained within physiological variation, does not interfering with the measurement of erythrocyte ZPP of calves with or without anemia. The correlation values between SI and TIBC with ZPP levels were: rs = - 0.45, p < 0.001 (ZPP x SI) and rs = 0.51, p < 0.001 (ZPP x TIBC), respectively, i.e. decreasing biochemical levels of iron metabolism will increase levels of ZPP. Therefore, the use of ZPP as an iron deficiency anemia predictor in newborn calves up to one month of life has proven its validity, and considering hematofluorometry as a quick and inexpensive method, it might be recommended as a routine exam. (AU)