Correlation between osmotic resistance and fetal hemoglobin in bovine erythrocytes

Effects of oral or parenteral iron supplementation on haematological parameters, blood iron status and growth in newborn calves fed milk replacer

BACKGROUND

This study aimed to assess the influence of early life iron supplementation on the haematological parameters of calves fed milk replacer on a high plane of nutrition.

METHODS

Thirty calves were allocated to receive either a sham treatment (CON), injection of 1000 mg Fe3+ (INJ) or oral administration of 1050 mg Fe3+ (ORAL), all administered less than 1 hour after birth. Blood was obtained before treatment, on days 1, 3, 5 and 7 of life and once weekly until week 9. Samples were analysed for haemoglobin (Hb), packed cell volume (PCV) and estimated transferrin saturation (%TSAT).

RESULTS

The Hb and PCV of calves in the INJ and ORAL groups were above the values of those in the CON group throughout the study. Hb and PCV of the CON group remained within the reference range for calves. The %TSAT exceeded reported ranges in the ORAL group in the first week. Values for the CON group were below the INJ and ORAL groups throughout the entire study. Average daily gain did not differ between treatments.

LIMITATIONS

The sample size was insufficient to assess the influence of iron supplementation on disease development. Furthermore, the study was set in a controlled environment and not performed under field conditions.

CONCLUSIONS

Oral and subcutaneous iron administration had similar effects on haematological development but resulted in numerically different transferrin saturation. Control animals showed lower Hb and PCV but did not develop overt anaemia.

Fitness of calves born from in vitro-produced fresh and cryopreserved embryos

In cattle, vitrified/warmed (V/W) and frozen/thawed (F/T), in vitro-produced (IVP) embryos, differ in their physiology and survival from fresh embryos. In this study, we analyzed the effects of embryo cryopreservation techniques on the offspring. IVP embryos cultured with albumin and with or without 0.1% serum until Day 6, and thereafter in single culture without protein, were transferred to recipients on Day 7 as F/T, V/W, or fresh, resulting in N = 24, 14, and 13 calves, respectively. Calves were clinically examined at birth, and blood was analyzed before and after colostrum intake (Day 0), and subsequently on Day 15 and Day 30. On Day 0, calves from V/W and F/T embryos showed increased creatinine and capillary refill time (CRT) and reduced heartbeats. Calves from F/T embryos showed lower PCO₂, hemoglobin, and packed cell volume than calves from V/W embryos while V/W embryos led to calves with increased Na⁺ levels. Colostrum effects did not differ between calves from fresh and cryopreserved embryos, indicating similar adaptive ability among calves. However, PCO₂ did not decrease in calves from V/W embryos after colostrum intake. Serum in culture led to calves with affected (P < 0.05) temperature, CRT, HCO 3 - , base excess (BE), TCO₂, creatinine, urea, and anion gap. On Day 15, the effects of embryo cryopreservation disappeared among calves. In contrast, Day 30 values were influenced by diarrhea appearance, mainly in calves from V/W embryos (i.e., lower values of TCO₂, HCO 3 - , and BE; and increased glucose, anion gap, and lactate), although with no more clinical compromise than calves from fresh and F/T embryos. Diarrhea affected PCO₂ and Na⁺ in all groups. Embryo cryopreservation, and/or culture, yield metabolically different calves, including effects on protein and acid-base metabolism.

Hematologic profiles and development of innate immune function in healthy Holstein calves during the pre-weaning period

BACKGROUND

The development and state of innate immune cell function during the first 90 days of life in dairy calves have not been fully described.

OBJECTIVE

This transversal study attempted to examine the changes that occur in circulating blood cells and the innate immune response in healthy calves from birth to 89 days of age.

METHODS

Healthy Holstein calves represent three windows of development, G1 from 1 to 7 days old (n = 26), G2 from 30 to 40 days old (n = 28), and G3 from 60 to 89 days old (n = 36) were sampled once each from a single herd. A few biomarkers of the general health and innate and inflammatory immune responses were measured.

RESULTS

The youngest calves had the lowest red blood cell (RBC) counts, cell hemoglobin concentration means (CHCMs), red cell distribution widths (RDWs), and cell hemoglobin contents of mature red blood cells (CHm) compared with the other groups. They also had the lowest iron concentrations and highest intracellular myeloperoxidase indices. However, white blood cell (WBC) and lymphocyte concentrations gradually increased from G1 to G3. G2 calves had the lowest serum protein concentrations and highest number of innate immune cells compared with the other groups. Calves were able to mount phagocytic and ROS responses from birth.

CONCLUSIONS

The physiologic responses of circulating blood cells and innate immune responses in dairy calves are shown according to age. Neonates had limitations in several RBC and WBC indices and immunologic responses that would likely impact overall vigor and health. Fortunately, these limitations resolve by 90 days of age.

Changes of the erythrocyte phenotype and blood biochemistry in dairy calves during the first ten weeks of age

Background

Bovine erythrocytes undergo important changes in their morphology and chemical composition during the first weeks of age, which must be understood to accurately interpret hematology results in calves. The objectives of this prospective cohort study were to describe physiological changes of calf erythrocytes and to investigate mechanisms potentially causing these changes.

Methods

Blood samples from 30 clinically healthy dairy calves were obtained from birth to the tenth week of age in weekly intervals. Hematological and plasma biochemical parameters as well as the mineral electrolyte content of erythrocytes were determined and followed over time. The changes of parameters characterizing the erythrocyte phenotype over time were compared to the changes of plasma and erythrocyte biochemical parameters and possible associations were investigated using correlation and stepwise regression analyses.

Results

Although the erythrocyte mean corpuscular volume (MCV) declined from 43.6 ± 3.7 fL to 35.6 ± 3.2 fL between the first and seventh week, the red blood cell count (RBC) increased from 7.2 ± 1.1 × 10¹²/L to 9.3 ± 1.0 × 10¹²/L until the fifth week of age. The blood hemoglobin (Hb) concentration increased from 0.96 ± 0.16 g/L to 1.16 ± 0.11 g/L in the first three weeks of age and remained at this level until the end of the study. Changes in MCV were accompanied by a decline of the erythrocyte potassium content (K_ERY) from 91.9 ± 13.5 to 24.6 ± 7.2 mmol/L and a concomitant increase of the erythrocyte sodium content from 45.0 ± 32.0 to 102.7 ± 26.5 mmol/L. MCV was found to be associated with K_ERY, the primary determinant of the intra-erythrocyte osmotic pressure from the sixth week of age and with blood hemoglobin, the primary determinant of the intra-erythrocyte oncotic pressure from the eighth week of age, when K_ERY, blood Hb and MCV already had reached or approached normal levels of adult cattle. The plasma iron concentration was not found to be associated to any of the studied hematological parameters.

Conclusion

A volume reduction of 20% in bovine neonatal erythrocytes is a physiological change occurring during the first weeks of age and is neither associated with sideropenia nor with anemia in healthy calves. The mechanism driving the observed erythrocyte volume change could not be identified. Results of the correlation and regression analyses indicate that changes in intra-erythrocyte osmotic or oncotic pressure are improbable underlying causes. Results reported here show that K_ERY is an unreliable indicator for the K homeostasis of the intracellular space in neonatal calves and that a decrease in MCV in early life per-se is an unreliable indicator for the development of microcytic anemia.

The relationship between the osmotic fragility of human erythrocytes and cell age

Erythrocytes in a normal blood sample are hemolyzed over a range of hypotonic salt concentrations. In order to investigate the relationship between the distribution of osmotic fragilities and the distribution of cellular ages, the osmotic fragility has been compared with three indices of cellular age. The activity of glutamic-oxalacetic transaminase (GOT) and the percentage hemoglobin A1C were measured in samples hemolyzed in different hypotonic salt concentrations. The osmotic fragility curve was also obtained for cells of different density separated by centrifugation. These experiments indicate that the fragility distribution is not an accurate reflection of the distribution of cellular ages. The mean fragility for older cells is higher than that of younger cells. However, cellular aging does not produce a gradual increase in osmotic fragility. Instead, it seems to produce changes which can both increase and decrease the fragility, resulting in a broader distribution of fragilities with some of the older cells actually less fragile than the younger ones.

Transitory postnatal hemolysis of calf red cells by amino acids

Among the amino acids which can be solubilized to give a concentration of 300 mm at near physiological pH, histidine and proline caused a complete hemolysis of newborn calf but not of adult cow red cells within 20 to 30 minutes at 38 degrees C. While hydroxyproline, valine, and serine resulted in a partial lysis of calf cells, threonine, glutamine, and glycine were ineffective. In this communication, emphasis has been focused on the mode of the lytic process by histidine which was found to be affected by several governing parameters including the pH, temperature and the extracellular salts in the solution. Unlike human red cells suspended in isotonic histidine, both calf and cow cells lost little Na and K ions. In the presence of 300 mm histidine, both calf and cow cells displayed an instantaneous uptake of histidine amounting to 20 to 45 mumoles/ml RBC followed by a slow influx rate of 0.25 to 0.5 mumoles/ml RBC X min. The extent to which histidine entry was allowed by the cell was counterbalanced by Cl- efflux, resulting in little change in cell volume prior to hemolysis. Moreover, histidine-induced hemolysis can be prevented by 1 mm or lower PCMBS without a discernible effect on histidine influx suggesting a possible membrane lesion or damage at the outer surface of the cell. Hemolysis induced by histidine decreased substantially when a calf reached two months of age at which time the red cells containing the fetal hemoglobin are virtually depleted. The results of hemoglobin electrophoresis obtained during this postnatal period revealed that those cells resistant to histidine hemolysis almost invariably contain the adult type hemoglobin suggesting a selective, specific action of the amino acids on the fetal cells.