Serum concentrations of selenium, copper, and zinc in neonatal foals: Influence of failure of passive transfer and age-related changes

Abstract

Background: An adequate supply of trace elements is very important for equine neonates, as deficiencies can lead to health problems and even death.

Objective: This study investigated serum concentrations of selenium (Se), copper (Cu), and zinc (Zn) in neonatal foals up to the 8th day of life. The influences of disease, age, and failure of passive transfer (FPT) on these concentrations were analyzed.

Animals and procedure: Serum concentrations of Se, Cu, and Zn were determined from blood samples of 93 foals by means of inductively coupled plasma mass spectrometry. The foals were divided into 2 groups based on health status: clinically sick (n = 51) and clinically healthy (n = 42). The latter group was further divided into foals with FPT (n = 20) and those without (n = 22).

Results: Mean serum concentrations for Se, Cu, and Zn were 60 ± 40 μg/L, 0.25 ± 0.22 mg/L, and 605 ± 285 μg/L, respectively. A significant influence of age on serum Cu concentration was observed (P < 0.0001). No differences were observed between any of the serum concentrations in clinically sick and clinically healthy foals on the 1st day of life. The FPT status was not associated with reduced serum concentrations of Se, Cu, or Zn.

Conclusion and clinical relevance: It is not necessary to supplement trace elements in all foals with FPT.

Figure 1

Relationships between age in days and serum concentrations of selenium, copper, and zinc, without consideration of health status, in foals up to 8 d of life (N = 93). Selenium and zinc concentrations demonstrated no statistically significant relationships with age. Copper concentrations increased in the first days of life (r = 0.64, P < 0.0001). The individual dots represent individual animals.

Figure 2

Serum selenium (Se), copper (Cu), and zinc (Zn) concentrations compared between clinically Healthy (n = 31) and clinically Sick (n = 28) neonatal foals on the 1st day of life. No statistically significant differences were identified between the groups. For each box-and-whisker plot: central box represents 25th to 75th percentile; middle line represents median; “×” inside box represents mean; vertical line represents minimum value to maximum value, excluding outliers, which are represented by dots. Blue area indicates the laboratory-specific reference ranges from the company IDEXX Laboratories for foals (unspecified age): Se: 50 to 90 μg/L, Cu and Zn: no reference ranges given for foals. Gray areas indicate the laboratory-specific reference ranges from the company IDEXX Laboratories for adult horses: Se: 70 to 170 μg/L, Cu: 0.5 to 1.5 mg/L, Zn: 400 to 1100 μg/L.

Figure 3

Box plot diagram of selenium, copper, and zinc concentrations in clinically healthy neonatal foals up to 5 d of life. Comparisons are between Group 1 (without failure of passive transfer; n = 22) and Group 2 (failure of passive transfer; n = 20). No statistically significant differences between the groups were identified. For each box-and-whisker plot: central box represents 25th to 75th percentile; middle line represents median; “×” inside box represents mean; vertical line represents minimum value to maximum value, excluding outliers, which are represented by dots.