Comparative analysis of some serum proteins and immunoglobulin G concentration in the blood of Yugoslav Trotter mares and newborn foals

The comparison of some serum protein concentrations was performed on 12 Yugoslav Trotter mares and their newborn foals. The mares included in the evaluation were divided into two groups of 6 each. The mares in the first group were vaccinated against equine herpes virus 1 and 4, in the 5th, 7th and 9th month of pregnancy, while mares in the second group were not vaccinated at all. Pregnant mares were clinically observed during the last stage of pregnancy and blood for biochemical evaluations was sampled immediately after foaling. Foals were clinically observed for seven days after birth and blood samples were collected immediately after foaling (before nursing), and 24, 48, 72 and 168 hours after birth. Foals included in the evaluation were divided into two groups according to the group allocation of the respective mares. All mares gave birth to normal foals in expected terms. Biochemical examination revealed slightly lower total gammaglobulin and IgG values in tested mares compared to the values obtained in other horse breeds. The antibody titres against equine herpes virus-1 reached the level that provides sufficient protection in vaccinated mares. Gammaglobulin and traces of IgG were present in the blood serum of foals tested immediately after birth and before nursing. A significant increase of IgG and gammaglobulin concentration was revealed in all foals after the first 24 hours of life. The observed first day increase of concentration was followed by stagnation of gammaglobulin and IgG levels in all foals. Total protein values showed a significant increase 24 hours after the first intake of colostrum in all foals. Immunoglobulin G concentration established by semiquantitative test was considered low positive in 16.67% and in 33.34% of foals from vaccinated and unvaccinated mares, respectively. Turbidimetric analyses of the same samples revealed sufficient Ig transfer, i.e. Ig concentration over 8 g/L. Comparison of the results obtained by the two methods indicates that semi-quantitative field test results were clinically valid. There were no antibodies against EHV 1 in foals immediately after birth and before the first colostrum intake, and a highly significant increase of serum antibody level was recordered 24 hours after the onset of nursing in foals born from vaccinated mothers.