Investigations of presence of antibodies against equine herpesvirus-1 in blood serum of foals prior and after colostral intake

Abstract

The titer of specific antibodies against equine herpesvirus-1 in blood serum was tested in two groups of mares and their foals. The first group consisted of 12 mares, Standardbred and Serbian Trotter breed, who were vaccinated against equine herpesvirus-1 and 4 in the 5th, 7th and 9th month of pregnancy. On the contrary, 12 mares from the second group, of Lipizzaner breed, were not vaccinated. The mares' blood samples for antibodies titer investigation were taken 30, 15 and 7 days before the expected partus, then immediately after the partus, while their foals' blood samples were taken immediately after foaling, then just before colostrum intake, and finally 1, 2, 3 and 7 days later. The titer of antibodies against equine herpesvirus-1 was tested by the method of virus - neutralization, on microtiter plates with constant dose of the virus and serial double dilutions of the serum. In unvaccinated mares, titer of antibodies against equine herpesvirus-1 was either low or not present, but on the contrary, in the vaccinated ones the antibodies titer ranged from 1:32 to 1:256. In the foals originating from both vaccinated and unvaccinated there were not found specific antibodies in the serum before colostrum intake. After the colostrum intake, the values of specific antibodies against equine herpesvirus-1 significantly increased in the foals originating from the vaccinated mares, and ranged from 1:8 to 1:32.

Titar specifičnih antitela protiv konjskog herpesvirusa-1 u krvnom serumu ispitan je kod dve grupe kobila i njihove ždrebadi. Prva grupa od 12 kobila, rase američki i srpski kasač, bila je vakcinisana protiv konjskog herpsvirusa-1 i 4 u 5, 7. i 9. mesecu graviditeta, za razliku od druge grupe od 12 lipicanskih kobila koje nisu bile vakcinisane. Uzorci krvi kobila za ispitivanje titra antitela bili su uzeti na 30, 15 i 7 dana pre očekivanog partusa, zatim neposredno posle partusa, a uzorci krvi njihove ždrebadi neposredno posle ždrebljenja, pre uzimanja kolostruma, zatim 1, 2, 3 i 7 dana kasnije. Titar antitela protiv konjskog herpesvirusa-1 ispitan je metodom virus - neutralizacije, na mikrotitar pločama sa konstantnom dozom virusa i dvostrukim serijskim razređenjem seruma. Kod nevakcinisanih kobila titar antitela protiv konjskog herpesvirusa-1 bio je nizak ili ga nije bilo, za razliku od vakcinisanih kobila kod kojih je ustanovljen titar atitela u rasponu od 1:32 do 1:256. Kod ždrebadi vakcinisanih i nevakcinisanih kobila nema specifičnih antitela u serumu pre unosa kolostruma. Nakon unosa kolostruma vrednost titra specifičnih antitela na konjski herpesvirus-1 značajno raste kod ždebadi vakcinisanih kobila i kreće se od 1:8 do 1:32.