%X In the adult stage, Haemonchus contortus worms infect the abomasum host causing anemia and even death in animals. However, identifying the H. contortus protein can be used as a reference for the diagnosis of diseases. The diagnosis is performed by serological cross-reaction between H. contortus protein and anti-L2 Toxocara vitulorum (T. vitulorum) serum using the western blot technique. The main purpose of the current research was to identify the cross-reaction between H. contortus proteins and anti-L2 T. vitulorum serum using the western blot technique. T. vitulorum worms were collected from the intestine of cattle and H. contortus worms were collected from the abomasum of goats. The first step was making antibodies by oral infection of rats with infective eggs (L2) of T. vitulorum. The blood was taken 21 days after infection. Then, the blood was centrifuged at 1500 rpm for 10 minutes to get the serum. The second step was making homogenates from the whole worm extract of H. contortus. After crushing the worms, it was centrifuged at 5000 rpm for 15 minutes and the supernatant was taken. The supernatant was then analyzed using Sodium Dodecyl Sulphate Polyacrylamide Gel Electrophoresis (SDS-PAGE) with coomassie brilliant blue staining. The third step was the analysis of H. contortus protein with serum anti-L2 T. vitulorum using the western blot technique. From the H. contortus homogenates analysis using SDS-PAGE, 16 protein bands were obtained. The cross-reactions were 141.3, 81.3, 64. 6, 51.3, 46.8, and 38 kDa. The data from cross-reactions suggested that the H. contortus protein cannot be used as a diagnostic material. It is serologically Haemonchosis because it caused false positives with diagnostic Toxocariasis. %K Cross reaction, Haemonchus contortus, SDS-PAGE, Toxocara vitulorum, Western blot %V 11 %P 504-509 %N 3 %R https://dx.doi.org/10.54203/scil.2021.wvj65 %A R. W. Asmorowati %A . Kusnoto %A H. Eliyani %D 2021 %J World's Veterinary Journal %I Scienceline Publication, Ltd %T Cross Reaction of Haemonchus contortus Protein with Toxocara vitulorum Anti-L2 Serum Using Western Blot Technique %L eprints376