The causative agent of neosporosis is a protozoan called Neospora caninum, a branch of the epicomplex. This Parasite can infect various species of domestic and wild animals. It is found in dogs, cattle, sheep, and goats in nature. It is noteworthy, however, that dogs are known to be the ultimate host of this protozoan, and other warm-blooded animals are the intermediate and random hosts of the Parasite, which become infected by eating oocytes excreted in dog feces. Therefore, considering the critical role of this Parasite in abortion and the significant damages caused by it, this study aimed to investigate the serological prevalence of Neospora caninum in healthy dairy cows and aborted in Aq Qala in Golestan province. In this study, 90 dairy cows from semi-industrial farms in Aq Qala and its suburbs were sampled in the winter of 2021. The sampling of the study population was blood sampling from the tail vein. The samples were stored at -20 ° C until testing. During sampling, the animal’s characteristics, such as calving belly (in three categories of several calves less than two bellies, between two to five bellies and more than five bellies), will be recorded. The ELISA method performed a serological examination of infection caused by Neospora caninum. The results were analyzed in three groups using the chi-square method using SPSS software version 20. The results obtained in the present study indicated that 45.6% of the samples were infected with Neospora caninum. Also, the frequency of repeat breeder was 44.4%, abortion was 38.9%, and healthy was 16.7%. It was also found that there is a substantial difference between the factors of repeat breeder, abortion and healthy, in positive and negative samples (p <0.05) and the number of positive samples between cows with a history of abortion and repeat breeder more than Cows are healthy. On the other hand, there was no significant difference between the repeat breeder, abortion and healthy samples (p <0.05). Therefore, due to the high prevalence of Neospora caninum infection in Aq Qala city of Golestan province, the use of health instructions to control this complication should be considered.

Brucellosis is one of the most common infectious diseases between humans and animals. It is caused by a gram-negative coccobacillus bacterium called Brucella. The disease is essential in two ways. It threatens public health and has many side effects, including abortion and reduced production in various livestock and, most importantly, infertility of infected animals, which causes significant economic losses. Since no research has been done on dogs in Mazandaran province in the field of prevalence and identification of infected foci of this disease, the present study was deemed necessary to determine the status of the disease in the region, control methods, prevention and appropriate treatment is applied. In this study, 20 pregnant dogs were sampled in dog kennels in Mazandaran province. Serum samples were sent to the laboratory for Brucella examination, and the steps were performed using Wright and Coombs Wright tests. Based on the results, all 20 models were negative. The results of the Wilcoxon test during the comparison of small and giant breed dogs in the two age groups of 1 to 3 years and 3 to 5 years show that there is no significant relationship between these two age groups in this breed in terms of stillbirth (P>0.05). Therefore, this research could be a window for future research investigating the cause of stillbirth in dogs.