Parasites remain a significant threat to horses’ health and welfare. The present paper reviews and discusses interactions between parasitic infections and reproductive efficiency in horses. The manuscript describes the interactions in a structured way, presenting the infecting parasites and the respective effects in the reproductive activity of horses. The following stages of the reproductive cycle are covered: ovarian activity and relevant body condition, breeding management (including effects in mares and stallions), pregnancy and neonatal period. A separate section covers the topic of transmission of pathogens to horses through parasites. Finally, parasite control strategies in relation to reproductive activity (strategies for breeding mares and foals) are discussed. Understanding the causality of impaired reproductive performance is essential in terms of maintaining productivity and efficient stud breeding strategies. Further collaboration of parasitologists, stud managers and veterinarians is necessary in order to implement novel control strategies with a greater emphasis on the emerging challenges.

Objectives of the study were (a) to investigate the incidence risk of peri-parturient mortality in dairy flocks in Greece, (b) to study when such mortality occurs in relation to lambing, (c) to identify clinical problems associated with the deaths, and (d) to evaluate potentially associated factors. The deaths of ewes during the peri-parturient period (10 days before to 7 days after lambing) were monitored in 60 flocks over two years. In the ewes that died, detailed post-mortems were performed. The incidence risk of peri-parturient deaths was 0.7%. The daily incidence rate of deaths before, at, and after lambing was 0.05, 0.04, and 0.03%, respectively. Clinical problems most frequently associated with peri-parturient deaths were pregnancy toxaemia, ruminal acidosis and post-partum genital problems. For the occurrence of peri-parturient deaths in flocks, the average lambing rate in the flocks was the only significant factor. Regarding deaths before or after lambing, the season during which lambing took place and the number of animals in the flock, respectively, were found to be significant. Most ewes (54.5%) that died at lambing (dystocia) were primigravidae.