Influence of pathological conditions caused by gastrointestinal parasites infection on pregnant ewe´s behavior

Background: Infection by helminthes is a main problem affecting sheep, causing significant economic losses. Among these parasites that may affect sheep, Haemonchus contortus, a hematophagous parasite caused of anemia. The anemia due to parasitosis causes animal apathy, the main goal of most studies is to show how anemia affects animal performance, with little research on the relationship of animal behavior and helminthosis. Therefore, the objective of this study was to evaluate the effect of anemia caused by helminthes on the behavior of pregnant ewes before and after antihelminthic treatment. Material, Methods & Results: Pregnant ewes (n = 18) Lacaune breed from the same herd in Southern of Brazil were classified into three groups of six animals each according to their degree of anemia based on the Famacha method (F) and hematocrit counts (H) in addition to fecal examination on day 0 of the study. The groups were formed as follow: Group A (level 1-2 (F), (H) ≥ 30%), Group B (level 3 (F); (H) among 21-29%), and Group C (level 4-5 (F); (H) ≤ 20%). Famacha method, hematological analysis and fecal examination were repeated at the end of the experiment on day 18. Behavioral assessment was done concomitantly by two methods: direct temporal observation with real-time registration and continuous observation with conspicuous registration for each event performed by the animal. Animal behavior was observed during six periods (P1 to P6) six h a day (08:00-10:00 AM, 12:00-02:00 PM, and from 04:00-06:00 PM), being tree-point periods prior (P1, P2 and P3) and three after the antihelminthic treatment (P4, P5 and P6). The animals from the Group C had higher eggs per gram (EPG) counts in faces when compared to other groups. The animals from the Group B showed higher ratios of the variable lying ruminating (1.74) when compared to the Group A. Animals from the Group C showed higher ratio for the variable ruminating standing (1.38), lying idle (4.75) and standing idle (1.34), compared to females from the Group A. In conspicuous method, it was noticed that animals from the Group B showed lower ratio of the variable drinking water (0.87) when compared to the Group A. The Group C showed higher ratios of the variable eating (1.47), when compared to the Group A. Discussion: Behavioral changes mostly of the time may be the first indication of disease, since there is a direct link between behavior and animal health. A study in order to identify the effects of H. contortus experimental infection on lambs and observed that there is an effect on age, behavior, and growth rate, but the degree of parasite infection did not influence the pattern of animal behavior, different from our experimental study. In our study the anemic animals from the Group C where seen eating and drinking more frequently but they were also standing and lying idle for longer periods of time. These behaviors may be related to the need of blood replacement due to anemia faced after helminthic infection. In addition, studies describe that gastrointestinal parasitism altered animal grazing behavior with parasitized animals becoming more selective when avoiding contaminated pasture, taking smaller bites at reduced bite rates compared with non-infected animals. Based on our results, we were able to conclude that the degrees of anemia, and therefore the helminthosis, play important influence on the behavior of pregnant ewes.