Factors affecting occurrence of demodecosis by Demodex bovis in Sindhi cattle (Bos indicus).

The objective was to evaluate the factors affecting the occurrence of bovine demodecosis from the clinical aspects of injuries, blood profile, and the correlation with weight gain and the season of the year in Sindhi-breed animal management in a tropical environment. Thirty-three Sindhi-breed animals were used: 23 females and 10 males. Clinical examination diagnosed that 90% of the examined animals presented skin lesions characteristic of bovine demodecosis caused by Demodex bovis (P < 0.05). The Sindhi presented a higher fecal parasite egg count and showed a lower body weight gain in the rainy season and a greater weight loss in the drought season (P < 0.05), medium injury predominating, with no effect of sex (P > 0.05). During the drought season, animals clinically infected with bovine demodecosis presented lower red blood cell and platelet counts and total plasma protein, and higher mean corpuscular volume and mean corpuscular hemoglobin concentration, a blood count typical of regenerative macrocytic anemia (P < 0.05). During the rainy season of the year (April to June), the animals showed greater weight gain, but a higher fecal parasite egg count with no effect on the incidence of bovine demodecosis. Infection by gastrointestinal nematodes negatively influenced body weight gain and demodecosis in the animals.