Parasitological Study on Cows During Lactation in Western Santa Catarina, Brazil.

Background: The milk production chain is an important component of the agribusiness in Western Santa Catarina, Brazil. However, this activity is facing problems regarding health of the herd that are often difficult to control because they can be caused by different etiologic agents such as viruses, bacteria, fungi and parasites. The damage caused by endoparasites may occur directly and indirectly, reflecting on weight gain, milk production, expenses with antiparasitic drugs, and mortality of untreated animals. To minimize these losses, all properties should implement a strategic program to monitor the herd. As a result, the objective of this study was to monitor dairy cattle properties from the West of Santa Catarina, by collecting information about the herd and parasitological stool examinations. Materials, Methods & Results: This study was conducted on farms from 12 cities of the Western region of Santa Catarina state during the months of November and December of 2010 and January and February of 2011 (summer). The study included 23 properties that have part of their farm income from dairy cattle activity; these animals had not been treated with anti-parasitic for at least 30 days. To assist research, a questionnaire was given to the farmers. For parasitological examination, fecal material was collected from at least 20% of the herd up to 100%, that is, was standardized the analysis of 8-10 samples per property for the McMaster technique using saturated salt solution to determine the degree of infection (EPG: eggs per gram of faeces). The total number of cows present in the properties was 648 animals, and of these 569 was lactating. All properties fed their animals with cultivated pasture and ration, whose amount ranged between 1 to 8 kg ration/day according to the productivity. In the interview, it was found that 100% of properties used anti-helmintic treatment. Of these, 70% of all treatments were performed usually with six months of interval and 75% conducted antiparasite rotations. Stool examination showed that only five farms had animals positive for gastrointestinal parasites the of Trichostrongylidae family (degree of infection between 100-300 EPG). Therefore, from 215 samples processed only 11 were positive for helminth eggs, which correspond to 5.16%. Discussion: Cattle raised on natural pastures and raised in Brazil are exposed to infection by larvae of gastrointestinal nematodes. The occurrence and distribution of endoparasites present regional and seasonal variations. Young animals are generally more susceptible to helminths, however, adult animals may be involved in situations such as post-partum, in association with other diseases, high exposure to the agent and stress conditions, like during the lactation period during the summer. Milk production has gained importance in rural properties of West Santa Catarina and in recent years has modernized and invested in technology and genetics. Based on the data it is possible to conclude that the occurrence of gastrointestinal parasites in dairy cows, in the summer, is low. This fact can be attributed to efficient parasite control achieved by owners; by adult animals with good immunity and probably low exposure to parasites in the environment due the excellent parasite control with drugs, held by owners. [ABSTRACT FROM AUTHOR]