Parâmetros clínicos e parasitológicos de ovinos mantidos em confinamento infectados experimentalmente com larvas de Haemonchus spp.

Abstract

The aim of this study was to establish parasitological parameters that determine the parasite load of anthelmintic intervention through monitoring of the parasitological behavior of groups of crossbred Santa Ines sheep experimentally infected and uninfected larvae of Haemonchus sp., Kept in total confinement system. The experiment was conducted in the period June to August 2013. 14 castrated male sheep were used, free of nematodes, which were divided into two groups of 7 animals each similar body weight .Later there was the experimental infection of one of the groups with 10,000 larvae of Haemonchus sp., basing the values and recommendations set by the World Association for the Advancement of Veterinary Parasitology (W.A.A.V.P.). The reviews parameter (eggs per gram of feces, Famacha©, weight, total plasma protein, hematocrit) were weekly reviews , the first from 21 days after infection, and therefore the day zero ( day infection) , time analysis 21, 28 , 35, 42, 49 , 56, 63 and 70 . At the end of the experimental period, the animals were slaughtered and the gastrointestinal tract collected for counting and identification of adult parasites . For OPG parameter was no significant difference between infected and control groups from day zero for all other analyzed time. In the infected group was no significant difference from zero for the other day, day 21 to day 28, 35 and 42 and day 35 and day 42 to 63 and 70. The hematocrit showed a significant difference between groups on days 21, 28, 35, 42, 49 and 63, and between day zero and day 28, 35, 42, 56, 63 and 70 in the infected group. For variable Famacha both groups remained classified as grade 1 and 2, ie without clinical signs of anemia. Plasma proteins showed no changes between times or between groups throughout the experimental period. For weight variable also no differences between groups at any time analyzed were found. The control group showed no statistically significant differences between time points throughout the experimental period for all variables. The correlation between OPG and number of adult parasites was considered strong (r = 0.93). Experimental infection with 10,000 larvae of Haemonchus sp. was not enough to change the general health status of animals under the conditions studied, and therefore animals with OPG to 2500 do not require anthelmintic intervention when in similar conditions to the present study.