Características de produção da ovinocaprinocultura e soroprevalência de lentiviroses de pequenos ruminantes no Estado de Tocantis

Abstract

The aim of the present study was to characterize the goat and sheep production systems, estimate the prevalence of small-ruminant lentiviruses (SRLV) and study predisposing factors to infection in herds in the state of Tocantins (Brazil). Investigative questionnaires were administered addressing data on 29 goat herds and 28 sheep herds distributed among 21 towns in the state of Tocantins. To estimate the prevalence of SRLV, 838 samples of sheep blood and 843 samples of goat blood were analyzed using the immunodiffusion test in agarose gel. There was a mean number of 79 and 340 animals for the goat and sheep herds, respectively. According to the survey, 79.3 and 71.4% of the goat and sheep farms, respectively, were implanted after 2001. The animals making up the herds originated in the states of Bahia and Sergipe. The Santa Inês (61.0%) and SRD (38.7%) were the most frequent breeds among the sheep, whereas the Anglo-Nubian (55.4%), SRD (36.6%) and Saanen (7.1%) were the most frequent goat breeds. 55.1% of the 49 properties surveyed bred cattle + goats or sheep. The semi-extensive system was adopted in 51.7 and 46.4% of the goat and sheep farms, respectively. The most frequently adopted hygiene practices among the breeders were de-worming, cuts and disinfection of the navel and burying dead animals. Vaccination is practiced by 24.1% of goat breeders, most frequently for clostridiosis (20.7%), aphthous fever (6.8%) and rabies (3.4%). The clinical signs and diseases most often cited as having considerable importance were caseous lymphadenitis (34.5%) and pododermatitis (17%) by goat breeders and pododermatitis (42.3%) and diarrhea (30.8%) by sheep breeders. 51.7 and 28.6% of the goat and sheep breeders, respectively, knew about lentiviruses (CAE and Maedi-Visna). The frequency of ovine blood reagents was 0.9 ±0.3% (8/838). The results regarding the micro-regions of the state were distributed in the following manner: 3.3 (2/60), 0.61 (1/178), 1.3 (2/150) and 2.0% (3/150) for Bico Papagaio, North, Miracema and South, respectively. No animals tested positive in the Jalapão, Porto Nacional, Rio Formoso and Southeast micro-regions. The Santa Inês was the breed with the highest percentage of blood reagent animals (3.9%; 6/511), followed by Undefined Breed (0.6%; 2/324). Regarding age, 0.6% (2/238) and 1.2% (96/510)of animals under 24 and over months of age, respectively, tested positive. 1.2% (2/161) of males and 0.9% (6/677) of females tested positive. There were no statistically significant differences in the prevalence of blood reagent regarding breed,age and gender (p > 0.05). The frequency of blood reagent goats was 2.7% (23/843). The results were distributed according to micro-region in the following manner: 10.0 (20/200) and 1.4% (3/207) for the North and Miracema micro-regions, respectively. The Saanen was the breed with the highest percentage of blood reagent animals (11.7%; 7/60), followed by the SRD (0.6%; 2/310) and Anglo-Nubian (3.0%; 14/466). Regarding age, 1.9% (6/314) and 3.2% (17/529) of animals under 24 and over months of age, respectively, tested positive. 2.4% (4/166) of males and 2.8% (19/677) of females tested positive. Analysis of the data revealed a predominance of the semiextensive breeding system with good installations, but little use of reproduction biotechniques and important hygiene management practices. The activity has been expanding in the state, with a tendency toward professionalization. SRLV infection occurs at a low prevalence among sheep and goats in the state of Tocantins and is evenly distributed according to micro-region, breeding system, breed, age and origin of the base herds. Control measures should be implanted to avoid the dissemination of the disease among the herds.