Control measures recommended for goat gastrointestinal nematode infections after analysis of infection dynamics in the semiarid region of Brazil

Vanessa Diniz Vieira,Lídio Ricardo Bezerra De Melo,Jouberdan Aurino Batista,Dayana Firmino De Morais,Vinícius Longo Ribeiro Vilela,Samara Dos Santos Silva,Márcia Alves De Medeiros,Franklin Riet Correa,Sérgio Santos De Azevêdo ,Thaís Ferreira Feitosa

doi:10.1590/0103-8478cr20200383

Abstract

ABSTRACT: This study aimed to determine control measures for gastrointestinal nematodes in goats in the northeastern semiarid after analyzing the dynamics of gastrointestinal helminths during the drought, the evolution of the parasitic load after the first rains and the differences in susceptibility between goats of different categories and ages. Five farms were studied from March 2013 to January 2015. Feces were collected from all goats every month, for fecal egg counts (FECs). No treatment was required on any farm during the dry period. In 2013, with annual rainfall of 265-533 mm, treatments were not necessary during the rainy season. However, in 2014, with rainfall of 604-778 mm, treatments were necessary 60-90 days, after the first rains. On three farms, gastrointestinal nematodes showed multiple anthelmintic resistance. The FECs from lactating goats were significantly higher than from dry and young goats. In conclusion, in the Brazilian semi-arid region (Caatinga biome), it is generally unnecessary to treat grazing goats during the dry season. In the rainy season, the parasite load increases 2-3 months after the first rains. In both, the dry and the rainy season, farmers should monitor their herds by means of FEC or another criterion (anemia or submandibular edema), to determine the need to treat.

Highlights

Brazilian goat herd has about 11 million animals, most of which belongs to Northeastern region, with 94% of the goats
In 2014, it was not necessary to deworm any farm during the dry season because the fecal egg counts (FECs) remained below 500
The farmer administered moxidectin, which had not been used for two years, but 10 days later the fecal egg count reduction test (FECRT) showed that the efficiency of this anthelmintic was only 64% (Table 2)

Summary

Introduction

Brazilian goat herd has about 11 million animals, most of which belongs to Northeastern region, with 94% of the goats. Paraíba state in the Northeast region is the fifth largest in number of goats, with approximately 650,000 heads (IBGE, 2018). The Northeast of this state is mainly semiarid (approximately 74%) and the goats there are adapted to conditions of high temperature, irregular rainfalls and periodic droughts (CORREIA et al, 2011). The high prevalence of gastrointestinal nematodes and anthelmintic resistance makes the effective control of these helminths difficult. They are the main problem for goat and sheep production in the Brazilian semiarid region (RIET-CORREA et al, 2013b; VIEIRA et al, 2014). Several factors contributed to the development of anthelmintic resistance in this region, such as the indiscriminate use of anthelmintics, due to the lack of knowledge by producers, poor management practices and easy drug purchase (SILVA et al, 2018)

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