Multiple anthelmintic resistance in Southern Brazil sheep flocks

Oliveira, Plínio Aguiar de; Riet-Correa, Beatriz; Estima-Silva, Pablo; Coelho, Ana Carolina Barreto; Santos, Bianca Lemos dos; Costa, Marco André Paldês da; Ruas, Jerônimo Lopes; Schild, Ana Lúcia

doi:10.1590/s1984-29612017058

Cited by 21 publications

(10 citation statements)

References 29 publications

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“…In both years the reduction in the EPG values after the treatment with closantel was followed by an increase in EPG means in the next sampling demonstrating low efficacy of such anthelmintic. Resistance to closantel is widespread in Rio Grande do Sul, where of the 22 sheep flocks evaluated only in one closantel presented efficacy above 95% (Oliveira et al, 2017b).…”

Section: Discussionmentioning

confidence: 99%

Infection with gastrointestinal nematodes in lambs in different integrated crop-livestock systems (ICL)

Almeida

Piza

Bassetto

et al. 2018

Small Ruminant Research

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Lamb performance was evaluated in four integrated crop-livestock (ICL) systems. The ICL areas were previously planted with maize and marandu palisade grass in December 2013. ICL systems 1 and 2 were also seeded with pigeon pea. After harvesting in April 2014, black oats were sown in rows (ICL 1 and 3) or by broadcast seeding (ICL 2 and 4). Each ICL area was divided into 12 paddocks of 225 m 2 to be grazed by young sheep from July 23 to September 30, 2014. To determine if the pasture remained contaminated by free-living stages of sheep gastrointestinal nematodes (GIN) after approximately ten months without animals in the area, 12 worm-free "tracer" lambs (n = 3/ ICL system) grazed each ICL pasture for 14 consecutive days in July 2015 and were later housed in pens, where they remained for another 14 days. The tracer lambs acquired no worm infections, demonstrating that the area was cleared after 300 days without animals. To evaluate GIN infection and uncastrated male lamb performance, we used 60 (n = 15/ system) Poll Dorset x Corriedale (crossbred) sheep with mean body weights of 24.4 ± 3.4 kg from July to September 2015 and 48 (n = 12/ system) Texel x Corriedale sheep with body weights of 26.4 ± 3.5 kg from June to September 2016. Lambs were allocated to the following groups: Group 1 rotated on the 12 ICL1 paddocks; Group 2 rotated on the 12 ICL2 paddocks; Group 3 rotated on the 12 ICL3 paddocks; and Group 4 rotated on the 12 ICL4 paddocks. Each paddock was grazed by sheep twice for three days, with a 33-day interval between grazing. At the end of the day the lambs were supplemented with concentrate plus silage. Groups 1 and 2 received mixed silage made of maize, marandu palisade grass and pigeon pea and groups 3 and 4 received mixed silage made of maize and marandu palisade grass. Faecal and blood samples were taken from all the animals every two weeks, and body weight was recorded on the same occasion. Nematode faecal egg counts (FEC), packed cell volume and total plasma protein means did not differ (P > 0.05) between the four lamb groups. In 2015, throughout the experimental period, the FEC decreased in all animals, with 6733 and 1407 eggs per gram (EPG) on average at the beginning and end of the trial, respectively. At the beginning of the trial in 2016, the animals had mild GIN infections (1077 EPG on average), and the individual faecal egg counts did not exceed 10,000 EPG during the trial. In decreasing order, Haemonchus spp., Trichostrongylus spp. and Cooperia spp. third stage larvae were found in the faecal cultures in both years. The performance of lambs were similar in the four ICL systems (P > 0.05), in the first and second years, the daily weight gains were 0.192 ± 0.05 kg and 0.221 ± 0.06 kg, respectively. In conclusion, a period of withdrawal of contaminated sheep results in plots free of infective larvae. The use of clean pastures during the dry season, in the different ICL systems, associated with a good nutrition plan, resulted in progressively declining degrees of GIN infections and satisfactory ...

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Section: Discussionmentioning

confidence: 99%

Infection with gastrointestinal nematodes in lambs in different integrated crop-livestock systems (ICL)

Almeida

Piza

Bassetto

et al. 2018

Small Ruminant Research

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“…It is a blood-sucking parasite that causes, in acute infections, mortality, which is considered the most important economic effect attributable to this parasite (BARGER & COX, 1984). In addition, it presents high prolificacy and great capacity of developing anthelmintic resistance (ALBUQUERQUE et al, 2017;MARTINS et al, 2017;OLIVEIRA et al, 2017). Other trichostrongylid parasites produce significant reductions in weight gain, which is the case of Trichostrongylus colubriformis, considered the second most important nematode in sheep in Brazil (WILMSEN et al, 2014;ALMEIDA et al, 2018).…”

Section: Losses Caused By Gastrointestinal Nematode Infections In Dormentioning

confidence: 99%

Losses caused by gastrointestinal nematode infections in Dorper lambs under two nutritional status

Starling

Almeida

Viana

et al. 2019

Rev. Bras. Parasitol. Vet.

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The aim of this study was to evaluate the effect of two nutritional statuses on the productive performance of Dorper lambs naturally infected with gastrointestinal nematodes. Thirty-two lambs, grazing together on the same pasture, were allocated into four experimental groups: (G1) infected-supplemented diet, (G2) control-supplemented diet, (G3) infected-basal diet, and (G4) control-basal diet. Control animals received suppressive treatment with monepantel every two weeks, while precautionary anthelmintic treatments were given to all lambs of the infected groups with packed cell volume (PCV) <23%. There was reduction in the PCV means of all groups, which was more pronounced in the infected lambs that also presented reduction in total plasma protein values in comparison with the controls. Weight gain was affected by diet and infection status (P < 0.05). Daily body weight gain was 0.170 kg in the G1, 0.205 kg in the G2, 0.085 kg in the G3, and 0.116 kg in the G4. The cold carcass weight was 4.1% and 13.7% higher in controls in comparison with infected lambs, respectively, in the supplemented and basal diets. The infected groups, despite receiving precautionary anthelmintic treatments to prevent deaths due to haemonchosis, presented reduction in the production parameters in comparison with the controls.

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“…There are numerous similar reports of AHR worldwide, with emphasis on the countries where sheep production is significant, such as Australia, the UK, New Zealand and Uruguay (FALZON et al, 2014). Resistance to active substances can be established rapidly, even after the introduction of new molecules, especially in the absence of alternative control programs (OLIVEIRA et al, 2017).…”

Section: Fecrt(%)mentioning

confidence: 99%

Implication of the fecal egg count reduction test (FECRT) in sheep for better use of available drugs

Salgado

Cruz

Rocha

et al. 2019

Rev. Bras. Parasitol. Vet.

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The aim here is to present data on the efficacy of anthelmintics in sheep flocks in Rio de Janeiro, Brazil, and to discuss the interpretation of the fecal egg count reduction test (FECRT) for each nematode genus. Fecal eggs counts and pre- and post-treatment coprocultures were performed, the former to evaluate the efficacy of and the latter to determine the overall parasite prevalence. An additional efficacy test was performed at Farm # 1 a year after the initial test. Severe anthelmintic resistance was found for the flocks, with no FECRT sensitivity at any of the 22 farms evaluated. However, an analysis of the infective larvae showed that some drugs were effective against certain parasitic genera; i.e., levamisole was more effective against Haemonchus spp. and moxidectin against Trichostrongylus spp. In the additional FECRT performed at Farm # 1, moxidectin and nitroxynil were ineffective separately, but when applied in combination they were highly effective due to their efficacy against Haemonchus (nitroxynil) and Trichostrongylus (moxidectin), respectively. The use of the FECRT targeting the parasitic nematode species prevalent on farms may make it possible to choose more effective anthelmintics.

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Multiple anthelmintic resistance in Southern Brazil sheep flocks

Cited by 21 publications

References 29 publications

Infection with gastrointestinal nematodes in lambs in different integrated crop-livestock systems (ICL)

Infection with gastrointestinal nematodes in lambs in different integrated crop-livestock systems (ICL)

Losses caused by gastrointestinal nematode infections in Dorper lambs under two nutritional status

Implication of the fecal egg count reduction test (FECRT) in sheep for better use of available drugs

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