PESQUISA VETERINÁRIA BRASILEIRA

Abstract in English:

RESUMO.- Sczesny-Moraes E.A., Bianchin I., Silva K.F., Catto J.B., Honer M.R. & Paiva F. 2010. [Anthelmintic resistance of gastrointestinal nematodes in sheep, Mato Grosso do Sul, Brazil.] Resistência anti-helmíntica de nematóides gastrintestinais em ovinos, Mato Grosso do Sul. Pesquisa Veterinária Brasileira 30(3):229-236. Departamento de Patologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, Cidade Universitária, Campo Grande, MS 79070-900, Brazil. E-mail: eurico_sczesny@hotmail.com Entre os métodos de controle da verminose gastrintestinal em ovinos, a utilização de produtos químicos é o mais empregado. Porém, o uso indiscriminado e continuado desses produtos tem selecionado populações de helmintos resistentes aos anti-helmínticos, fenômeno relatado no mundo todo. Este trabalho teve como objetivo identificar as espécies de parasitos gastrintestinais e diagnosticar a situação da resistência anti-helmíntica em ovinos no Estado de Mato Grosso do Sul. Foram realizados testes de redução na contagem de ovos por grama de fezes (OPG) em rebanhos de dezesseis propriedades rurais; as sete formulações utilizadas continham as seguintes bases farmacológicas: Albendazol, Ivermectina, Levamisole, Triclorfon, Moxidectina, Closantel e uma contendo as três primeiras associadas. As espécies identificadas nas necropsias, em ovinos adultos, foram: Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, C. punctata, C. pectinata e Oesophagostomum columbianum; em ordem de prevalência. As formulações contendo Albendazol e Ivermectina não apresentaram eficácia na redução de OPG nos rebanhos testados, com médias de redução de 0,7 e -19,6%, respectivamente. Closantel apresentou eficácia média de 6,7%; Levamisole, Moxidectina e Triclorfon de 28,7, 26,8 e 65%, respectivamente; a associação das três bases (Albendazol, Ivermectina e Levamisole), uma média de eficácia de 55,8%. As percentagens médias de larvas infectantes recuperadas nas coproculturas, tanto no pré como no pós-tratamento, foram semelhantes; indicando que a resistência às bases testadas está presente em todas as espécies citadas, em maior ou menor intensidade. Os dois gêneros predominantemente resistentes são Haemonchus sp., com 86,9%; seguido por Trichostrongylus sp., com média de 47,5%; Strongyloides sp. 33,6%; Oesophagostomum, sp. 21,4% e Cooperia sp. 19,7%.

• Anthelmintic resistance nematodes Haemonchus contortus Trichostrongylus colubriformis Cooperia curticei C. punctata C. pectinata Oesophagostomum columbianum Closantel Levamisolee Moxidectin Trichlorfon Albendazole Ivermectin Levamizol

Abstract in Portuguese:

ABSTRACT.- Sczesny-Moraes E.A., Bianchin I., Silva K.F., Catto J.B., Honer M.R. & Paiva F. 2010. [Anthelmintic resistance of gastrointestinal nematodes in sheep, Mato Grosso do Sul, Brazil.] Resistência anti-helmíntica de nematóides gastrintestinais em ovinos, Mato Grosso do Sul. Pesquisa Veterinária Brasileira 30(3):229-236. Departamento de Patologia, Centro de Ciências Biológicas e da Saúde, Universidade Federal de Mato Grosso do Sul, Cidade Universitária, Campo Grande, MS 79070-900, Brazil. E-mail: eurico_sczesny@hotmail.com Among the methods of control of gastrointestinal worms in sheep, the use of chemicals is the most common. However, the continued, and indiscriminate, use of these products has selected populations of resistant helminths to anthelmintics, a phenomenon reported in the whole world. This study aimed to identify the species of gastrointestinal parasites and diagnose the status of anthelmintic resistance in sheep in the State of Mato Grosso do Sul Brazil. Feacal egg count reduction tests (FECRT) were performed in flocks of sixteen farms, and the seven formulations used contained the following pharmacological bases: Albendazole, Ivermectin, Levamizol, Trichlorfon, Moxidectin, Closantel and one containing the first three in association. The species identified at necropsy, in adult sheep, were: Haemonchus contortus, Trichostrongylus colubriformis, Cooperia curticei, C. punctata, C. pectinata and Oesophagostomum columbianum, in order of prevalence. The formulations containing Albendazole and Ivermectin did not show efficacy in reducing the EPG in the flocks tested, with average reductions of 0.7 and -19.6%, respectively. Closantel presented an average efficacy of 6.7%; Levamisolee, Moxidectin and Trichlorfon, 28.7, 26.8 and 65% respectively, the combination of three bases (Albendazole, Ivermectin and Levamizol), an average efficacy of 55.8 %. The average percentages of infective larvae recovered in the faecal cultures, pre and post treatment were similar, indicating that resistance to the bases tested is present in all species cited, to a greater or lesser degree. The two genera predominantly resistant are Haemonchus sp., with 86.9%, followed by Trichostrongylus sp., with an average of 47.5%, Strongyloides sp. 33.6%, Oesophagostomum sp. 21.4% and Cooperia sp. 19.7%.

Abstract in English:

ABSTRACT.- Bianchin I., Koller W.W. & Detmann E. 2006. [The seasonality of Haematobia irritans in central Brazil.] Sazonalidade de Haematobia irritans no Brasil Central. Pesquisa Veterinária Brasileira 26(2):79-86. Área de Sanidade Animal, Embrapa Gado de Corte, Cx. Postal 154, Campo Grande, MS 79002-970, Brazil. E-mail: bianchin@cnpgc.embrapa.br Horn fly (Haematobia irritans) is one of the most important Brazilian cattle ectoparasites. Epidemiological studies are needed due the increasing difficulty of their chemical control. In order to obtain a better knowledge of their seasonal population dynamics, 14 days interval fly counts were made on 7-30 month old beef cattle, from winter 1996 to summer 2002. Horn fly population levels increase (P<0.05) was observed during the seasons of each infestation period (spring until autumn), mainly in spring and summer, and sometimes in autumn, followed by a significant reduction (P<0.05) in winter, when the relative humidity decreases to less than 60%. A straight (P<0.05) and immediate correlation between the relative humidity and the fly count was found, whilst the most evident effects of temperature and rain fall (P<0.05) were associated with counts done 42-56 days after attainment of the climatic data. The highest parasitism load (average number of flies per animal) observed for the genetic groups used were: Aberdeen Angus x Nellore = 173.5 (134-254); ½ Brown Swiss x Nellore = 183.5 (32-540); ¾ Aberdeen Angus x Nellore = 133.0 (18-374), and Valdostana x Nellore = 219.0 (58-620). Torrential rain falls during the initial half of the infestation period (spring until midsummer) are common in this region and were considered the main reason for the low to moderate population levels verified at that time, in comparison with those which occurred during the last half of the infestation period.

• Horn fly epidemiology population dynamics ectoparasites cattle.

Abstract in Portuguese:

ABSTRACT.- Bianchin I., Koller W.W. & Detmann E. 2006. [The seasonality of Haematobia irritans in central Brazil.] Sazonalidade de Haematobia irritans no Brasil Central. Pesquisa Veterinária Brasileira 26(2):79-86. Área de Sanidade Animal, Embrapa Gado de Corte, Cx. Postal 154, Campo Grande, MS 79002-970, Brazil. E-mail: bianchin@cnpgc.embrapa.br Horn fly (Haematobia irritans) is one of the most important Brazilian cattle ectoparasites. Epidemiological studies are needed due the increasing difficulty of their chemical control. In order to obtain a better knowledge of their seasonal population dynamics, 14 days interval fly counts were made on 7-30 month old beef cattle, from winter 1996 to summer 2002. Horn fly population levels increase (P<0.05) was observed during the seasons of each infestation period (spring until autumn), mainly in spring and summer, and sometimes in autumn, followed by a significant reduction (P<0.05) in winter, when the relative humidity decreases to less than 60%. A straight (P<0.05) and immediate correlation between the relative humidity and the fly count was found, whilst the most evident effects of temperature and rain fall (P<0.05) were associated with counts done 42-56 days after attainment of the climatic data. The highest parasitism load (average number of flies per animal) observed for the genetic groups used were: Aberdeen Angus x Nellore = 173.5 (134-254); ½ Brown Swiss x Nellore = 183.5 (32-540); ¾ Aberdeen Angus x Nellore = 133.0 (18-374), and Valdostana x Nellore = 219.0 (58-620). Torrential rain falls during the initial half of the infestation period (spring until midsummer) are common in this region and were considered the main reason for the low to moderate population levels verified at that time, in comparison with those which occurred during the last half of the infestation period.

Abstract in English:

Catto J.B., Bianchin I., Torres Junior R.A.A. 2005. [Effects of deworming of cow-calf beef herds in brazilian savannas.] Efeitos da everminação de matrizes e de bezerros lactentes em sistema de produção de bovinos de corte na região de Cerrado. Pesquisa Veterinária Brasileira 25(3):188-194. Embrapa Gado de Corte, Rodov. 162, Km 4, Campo Grande, MS 79002-950, Brazil. E-mail: catto@cnpgc.embrapa.br The effect of deworming with ivermectin of cows before calving and of suckling calves on fecal egg counts (EPG) and productive performance of two beef cattle herds in Central Brazil was studied. Four groups of pregnant cows received the following treatments: T1- cows and calves not treated, T2- only calves treated, T3- only cows treated, and T4- cows and calves treated. The calves of T2 and T4 were distributed in the following treatments: A- calves treated at 3 to 5 months of age with long action ivermectin, B- treated with ivermectin, and C- control. For the cows, the deworming did not diminish the EPG during lactation and also did not have significant effect on the conception rate, live weight gain and the body weight of their calves at 3 to 5 months of age. The calves of treatment A gained, from the time of treatment to weaning (84 to 108 days), an average of 4.2kg (P=0.0003) and 7.1kg (P<0.0001) more than those of treatment B and C, respectively. The average difference in live weight gain of 2.9kg between the animals of treatment B and C was not significant. The EPG before treatment was not significantly different from the treatments (P=0.8665); but at weaning, the average EPG of the calves from treatment A was lower than for treatment B (P=0.0004) and C (P<0.0001). There was no significant difference in the mean EPG for the calves from treatment B and C.

• Beef cattle cows suckling calves nematodes treatment Brazilian savannas.

Abstract in Portuguese:

Catto J.B., Bianchin I., Torres Junior R.A.A. 2005. [Effects of deworming of cow-calf beef herds in brazilian savannas.] Efeitos da everminação de matrizes e de bezerros lactentes em sistema de produção de bovinos de corte na região de Cerrado. Pesquisa Veterinária Brasileira 25(3):188-194. Embrapa Gado de Corte, Rodov. 162, Km 4, Campo Grande, MS 79002-950, Brazil. E-mail: catto@cnpgc.embrapa.br The effect of deworming with ivermectin of cows before calving and of suckling calves on fecal egg counts (EPG) and productive performance of two beef cattle herds in Central Brazil was studied. Four groups of pregnant cows received the following treatments: T1- cows and calves not treated, T2- only calves treated, T3- only cows treated, and T4- cows and calves treated. The calves of T2 and T4 were distributed in the following treatments: A- calves treated at 3 to 5 months of age with long action ivermectin, B- treated with ivermectin, and C- control. For the cows, the deworming did not diminish the EPG during lactation and also did not have significant effect on the conception rate, live weight gain and the body weight of their calves at 3 to 5 months of age. The calves of treatment A gained, from the time of treatment to weaning (84 to 108 days), an average of 4.2kg (P=0.0003) and 7.1kg (P<0.0001) more than those of treatment B and C, respectively. The average difference in live weight gain of 2.9kg between the animals of treatment B and C was not significant. The EPG before treatment was not significantly different from the treatments (P=0.8665); but at weaning, the average EPG of the calves from treatment A was lower than for treatment B (P=0.0004) and C (P<0.0001). There was no significant difference in the mean EPG for the calves from treatment B and C.

Abstract in English:

ABSTRACT.- Bianchin I. & Alves R.G.O. 2002. [The hornfly, Haematobia irritans: behavior and damage caused in Nellore cows and pre-weaning calves.] Mosca-dos-chifres, Haematobia irritans: comportamento e danos em vacas e bezerros Nelore antes da desmama. Pesquisa Veterinária Brasileira 22(3):109-113. Embrapa Gado de Corte, Rodovia BR 262 Km 4, Cx. Postal 154, Campo Grande, MS 79002-970, Brazil. The hornfly and tosses caused by it in Nellore cows and pre-weaning calves where studied, using two groups of 60 animals each, one group with a natural infestation and the other without hornfly, during four consecutive years. It was seen that the number of flies on the cows did not exceed an average of 80 flies/animal in all years of observation. The majority of the cows (83%) had few flies, whereas 17% had larger numbers. The calves were infested with few flies. Rainfall in excess of 100 mm during short periods diminished fly infestation. Weight gain in the cows without flies (treated with insecticides) as well as their calves was greater than in the control cows, but not statistically significant (P>0.05). Mean percentage pregnancy during the four years was 15% more in treated cows than the non-treated animals, and this difference was probably due to the infestation of the bulls.

• Hornfly Haematobia irritans cattle epidemiology contral weight gains Mosca-dos-chifres bovinos epidemiologia controle ganho de peso.

Abstract in Portuguese:

RESUMO.- Bianchin I. & Alves R.G.O. 2002. [The hornfly, Haematobia irritans: behavior and damage caused in Nellore cows and pre-weaning calves.] Mosca-dos-chifres, Haematobia irritans: comportamento e danos em vacas e bezerros Nelore antes da desmama. Pesquisa Veterinária Brasileira 22(3):109-113. Embrapa Gado de Corte, Rodovia BR 262 Km 4, Cx. Postal 154, Campo Grande, MS 79002-970, Brazil. Estudaram-se o comportamentos e os danos causados pela mosca-dos-chifres em vacas e bezerros Nelore antes da desmama. Foram utilizados dois grupos de 60 animais cada um, sendo um grupo com infestação natural de moscas e o outro sem moscas, por quatro anos consecutivos. Observou-se que o número de moscas das vacas não ultrapassou a média de 80 moscas/animal, em todos os anos experimentais. A maioria das vacas (83%) apresentou poucas moscas, enquanto a minoria (17%) teve maior quantidade. Os bezerros foram pouco infestados pelas moscas. Chuvas acima de 100 mm em curto espaço de tempo diminuíram a infestação de moscas. O ganho de peso das vacas tratadas com inseticida (sem infestação por moscas) bem como os seus bezerros foi maior do que as vacas controle, porém não foi estatisticamente significativo (P>0,05). A percentagem média de prenhez, nos quatro anos, das vacas tratadas foi 15% superior a das não tratadas e esta diferença foi causada provavelmente pela infestação de moscas nos touros.