Reproductive, productive and financial consequences of chronic Trypanosoma vivax infection in a dairy cattle herd in a region without a cyclic vector.

This study evaluated the reproductive, productive and financial consequences of chronic Trypanosoma vivax infection in a dairy cattle herd located in a region without the cyclic vector during two years. Animals were categorized as either positive (chronically infected) or negative for T. vivax antibodies using a commercial rapid test. Additionally, serum samples from cows were analyzed for the presence of anti-Neospora caninum antibodies. Pregnancy diagnoses were performed through rectal palpation and ultrasonography after 30, 60 and every 21 days until the 144th day of pregnancy. If an abortion occurred in the final trimester, serology and cPCR were performed on calves for T. vivax and N. caninum. The breeding period, calving interval and pregnancy losses were recorded. The milk production of each animal during the 305 days of lactation was measured, and the annual financial impact of milk production was calculated using a revenue minus feed cost (RMFC) indicator. Out of 177 cows, 71.75 % were chronically infected, and 13.50 % were T. vivax-negative. No correlation (p = 0.8854) of co-infection between T. vivax and N. caninum was observed. Negative cows required fewer (p≤0.05) artificial inseminations than chronically infected ones. T. vivax was not significantly associated (p = 0.7893) with pregnancy loss up to 81 days of pregnancy. Cows chronically infected by T. vivax had 4-fold greater chance (p = 0.0280) of experiencing pregnancy loss between 82 and 144 days of gestation. Eighteen cows aborted, two were positive for T. vivax antibodies, and one for N. caninum antibodies. The calves were negative for T. vivax and N. caninum. Chronically infected cows and negative cows for T. vivax that experienced pregnancy loss (82-144 days of pregnancy) had a longer (p≤0.05) breeding period to become pregnant, and consequently a longer calving interval compared to cows that maintained pregnancy. The difference (p≤0.05) in milk production was evident when pregnancy loss occurred between 82 and 144 days of gestation in cows chronically infected by T. vivax. The RMFC indicated a negative impact of 38.2 % on the farm's annual milk revenue due to the presence of chronically infected cows.

Gastrointestinal nematode control programs in yearling Nellore heifers: Analysis of fecal egg counts, weight gain and reproductive indices.

The objective of this study was to evaluate two different gastrointestinal nematode treatment regimens. Fecal egg counts (FECs), proportion of nematode genera, weight gain, body condition score and reproductive indices (estrous cyclicity, conception and pregnancy rates) were evaluated in yearling heifers after imposing two treatment regimens for gastrointestinal nematodes: T1 = 306 calves treated in May and November with 3.5 % doramectin (700 µg/kg) and August (Aug) with saline solution; and T2 = 307 calves treated in May with 3.5 % doramectin (700 µg/kg), in August with 1% moxidectin (200 µg/kg) and in November with 3.5 % doramectin (700 µg/kg). The animals were weighed, and feces were collected for conducting FECs and coproculture. There was imposing of three fixed-time artificial inseminations (TAIs), and estrous cyclic and pregnancy statuses were determined. Cooperia was the most frequent genus detected in both groups. Heifers of the T2, as compared to those in the T1 group, had fewer FECs in November (P ≤  0.05) and greater weight gain and average daily weight gain (P ≤  0.05) from August to November. There tended to be more heifers of the T2 than T1 group estrous cycling (P =  0.07) at the beginning of the breeding season as well as greater pregnancy rates (P =  0.03) and conception rates (P =  0.03) as a result of the second FTAI. The results indicate there is greater reproduction outcomes as a result of strategic control of gastrointestinal nematodes in yearling Nellore heifers using the T1 as compared with T2 treatment regimen.

Occurrences of Oestrus ovis parasitism in necropsied sheep in the Umuarama microregion, Paraná, Brazil.

Between January 2007 and September 2013, 71 sheep belonging to 12 farms in the Umuarama microregion, State of Paraná, were evaluated regarding presence of Oestrus ovis larvae, during necropsies. The farms from which these animals originated were visited and the owners and employees were interviewed. Occurrences of O. ovis parasitism in sheep were diagnosed for the first time on this microregion. Of the 71 animals, 12 (16.9%) were parasitized by O. ovis, with mean intensity of 2.25 larvae per infested head (1 to 8 larvae/infested head). There was a high correlation (0.81, p=0.0346) between the number of larvae and the macroscopic lesions observed in these animals' nasal cavities, such that sheep with more than 3 larvae may contain mucupurulent secretions or epistaxis. From the interviews conducted, it was found that all the farm owners were applying chemical parasite control methods (helminths and/or O. ovis), administered to all animals in the herds every 30 days (91.6% of the producers), using derivatives of macrocyclic lactones and/or benzimidazoles/imidazothiazoles. Further studies need to be conducted in this particular region, in an attempt to elucidate the prevalence of O. ovis parasitism in herds.

Susceptibility of Rhipicephalus (Boophilus) microplus to ivermectin (200, 500 and 630 µg/kg) in field studies in Brazil.

The present study aimed to determine the susceptibility of 17 Rhipicephalus (Boophilus) microplus populations, originating in the Southeast and Southern regions of Brazil, to different ivermectin concentrations (200, 500 and 630 µg/kg), administered through subcutaneous or topical (pour-on) routes. R. (B.) microplus populations from the states of Minas Gerais (seven populations), São Paulo (seven populations) and Paraná (three populations) were chosen for the tests. The selected cattle were allocated to treatment groups on day 0, and block formation was based on the arithmetic mean of female ticks (4.5-8.0 mm long) counted on three consecutive days (-3, -2 and -1). To evaluate the therapeutic and residual efficacies of these formulations, tick counts (females ranging from 4.5 to 8.0 mm long) were performed on days 3, 7 and 14 post-treatment, and continued on a weekly basis thereafter until the end of each experiment. The results obtained throughout this study, utilizing field efficacy studies, allowed us to conclude that the resistance of R. (B.) microplus against 200 and 500 µg/kg ivermectin is widely disseminated because all tick populations that had contact with these specific concentrations were diagnosed as resistant. However, it is possible to infer that R. (B.) microplus resistance against 630 µg/kg ivermectin was also widespread, diagnosed at six of ten analyzed properties. Resistance of these ectoparasites to 630 µg/kg ivermectin is most likely emerging in three other populations of R. (B.) microplus. Strategies of resistance management need to be quickly determined to keep the selection pressure at a minimum level in Brazil.

Comportamento de éguas após a inserção de dispositivo intravaginal impregnado com progesterona / Behavior of mares after insertion of intravaginal progesterone device / Comportamiento en yeguas después de la inserción del dispositivo intravaginal impregnado con progesterona

Considerando a escassez de estudos sobre o temperamento ou reatividade de equinos, objetivou-se com esse estudo avaliar o comportamento de éguas após a inserção do implante intravaginal de progesterona, para utilização em bovinos, por meio da observação de comportamentos individuais e coletivos. Para tanto, utilizou-se sete éguas que receberam dispositivo intravaginal impregnado com progesterona e agente luteolítico. Após a colocação dos implantes e soltura das éguas, se iniciou a observação (cinco observadores sem contato entre eles) de seus comportamentos até o tempo de 120 minutos, seguindo o modelo proposto por Heleski et al. (2002). Os resultados indicaram que durante os 120 minutos de observação todas as éguas demonstraram estar alertas, pelo menos em uma observação; que o ato de comer foi observado em todos os animais durante o período estudado e que o ato de urinar e defecar foram observados, em aproximadamente, 70 e 60%, respectivamente, dos comportamentos avaliados. Comportamentos prováveis da indicação de dor e/ou desconforto, como bater da cauda, mímica de urinar, eversão do clitóris e urinando foram observados até 65 minutos, sendo que os três primeiros cessaram aos 55 minutos. De todos os comportamentos analisados, nenhum deles foi visualizado após 65 minutos de observação. Concluiu-se que a inserção do dispositivo intravaginal impregnado com progesterona não afeta negativamente o comportamento de éguas, podendo ser utilizado sem comprometer o bem-estar desses animais.

Considering the scarcity of studies on the behavior or reactivity of horses, this study aimed to assess the behavior of mares after insertion of intravaginal progesterone implant for use in cattle, through the observation of individual and collective behavior. In order to do so, seven mares received intravaginal devices impregnated with progesterone and luteolitic agent. After the implant was placed, the mares were released, and their behavior was observed (five observers with no contact between them) for a period of 120 minutes, following the model proposed by Heleski et al. (2002). The results indicated that during the 120-minute period, all mares were alert, in at least one observation; that all animals ate during the study period, and urination and defecation were observed in approximately 70 and 60%, respectively, of the assessed behavior. Behaviors that were likely an indication of pain and/or discomfort, like hitting the tail, miming to urinate, eversion of the clitoris and urinating were observed in up to 65 minutes, with the first three symptoms ceasing after 55 minutes. None of the analyzed behaviors were viewed after 65 minutes of observation. It can be concluded that the insertion of the intravaginal device impregnated with progesterone does not adversely affect the behavior of mares, and therefore, it can be used without compromising the well-being of the animals.

Teniendo en cuenta la escasez de estudios sobre el temperamento o la reactividad de equinos, este estudio buscó evaluar el comportamiento de yeguas después de la inserción del implante de progesterona intravaginal, para su uso en ganado, a través de observación de conductas individuales y colectivas. Para ello, se utilizó siete yeguas que recibieron dispositivo intravaginal impregnado con progesterona y agente luteolítico. Después de los implantes y la liberación de las yeguas, comenzó la observación (cinco observadores sin contacto entre ellos) de sus comportamientos hasta el tiempo de 120 minutos, siguiendo el modelo propuesto por Heleski et al. (2002). Los resultados indicaron que durante los 120 minutos de observación todas las yeguas demostraron estar alertas, por lo menos en una observación; el acto de comer se observó en todos los animales durante el periodo de estudio y que el acto de la micción y la defecación, en aproximadamente, 70 y 60%, respectivamente, de los comportamientos evaluados. Comportamientos probables de indicación de dolor y/o malestar, como golpear la cola, la mímica de orinar, eversión del clítoris y orinando, observados hasta 65 minutos, siendo que los tres primeros cesaron después de 55 minutos. De todos los comportamientos analizados, ninguno de ellos se visualizó después de la observación de 65 minutos. Se concluyó que la inserción del dispositivo intravaginal impregnado con progesterona no afecta negativamente el comportamiento de yeguas, que puede ser utilizado sin comprometer el bienestar de esos animales.

Occurrences of Oestrus ovis parasitism in necropsied sheep in the Umuarama microregion, Paraná, Brazil / Ocorrência de parasitismo por Oestrus ovis em ovinos necropsiados da microrregião de Umuarama - Paraná, Brasil

Between January 2007 and September 2013, 71 sheep belonging to 12 farms in the Umuarama microregion, State of Paraná, were evaluated regarding presence of Oestrus ovis larvae, during necropsies. The farms from which these animals originated were visited and the owners and employees were interviewed. Occurrences of O. ovis parasitism in sheep were diagnosed for the first time on this microregion. Of the 71 animals, 12 (16.9%) were parasitized by O. ovis, with mean intensity of 2.25 larvae per infested head (1 to 8 larvae/infested head). There was a high correlation (0.81, p=0.0346) between the number of larvae and the macroscopic lesions observed in these animals nasal cavities, such that sheep with more than 3 larvae may contain mucupurulent secretions or epistaxis. From the interviews conducted, it was found that all the farm owners were applying chemical parasite control methods (helminths and/or O. ovis), administered to all animals in the herds every 30 days (91.6% of the producers), using derivatives of macrocyclic lactones and/or benzimidazoles/imidazothiazoles. Further studies need to be conducted in this particular region, in an attempt to elucidate the prevalence of O. ovis parasitism in herds.

De janeiro de 2007 a setembro de 2013, foram avaliados, durante a necropsia, 71 ovinos pertencentes a 12 propriedades rurais da microrregião de Umuarama, Paraná, Brasil, quanto à presença de larvas de Oestrus ovis. Entre outubro e dezembro de 2013, as 12 propriedades de onde os animais eram provenientes foram visitadas, e os proprietários e funcionários foram entrevistados. A ocorrência do parasitismo por O. ovis em ovinos foi constatada pela primeira vez em propriedades rurais da microrregião de Umuarama, Estado do Paraná. Dos 71 animais, 12 (16,9%) estavam parasitados por O. ovis, com intensidade média de parasitismo de 2,25 larvas por cabeça infestada (1 a 8 larvas). Foi possível verificar correlação elevada (0,81, p=0,0346) apenas entre o número de larvas versus lesões macroscópicas observadas na cavidade nasal desses animais, de modo que ovinos com mais de 3 larvas continham secreção mucopurulenta ou epistaxe na cavidade. Quando da entrevista constatou-se que todos os proprietários fazem controle químico contra parasitas (helmintos e/ou O. ovis) e esse. controle é feito a cada 30 dias por 91,6% dos produtores, que utilizam derivados de lactonas macrocíclicas e/ou benzimidazóis/imidatiazóis. Futuros estudos ainda precisam ser realizados nesta região, na tentativa de elucidar a prevalência de parasitismo por O. ovis nos rebanhos.