Diagnosis of anthelmintic resistance in cattle in Brazil: a comparison of different methodologies

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Supplementation with protected fat to manage gastro-intestinal nematode infection in Santa Ines sheep

This experiment aimed to determine the influence of supplementation with protected fat on nematode infections in periparturient sheep or sheep in their final stage of pregnancy. Fifty Santa Ines ewes received 200 g of concentrate/animal/day, mineral salt and water and were grouped according to their weight, hematocrit and the number of eggs per gram of feces (EPG). Two diets were used: a control treatment and a treatment consisting of supplementation with 30 g/animal/day of protected fat in the concentrate. Three monthly evaluations were performed over a total of 84 days of testing. The variables analyzed were weight, body condition, EPG and coprocultures; blood tests were performed for the determination of packed cell volume, hemoglobin concentration and total plasma protein, and leukograms and eosinophil counts were performed. For weight and hemoglobin concentrations, interactions were observed between diet and collection date (P<0.05); body condition, total plasma protein, packed cell volume and total leukocytes did not differ statistically among treatments (P> 0. 05) but did differ by collection day (P <0.05). The EPG and eosinophil counts did not differ statistically by either diet or collection date (P>0.05). The genus Haemonchus was predominant, followed by the genera Cooperia, Trichostrongylus and Oesophagostomum. The protected fat did not decrease EPG and did not improve the blood parameters of infected sheep.

Parasitism by Oestrus ovis: Influence of sheep breed and nematode infections

Previous studies showed that Santa Ines (SI) hair sheep were more resistant to gastrointestinal nematode infections (GIN) than Ile de France (IF) sheep. The present experiment aimed to evaluate if that reported resistance difference against GIN also occurred against Oestrus ovis infestation and also to evaluate the influence of O. ovis infestation on the gastrointestinal nematodes (GIN) infections. SI (n = 12) and IF (n = 12) young male lambs were weaned at 2 months of age and moved to a paddock (0.3 ha) with Brachiaria decumbens grass, where they also received concentrate ration. The animals were kept together during the experimental period (September to early December 2009). Fecal and blood samples were taken from all animals every 2 weeks and body weight and nasal discharge score (oestrosis clinic signs) were recorded on the same occasion. In early December 2009, all lambs were sacrificed and O. ovis larvae and GIN were recovered, counted and identified according to the larval stage. All animals were infested by different larval instars of O. ovis without any statistical difference between breeds (P > 0.05). The SI lambs had an average of 24.8 larvae, and the intensity of infection ranged between 14 and 39 larvae, while the IF lambs showed an average of 23.5 larvae with the minimum and maximum from 11 to 36 larvae, respectively. SI lambs presented the lowest nematode fecal egg counts (FECs) and the lowest mean numbers of Haemonchus contort us, Trichostrongylus colubriformis and Strongyloides papillosus, however, there was no significant differences between group means (P > 0.05). Inverse relationship between numbers of O. ovis larvae and gastrointestinal nematodes was observed in both breeds. SI sheep showed a significant increase in blood eosinophils and total IgE serum levels and these variables were negatively correlated with nematode FEC. A negative correlation was observed between total IgE serum level and H. contortus burden in both breeds. In conclusion, there was no breed difference regarding O. ovis infestation and in each breed, animals with more nasal bot fly larvae tended to display smaller worm burden. (C) 2011 Elsevier B.V. All rights reserved.

How promising is Lasioseius floridensis as a control agent of Polyphagotarsonemus latus?

The blattisociid mite Lasioseius floridensis Berlese was found associated with the broad mite, Polyphagotarsonemus latus (Banks), on gerbera leaves in Mogi das Cruzes, State of Sao Paulo, Brazil. Blattisociid mites are not common on aerial plant parts, except under high air humidity levels. Some Lasioseius species have been mentioned as effective control agents of rice pest mites, but nothing is known about the biology of L. floridensis. The objective of this study was to evaluate whether the observed co-occurrence of L. floridensis and P. latus was just occasional or whether the latter could be important as food source for the former, assumed by laboratory evaluation of the ability of the predator to maintain itself, reproduce and develop on that prey. Biological parameters of L. floridensis were compared when exposed to P. latus and to other items as food. The study showed that mating is a pre-requisite for L. floridensis to oviposit and that oviposition rate was much higher on the soil nematode Rhabditella axei (Cobbold) (Rhabditidae) than on P. latus. Ovipositon on the acarid mite Tyrophagus putrescentiae (Schrank) was about the same as on P. latus, but it was nearly zero when the predator was fed the fungi Aspergillus flavus Link or Penicillium sp., or cattail (Typha sp.) pollen. Survivorship was higher in the presence of pollen and lower in the presence of A. flavus or Penicillium sp. than in the absence of those types of food. Life table parameters indicated that the predator performed much better on R. axei than on P. latus. To evaluate the potential effect of L. floridensis as predator of P. latus, complementary studies are warranted to determine the frequency of migration of L. floridensis to aerial plant parts, when predation on P. latus could occur.

Resposta de ovinos naturalmente infectados por nematoides gastrintestinais em pastos de capim-massai

The aim of this study was to evaluate the crossbred sheep Santa Ines response to natural infections by gastrointestinal nematodes in Panicum maximum cv. pastures Massai at different times of grazing. For this it was used 36 crossbred sheep Santa Inês, divided into four groups and randomly distributed in massai-grass pickets naturally infected by gastrointestinal nematodes. In the period from October 2013 to May 2014, the animals were weekly monitored for hematology tests (packed cell volume) and parasitological (egg counts per gram of feces and fecal culture) in order to monitor the level of infection of sheep and they were assessed for weight, body condition score and staining ocular mucosa by FAMACHA© method. Furthermore infective larvae was recovery from pasture in times of pre-and post-grazing pasture. At 35 kg body weight, the animals were slaughtered and necropsied to collect the contents of the abomasum and small and large intestines to recover the adult parasites, carrying out the count and identification. The animals on pasture with a height of 40 cm pre-grazing obtained low nematode eggs in feces (1608 eggs / g) and 33 cm those in pre-grazing the highest average (2,539 eggs / g). The animals in different groups showed mean values of packed cell volume less than 23% (P> 0.05). Regarding to FAMACHA, the animals belonging to the groups 40 and 50 cm pre-grazing remained over 50% of individuals between FAMACHA 1 and 2 , and those to 33 and 45 cm pre-grazing showed mostly between FAMACHA 3, 4 and 5 (69.06% and 58.93%, respectively). In the culture of larvae in feces and recovery of pasture larvae before and after grazing the following genera were found, in order of prevalence: Haemonchus, Trichostrongylus, Oesophagostomum and Strongyloides. The pasture with 33 cm of pre-grazing provided the highest number of larvae recovered both in the pre and post-grazing (1,081 and 715 L3 / 100 g of green matter, respectively). Among the different groups, the sheep had an average weight of between 23 and 26 kg and variation between the body 1 and 3 scores with scores greater frequency of 1.5 to 2.It can be observed that the animals kept at different times of grazing got different answers on the parasite load. Animals kept in 40 cm pre-grazing expressed a satisfactory answer than the other groups (33, 45 and 50 cm), best supporting the action of endoparasites. Moreover, this same height, was recovered fewer infective larvae on pasture in pre and post-grazing.

Gastrointestinal nematode infection in beef cattle raised in silvopastoral and conventional systems in São Paulo state, Brazil.

The use of silvopastoral systems (SPS) can be a good alternative to reduce the environmental impacts of livestock breeding in Brazil. Despite the advantages offered by public policies, many producers hesitate to use this system. One of the reasons is the lack of information on health and productivity of cattle raised under these conditions. The experiment reported here was designed to compare the behavior of infection by gastrointestinal nematodes and weight gain of beef cattle raised in a SPS and a conventional pasture system. We monitored the number of eggs per gram of feces, the prevalent nematode genus, data on climate, forage availability, weight gain and packed cell volume (PCV) of the animals bred in the two systems. The infection by nematodes was significantly higher in the cattle raised in the SPS (p\0.05). The coprocultures revealed the presence of nematodes of the genera Haemonchus, Cooperia, Oesophagostomum and Trichostrongylus, in both systems, but the mean infestation rates of Haemonchus and Cooperia were higher in the SPS (p\0.05). The average of PCV values did not differ between the cattle in the two systems. The individual weight gain and stocking rate in the period did not vary between the systems (p[0.05). Despite the higher prevalence of nematodes in the SPS, no negative impact was detected on the animals? weight gain and health. The results of this experiment indicate that under the conditions studied, there is no need to alter the parasite management to assure good productive performance of cattle