The study found ideal levels for the intake of metabolizable proteins – those that are absorbed by the animal organism. The use of diets with 58% of concentrates, following the dietary formulas developed by the study, ensures increased resilience to parasitic infections. The study demonstrated that there is no need for an excessive use of protein concentrates, which are more expensive. The results open prospects for partnerships with the production sector for the joint development of animal feed, food additives and specific supplements for given animal categories. An adequate diet can reduce the need for vermifuges and make animal farming more sustainable. A research conducted by Embrapa demonstrates that with adjustments to the food ratios in their diets, sheep infected with verminosis can have performance indicators like weight gain and carcass characteristics that are similar to healthy animals. With different nutritional management practices that balanced foods that are sources of the two main groups of dietary nutrients, protein and energy, the lambs of the experiment even manifested a lower presence of parasites. The result demonstrates higher capacity to resist to parasitic infection through metabolic compensations and thus maintain production indicators, that is, an adequate diet promotes resilience to verminosis. According to the researcher Marcos Cláudio Rogério, from the area of Animal Nutrition at Embrapa Goats and Sheep, the experiment points to a novelty: what improved animal resilience was not simply a higher input of food sources of protein, but rather finding an ideal level of the so-called metabolizable proteins (those that are actually absorbable by the animal organism) in their diet. This adjustment entails balancing not only protein-rich food, but also the energy ones, because the latter supply energy for the synthesis of microbial protein, which happens in the animals’ digestive tracts. “It was believed that increased resilience to parasitic infections due adequate animal nutrition simply lay in increasing protein input in the diets for the small ruminants. This works well to a certain extent. Because if we indefinitely added protein concentrates, the excess would be eliminated in the faeces and not used. Furthermore, simply increasing the levels of raw protein does not ensure the absorption of these proteins and their amino acids, which can be indigestible”, Rogério, who leads the team responsible for the research, observes. The research In the experiment, 40 male lambs were used and divided into groups, and some were artificially infected by Haemoncchus contortus, a gastrointestinal parasite which is one of the main causative agents of verminosis in goats and sheep. Once divided into groups, they received diets with different ratios of roughage (energy sources) and concentrates (protein sources). Upon the inclusion of 35% of concentrate (65% of roughage ratio in the diet), there was a reduction of more than 65% in the egg count per gram of faeces (EPG, eggs per gram) of infected animals, and a reduction of more than 63% of the quantity of Haemonchus contortus present in the abomasum, a structure in the ruminant’s stomach. The EPG is an indicator that shows the degree of parasitic infection. According to the evaluated diets, food conversion values that were similar to those verified for non-infected animals receiving the same ratio of concentrates were also verified in infected ones that consumed between 58% and 69% of concentrates. In the infected lambs that received a diet with the proportional formulation of 69% of concentrate and 31% of roughage, for example, there was an average weight gain of 261 grams (g), a return that was very similar to those of non-infected animals that, with the same diet, presented an average weight gain of 265 g/day. The final body score for the animals following the diet with this composition was the same for both infected and non-infected animals: 3 (see the table below). Lambs with the diet formulation of 69% concentrates and 31% roughage Infected lambs Non-infected lambs Average weight gain 261 grams/day 265 grams/day Body condition score 3.00 3.00 “The use of diets with 58% of concentrate following the dietary formulation developed with the research, for example, grants the increase in resilience to parasitic infections. It does not need to use diets with high concentrate ratios to reach this objective and does not need an excessive quantity of protein concentrates, which are expensive. The important thing is the dietary adjustment aiming at the increase in metabolizable protein supply”, Rogério explains. According to him, the results open a new perspective: to establish partnerships with the production sector for the joint development of animal feed, food additives and specific supplements for given categories of animal – such as offspring, confined animals, and lactating females – according to their nutritional needs. This increase in the resilience to infections can also collaborate to the sustainability of production systems, reducing the dependence on vermifuges to minimise production losses due to verminoses. In the assessment of the zootechnician Rafaela Miranda, who researched the issue in her PhD thesis in Tropical Animal Science at the Federal University of Tocantins (UFT, acronym in Portuguese), the studies that investigate the relationship between the nutritional components and verminosis reduction have the potential for more economically viable farming. “These studies can contribute to increased flock productivity, reduced mortality, and reduced age on slaughter. Thus they produce young animals with better carcass characteristics, " Rafaela affirms. For the zootechnician, who works as a consultant in the company Granforte Nutrição Animal, a scientific advance in this area can favour the coming of new products for sheep diets and also alternatives of nutritional management for breeders. “The products can result in higher animal productivity and guide breeders on the choice of diets and adequate nutritional plans according to their reality, thus making mutton production viable in Brasil”. Resilience and sustainability in production Upon the study results, it is possible to think about alternatives that, by promoting a better resilience to verminosis, also ensure better economic and environmental sustainability of the sheep production systems. Verminosis is considered one of the infirmities with higher impact on economic and production losses, causing mortality to animals and financial damages to the quality of sheep farming products, and hence difficulties to consolidate the activity in light of market demands. Moreover, the indiscriminate use of vermifuge produces chemical waste in the products and the environment; it can also generate problems of parasite resistance to the drugs. These nutritional strategies can be interesting both for breeding in confinement, allowing better planning in food purchases and animal sales, and for breeding in pastures, as factors like high humidity, high concentration of animals and unavailability of nutrients can harm the animals’ immunological response to verminosis. “More and more thought has been given to production systems that are environmentally sustainable and even organic. Using diets that increase the animals’ resilience to parasitic infections reduces dependence on anthelmintics for parasitic control. Therefore, there will be no need to administer vermifuges or at least there will be a considerable reduction to their use. There will be also a reduction in labour costs for sanitary management. Another aspect is avoiding helminth resistance to the pharmacological principles that compose the anthelmintics”, Luiz Vieira, Embrapa’s researcher who also integrated the research team, details. Meanwhile Rogério reinforces that the nutrient supply in quantity and quality is the path to be followed to strengthen this strategy. “The animals will keep presenting adequate production indexes in more harmonious coexistence with the helminths. The main point of the research is not to [fully] eliminate the helminths, but rather to stop their presence from making production indicators go down”, the scientist emphasizes. Nutrition as part of integrated control The possibility of nutritional management that results in higher resilience against verminosis in goats and sheep does not exclude the importance of an adequate deworming strategy and sanitary management to minimise illness harm. Animal nutrition, in fact, is one of the pillars of integrated strategy control of verminosis, recommended by Embrapa for the goat and sheep flocks. The vermifuges, in association with diets that offer ideal nutrients for an adequate immune response to parasitism, can also be a sustainable alternative for the maintenance of production performance of the flocks. Beyond animal nutrition, the integrated control strategy brings recommendations about pasture management, installations care, food supplies, and animal division in stalls and pickets. All of this adds to the optimised use of the vermifuges, with attention to the right selection of the animals for deworming (according to the flock’s production category) and of the medicines, according to the active ingredient. These recommendations diminish the possibility of the parasites creating resistance against the action of the use of medicines. The Paratec web portal brings the main recommendations for the integrated control of verminoses in goats and sheep, according to the main Brazilian biomes. To consult the information, just click here. To better understand the finding: - Sheep have “roughage” and “concentrates” as their main nutritional sources . The roughage has a high content of fibre and comprises natural and cultivated pastures, as well as silage, hay and crop remains. The concentrates have a low content of water and fibre and can have high concentrations of energy and/or protein. - The main roughage used in sheep farming in the Brazilian semi-arid region include grasses such as Buffel grass and Tifton grass, besides other plants such as Opuntia cactus, Leucaena, jamacaru, pigeon pea, millet or sorghum. They are foods that can constitute a food reserve for the dry season, in the form of hay or silage. - The food concentrates that are most used for sheep in the Brazilian semi-arid are soybean bran; corn, millet and sorghum grains; and cotton and castor meal. - In the research that investigated the relationship between diets and resilience to verminosis in sheep, the diet supplied to the animals was composed of Tifton hay as roughage, and corn and soybean bran as concentrates, in addition to plant oil and limestone. - According to the researcher Marcos Cláudio Rogério, there are many diet possibilities according to production system goals, but the general rule respects the inclusion of quality food: when considering proteins or foods that can lead to interesting protein addition, one should prioritize foods that have proteins of high biological value and high digestibility.