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A atividade pecuária no Brasil é basicamente representada pelo sistema pastoril. No entanto as adversidades edafoclimáticas promovem uma falta de uniformidade na oferta e qualidade de forragem, acarretando na maior intensificação dos sistemas de produção. A busca por alternativas de alimentação visando à melhoria no desempenho animal, tem sido objeto de muitas pesquisas, como o uso de forrageiras adaptadas a determinadas condições ambientais. Geralmente, estas plantas podem apresentar compostos que alteram a produção animal, seja positiva ou negativamente. Dentre estes compostos, destacam-se os taninos condensados (TC) que são compostos polifenólicos oriundos do metabolismo secundário das plantas. Em concentrações elevadas (6 a 12 % da matéria seca (MS)) eles reduzem a palatabilidade, o consumo, atividade enzimática, digestibilidade de proteínas e carboidratos, e consequentemente reduzem o desempenho animal. Porém, quando esse consumo é médio ou baixo (2 a 5 % da MS), permite uma eficiência na utilização da proteína dietética, formando complexos através de ligações de hidrogênio, assim, acaba protegendo a proteína da degradação ruminal, aumentando o fluxo de aminoácidos para absorção intestinal. Além de melhorar a eficiência proteica da dieta, pode-se dizer que os TC reduzem a produção de metano, e trazem benefícios no controle de parasitas gastrintestinais, melhora o desempenho reprodutivo, desenvolvimento fetal, a resposta do sistema imunológico, as concentrações séricas de hormônio, a produção de lã e lactação. O uso de plantas com baixa concentração de taninos condensados pode ser uma boa estratégia nutricional para ruminantes, desde que seu mecanismo de ação sobre o metabolismo proteico seja considerado. Esta revisão tem como objetivo, trazer algumas respostas ao uso de TC na alimentação de ruminantes, com o foco nas alterações da fisiologia digestiva do rúmen, que se torna responsável pelas consequências secundárias dos taninos sobre a produção animal.

Tropical erect grass pastures have high forage production potential in subtropical and tropical regions of the world. However, in this kind of pasture, the body weight gain of weaned lambs is usually below of their potential. We determined the effect of pasture height of an erect tropical grass, consequently its structure, on intake and performance of young lambs. The experiment was repeated in two years. Thirty young weaned lambs (4-5 months) were assigned, each year, to three Panicum maximum pasture heights: 1) Tall-75 cm; 2) Medium-50 cm and 3) Short-25 cm. Herbage mass, pasture height, plant morphological composition, pasture nutritional quality, lamb’s average daily gain, gain per hectare and herbage intake were measured. The experiment was installed in a completely randomized design, evaluated in two periods each year. The Short treatment presented, on average and for longer, the highest leaf:stem ratio (1.3 ± 0.23) and average daily gain (91 ± 10 g/day) in relation to the Medium and Tall treatments (68 ± 10 and 40 ± 13 g, respectively). There was a significant interaction between treatment*period for herbage intake. The Tall treatment showed a marked decrease in intake from the first to the second period. The pasture height management interferes in the speed at which the number of stems increases of a tropical erect grass, in relation to leaves. For a better performance of weaned young lambs during summer-autumn period, it is important to manage tropical erect grass pastures at lower height than is generally recommended, lower than 25 cm.

O objetivo do trabalho foi avaliar a eficiência dos anti-helmínticos naturais, torta de alho e torta de Neem adicionados ao sal mineral na dieta dos animais, comparado a eficiência de um anti-helmíntico químico. Foram utilizadas 56 fêmeas da raça Corriedale divididas homogeneamente em dois lotes. No dia 0 realizou-se a coleta de dados inicial dos animais compreendendo, pesagem, avaliação de escore de condição corporal (ECC) e o grau de anemia através da técnica FAMACHA, coleta de fezes para realização da contagem de ovos por grama de fezes (OPG) e coprocultura além da coleta de sangue para determinação de Hematócrito e Proteínas Plasmáticas Totais (PPT). Após, os animais foram distribuídos aleatoriamente os seguintes tratamentos, T1 – inclusão dos anti-helmínticos naturais, misturados ao sal mineral na dieta dos animais; T2 - dosificação com Closantel via oral, conforme recomendação do fabricante (1 ml para cada 10 kg/PV). Durante os 60 dias experimentais, as avaliações dos animais foram realizadas quinzenalmente com exceção da pesagem e ECC, incluídos apenas na coleta inicial e final. Não foi observada diferença estatística significativa entre os tratamentos, observando-se apenas uma diminuição do OPG, e as demais variáveis se mantendo nos níveis esperados. Pode-se afirmar que os anti-helmínticos naturais (Torta de alho e Neem), usados de forma consorciada e o anti-helmíntico químico (Closantel), não se mostraram eficazes para o combate de nematódeos gastrintestinais em ovinos.

Tropical pastures can be important natural sources of antioxidant compounds and may impact production and quality of animal protein with repercussions on human health. The objective of this study w...

Knowledge of free-living stages of endoparasite population ecology may guide their control in domesticated ruminants. Our objective was to evaluate sheep gastro-intestinal nematode (GIN) L3 distribution in tropical pasture profiles (grass and legume). Three different swards (treatments) were compared: 1) grass-only (G), 2) legume-only (L), and 3) one half of the paddock with grass and another half with legume (GL). We assessed pasture larval counts (PLC) in upper, medium and bottom strata, each representing one third of the sward height. Lamb health and performance characteristics were also evaluated. The PLC per kg of herbage dry matter (DM) tended to be 129% greater (P = 0.08) in the upper pasture profile compared to the lower stratum in GL pasture. However, the largest PLC dispersed per area (PLC/m²) was found (P

The present study assessed the influence of the type of the tropical pastures on lamb body weight (BW) gain and meat quality. Fifty-four lambs were allocated to three grazing pastures: (1) AG — Aruana grass (Panicum maximum cv. IZ-5); (2) PP — pigeon pea legume (Cajanus cajan cv. Anão); and (3) CS — contiguous swards, half of the paddock with AG and half with PP. After 92 days of grazing, the lambs were slaughtered. Carcasses were evaluated and the longissimus muscle was collected to determine color, lipid profile, tocopherol concentrations, and lipid oxidation. Although the pastures present differences in the characteristics of nutritional quality, the animals did not show difference in BW gain. The results show that all forage presented similar concentration of alpha-tocopherol (137 ± 14.37 mg kg-1 of fresh matter), whereas total and condensed tannin contents were greater in PP, intermediate in CS, and the lowest in AG treatment (P = 0.0001). Meat a-tocopherol content was similar among treatments (P = 0.1392), with an average concentration close to the optimal level to reduce the meat oxidation. Meat from AG treatment had 45 and 25% lower n-6/n-3 ratio than meat from PP and CS treatments, respectively. The legume increases the unsaturated fatty acids and the grass can reduce the n6/n3 ratio. The level of condensed tannin concentration did show to have important effect on meat characteristics. Both tropical pastures studied can provide a high amount of alpha-tocopherol, generating a great potential to increase the concentration of this antioxidant in lamb’s meat. © 2021, The Author(s), under exclusive licence to Springer Nature B.V.

The efficiency of grazing ruminant production systems is directly associated to the animals' ingestive behavior, and to structural characteristics of the pastures. The objective of this study was to evaluate the ingestive behavior of young lambs grazing three different heights of Capim Aruana (Panicum maximum). The experiment was carried out in two consecutive years, in which 30 tester lambs (4–5 months old) were equally divided into three paddocks (treatments) corresponding to different average sward heights of Aruana grass: (1) Tall-75 cm; (2) Medium-50 cm; and (3) Short-25 cm in a randomized block design. Ingestive behavior assessments were carried out every 28 days through 10-min observations of the main activities of the animals (grazing, ruminating, idling) and biting rate, from sunrise to sunset. In addition, the productive and qualitative characteristics of the pastures were assessed. Despite differences in pasture structure, grazing time (GT) and idling time were similar among treatments (P = 0.4266 and P = 0.2939, respectively). The shortest ruminating time (RT, P = 0.0181) was recorded in the treatment of lowest sward height. Lambs grazing on this treatment also showed 23% more bites per minute (P= < 0.0001) than animals in the Tall and Medium treatments. A Decision Tree analysis was performed for GT, identifying in a hierarchical order that the initial weight of the animals and sward height explained 62% (R2 = 0.621) of the variation, representing the variables with the greatest influence on GT. Initial body weight explained 48% of the model. Thus, our research shows that the different sward heights of Capim Aruana mainly alter the lamb's RT and biting rate, and that the animals' initial body weight is a key factor influencing GT, given that this variable makes lambs more susceptible to changes in sward height.

Nutritional requirements at the end of gestation in ewes carrying multiple fetuses are rarely fully met in pasture production systems. Thus, concentrate feeds entail an alternative for increasing herd productivity. However, daily offer of complementary feed in extensive livestock production systems is not always possible due to climatic or geographic constraints or to labor shortages. One alternative is to offer large amounts of concentrate feed with the addition of NaCl that limits voluntary consumption, eliminating the need for daily supplement delivery. Our objective was to evaluate the effect of high salt levels added to concentrate feed on pre- and post-lambing twin-gestating ewes and their responses on feed intake, colostrum and milk production and composition, plasma biochemical profile variation and lamb growth. Twenty-four adult Corriedale females were housed in individual stalls and divided into four treatments: S13: ad libitum concentrate feed plus 13 % of salt; C13: the same amount of concentrate feed consumed by S13 ewes the day before, but without salt; S17: ad libitum concentrate feed with 17 % of salt, and C17: the same amount of concentrate feed consumed by S17 ewes the day before, but without salt. Fresh water and forage were offered in ad libitum amounts. Treatments were applied in the period of highest ewe nutrient demand, from day 123 of pregnancy to day 21 of lactation. The four percentage points in salt content resulted in a decrease of organic matter daily intake of concentrate (23 % of reduction in pre-lambing and 35 % of reduction in post-lambing for S17 relative to S13; P = 0.0134 and P = 0.0164, respectively). Lamb birth weights were similar between S13 and C13 (P = 0.1002) and between S17 and C17 (P = 0.8449) treatments. Colostrum and milk production did not differ between S13 and C13 (P = 0.9776 and P = 0.8928, respectively) or between S17 and C17 groups (P = 0.4943 and P = 0.7705, respectively). Plasma insulin, hematocrit and total protein levels were not influenced by the treatments and these parameters remained within normal physiological limits. Thus, the addition of 13 or 17 % of salt to concentrate feed did not affect the reproductive capacity of ewes or offspring growth, showing that ewes are able to withstand high doses of NaCl and supporting the potential of salt as a limiter of voluntary intake in pre- and post-lambing diets.

Tropical pasture canopy characteristics can alter lamb ingestive behavior. Our study evaluated the ingestive behavior of young lambs in different tropical pastures to identify which variables interfere in their grazing activity. Two years of study were carried out with 54 weaned lambs distributed in three different pasture canopies: 1) monoculture of an upright grass, guinea grass (Panicum maximum; GG); 2) monoculture of a shrubby legume pigeon pea (Cajanus cajan; PP) and 3) contiguous paddock with half GG and half PP (GP). The experiment was set out in a randomized complete block design (3 blocks). Lamb ingestive behavior was observed from sunrise to sunset with records every 5 minutes. To identify the main variables that affected lamb grazing activity, a multivariate analysis of the Decision Tree was performed. Our results showed that there was no difference in the ingestive behavior parameters of young lambs in different canopies (P > 0.05). There was interaction among the canopies and the experimental periods for the variables idleness time and biting rate (P ≤ 0.05). Lambs in all canopies showed more idleness time in the first evaluation period. Lambs in canopies containing grass (GG and GP) exhibited greater bites per minute throughout the experimental period. Lamb grazing time increased 40% as experimental period progressed and plants matured. The Decision Tree identified leaf:stem ratio as the variable that most influenced lamb grazing time in GG and GP canopies while in the PP, grazing time was directly related to canopy height. The behavior of young lambs on tropical pasture is variable as there is a change in the behavioral response to canopy characteristics over time. In addition, the grazing time of these animals can be estimated by means of variables related to canopy structural characteristics (leaf:stem ratio and height) together with chemical variables.

This study examined tropical pasture contamination dynamics under different feeding systems for finishing lambs. The experiment aimed to evaluate the vertical distribution of gastrointestinal helminth infective larvae (L3) in erect grass subjected to grazing and to assess the parasite load and its impact on lamb performance in three production systems. Three treatments based on Aruana grass (Panicum maximum cv. IZ-5) were as follows: T1, grass only; T2, grass with 1.5% of body weight (BW) nutrient concentrate supplementation; and T3, grass with 2.5% BW concentrate supplementation. The randomized block design had three replicates of three treatments, with six lambs per replicate. L3 were recovered from three pasture strata (upper, middle, and bottom), each representing one third of the sward height, and correlated with microclimatic data. Significant differences (P 0.05) were observed among treatments in the L3 recovery. Despite different grass heights between treatments and microclimates within the sward, the L3 concentration generally did not differ significantly among the three strata within a treatment (P 0.05). Pasture microclimate did not correlate with larval recovery. At the end of the experiment, the animal fecal egg count was similar among treatments (P 0.05). The results indicated that different lamb feeding systems in a tropical erect grassland caused differences in grass height but did not affect the distribution of infective larvae among strata. Larvae were found from the base to the top of the grass sward.

O trabalho foi desenvolvido entre os meses de marco e junho, em uma propriedade particular de um membro da Associacao de Criadores de Ovinos de Dom Pedrito (ACODOPE). Foram avaliados 60 cordeiros todos machos castrados, dente de leite com 5 a 7 meses de idade. Destes 50 animais da raca Corriedale e 10 da raca Texel. Buscou-se no decorrer do experimento avaliar o custo de implantacao de um sistema de confinamento e sua lucratividade. A pesagem realizada na entrada dos animais ao confinamento serviu para ser feito o controle de custo da producao relacionado a quantidade de racao fornecida aos animais, possibilitando atraves disso saber exatamente quantos quilos de racao foram necessarios para cada animal atingir o peso de abate. Para atingir os resultados exatos da producao, foram avaliados e representados todos os custeios de implantacao e funcionamento do confinamento como: Despesas gerais, Custos Fixos, Custos Variaveis; Custos dos animais ate a entrada ao confinamento; Custos com instalacoes e manutencao dos animais. Foi observado que o os animais do lote Texel permaneceram menos tempo para atingir o peso de abate, consequentemente o custo de producao dos mesmos foi inferior aos demais. Mesmo assim apresentaram um prejuizo de R$ 0,85 por kg de peso vivo. Resultados negativos foram encontrados no outro dois lotes, sendo que o lote com aplicacao de Fosforo Orgânico associado a Vitamina B12 (FOB12) apresentou um prejuizo de R$ 1,66 por kg de peso vivo, e o lote dos animais sem aplicacao de FOB12, R$ 1,44 por kg de peso vivo. Tais resultados tornaram o sistema de terminacao de cordeiros em confinamento, testado nesta experimentacao, inviavel economicamente.

The aim of this study was to evaluate the effects of concentrate supplementation on the performance and ingestive behaviour of lambs grazing tropical grasslands of Panicum maximum cv. IZ-5 and its effect on pasture characteristics. Different levels of daily supplementation with concentrate were compared: no supplementation; or supplemented at 1.5% and 2.5% of lamb liveweight. The grazing simulation technique was used for qualitative assessment of the pasture every 28 days. Herbage mass, pasture growth rate, sward height as well as botanical and morphological composition of the pasture were evaluated. Average daily gain, gain per hectare and ingestive behaviour were measured on the lambs. The forage supply was 4% of green leaves (4 kg dry matter per 100 kg of liveweight) in all treatments. Six 3–4-month-old Texel and Corriedale lambs were used per paddock. The design was a randomised block design with three replications. Concentrate supplementation had a direct effect on pasture structure, especially height (significant interaction treatment vs period – P = 0.0373). In the treatment without supplementation, the animals grazed for a longer period than the others. Idle time was higher in the treatment with the highest level of supplementation, and rumination time was similar among the treatments. Supplementation with 2.5% significantly increased the average daily gain (0.143 g vs 0.026 g for no supplementation) and gain per hectare (30 kg vs 258 kg for no supplementation vs supplementation at 2.5% of lamb liveweight, respectively). The results show the potential increase in production and productivity with the use of concentrate supplementation at 2.5% lamb bodyweight. Notwithstanding the increase in production, supplementation with concentrate provided a strong negative impact on pasture structure and behaviour of animals that should be considered when using concentrate supplementation for finishing lambs in tropical regions.