Gilmar Roberto Meinerz

Óleo de citronela no controle do carrapato de bovinos

This research was aimed at evaluating in vitro and in vivo effects of citronella (Cymbopogon nardus (L.) Rendle) oil on catle ticks. The volatile oil was obtained from de fresh leaves of citronella grass by steam destilation and the yelds was 0.7%. Seven (0; 0.5; 1.0; 10.0; 25.0; 50.0; 100.0%) and nine (0.1; 0.25; 0.5; 1.0; 2.0; 10.0; 25.0; 50.0; 100.0%) concentrations of citonella oil were used on in vitro trials with engorged female ticks. The efficacy control ticks was 0; 44.2; 92.1; 85.6; 87.8; 87.0; 88.9 and 0; 0.7; 2.8; 51.6; 79.3; 81.0; 87.1; 86.7 89.5 %, respectively. These sugest that the citronella oil can be practical used for controlling of catle ticks.

Eficácia do óleo de citronela [Cymbopogon nardus (L.) Rendle] no controle de ectoparasitas de bovinos

This study aimed to evaluate the in vivo effect of citronella oil on the control of bovine ticks [Rhipicephalus (Boophilus) microplus], horn flies (Haematobia irritans), stable flies (Stomoxys calcitrans) and houseflies (Musca domestica). Fifteen Holstein cows were allocated to three groups of five animals each. The treatments were: negative control, amitraz at 0.025% and citronella oil at 4%. Engorged female ticks and flies were counted before (mean of days -3, -2, -1) and at 7, 14, 21 and 28 days after treatment; blood samples were also collected. Within 28 days, amitraz and the phytotherapic agent had to be reapplied to control tick infestation. The relationship among the number of applications was 1:2.5 for amitraz and citronella oil, respectively. The efficacy of tick control was, on average, 71.8 and 30.9% for amitraz and citronella oil at 4% respectively, post-treatment. Lower control of flies was observed for the phytotherapic group. There was no difference among treatments for blood parameters.

Produtividade e valor nutritivo de pasto de capim-elefante manejado sob princípios agroecológicos

Objetivou-se avaliar o valor nutritivo do capim-elefante, quanto aos teores de PB e FDN e a digestibilidade in vitro da MS (DIVMS), submetido a algumas praticas agroecologicas. Foram usados dois piquetes (0,15 ha cada), onde foi estabelecido o capim-elefante, em 2001, com espacamento entrelinhas de tres metros. Nas entrelinhas, estabeleceram-se aveia (Avena strigosa Schreb.) e azevem (Lolium multiflorum Lam.) no periodo hibernal e, no estival, permitiu-se o desenvolvimento de especies de crescimento espontâneo. A adubacao foi feita com fertilizantes orgânicos (150 kg de N /ha). No periodo experimental (24/04/2004 a 05/05/2005), foram conduzidos sete pastejos. Os animais experimentais foram vacas da raca Holandesa que receberam, como complementacao alimentar, 3,5 kg/dia de concentrado. Avaliaram-se a massa de forragem inicial, composicao botânica do pasto e os componentes estruturais. Para as analises de valor nutritivo do pasto, foram feitas amostragens simulando o pastejo. O delineamento experimental foi de blocos ao acaso com duas repeticoes (piquetes) e sete tratamentos (pastejos). Os melhores resultados do valor nutritivo foram obtidos no periodo hibernal. Foram encontradas correlacoes negativas da PB e DIVMS e positivas da FDN com a biomassa de lâminas foliares do capim-elefante. O capim-elefante, manejado sob principios agroecologicos, apresentou alto valor nutritivo e produtividade, tanto no verao quanto no inverno, possibilitando que a producao animal seja mais sustentavel no decorrer do ano.

Extrato aquoso de fumo em corda no controle do carrapato de bovinos

This study aimed to evaluate the effectiveness of severals concentrations of rope tobacco against the tick (Boophilus microplus) naturally infested on Rolstein dairy cattle. The treatments used were Amitraz at 0.025%; rope tobacco aqueous extract (RT) at 1.25% + neutral detergent at 0.5% (tree aspersions, with interval of 24 hours among them), RT at 1.75% + withewash at 0.5% (tree aspersions); RT at 5.0% + withewash at 2.0% (tree aspersions); RT at 3.75% + neutral detergent at 0.5% (one aspersion) and the control group. Engorged ticks were evaluate with length superior to 4.0 mm, before and at 1st, 2nd, 3rd, 4th, 5th, 6th, 7th and 14th day after treatment. The mean efficacy was 100.0; 77.5; 22.0; 63.8; 25.3 and 0.0%, respectively. Differences (P<0.05) among treatments with chemical product and rope tobacco formulations were observed.This study aimed to evaluate the effectiveness of severals concentrations of rope tobacco against the tick (Boophilus microplus) naturally infested on Rolstein dairy cattle. The treatments used were Amitraz at 0.025%; rope tobacco aqueous extract (RT) at 1.25% + neutral detergent at 0.5% (tree aspersions, with interval of 24 hours among them), RT at 1.75% + withewash at 0.5% (tree aspersions); RT at 5.0% + withewash at 2.0% (tree aspersions); RT at 3.75% + neutral detergent at 0.5% (one aspersion) and the control group. Engorged ticks were evaluate with length superior to 4.0 mm, before and at 1st, 2nd, 3rd, 4th, 5th, 6th, 7th and 14th day after treatment. The mean efficacy was 100.0; 77.5; 22.0; 63.8; 25.3 and 0.0%, respectively. Differences (P<0.05) among treatments with chemical product and rope tobacco formulations were observed.

Composição botânica e estrutural e valor nutricional de pastagens de azevém consorciadas

The objective of this work was to evaluate the influence of species intercropped with ryegrass on the botanical and structural composition and the nutritional values of pastures in an agroecological transition system. It was evaluated ryegrass (Lolium multiflorum Lam.) intercropped with black oats (Avena strigosa Schreb.), white clover (Trifolium repens L.) and forage peanut (Arachis pintoi Krapov. & Gregory). It was used a complete random design with three treatments and three repetitions. The first grazing was done 21 days after emergence of the plants on the pastures with ryegrass and black oats and ryegrass and forage peanuts and 28 days after emergence on the pasture of ryegrass + white clover. The second grazing, on the pasture with ryegras + black oats, occurred 30 days after the first one, whereas on the other pastures, grazing occurred 37 days later. The rates of dry matter (DM) accumulation, from the beginning of period of exclusion until maximal production of dry matter were: 77.7; 75.0 and 71.3 kg/ha/day of DM for the pastures intercropped with white clover, forage peanut and black cover, respectively. Leaf/culm ratio until second grazing, was high on all pastures. Reduction on contents of crude protein according to exclusion days on ryegrass + black oat pasture is lower than on pastures of ryegrass intercropped with white clover or forage peanut.Neste trabalho objetivou-se avaliar a influencia de especies em consorcio com azevem sobre a composicao botânica e estrutural e o valor nutritivo dos pastos em um sistema de transicao agroecologica. Foi avaliada a cultura do azevem (Lolium multiflorum Lam.) consorciada com aveia-preta (Avena strigosa Schreb.), trevo-branco (Trifolium repens L.) e amendoim-forrageiro (Arachis pintoi Krapov. & Gregory). O delineamento experimental foi o inteiramente casualizado, com tres tratamentos e tres repeticoes. O primeiro pastejo foi realizado 21 dias apos a emergencia das plantas nas pastagens de azevem + aveia-preta e azevem + amendoim-forrageiro e 28 dias apos a emergencia na pastagem de azevem + trevo-branco. O segundo pastejo na pastagem de azevem + aveia-preta ocorreu 30 dias apos o primeiro pastejo, enquanto nas demais pastagens ocorreu 37 dias depois. As taxas de acumulo de materia seca (MS) do inicio do periodo de exclusao ate o pico de producao de MS foram de 77,7; 75,0 e 71,3 kg/ha/dia de MS para as pastagens consorciadas com trevo-branco, amendoim-forrageiro e aveia-preta, respectivamente. A razao folha/colmo ate o segundo pastejo foi elevada em todas as pastagens. A reducao dos teores de PB conforme os dias de exclusao no pasto de azevem + aveia-preta e menor que nos pastos de azevem consorciado com trevo-branco ou amendoim-forrageiro.

Forage production and stocking rate of Coastcross pastures overseeded with winter grasses

The objective of this research was to evaluate the forage production and stocking rate (SR) of four Coastcross (Cynodon dactylon L. Pers.) pastures overseeded with ryegrass (Lolium multiflorum Lam. cv. Common); ryegrass plus white clover (Trifolium repens L., cv. Yi) over bermudagrass; ryegrass plus white clover and ryegrass. The experiment was carried out from May 15 to October 24, 2006, in five grazing periods. Holstein cows receiving 3.5 kg/daily complementary concentrate feed were used in the evaluation. In the pre and post grazing periods, the forage mass, botanical and structural pasture composition and the stocking rate were assessed. A randomized complete design was used, with four treatments (pastures) and two replications (paddocks), in five grazing cycles. No differences in herbage mass and stocking rate averages were detected among pastures. The ryegrass pastures had larger ryegrass leaf blade herbage mass production. The overseeded pastures had larger forage production. Overseeding with ryegrass and white clover on Coastcross extend the use period of annual grass and increase forage production.

Nutritive value of mixed pastures with different legumes species.

O objetivo neste trabalho foi avaliar o valor nutritivo de dois sistemas forrageiros (SF): capim-elefante (CE) + azevem + trevo-branco + especies de crescimento espontâneo (SF1); e capim-elefante + azevem + amendoim forrageiro + especies de crescimento espontâneo (SF2). O delineamento experimental utilizado foi de blocos ao acaso com duas repeticoes (piquetes), totalizando quatro piquetes de 0,25 ha. O capim-elefante foi estabelecido em linhas espacadas a cada 4 m e as pastagens foram adubadas com 50-40-40 kg/ha do formulado NPK. Durante o periodo experimental, foram realizados nove pastejos (326 dias no SF1 e 336 dias no SF2). Para avaliacao, foram usadas vacas em lactacao da raca Holandesa, recebendo suplementacao alimentar de concentrado (3,5 kg/dia). Avaliaram-se a massa de forragem inicial, a composicao botânica e os componentes estruturais do capim-elefante. Amostras de simulacao de pastejo foram coletadas para analises dos teores de fibra em detergente neutro (FDN) e proteina bruta (PB), da digestibilidade in vitro da materia seca (DIVMS) e materia orgânica (DIVMO) e da composicao em nutrientes digestiveis totais (NDT). No sistema forrageiro com trevo-branco, os valores medios de FDN foram de 47,71%; os de PB, 15,69%; a DIVMS, 77,28%; a DIVMO, 75,92%; e o teor de NDT, 65,00%, enquanto, no sistema com amendoim forrageiro, foram de 51,84; 14,62; 73,7; 72,27; e 63,06%, respectivamente. Os resultados de PB, DIVMS e DIVMO na pastagem total foram melhores no sistema forrageiro com trevo-branco, enquanto os de FDN foram melhores no sistema com amendoim forrageiro. O valor nutritivo das duas pastagens e melhor no periodo hibernal. Considerando a adubacao, o manejo e o tempo de utilizacao da pastagem, pode-se afirmar que os valores qualitativos de ambos os sistemas sao elevados.

Silagem de cereais de inverno submetidos ao manejo de duplo propósito

The objective of this research was to evaluate the silage of 12 genotypes of six species of double purpose winter cereals (forage and grains) submitted to harvest at Depressao Central region of Rio Grande do Sul state. Species and genotypes tested were: BRS 277, BRS Guatambu, BRS Taruma and BRS Umbu wheat; Agro Zebu, UPFA 21 - Moreninha and Commom black-oat; UPF 18 white oat; BR 1 and BRS Serrano rye; BRS Marciana barley; and BRS 148 triticale. Genotypes were submitted to tree harvests with the objective to simulate grazing, according to double purpose management. After the third harvest, the development of cultures was permitted for silage production. The genotypes were distributed in 36 experimental plots in a completely randomized experimental design with 12 treatments (genotypes) and three replications (plots). Silages were made in PVC experimental silos when forages achieved phenological stage of soft dough. Fermentative parameters, dry matter production, structural and botanical composition of ensilage material and nutritive value of silages were determined. BR 1 rye and UPF 18 white oat presented the highest dry matter yield. BRS Umbu wheat produced silage with higher grain participation and better nutritive value. All genotypes presented satisfactory conditions for ensilage

Ingestive behavior of dairy cows in different systems fodder

Estudou-se o comportamento alimentar de vacas da raca Holandesa em lactacao mantidas em pastagem de misturas de especies de capim-elefante (Pennisetum purpureum Schum.), azevem (Lolium multiflorum Lam.) e outras de crescimento espontâneo. Como diferencial destas pastagens, introduziu-se trevo-branco (Trifolium repens L.) ou amendoim forrageiro (Arachis pintoi Krapov. & Greg.). Nos meses de julho, agosto e outubro de 2005, foram feitas avaliacoes em pastejo utilizando-se em cada uma seis vacas entre o segundo e o quinto mes de lactacao, observadas nos periodos de 18 as 6 h e de 8 as 16 h, a cada 10 minutos, por dois observadores. Foram observados o tempo de pastejo nas linhas constituidas por capim-elefante (CE), o tempo de pastejo nas especies estabelecidas na entrelinha e os tempos de pastejo total (pastejo de CE + entrelinha), ruminacao e ocio. Tambem foram avaliados a massa de forragem inicial, o valor nutritivo da forragem ingerida e as condicoes climaticas do periodo. O tempo medio de pastejo na entrelinha foi de 4 horas e 9 minutos para o trevo-branco e de 3 horas e 6 minutos para o amendoim forrageiro. O tempo medio de pastejo do capim-elefante nao diferiu entre as misturas com trevo-branco (4 horas e 27 minutos) e com amendoim forrageiro (5 horas e 51 minutos), assim como os tempos de ruminacao e ocio, que tambem nao diferiram entre as especies associadas. A presenca de forrageiras de inverno esta associada ao maior tempo de consumo de forragem. A presenca de especies de ciclos diferentes possibilitou que os animais equilibrassem a dieta volumosa.

Produtividade de cereais de inverno de duplo propósito na depressão central do Rio Grande do Sul

The objective of this research was to evaluate early growth, yield and canopy characteristics of 12 genotypes of six species of winter cereals with double purpose (forage and grains) submitted to harvest at Depressao Central region of Rio Grande do Sul state, South Region of Brazil. Species and genotypes tested were: BRS 277, BRS Guatambu, BRS Taruma and BRS Umbu wheat; Agro Zebu, UPFA 21 - Moreninha and Commom black-oat; UPF 18 white-oat; BR 1 and BRS Serrano rye; BRS Marciana barley; and BRS 148 triticale. The genotypes were distributed in 36 experimental plots, in a completely randomized design with 12 treatments, three replications and repeated measure. Studied variables were herbage mass, botanical and structural composition, forage and grains production. The earliest genotypes for forage production were BR 1 rye and BRS 148 triticale. BRS Taruma wheat presented higher forage and leaf blade production. BRS Umbu wheat presented higher grains yield and hectoliter weight. Among the genotypes evaluated, BRS Taruma wheat is the most suitable for double purpose in Depressao Central region of Rio Grande do Sul state.