Short-Term Herbage Intake Rate in Temperate Pastures Grasses Grown in Pure or in Intercropping Stands

Oat and ryegrass pastures grown in intercropping systems are the most common forages used during the fall and winter in subtropical and in some temperate climate regions. Nevertheless, it must be taken into account that the way in which the different species of plants are presented to the animals may lead to consequences for the efficiency of the grazing process (Prache and Damasceno 2006). Moreover, in hetero-geneous environments, animals may reduce intake rate due to a partial preference for a specific species (Gonçalves et al. 2009). Regarding the pasture development stage, it is known that the decrease of the leaf/stem ratio causes the animal to reduce the instantaneous herbage intake rate due to the reduction of the bite depth because of the physical barrier imposed by the stem (Benvenutti et al. 2006; Drescher et al. 2006) and/or the search for a higher food quality, in this case, leaf lamina (Soder et al. 2009). However, the dynamics of changes in temperate sward structures grown in pure stands compared to inter-cropping systems and its consequence in heifers\u27 short-term herbage intake rate (STHIR) are scarce. The objective of this work was to assess the changes in the STHIR in pastures of oat, ryegrass and their intercrop during the growing season. The hypothesis tested was that cattle reduce the STHIR in intercropping pastures compared to pure stands, and as the grazing season progress

Tiller Size/Density Compensation in Temperate Climate Grasses Grown in Monoculture or Intercropping Systems under Rotational Grazing

From the standpoint of tiller population dynamics, it is well known that the size and numbers of tillers in forage grasses are inversely related, where a greater tiller population density (TPD) is associated with smaller tillers and vice versa (Sbrissia et al. 2003; Hernandez-Garay et al. 1999; Matthew et al. 1995). This relationship has traditionally been made with the self-thinning power law described by Yoda et al. (1963), which considers the leaf area index (LAI) of the pasture constant when the slope of the relationship between numbers and size of tillers, on a logarithmic scale, is approximately -3/2 (Matthew et al. 1995). Notably few studies have assessed this relationship in intercropping systems. Moreover, although studies that evaluated intercrops showed relationships that were nearly -3/2 for the individually analysed species (Yu et al. 2008; Nie et al. 1997;White and Harper 1970), Nie et al. (1997) suggested that all plants that occur in the grass field should be used to properly estimate self-thinning in mixed species pastures. Thus, the aim of the present study was to test the main hypothesis that the tiller size/density compensation mechanisms operate in the same way in mixed pastures of oat and Italian ryegrass under rotational grazing and that the plant communities adapt their population to maintain a relatively constant LAI

Fatty Acid Profile of Elephant Grass Pastures with Different Grazing Heights

Ruminant milk and meat are a source of CLA and omega-3 in the human diet and these fatty acids (FAs) have a beneficial effect on human health (Mcguire and Mcguire 2000). The increase in CLA and omega-3 in ruminant products is mainly related to proportion of C18:2 and C18:3 in the animal feed, like forage and to incomplete ruminal biohydrogenation (Bauman et al. 2000). Evaluation of FAs have been performed in temperate forage pastures, without the interaction of animal grazing, and presenting samples collected at ground level and at fixed re-growth intervals or seasons as the main sampling criteria. Therefore, the objective of this study was to evaluate the proportion of fatty acid in strata of elephant grass cv. Pioneiro with different grazing heights

Capacidade produtiva de consórcios entre gramíneas tropicais submetidos a diferentes estratégias de manejo.

Ambientes pastoris biodiversos podem promover maior produção de biomassa em função da potencial complementariedade produtiva das espécies. Nesse sentido, consórcios entre gramíneas submetidas a estratégias de manejo possivelmente promoveriam maior estabilidade produtiva quando comparados ao monocultivo. Assim, o objetivo deste projeto é avaliar produtividade forrageira e a persistência de dois consórcios entre gramíneas tropicais submetidos a duas severidades de desfolhação

Morphogenetic and structural characteristics of guinea grass pastures submitted to three frequencies and two defoliation severities.

It was evaluated the morphogenic and structural characteristics of guinea grass under rotational at three grazing intervals and two defoliation intensities. Grazing intervals corresponded to the time needed by the forage canopy to reach 90, 95 or 100% of incident light interception during regrowth and they were evaluated combined to two defoliation severities (post-grazing conditions, 25 and 50 cm of height), being allocated to experimental units according to a complete randomized design, with three replicates and 3 × 2 factorial arrangement. The experiment was conducted from July 2003 to May 2004. For evaluation of morphogenetic and structural characteristics, ten tillers per experimental unit were selected. Morphogenetic and structural characteristics were strongly influenced by seasons of the year inasmuch as leaf elongation rate increased 3.5 fold from winter to summer. In addition to year season effect, there was also an effect of defoliation frequencies on tiller population density, which was greater in the defoliation period corresponding to 90% of light interception, especially if evaluated in relation to the interval corresponding to 100% of light interception. Defoliation frequency is determinant in expression of phenotypic plasticit, acting on the control of stem elongation

Morphogenetic and structural characteristics of guinea grass pastures submitted to three frequencies and two defoliation severities.

It was evaluated the morphogenic and structural characteristics of guinea grass under rotational at three grazing intervals and two defoliation intensities. Grazing intervals corresponded to the time needed by the forage canopy to reach 90, 95 or 100% of incident light interception during regrowth and they were evaluated combined to two defoliation severities (post-grazing conditions, 25 and 50 cm of height), being allocated to experimental units according to a complete randomized design, with three replicates and 3 × 2 factorial arrangement. The experiment was conducted from July 2003 to May 2004. For evaluation of morphogenetic and structural characteristics, ten tillers per experimental unit were selected. Morphogenetic and structural characteristics were strongly influenced by seasons of the year inasmuch as leaf elongation rate increased 3.5 fold from winter to summer. In addition to year season effect, there was also an effect of defoliation frequencies on tiller population density, which was greater in the defoliation period corresponding to 90% of light interception, especially if evaluated in relation to the interval corresponding to 100% of light interception. Defoliation frequency is determinant in expression of phenotypic plasticit, acting on the control of stem elongation

O pastejo de bovinos em pastagem natural compacta moderadamente o solo sem afetar o desenvolvimento das plantas.

O objetivo do trabalho foi avaliar efeito do bovino, sob diferentes alturas de pré pastejo de uma pastagem natural, na qualidade estrutural de um Cambissolo Húmico. O trabalho foi realizado no ano de 2018 em Lages/SC. Os tratamentos consistiram em diferentes alturas de pré pastejo de uma pastagem natural com predomínio de Andropogon lateralis Nees, de 12, 20, 28 e 36 cm, em um sistema de pastejo rotacionado com 40 % de severidade. Adjunto ao protocolo foi mantida uma área de exclusão ao pastejo. Avaliamos a qualidade estrutural do solo ao cessarem os pastejos da temporada de 2018. Não houve alteração da estrutura do solo nas regiões de touceira e entre touceira do capim caninha entre as alturas de pré pastejo, mas todos os tratamentos pastejados aumentaram o grau de compactação na região de entre touceira na superfície do solo (0-5 cm) para a faixa de 80 a 90%, considerada ótima para as plantas, comparativamente à área de exclusão, que apresentou um grau de compactação de 78%. O pastejo ocasionou uma compactação moderada na superfície do solo que não compromete os processos do solo e o crescimento e desenvolvimento das plantas

Estrutura vertical de uma pastagem natural com predomínio de capim-caninha sob manejos de altura.

As pastagens naturais, além de possuírem uma grande diversidade de fauna e flora, servem de base para a produção pecuária. O objetivo deste estudo foi detectar variações na estrutura do dossel de uma pastagem natural com predomínio de capim-caninha (A. lateralis), submetida a diferentes intensidades de pastejo, com alturas pré-pastejo de 12, 20, 28 e 36 cm e severidade de 40% dessas alturas. A metodologia utilizada foi a do ponto inclinado, na condição de pré-pastejo, com a qual se constatou que o4 manejo é um fator determinante da estrutura vertical dessa pastagem natural