Mixed Grazing and Climatic Determinants of White Clover (Trifolium repens L.) Content in a Permanent Pasture

Abstract

The effects of grazing regime (cattle, sheep and mixed cattle + sheep) on white clover content (clover dry matter as a percentage of total dry matter) were measured in a permanent pasture over a 7 year period in the west of Ireland (53°17'N 847'E). Rotational grazing was simulated by grazing for short intense periods of 3 4 d at 3 to 5 week intervals. In general, cattle grazing resulted in higher clover content (13-5 %) compared with mixed (9.5 %) or sheep (4-9 %) grazing. The ranking of clover contents (cattle > mixed > sheep) which developed rapidly in 1990 persisted until 1996. Clover contents under mixed grazing tracked those under cattle grazing during the first 4 years, and sheep grazing during the final 3 years. Within-year relativities in clover content among grazing regimes that existed at the start of the grazing season persisted throughout the year. There was an indication that differences in clover content between grazing regimes at the end of grazing persisted until the following spring. A regression analysis of clover content in each grazing period showed strong effects of grazing regime, generally positive relationships with mean air temperature in the period and clover content in the preceding period, and an interaction between air temperature and clover content in the previous period. Implications for pasture management and experimentation are discussed.

Effect of stocking rate on pasture and sheep production in winter and spring lambing systems

“…Both pasture legumes did not appear to be negatively affected by excessive competition from the other species or high temperatures under irrigated conditions in summer. This was also highlighted by Davies (21) and Nolan et al (22), who reported that clovers are generally more favored by higher temperatures than temperate pasture grasses. Given its tolerance to high temperatures, drought, and grazing with its prostrate growth habit, birdsfoot trefoil appears to be a valuable plant for pastures in dry continental climates.…”

Composição bromatológica da cana-de-açúcar como forrageira em função da altura de corte e da época de colheita

“…Segundo Nussio et al (2001), o consumo de cana-de-açúcar por bovinos está diretamente relacionado com o conteúdo de fibra, pois quanto maior o teor de fibra da cana-de-açúcar e menor a digestibilidade da fração fibrosa, menor será o consumo deste volumoso, ou seja, a taxa de digestão da fibra da cana-de-açúcar no rúmen é muito baixa e o consumo de fibra não digerida no rúmen limita o consumo. Portanto, os maiores valores dessa variável na RB72454 podem limitar seu consumo.…”

“…(Acunha & Coelho, 1997;Santos et al, 2001;Xavier et al, 2001), capim-colonião (Panicum maximum Jacq.) (Ezequiel & Favoretto, 2000) e trevo-branco (Trifolium repens L.) (Nolan et al, 2001;Simon et al, 2004). Em milho (Zea mays L.), estudos foram realizados para verificar o efeito da altura de corte da planta na composição bromatológica da forragem (Vasconcelos et al, 2005) ou da silagem (Pedó et al, 2009) dentro do mesmo ciclo.…”

Assessing determinants of community biomass composition in two-species plant competition studies

“…In these stands, where repeated measurements may be available, perhaps over several years, it may be useful to use the most recent measurement of stand state rather than its initial state as the reference point for change in any period (see Eq. 7 and Connolly and Wachendorf 2001;Wachendorf et al 2001;Nolan et al 2001). Apart from probably giving a better fit for the models, this may provide insight into the relationship between community change over a period and its status at the start of the period.…”

“…Using the community status at the start of a period, which incorporates the history of the community, may give a better insight into the drivers of compositional change in the period than the temporally more remote initial species' biomass. Similar approaches to modelling community dynamics have been developed by Connolly and Wachendorf (2001), Nolan et al (2001) and Wachendorf et al (2001). When successive harvests are taken on the same plots, RGR more properly refers to growth from a post harvest residue rather than being based on the previous harvest yield.…”