Fine‐scale spatial distribution of herbage mass, herbage consumption and fecal deposition by cattle in a pasture under intensive rotational grazing

Abstract

Herbage mass, herbage consumption and fecal deposition by animals were monitored for 2 years in 182 fixed locations (0.5 · 0.5 or 1 · 1 m) in a sown pasture (1.1 ha) grazed rotationally by cattle (42-45 animals). Fecal deposition was more spatially variable (higher values of coefficient of variation) than herbage mass and consumption, with consistently significant bias from the normal distribution in both skewness and kurtosis. In terms of spatial pattern, herbage mass and consumption were always or almost always spatially heterogeneous (nonrandom spatial pattern), while fecal deposition was less frequently heterogeneous or usually homogeneous (random spatial pattern). The spatial heterogeneity in herbage mass was interpreted as being created in the early grazing season possibly through spatial heterogeneity in soil-related factors, and maintained until the late grazing season mainly by herbivory where the animals always left more herbage uneaten at locations with higher pre-grazing herbage mass. Even when cumulated for 2 years (56 days of grazing), herbage consumption and fecal deposition were still considerably spatially variable. Such nonuniform cumulation of animal impacts, however, is not likely to have a negative effect on the grazing system (paddock as the major grazing area) because (1) the animals almost always consumed more herbage from locations with higher herbage mass, resulting in a less variable degree of utilization (consumption/production) across the paddock; (2) fecal deposition on the paddock was not abundant, due to the concentration of feces in the resting area adjoined; and (3) fertilizer was regularly applied to the paddock as management.

Spatiotemporal variation in aboveground biomass in a tropical grass pasture over a 22‐year period

“…Although the present study shows a link between the stocking of cattle and the within-paddock variability in aboveground biomass (see above discussion), this does not exclude the involvement of abiotic factors such as edaphic factors. No indubitable evidence that the partial replacement of bahiagrass by Japanese lawngrass and centipedegrass destabilized the pattern (see Section 3.2.3), which could not be obtained by the previous short-term studies (Hirata, 1998;Hirata et al, 2011), would reflect the situation that biomasses at locations with poor soil conditions (e.g., low nutrient or moisture availability) remained relatively low throughout the study period irrespective of the dominant species. The maintenance of the pattern over the mowing (see Section 3.2.3) despite no stocking of the paddock after the mowing until the postmowing measurements also suggests a contribution of edaphic factors, which supports the discussion in Hirata et al (2011).…”

“…No indubitable evidence that the partial replacement of bahiagrass by Japanese lawngrass and centipedegrass destabilized the pattern (see Section 3.2.3), which could not be obtained by the previous short-term studies (Hirata, 1998;Hirata et al, 2011), would reflect the situation that biomasses at locations with poor soil conditions (e.g., low nutrient or moisture availability) remained relatively low throughout the study period irrespective of the dominant species. The maintenance of the pattern over the mowing (see Section 3.2.3) despite no stocking of the paddock after the mowing until the postmowing measurements also suggests a contribution of edaphic factors, which supports the discussion in Hirata et al (2011). However, the present study is not able to quantitatively evaluate the relative contributions of cattle stocking and edaphic factors to the stability of the spatial pattern of biomass because of the lack of data on the spatial patterns of both cattle behavior and soil conditions.…”

“…They also did not incorporate management as a possible predictor because of the extensive system (e.g., free-range grazing of animals and no fertilizer application). With respect to spatial variation, previous studies that monitored within-pasture variation in aboveground biomass under livestock grazing covered relatively short periods of 5 months to 3 years (Dos Reis et al, 2020;Hirata, 1998Hirata, , 2000aHirata, , 2000bHirata, , 2002Hirata et al, 2011;Hirata & Fukuyama, 1997;Ogura et al, 2002;Ogura & Hirata, 2001)…”

“…They also did not incorporate management as a possible predictor because of the extensive system (e.g., free-range grazing of animals and no fertilizer application). With respect to spatial variation, previous studies that monitored within-pasture variation in aboveground biomass under livestock grazing covered relatively short periods of 5 months to 3 years (Dos Reis et al, 2020;Hirata, 1998Hirata, , 2000aHirata, , 2000bHirata, , 2002Hirata et al, 2011;Hirata & Fukuyama, 1997;Ogura et al, 2002;Ogura & Hirata, 2001) During the stocking season (May to October or November) in the study years, the paddock was stocked 6-9 (mean ± SD = 6.4 ± 0.8) times by a herd of 24-35 (28.1 ± 1.7) cows and 4-18 (7.6 ± 1.9) calves for 1-7 (4.3 ± 1.2) days at about half monthly to monthly intervals. Total duration of stocking and cumulative stocking density during the stocking season were 22-32 (27.3 ± 2.8) days and 625-970 (768 ± 87) cow-days per ha, respectively.…”

Measuring larval nematode contamination on cattle pastures: Comparing two herbage sampling methods

“…This is to be expected, as faecal pats are not evenly distributed across pasture (MacDiarmid and Watkin, 1972;Gruner and Sauve, 1982;Hirata et al, 2011;da Silva et al, 2013) and as most L 3 do not migrate considerable distances away from the faecal pat (Gruner and Sauve, 1982;Stromberg, 1997). The extent of the aggregation of faecal pats varies in time during the pasture season (MacDiarmid and Watkin, 1972;Gruner and Sauve, 1982) and so does the level of larval aggregation (Flota-Bañuelos et al, 2013).…”