Some Estimates of the Areas of Pasture Fouled by the Excreta of Dairy Cows

Abstract

Observations were made of the areas of herbage receiving the faeces of grazing dairy cattle and of the areas and relative palatability of herbage whose growth was alTected by faeces and urine. The average area covered by faeces was 1-i sq. Tt./cow/day. Faeces dropped during grazing had a negligible affect on the utilization of herbage at thai grazing, but each dung-pat probably affected Ihe growth and palaiability of an area of herbage about six times as great at the next grazing. The area of herbage whose growth wasafTecied by urine was equal to that affected by faeces, but unlike faeces, urine improved the palatabilily of the herbage to dairy cows. The dala were used to calculate approximate areas of herbage likely to be afTecied by excreta at ditTerent levels of stocking, and it appeared that excreta return plani nutrients to a given pasture acreage more quickly than some other estimates suggest-

The role of grassland sward islets in the distribution of arthropods in cattle pastures

“…It may be that the dung causes an initial rejection in the proximal sward. With consequent differences in the chemical or physical characteristics the grazed and ungrazed vegetation maintaining the rejection by cattle (MacLusky, 1960;Norman & Green, 1958). Whatever the present reasons for such behaviour in grazing cattle, the underlying evolutionary explanation may lie in avoidance of infection by gastrointestinal parasite larvae, the distribution of which tends to remain highly concentrated in the vicinity of dung patches during the grazing season (Boom & Sheath, 2008).…”

“…Islets have been estimated to cover between 10 and 47% of pasture area and to persist for between a few months to over a year, although both these characteristics vary with grazing intensity, rainfall and management such as cutting (Boswell, 1971;Castle & MacDaid, 1972;Gibb et al, 1997;MacLusky, 1960;Norman & Green, 1958; Tayler & Large, 1955; Weeda, 1967). The extent and persistence of islets has often been considered to represent a reduction in productivity and consequently has stimulated many studies from an agronomic perspective (Bosker et al, 2002;Castle & MacDaid, 1972;Greenhalgh & Reid, 1968;MacLusky, 1960; Tayler & Rudman, 1966).…”

“…Although islets have taller vegetation, the botanical composition is initially little changed from the remaining sward (MacDiarmid & Watkin, 1971;Norman & Green, 1958;. However, some studies suggest that the spatial heterogeneity created by such patches, especially in soil nutrient status (Haynes & Williams, 1993; Lantinga et al, 1987), is likely to influence relative plant population dynamics and the Schwinning & Parsons, 1996).Islets have been estimated to cover between 10 and 47% of pasture area and to persist for between a few months to over a year, although both these characteristics vary with grazing intensity, rainfall and management such as cutting (Boswell, 1971;Castle & MacDaid, 1972;Gibb et al, 1997;MacLusky, 1960;Norman & Green, 1958; Tayler & Large, 1955; Weeda, 1967). The extent and persistence of islets has often been considered to represent a reduction in productivity and consequently has stimulated many studies from an agronomic perspective (Bosker et al, 2002;Castle & MacDaid, 1972;Greenhalgh & Reid, 1968;MacLusky, 1960; Tayler & Rudman, 1966).…”

“…Humbert (2009) recently presented a very similar idea when proposing that 20 un-cut patches should be left after mowing as a way of maintaining arthropod biodiversity in cut grasslands. Given this, the common and often, although not universally, recommended practice of topping (mowing) after grazing, to return a sward to a uniform height Boswell, 1971;Castle & MacDaid, 1972;MacLusky, 1960;Norman & Green, 1958), is likely to be detrimental to grassland arthropod biodiversity. Such topping is likely to lead to the death and/or migration of much of arthropod population (Humbert et al, 2009).…”

“…The extent and persistence of islets has often been considered to represent a reduction in productivity and consequently has stimulated many studies from an agronomic perspective (Bosker et al, 2002;Castle & MacDaid, 1972;Greenhalgh & Reid, 1968;MacLusky, 1960; Tayler & Rudman, 1966). It is also a major reason for the practices of sward topping to reduce physical sward heterogeneity (and control weeds) and chain harrowing to re-distribute surface dung Boswell, 1971;MacLusky, 1960;Norman & Green, 1958; Weeda, 1967).In contrast there has been little work done on the possible ecological effects of islets.Mikola (2009) recently reported a major study of the ecological effects of localised dungdeposition on plant and soil faunal communities in grazed pasture. Desender (1982), Desender et al (1989 found evidence that islets may be important overwintering sites for Carabidae and Staphylinidae, particularly as they are not trampled by cattle and cover a relatively large area.…”