Treading Loss Studied

Press, Volume CVIII, Issue 31730, 13 July 1968, Page 9

Treading Loss Studied

More and more New Zealand dairy farmers are using concrete feeding platforms or other devices to keep their cows from trampling wet pastures in winter, but sheepfarmers, on whose pastures hoof damage is less obvious, generally take no special measures to prevent it.

Research findings of the Grasslands Division of the Department of Scientific and Industrial Research suggest that sheep men are losing more than they think through this cause. It is even likely that annual pasture production is reduced more by sheep treading than by cattle treading.

In trials on a well drained Massey University pasture, Mr D. B. Edmond, of the Grasslands Division’s staff, has compared the effects of treading by sheep and cattle at different stocking rates on moist pasture in December and on drier pastures in January and February. As measured by pasture regrowth in the four weeks

after each treading, sheep caused as much damage as cattle on the moist pasture, and were definitely more damaging than cattle to the drier pastures.

Over the whole trial period, the total loss of pasture production attributable to treading was 35 per cent under heavily stocked sheep; 23 per cent under heavily stocked cattle; 8 per cent under lightly stocked sheep; and 3 per cent under lightly stocked cattle. In other trials on the Grasslands Division’s own station, Mr Edmond has measured the effects of sheep treading on a range of soils representing the main North Island types, and has found that winter treading caused substantial reductions of pasture growth on all of them. Soils for these trials were obtained from various districts, transported to Palmerston North, laid to a depth of 18 ipches in excavated, well drained beds, sown with Manawa ryegrass, and given a year for sward establishment.

They ( were then trodden at rates equivalent to set stocking with 20 sheep per acre in the three months June to September. Resultant reductions

of pasture growth were 31 per cent on Taupo sandy silt, 36 per cent on Egmont brown loam, 40 per cent on Manawatu fine sandy loam, and 38 per cent on Kairanga silt loam. “Except in Southland, where there is some recognition of the problem, the effects of sheep treading have been widely underestimated," says Mr Edmond. “It might pay sheepfarmers generally to give thought to protecting their pastures against hoof damage. "I am not in a position to say how this should be done, but one obvious starting point would be the construction of access races, which most sheep farms lack. These would at least facilitate the movement of stock as required to relieve the pressure on particular paddocks—and with the minimum disturbance of other stock on the farm.”