Nutritive Value of Pasture. IX. The Influence of the Intensity of Grazing on the Yield, Composition and Nutritive Value of Pasture Herbage.

Abstract

The main conclusions from the present investigation, which was undertaken in order to obtain an insight into the consequences of the adoption of a 5-weekly rotational close-grazing system, may be summarized as follows:The lengthening of the interval between successive cuts from a month to 5 weeks leads to a definite, though not very serious, reduction in the digestibility of the herbage. This reduction is most noticeable during the flush period of growth, and the constituent most affected is the crude protein. During the fore-flush and post-flush periods, it appears to be immaterial, from the standpoint of digestibility, whether a system of monthly or 5-weekly cutting is adopted. The falling off in digestibility is not connected with the onset of lignification in the herbage, since the digestion coefficient of the fibrous constituent remains high throughout the season, and it may be concluded that, during a season of favourable rainfall, it is possible by cutting (or close-grazing) at intervals of 5 weeks, to prevent the herbage from becoming lignified and of greatly reduced digestibility. The possibility, however, during seasons of a droughty character, of a premature onset of lignification under a system of cutting (or close-grazing) at 5-weekly intervals is discussed.

The productivity and nutritive value of tropical grass/legume pastures rotationally grazed by N'Dama cattle at Ibadan, Nigeria

“…There was no significant difference between the treatments and between the periods. The digestibility of the organic matter of the herbage was moderately high and within the range quoted by Woodman & Norman (1932) for young grass. T.D.N.…”

Grazing interval, stocking rate, and pasture production

“…Many experiments have confirmed the findings of Woodman and Norman (1932) that pastures mown infrequently yield more dry matter (D.M.) than those mown more frequently, when both are harvested to the same height.…”

Studies in grazing management I. A comparison of the production obtained from close-folding and rotational grazing of dairy cows

“…It has been accepted in this study that, as Woodman & Norman (1932) have indicated, rotational grazing with intervals of 3-6 weeks between grazings and judicious manurial treatment is the method of producing the greatest quantity of good-quality grazing. In such a system the yield of cow-days obtained at a single grazing depends on the closeness and uniformity with which the sward is grazed and the quantity of herbage consumed per cow per day.…”

“…Factors affecting the production and seasonal distribution of grassland herbage have been discussed by Woodman & Norman (1932), and the problems are akin to those in the production of herbage for crop-drying which have been studied at this Institute (McNair & Fowler, 1942;Holmes, 19486, 1949Holmes, 19486, , 1951. Attention in this discussion is therefore concentrated on the question of the proportion of the available herbage which is consumed and its effect on production, although incidental reference is also made to some of the associated problems.…”