Article: The Charter Estate Grazing Trial Animal Production And Management
Author: Worthington, D.K.
Published: Zimbabwe Journal of Agricultural Research (1984), Vol. 81 (2)
The Charter Trials were a seven year study conducted on the 2,500 ha Charter Estate by Allan Savory and Stan Parsons from the years 1968 to 1975. The principle objective of this study was to compare the economics of different grazing management approaches on south African veld. This post will summarize the study design and the results of the published animal performance data associated with the trials.
The basic study design was treatment-control with 2 replications of each. The treatments were designated S1 and S2, which were under the management of Allan Savory. At these early stages in the development of Holistic Management, grazing planning was not yet “holistic”, but many of the same principles applied: a general exclusion of fire, increases in stocking rate, planned grazing/recovery periods, the division of the landscape into paddocks with fencing and water, and high density/short duration grazing to achieve herd effect and animal impact.
The controls were the traditional Charter System of Management, designated C1 and C2. The author describes this management system:
…on our sour veld, periodic burning – possibly at least every four years – was not only beneficial to the cattle but was necessary to “even up” the range and avoid “patch grazing” and to control bush encroachment. The paddock due for the burning the following spring would receive a late season rest to ensure adequate fuel for a clean burn. [The stocking rate] was about 1 cow to 5.5 ha…paddocks were not grazed rotationally, but decisions on moves were made with both cattle and condition of grazing in mind.
During the first two years of grazing, stocking rates across treatments were roughly equivalent, presumably to allow for infrastructure development associated with fencing and water. During the last five years of the study, however, the S1/S2 treatments had an average stocking rate of 2.6 ha/breeding cow, while the C1/C2 treatments had an average stocking rate of 4.6 ha/breeding cow. The graze:recovery ratio was planned to be intensive in S1 at 3 grazing days:60 recovery days, while S2 was planned to be moderate at 14 grazing days:56 recovery days. The paper clearly illustrates that the entire study was a learning process, and therefore actual average graze:recovery ratios for the final year were 4:57 for S1 and 6:41 for S2. Variation during the year was a function of seasonality.
Average weight per animal for the S1/S2 was 175 kg, while the C1/C2 average was 192 kg. Animal reproduction as a measure of performance is summarized as follows:
…the pregnancy rates for C1 were 12.6 percent better than S1, and the pregnancy rates for C2 were 10.7 percent better than S2. The kg/ha of live weaners were, however 39.7 percent in S1 against 29.9 percent in C1, and 39.99 percent in S2 against 31.5 percent in C2, in this case showing an improvement of over 30 percent over controls.
The above data indicate that increases in stocking rate allowed for greater cattle biomass on equal amounts of land, hence the 30 percent improvement in kg/ha of live weaners. However, this radical shift in management also resulted in increased stress on individual animals, evidenced by the decreases in pregnancy rates and the lower per animal weights for the S1/S2 treatments. Lack of ovarian activity in the S1 animals during the year 1975 is another potential signal of animal stress.
The author agrees with the sentiment of this assessment: “The apparent stress on the cattle in the early years led us on frequent occasions to commit that unpardonable sin of ‘untoward acceleration’ and we found ourselves completing a rotation within 35 and even 30 days.”
The reasons for this stress were multiple:
The poor performance of the cattle on the S1 and S2 in the first three or four years may be attributed in part to the vast quantities of old grass in these paddocks resulting from the original decision not to burn, which heavy stocking was only able to rectify very slowly and with very considerable levels of stress on the cattle.
We found the stress to be very high in the early years of the groups being moved every second or third day. With acclimatization, this factor became of less importance.
From the research of Dr. Fred Provenza, we now can characterize this early decline in performance as an “Adaptation Trough”. In his informational booklet Foraging Behavior: Managing to Survive in a World of Change, Provenza explains:
Changes in grazing regimens affect every facet of the system – soils, plants, herbivores, people – and as many as 3 or more years are required for systems to adapt to changes in management….In the end, productivity [will improve]…during adaptation, however, animal performance – food intake, weight gains, reproductive rates – typically declines before it improves. The degree and duration of the decline depend on the magnitude and direction of change. The greater the change and the more challenging the terrain, the greater the impact.
In this case, improvements in system productivity per hectare were achieved by increasing stocking rates. With hindsight as our ally, anticipating and planning for decreases in animal performance when stocking rates are increased will be important for land managers. Understanding animal behavior and the sources of stress will help to mitigate stress on individual animals and reduce the severity of the adaptation trough. Subsequent posts will consider the results of the economic and botanical analysis of the Charter Trials.