DISTANCE CATTLE TRAVEL TO WATER AFFECTS
PASTURE UTILIZATION RATE
J.R. Gerrish, P.R. Peterson, and R. E. Morrow1
Abstract
It is a commonly accepted principle that location of watering sources in pasture and range
situations affects distribution of grazing by ruminant animals. A study was conducted to
determine the effect of distance travelled to water on pasture utilization rate by beef cow-calf pairs. Ten acre pastures with length width ratios of approximately 1 versus 4 were
compared for uniformity of grazing distribution. The pastures more nearly square were
grazed uniformly in all areas with a mean individual grazing period utilization rate of
approximately 35% for a single grazing period. Rectangular pastures were more variable
in grazing distribution with utilization rate ranging from between 40 and 50% at the front
100 to 200 ft of the pasture to less than 20% when distance from water exceeded
approximately 1100 ft.
Introduction: Location of watering facilities on grazing lands has been widely recognized
as a factor controlling grazing distribution by ruminants. In rangeland environments, the
typical recommendations are that animals travel no farther than 2 miles to water on flat
topography and no more than 1 mile in rough country (Smith, et al, 1986). In humid
temperate environments less attention has been paid to water location and its effects on
grazing distribution. Over several years we had visually noted that differences in grazing
distribution occurred even in relatively small pastures and seemed to be oriented around
water location.
The objective of this research was to determine how distance beef cows must travel
to water affected grazing distribution and pasture utilization rate. As with most biological
research, more than one parameter affects the final outcome. Stock density, topography,
plant community will all affect grazing distribution. In this project stock density and total
acreage in each paddock were held constant. Given this fact, distance from water
necessarily became confounded with shape of paddock. That is a ten acre paddock with a
maximum distance to water of 700 ft must be nearly square while a paddock with a
maximum distance of 1400 ft to water cannot be square but must be rectangular with given
dimfensions.
Materials and Methods: The experimental site was a 160 acre grazing cell located at the
University of Missouri Forage Systems Research Center in north-central Missouri. The
160 acre cell was subdivided into 16, ten acre paddocks and was rotationally stocked with
a single herd of beef cow-calf pairs. The pastures were well established cool-season grass-legume mixtures. Grazing periods were typically 2 to 4 days with a stocking density of 8.5
cow-calf pairs/acre. Paddock shifts were based upon pasture residual and animal
observation. From approximately May 10 to July 10 either 2 or 3 bulls were also present
on the pasture. The individual pastures used in this project have been established and
grazed in the same configuration since 1982. However, from 1982 through 1991 they were
typically continuously stocked from approximately May 1 through August.
Six paddocks were selected from the sixteen to provide a range in maximum distance
which the stock must travel to water. All experimental pastures were 10 acres but were
either nearly square (600 x 720 ft) or rectangular (1320 x 330 ft). Three rectangular
pastures had water available at a corner location while the other two accessed water from
a corner gate and travelled an additional 300 to 600 ft of lane to the water tank.
Paddocks were sampled during either 2 or 3 grazing cycles during the months of
May, June, July, and August. Herbage on offer was determined prior to grazing and
immediately following grazing on each of the selected paddocks. Each paddock was
divided into sampling zones 100 ft in width beginning at the watering site. In each zone,
four 20 x 3 ft strips were harvested prior to grazing using a Carter Harvester set at a 2 in
cutting height. Strip samples were weighed wet in the field, a subsample taken for
determination of moisture content, and dry matter yield was determined. Following
grazing, a paired, parallel strip was harvested from within 4 to 8 ft of each pre-grazing
harvest strip. Pasture utilization rate was determined to be the difference between the pre
and post-grazing dry matter yields.
Regression analysis using distance from water as the independent variable and
utilization rate as the dependent variable was used to determine grazing distribution across
the paddocks. Individual analyses were conducted for each paddock at each grazing cycle.
While a large degree of variance existed on a pasture to pasture basis, largely due to
landscape differences, the general trend in utilization pattern was consistent. For this
reason, all rectangular paddocks were combined in the final analysis and compared to the
square paddock.
Results and Discussion: It is important to understand that grazing distribution across the
landscape is influenced by a number of factors. These include topography, plant
community, length:width ratio of the paddock, and stock density as well as distance
travelled to water. In the rolling landscape typical of north Missouri, topographical
location of the watering site will have an impact on grazing distribution in and of itself.
As the pastures used in this project had been grazed in the same configuration for the 10
years preceding this study, pre-existing gradients in soil fertility and plant community were
likely to exist. The type of relationships discussed in this paper must be considered in the
context of the time continuum.
In all paddocks sampled, measured pre-grazing forage mass increased from front to
rear (Figures 1 and 3). For some paddocks the increase was only marginally significant
while for others it was quite significant. In the case of the square paddock, soil type
changed from front to rear, with the soil to the rear being the more productive soil. The
soil type in the front half of the square paddock had a productivity index of 56 while the
soil in the back half had a productivity index of 74. This may explain a large part of the
yield distribution in this paddock. In most of the rectangular paddocks, the increasing yield
cannot be explained by soil type. Soil nutrient gradients in the paddocks were not
significant in all paddocks and in some cases were high in the front and low in the back
while other paddocks exhibited higher fertility in the back of the paddock compared to the
front. Thus, the yield gradient cannot be explained adequately from a soil perspective in
most cases.
We hypothesize that the yield distribution gradient in the rectangular paddocks is the
result of several years of nonuniform grazing distribution. For the 10 years prior to this
study each pasture had been used as an individual continuously stocked pasture. The plant
species present in the front parts of the pastures tended to be those more tolerant of heavy
grazing, such as bluegrass and white clover, while orchardgrass and red clover tended to
be more common toward the rear of the pasture.
Grazing distribution was markedly different between the square paddock (Figure 2)
and rectangular paddocks (Figure 4). Pasture utilization was very uniform across the
square paddock whereas utilization rate in the rectangular paddocks began to decline
rapidly once the animals had to travel more than 600 to 800 ft to water. Virtually all
reports in the literature dealing with grazing distribution as it relates to water location are
from semi-arid to arid range environments. Hart et al (1989) reported that distance to
water had no effect on pasture utilization in relatively small pastures (60 acres) that were
either continuously or rotationally grazed. In a larger 512 acre pasture, utilization rate
dropped from 60% in the zone nearest to the water source to less than 30% when the cattle
travelled 3 miles distance. These figures, however, represent total season utilization rate
and not individual grazing period responses. It is likely that later in the season as forage
supply nearer the water source becomes more limiting, the animals will in fact travel
greater distances to satisfy dietary needs. Stuth (1991) indicated that no difference in
range utilization occurred within 1/2 mile of the watering site but indicated a 10% drop
in utilization rate when cattle travelled between 1/2 and 1 mile to water. Pasture and range
cattle are very different in their foraging behavior. Part of these differences can be
attributed to the forage mass typically available to the animals. Range cattle must travel
greater distances to satisfy their intake needs than pasture cattle and are thus forced to
travel greater distances on a regular basis. Pasture cattle will likely stay closer to water as
long as forage is abundant in the front part of the pasture. A question that must be
considered is whether the observed grazing distribution is the result of the distance the
animals travel from water or is it the result of a square paddock compared to a rectangular
paddock. Reports have been mixed regarding impact of paddock shape on grazing
distribution but in almost all studies distance to water and shape have been confounded.
In conclusion this data illustrates that distance that livestock travel to water has a
profound influence on grazing distribution and subsequent pasture utilization rates. This
distance is apparently much less in humid temperate pastures than in semi-arid range
environments. We recommend that pasture systems be designed to provide water sources
within 600 to 800 feet of all areas of the pasture for optimum uniformity of grazing.
Literature cited:
Smith, Burt, PingSun Leung, and George Love. 1986. Intensive Grazing Management: Forage. Animals, Men, Profits. The Graziers Hui, Kamuela, Hawaii.
Hart, R.H., M.J. Samuel, J.W. Waggoner, and M.A. Smith. 1989. J. Soil Water Cons.
Stuth, J.W. 1991. Foraging Behavior in R.K. Heitschmidt and J.W. Stuth (eds) Grazing Management: An Ecological Perspective. Timber Press, Portland Oregon
Figure 1. Forage mass distribution in a 10 acre paddock with a length: width ratio of 1.
Figure 2. Pasture utilization rate in a 10 acre paddock with a length: width ratio of 1.
Figure 3. Forage mass distribution in 10 acre paddock with a length: width ratio of 4.
Figure 4. Pasture utilization rate in a 10 acre paddock with a length: width ratio of 4
1 Research Assistant Professor, University of Missouri-Forage Systems Research Center,
RR1 Box 80, Linneus MO 64653; Formerly Research Associate, presently Assistant Professor, Department
of Plant Science, McGill Univ. Montreal; and formerly Professor Animal Science, University of Missouri.
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