Evaluating Grazing Strategies for Cattle: Deer and Cattle Food Partitioning

Collaborative Adaptive Rangeland Management, Multipaddock Rotational Grazing, and the Story of the Regrazed Grass Plant

Effects of Livestock Grazing on Infiltration Rates, Edwards Plateau of Texas

Pasture productivity and wool production on the Warrego Mitchell grass (Astrebla spp.) rangeland in south-westem Queensland were studied over a period of 13 years under continuous or rotational grazing, each at three stocking rates. The stocking rates were one sheep to three, two or one hectares and the rotational grazing was a six- monthly system of summer or winter grazing. The grazing treatments were applied over two five- year terms with a nil-grazing period at the conclusion of each. The latter periods provided a means of measuring the cumulative effects of the grazing treatments. Drought conditions prevailed during the first term so that supplementary feeding was necessary, but the second experienced above average rainfall. Quarterly measurements were made of the pasture dry matter on offer and its botanical and chemical composition. Monthly sheep liveweights, annual wool production and sheep size development in each term were also measured and monetary returns from wool calculated. Rainfall had a major influence on the results recorded and tended to nullify the effects of grazing treatments. Its unpredictability precludes the reliable use of complex techniques in management planning. The overall results suggested that the optimum grazing management of this Mitchell grass rangeland would be continuous grazing at a stocking rate of one sheep to two hectares. Supplementary feeding during drought would be obligatory and should be budgeted for in long-term planning. There was a 50% higher monetary return from this grazing treatment than from the lighter stocking rate and pasture stability (maintenance of Astrebla spp.) was sustained. Pasture stability was adversely affected by the heavier stocking rate. There was no srlstained advantage from rotational grazing compared with continuous grazing.

Lamb production from pastures under continuous and rotational grazing was compared for 3 years at stocking rates of 20, 30, and 40 ewes/ha with and without initial pasture reserves. Lamb growth rate was similar for each grazing system and was increased when feed reserves were present. Increasing stocking rate lowered per animal performance but increased output/ha. Ewe live weights declined in 2 of the 3 years. Rotationally grazed ewes maintained body weight better than continuously grazed animals. In the 4th year, pastures were maintained at differing heights and lamb output was higher from long pastures. Continuous grazing gave higher gains than rotational grazing and there was no difference in lamb or ewe performance between 1‐day and 4‐day rotational shifts.

As part of the Sustainable Grazing Systems (SGS) National Experiment a study was conducted on a native pasture in the Manilla district of northern New South Wales to examine the effects of 5 grazing treatments on total herbage mass, litter mass, basal cover, ground cover, sheep liveweight, wool production and soil water content (SWC, mm) at different depths. The pasture was a mixture of native perennial grasses, with redgrass ( Bothriochloa macra ) and wiregrass ( Aristida ramosa ) dominant on a red Chromosol soil type and bluegrass ( Dichanthium sericeum ) on a brown Vertosol. Wallaby grasses ( Austrodanthonia richardsonii and A. bipartita ) were common on both soils. Plots were grazed with Merino wethers and data collected from spring 1997 to spring 2001 were analysed to determine the effect of treatments on both production and sustainability. Five grazing treatments were applied in a randomised 3 replicate design. Grazing treatments were: continuous grazing at 3.1 and 6.2 sheep/ha (C3 and C6), continuous grazing at 9.2 sheep/ha, with subterranean clover ( Trifolium subterraneum ) oversown and fertiliser applied (C9+sub) and rotational grazing at an annual stocking rate of 3.1 sheep/ha with pasture grazed for 4 weeks and rested for 4 weeks (R4/4), or rested for 12 weeks (R4/12). Over time, treatments had no significant effect on either total pasture herbage mass (compared with the C3 control) or the basal cover of the major perennial grasses. Treatments had inconsistent significant effects on ground cover, litter mass, sheep liveweight and wool production (kg/head) over time. Compared with all other treatments ground cover was less ( P <0.05) in the C6 treatment in only May and September 2000 and litter mass less ( P <0.05) in only December 1998 and March 1999. Treatment sheep liveweights were not significantly different from the C3 treatment from September 1997 to 1999. However, from October 1999 to October 2001 sheep liveweight in the C6 treatment was significantly less than in the C3 treatment, while in the C9+sub and R4/12 treatments it was significantly greater than the control. In 1999, wool production per head was higher ( P <0.05) in the C9+sub and R4/12 treatments compared with all other treatments but treatment differences were not significant in all other years. Significant differences in SWC only occurred at the 0–30 cm depth between the C3 and the C6 and R4/12 treatments, but were predicted to be <1.5 mm/year. A sustainability index derived from economic [equivalent annual net return ($/ha) for a 10-year period], animal production, pasture, soil health and soil water data indicated that the overall indices were lowest for the C3, C6 and C9+sub treatments and highest for the R4/4 and R4/12 treatments.

Beef production from veld, in the short term, was found to be greater under a continuous grazing system than under a rotational grazing system. Average daily gains decreased from a maximum in late‐spring and the highest three‐year mean value was 0,5 kg/animal/day. Livemass gains/ha were highest at a stocking rate of 2,2 animals/ha and were 131,4 kg/ha under continuous grazing and 88,6 kg/ha under rotational grazing. Estimated mean maximum gains/ha were 0,78 kg/ha/day at a stocking rate of 2,5 animals/ha under continuous grazing and 0,55 kg/ha/day at a stocking rate of 1,7 animals/ha under rotational grazing. However, optimum economic stocking rates were estimated to occur below those where beef production/ha was maximum.

To observe forage competition between deer and livestock, the forage selections of a tame deer (Odocoileus virginianus), a goat, a sheep, and a cow were observed under four range conditions, using both stocked and unstocked experimental pastures, on the Kerr Wildlife Management Area in the Edwards Plateau region of Texas in 1959. The animals were trained in 2 months of preliminary testing. The technique employed consisted of recording the number of bites taken of each plant species by each animal during a 45-minute grazing period in each pasture each week for 1 year. Results indicated moderate to heavy competition for browse and mast between the deer and goat in all pastures during all seasons, and between the deer and all three classes of livestock in the winter. Browse and mast comprised over 50 percent of the deer's diet, except in the spring and summer, and over 50 percent of the goat's diet in all seasons. Following a decrease in available browse, sheep become competitive with deer for forbs. Forbs formed an average of 68 percent of the deer's diet and 65 percent of the sheep's diet in the ungrazed control pasture in the summer; the animals generally were grazing the same species. The added factors of bearing and nursing fawns, and growing antlers, contribute to the nutritional stresses on deer in the summer, the period when extensive die-offs of deer most frequently occur in the Edwards Plateau region. Competition for grass between deer and livestock probably is important only when grass is in a succulent stage in the spring and no other forage is available in quantity. Continuous grazing by animals tends to remove the most palatable species and concentrates competition on fewer, less palatable ones. Observations from the numerous replications of feeding times and places allow the conclusion that this technique provides a reliable index to preferred foods and staple foods. In the Edwards Plateau region of Texas, most of the rangelands are grazed by two or more classes of livestock along with deer. Research on the Kerr Wildlife Management Area, near Hunt, Texas, indicates that deer when managed and harvested properly can provide economic returns comparable to those from domestic livestock. But a study of the economic feasibility of management for livestock and deer in combination revealed the need for more exact knowledge of their competition for forage. To provide such information, a study of the food habits of cattle, sheep, goats, and deer was initiated in May, 1959, and concluded in May, 1960. The Kerr Wildlife Management Area is a research facility of the Texas Parks and Wildlife Department located in Kerr County in the eastern portion of the Edwards Plateau. This region, encompassing some 26,000 square miles of central Texas, probably is unique in its combined productivity of deer and livestock in high densities (Hahn 1945, Taylor and Hahn 1947). Previous studies of its vegetation in relation to deer and livestock were reported by Buechner (1944), Taylor and Beuchner (1943), and Whisenhunt (1949). On the Kerr Area, particularly the pastures involved in this study, the prominent vegetal expression is a savannah of live oak, in which Ashe juniper (Juniperus ashei) and shin oak are conspicuous. Part of the Kerr Wildlife Management Area contains 10, 96-acre deer-proof pastures which are used for a long-term study of the influence of combined sheep, goat, and cattle grazing rates on deer production. Each species of animal obviously has a different influence on the welfare of the others and on the forage resource in general, but the experimental design had revealed only the gross influence of combinations of animals. Performances of deer in experimental pas-

Growth of yearling horses managed in continuous or rotational grazing systems at three levels of forage-on-offer

Managing Forbs Preferred by Greater Sage-Grouse and Soil Moisture in Mesic Meadows with Short-Duration Grazing

QuestionsGrazing management influences grassland community dynamics, but few studies exist on the effects of specific management regimes in subtropical grasslands. Here, we ask how rotational and continuous grazing influences the composition, diversity, and biomass production of natural grasslands in southern Brazil.LocationThe study was conducted at four cattle farms within the south Brazilian grassland region (Campos Sulinos), in the upper area of the Camaquã river basin of Rio Grande do Sul, Brazil.MethodsOn each farm, grassland that had previously been subjected to continuous grazing (freely grazed by cattle) was divided into two experimental units; one managed by rotational grazing and the other maintained under continuous grazing. In each experimental unit, 14 permanent plots were monitored over six years for species composition and species biomass. Data were analyzed using linear mixed models to evaluate the effects of grazing management strategies on composition dissimilarity, diversity indices, and plant biomass.ResultsGrasslands under a rotational grazing regime changed steadily over the period of evaluation. Total biomass and species distribution patterns greatly differed from those in plots subjected to continuous grazing, leading to changes in species richness, dominance, and composition, as well as to an increase in overall plant biomass.ConclusionsCommunity changes during the six‐year study period as a consequence of the distinct grazing treatments were evident. Grasslands under rotational grazing management benefitted from less selective grazing, enabling a more uniform growth of species within the communities, which in turn were richer at the end of the six‐year experiment. In contrast, the proportion of grazing‐resistant species or less‐consumed species was higher under continuous grazing, where foraging by cattle appears to be more selective. Rotational grazing thus not only leads to higher species richness and diversity, but also to higher primary and, in consequence, secondary productivity.

The objective was to compare estimates of forage mass (FM) determined with a rising plate meter (RPM) with forage mass determined by total collection method. Estimates of FM impact management decisions and give the producer a greater understanding of forage availability for their herd. Traditional methods of FM estimation using a forage ring or quadrat and total collection are labor intensive and time consuming. The RPM tool aims to provide a quicker method of FM estimation without sacrificing accuracy. The reliability of this tool can be impacted by season, species composition, plant growth state, and pasture management. Forage samples were collected from six random locations within both continuous and rotationally grazed systems. The predominant forage species was endophyte-infected tall fescue. A 0.25 m2 forage ring was randomly thrown, then two RPM (Jenquip Manual Platemeter) measurements were collected in the ring, followed by five measurements adjacent to the ring. The RPM determined the compressed sward height (CSH). Subsequently, forage within the ring was hand-clipped at ground level and collected. Samples were dried for 120 h at 55° C to determine forage availability (kg/ha). This process was repeated weekly for 6 wk. Rising plate meter FM was estimated using the equation: kg dry matter (DM)/ha = CSH × 158 + 200. Data were analyzed using the CORR procedure of SAS 9.4. Forage mass estimates from total ring collection method and RPM were weakly correlated in the rotational grazing system (r = 0.26; P = 0.13) and in the continuous grazing system (r = 0.20; P = 0.24). It is important to note that certain sample collection dates had stronger correlations than others. In the rotationally grazed paddocks, FM from RPM were strongly correlated (r ≥ 0.89, P ≤ 0.02) with FM from total ring collection on 6/23/23 and 7/26/23. In the continuously grazed paddocks, FM estimations from RPM were strongly correlated (r ≥ 0.73, P ≤ 0.10) with forage mass from total collection on 7/20/23 and 7/26/23. Variation among the seven RPM readings at each collection site could have contributed to variability. Coefficient of variation ranged from 9 to 48% and averaged 18% for all samples. The inconsistencies in relationship of forage mass determination methods suggests that more variables need to be considered when determining the accuracy of RPM-derived estimates of forage mass of tall fescue.

This work aimed to evaluate edaphic macrofauna under different soil use systems. Two systems were evaluated: conventional system, no-till, continuous grazing, crop-cattle integration, eucalyptus and native vegetation. Sampling was carried out in five points at one transect per system. Organisms were manually extracted and identified to the level of broad taxonomic groups. Native vegetation did show the highest variety of edaphic macrofauna groups when compared to monocultures and/or high intensity of soil tillage. Among cropped systems, the highest density of edaphic macrofauna organisms was observed in crop-cattle integration and continuous grazing systems. The total density of individuals and the macrofauna group richness were not influenced by soil physical attributes. Regarding to chemical attributes, only the group richness was correlated to some of such proprieties.

Stiff Sunflower Population Dynamics on Summer-grazed Sandhills Rangeland

Stiff Sunflower Population Dynamics on Summer-grazed Sandhills Rangeland

When combining pines and cattle on tame pasture, grazing is often delayed for several years until trees are large enough to resist injury. As an alternative approach to delayed or deferred grazing during the early years, this study in central Louisiana, USA, examined the effects of cattle grazing in subterranean clover (Trifolium subterraneum L.) pastures on slash (Pinus elliottii Engelm.) and loblolly pine (P. taeda L.) seeding survival and growth during the first 3 years of tree establishment. Pines were planted at about 1200 trees/ha in 3 rows on 0.4-ha subclover units with 1.3 m spacing within rows. Three grazing treatments included: (1) ungrazed pines, (2) limited grazing with a single-wire electric fence above the planted pines, and (3) grazed pines. Thirty Brahman crossbred cows with calves and a bull grazed the tame pasture on a controlled grazing, rotational basis from December through May each year, during the subterranean clover growing season. Pine trampling injury during the year was 8% on the grazed seedlings while essentially none occured under limited grazing. During the first 2 growing seasons, survival and height of the pines were significantly less on the grazed seedlings than on either the limited grazing or ungrazed seedlings. Pine heights from the limited grazing and ungrazed treatments were not different during the 3-year study; loblolly pine heights from the limited grazing treatment continued to be taller than the grazed treatment through the third year while the slash pine heights were similar for all treatments by the third year. Seedling mortality became more acute as severity of grazing injury increased; the greatest mortality occured when the terminal bud and needles were both browsed off.