Bermudagrass Pastures Research Articles

Effects of monensin dose from a self-fed mineral supplement on performance of growing beef steers on forage-based diets

ABSTRACT Objective The objective of this research was to determine the effect of differential monensin (Rumensin, Elanco Animal Health, Greenfield, IN) intake in a free-choice loose mineral on performance of grazing beef steers. Material and Methods Treatments consisted of offering ad libitum access to minerals (AMPT-A, ADM Animal Nutrition, Quincy, IL) supplying 0 (0M), 882 (800M), or 1,764 (1600M) g of monensin/t with targeted daily monensin intakes of 0, 100, or 200 mg of monensin per steer. Steer calves (n = 605, BW = 278 ± 27 kg) were fed hay with a hand-fed supplement (block 1); grazed wheat (Triticum aestivum) pasture (blocks 2, 3, and 6); or bermudagrass (Cynodon dactylon) pasture (blocks 4 and 5). There were no treatment × diet interactions (P ≥ 0.97); therefore, data were pooled across blocks for statistical analysis. Results and Discussion Steers offered 800M and 1600M had greater (P ≤ 0.02) final BW, ADG, and total BW gain compared with 0M steers fed mineral without monensin. Mineral intake decreased linearly (P Implications and Applications Monensin supplementation improved growth performance compared with an unmedicated control within the doses observed in this experiment and regardless of basal forage quality. Intake of a self-fed monensin-containing mineral can be decreased by at least 50% without affecting performance response to monensin of steers on forage-based diets.

Greenhouse gas emission from the soils fertilized with liquid pig slurry (LPS) in Tifton 85 bermudagrass pasture in tropical savanna

Soils have important roles in the global budgets of the greenhouse gases. The liquid pig slurry (LPS) in pastures has high potential as a fertilizer but could have a direct influence on emission of greenhouse gasses. This study evaluated the effects of the application of LPS and inorganic mineral fertilization during the rainy and dry seasons on the emissions of CO2, CH4 and N2O in pastures planted with Tifton-85. The following treatments were tested: Control - no fertilization; LPS30 - 30 m3 ha-1; LPS60 - 60 m3 ha-1; LPS90 - 90 m3 ha-1 and inorganic mineral fertilization. Gasses were sampled using static chambers first during the months of March and April, then in June and July. Fertilization with LPS caused an increase in the flux of CO2 and CH4 during the first hours after its application, and CO2 emissions are greater during the rainy than in the dry season. However, the application of LPS in Tifton-85 pasture during rainy periods did not show high potential for emission of CO2, in contrast to application during the dry season. Fertilization with LPS increases the emission of N2O, and this varies as a function of the volume of LPS applied and the experimental conditions experimental conditions. The application of LPS in Tifton-85 pasture has a high potential for N2O emission during the rainy season, but the magnitude is similar to that resulting from inorganic mineral fertilization.

Sows-Gilts Stocking Rates and Their Environmental Impact in Rotationally Managed Bermudagrass Paddocks.

Simple SummaryMaintaining a ground cover greater than 75% and controlling nutrient loading and distribution are considered best management practices for pasture pig operations. These practices improve soil health and water quality, by minimizing runoff containing soil, water and nutrients. Those goals are not easily reached when managing pigs on pastures. This study was conducted to evaluate the effect of three sow stocking rates (10, 15 or 25 sows-gilts ha−1) on ground cover and soil nutrient concentrations of bermudagrass (Cynodon dactylon L. Pers) paddocks managed in a rotational stocking system. Increasing the Stocking rates were inversely related with the deterioration of vegetative ground cover and directly related to soil nutrient loads in the soil. The stocking rates should be kept in the range of 10 to 15 sows-gilts ha−1 to minimize the environmental impact of sows-gilts managed on bermudagrass.Ground cover maintenance and nutrients management are key elements to reduce the environmental impact of outdoor swine production. The objective of this study was to determine the effects of sows-gilts stocking rates on vegetative ground cover and soil nutrient concentrations in rotationally stocked bermudagrass (Cynodon dactylon L. Pers) pastures. Three stocking rates (10, 15 and 25 sows-gilts ha−1) were compared during three 8-week grazing periods. Increasing the stocking rate from 10 to 25 sows-gilts ha−1 decreased the ground cover of the paddocks from 65 to 48%, and increased soil nutrient concentrations (ammonium 47%; nitrate 129%; phosphorus 53%; zinc 84%; and copper 29%).

Evaluation of growth performance and carcass characteristics of beef stocker cattle grazing Tifton 85 bermudagrass supplemented with dried distillers grains with solubles then finished in the feedlot

ABSTRACT Objective The objective of this study was to determine the influence of varying rates of dried distillers grains with solubles (DDGS) supplemented daily on performance of beef stocker cattle grazing Tifton 85 (Cynodon dactylon [L.] Pers. × Cynodon nlemfuensis Vanderyst) bermudagrass pastures. Materials and Methods Steers (n = 112, 379 ± 35.5 kg of BW) were stratified by BW and randomly allocated to 16 pastures (0.7 ± 0.01 ha) during each summer of 2 yr (2014, 2015). Pastures were allocated randomly to 3 daily rates of a DDGS supplement (SUPP; 0.25, 0.5, or 1% BW) and a nonsupplemented control (PAS) for 110 d in 2014 and 112 d in 2015. Results and Discussion Steer ADG increased linearly (P Implications and Applications Supplementation of beef stocker cattle with DDGS while grazing Tifton 85 bermudagrass may be a viable management strategy to enhance gain per animal or land area.

Including Legumes in Bermudagrass Pastures

Including Legumes in Bermudagrass Pastures

Economic evaluation of genetic markers for cow-calf operations differentiated by forage type and breed

When selecting breeding stock, the use of genetic marker information in beef cattle (Bos taurus L., and Bos indicus L.) is expected to enhance herd performance and thereby producer returns. Cattle performance data from experimental trials, tracking the single nucleotide polymorphism (SNP) P450 C994G and HSP70 CDS G2033C genotypic distributions in Angus (AA; Bos taurus), Brahman (BB; Bos indicus), and their reciprocal cross (RC) cows were investigated to determine economic performance differences when grazing endophyte infected tall fescue [Lolium arundinaceum (=Festuca arundinacea)] compared to Bermudagrass (BG; Cynodon dactylon L.) pastures. Since open cows were not culled, the study provides unique lifetime data on cow-calf breeding failure rates. These data are essential for economic comparisons of spring calving herds that were either exposed to fungal endophyte [Epichloë coenophiala (=Neotyphodium coenophialum=Acremonium coenophialum)] infected tall fescue grazing and hay (E+) or not (BG). The Forage and Cattle Analysis and Planning (FORCAP) decision support software was used to assess impact on profitability of birth weight, weaning weight, and breeding failure rate differences across treatment. Results showed that added SNP marker information did little to separate animal performance. A neural network approach also was used to assess the impact of genetic marker information to predict economic performance. Using either gene SNP, less than 5% of variation in economic returns was affected by genetic information, with the largest driver of profitability being breeding failure rate. Using the two genetic markers of this study to predict breeding failure rate showed little evidence to suggest that breeding decisions could be improved using genetic marker information. With more data, this conclusion may well change as observed least square mean differences by SNP were larger than the cost of obtaining the information but not statistically significant.

Cigarrinhas-das-pastagens em Santa Catarina: avaliação do complexo de espécies e da incidência natural de fungos entomopatogênicos

Abstract – Systematic surveys were conducted to determine the proportion of species of spittlebugs and assess the natural incidence of entomopathogenic fungi species on populations collected in pastures located in different municipalities of the state of Santa Catarina, Brazil. For such, adult specimens were collected in pastures of bermudagrass, Cynodon dactylon cv. Tifton 85, without application of mycoinsecticides from 12 municipalities using a sweeping net device. In the laboratory conditions, the proportion of spittlebugs species and their natural mortality was observed for 10 days. Their cadavers were stored and disinfected, being kept on Elisa plates to assess the incidence of fungi species and their subsequent isolation. Based on obtained samples, seven spittlebug species were identified ( Notozulia entreriana , Deois schach , Deois knoblauchii , Mahanarva integra , Deois flavopicta , Deois flexuosa , Deois incompleta ), being N. entreriana and D. schach classified as super-frequent, constant, super-dominant and super-abundant according to the faunistic analysis employed. Moreover, 15 fungi species were found ( Alternaria sp., Aspergillus sp., A. niger , Bipolaris sp., Cladosporium sp., Curvularia sp., Metarhizium sp., Mucor sp., Nigrospora sp., Penicillium sp., Pestalotia sp., Pithomiices sp., Monilia sp.) in association with spittlebugs. Most are recognized as opportunistic pathogens or plant endophytes. Natural incidence of entomopathogenic fungus Metarhizium spp. was low in all sampled areas (0.7% of the total of collected spittlebug).

Potential role of rumen microbiota in altering average daily gain and feed efficiency in meat goats fed simple and mixed pastures using bacterial tag-encoded FLX amplicon pyrosequencing1.

Cost-effective and feasible production system of meat goats requires that grazed forages are converted to profitable goat meat product. However, there are studies as how altering forage type influences ruminal fermentation parameters and animal growth performance, and interact with microbiota in meat goats. Our objective for current study was to examine whether the comparative abundance of the Bacteroidetes (B) and Firmicutes (F) bacterial phyla in meat goats fed simple and mixed forages influenced average daily gain (ADG) and rumen fermentation parameters. In the present study, a molecular approach, bacterial tag-encoded FLX amplicon pyrosequencing (bTEFAP) was applied to accomplish diversity analyses of rumen bacterial populations. Thirty-six Kiko-cross growing meat goats (body weight (BW) = 27.7 ± 2.83 kg) at approximately 7 mo of age were used in this study. Animals were randomly allocated to 3 pasture treatment groups (n = 12) as follows: 1) bermudagrass pasture (BG; Cynodon dactylon), 2) sunn hemp forage (SH; Crotalaria juncea), and 3) BG + SH forage combinations. There were 2 replicates per treatment and animals grazed these pastures for 45 d. Results indicated that treatments had similar initial BW, but final BW and ADG were higher (P < 0.01) for SH and BG + SH combinations than for BG alone. Animal ADG and rumen fermentation (acetate to propionate; A/P ratios) were highly correlated with the abundance of various bacterial populations within the rumen microbiome. There were linear decreases in percentage of Bacteroidetes (R2 = -0.84; P < 0.05) associated with decreasing ADG. In contrast, increased ADG was linearly associated with higher percentages of Firmicutes (R2 = 0.79; P < 0.05), F/B ratios (R2 = 0.88; P = 0.07), total VFA (R2 = 0.45; P < 0.05), and lower A/P ratio (R2 = -0.72; P < 0.01). This suggests that the substrates (diets) and bacterial community have the role in adapting host biological parameters in meat goats. The abundance examination of both Bacteroidetes and Firmicutes will be useful for exploring the structure of gut microbiota as an estimate of animal performance.

Comparison of water consumption estimates for tropical and winter forages by FDR probes and weighing lysimeters

Soil moisture determination is essential for a good use of available water resources. In this regard, the use of frequency domain reflectometry (FDR) probes has as advantages mobility and practicality in relation to lysimeters. The experiment was carried out between April and June 2016 at the Luiz de Queiroz College of Agriculture (ESALQ/USP), located in Piracicaba, SP at the geographical coordinates 22°42?14.6? S and 47°37?24.1? W and altitude of 546 m. This study aimed to assess these FDR probes to estimate water consumption in comparison to measurements by weighing lysimeters (ETcLys) and reference evapotranspiration (ETo) in Mombaça and Bermuda grass pastures under single cultivation and overseeded with oat and ryegrass. Soil moisture was assessed daily by FDR probes by estimating crop evapotranspiration (ETcFDR probe) from soil water balance calculation, which was correlated with ETcLys and ETo (Penman-Monteith, FAO 56). For all treatments, FDR probes presented the highest water consumptions when compared to the other two evapotranspiration methods, with accumulations of 126.5 and 125.6 mm for single and overseeded Mombaça grass, respectively. For Bermuda grass, water consumption was 123.4 mm in the single cultivation and 128.5 mm when overseeded. The method of estimating evapotranspiration by FDR probes showed good correlations with ETo and ETcLys.

Managing Bahiagrass in Hybrid Bermudagrass Pastures

Bahiagrass is the most common forage grown in Florida, covering approximately 2.5 million acres. The popularity of bahiagrass in Florida can be attributed to its drought tolerance, low fertility requirements, and persistence even under heavy grazing. Although bahiagrass is an important forage species, it can be a serious weed problem for those wishing to produce high-quality bermudagrass hay. Bahiagrass typically does not invade a healthy bermudagrass sward, but as the stand begins to thin and nutrients such as nitrogen become limiting, bahiagrass invasion is common. Additionally, a small percentage of bahiagrass seed can remain in the soil for several years. A healthy bermudagrass sward is necessary to prevent bahiagrass establishment, but herbicides can be used if encroachment begins. This document is SS-AGR-257, one of a series of the Agronomy Department, UF/IFAS Extension. Original publication date September 2005.&#x0D; SS-AGR-257/AG243: Managing Bahiagrass in Bermudagrass, Stargrass, and Limpograss Pastures (ufl.edu)

Insecticide Evaluations for Grasshopper Control in Bermuda Grass Pasture, 2019

Insecticide Evaluations for Grasshopper Control in Bermuda Grass Pasture, 2019

BERMUDAGRASS (CYNODON DACTYLON) RESPONSE TO SUMMER PRESCRIBED BURNING

Abstract Bermudagrass (Cynodon dactylon (L.) Pers.) is one of the principle hay and forage crops throughout Texas. However, maintaining the productivity of those pastures can be challenging due to high input costs such as fertilizer and herbicide. To offset fertilizer costs and increase vegetative reproduction of bermudagrass stands, a summer prescribed burn was implemented on an irrigated bermudagrass pasture in west-central Texas. Summer fires took place on 30 July 2015 near San Angelo, Texas. Soil response to burning was measured using plant root simulator probes (PRS Western Technologies) to determine the belowground effects of a hot summer prescribed burn. Vegetative reproduction of bermudagrass was assessed by determining active, dormant, and dead vegetative buds on bermudagrass tillers. Forage quality of bermudagrass hay samples were also assessed to determine prescribed burn effects. Prescribed burning was beneficial to bermudagrass irrigated pasture. Bioavailable nitrogen (N), calcium (Ca), magnesium (Mg), phosphorus (P), potassium (K), iron (Fe), manganese (Mn), zinc (Zn), and sulphur (S) increased following the prescribed burn compared to the non-burned control. Burned bermudagrass had increased bud bank activity and density compared to non-burned controls. Forage analysis also showed positive responses to prescribed burning with increases in crude protein (cp), total digestive nutrients (TDN), K, and Ca in hay forage samples compared to samples taken from non-burned controls. Prescribed burning presents a positive, inexpensive alternative to fertilizer on irrigated bermudagrass pastures. Prescribed burning offers both below-and aboveground positive effects through increased forage quality, soil fertility, and vegetative reproductive buds of bermudagrass.

Impacts of over-seeding bermudagrass pasture with multispecies cover crops on soil water availability, microbiology, and nutrient status in North Texas

Cover crops over-sown into established perennial bermudagrass (Cynodon dactylon) pastures has been effective in improving forage productivity and net farm profitability in wetter grasslands in US. To assess if the use of cover crops can do so in the relatively dry regions of Southern Great Plains of Texas, we evaluated what positive and negative impacts accrue from sowing winter growing mixed species cover crops into bermudagrass pastures by measuring soil water dynamics, soil nutrient and soil microbial dynamics on three separate commercial farms over three growing seasons. There was no evidence that annual, winter growing cover crops reduced soil moisture to negatively affect the following production of the bermudagrass pasture. This result was obtained in years that had average to above average precipitation and may have been different in drier years. At one of the farm sites the key biological function changes we measured positive changes in soil biological activity and fertility to indicate that positive biological changes had taken place and could after more years add up to greater improved outcomes. However, the lack of positive soil biological responses on the other two farms may indicate that soils initially having low soil organic matter, poor permeability, water holding capacity and fertility would need to develop greater levels of soil organic matter with better management before positive responses using cover crops would yield acceptable improvements. However, they are a likely means of contributing to these desired improvements. Cover crop biomass levels were greater on the drill than Broadcast and Control but the improved biomass with broadcasting to establish the cover crops on all three farm sites has important cost lowering implications even though it was applied at a 33% higher seeding rate. It is likely that improved grazing management of perennial pasture is necessary to improve soil organic carbon and soil biological function in conjunction with the use of cover crops.

PSXI-23 Effects of stocking rate on body condition of F-1 (Brahman x Hereford or Angus) cows at weaning and rebreeding performance.

Body condition score (BCS) of cows at weaning, at calving, and at time of rebreeding can affect percent rebreeding and calving interval. During a 26-yr period, 3282 head of average 6.5 yr old F-1 (Brahman x Hereford or Angus) cows that calved in fall (n=1451) or winter (n=1825) were used in stocking rates on pasture. Fall (FAL) calves were born 25 Sept, stocked on ryegrass or clover overseeded on bermudagrass (BG), and weaned 17 June. Winter (WIN) calves were born 14 Feb, stocked on BG pastures, and weaned 1 Oct. Cows were sorted at weaning into 3 groups of BCS: <=4 (LO); 5 (ME); or >=6 (HI). After weaning, FAL calvers grazed BG pastures without supplement (SUP), and WIN calvers grazed BG until 15 Nov, and thereafter on BG hay plus 2 kg per day SUP. At weaning, cow BCS was different (P<0.001) for each group with FAL BCS at 3.9, 5.1, and 6.5; and WIN BCS at 3.8, 5.0, and 6.3. Calving interval was similar within a calving season, but different (P<0.05) for WIN at 365 d and FAL at 375 d. Cows with different BCS at weaning varied (P<0.01) in body weight from 480 kg (LO) to 570 kg (HI). Cow BCS was different (P<0.001) at subsequent birth in FAL for each category of LO (5.5), ME (5.7), and HI (6.2); and different (P<.001) for WIN at LO 5.2, ME 5.5, and HI at 5.8. Rebreeding was similar for FAL vs WIN cow BCS at weaning with 90.5, 90.0, and 88%, respectively for LO, ME, and HI BCS. Brahman F-1 cows calving in FAL or WIN and with LO BCS at weaning regained BCS>5.2 on BG pasture or BG hay plus SUP by the time of the next calf for FAL (103 d) and WIN (132 d).

426 Economics of replacing N fertilization with legumes in bermudagrass pastures for growing beef steers in the Southeastern USA.

426 Economics of replacing N fertilization with legumes in bermudagrass pastures for growing beef steers in the Southeastern USA.

Short-term impacts of high levels of nitrogen fertilization on soil carbon dynamics in a tropical pasture

Bermudagrass (Cynodon spp.) is widely recognized by its ability to respond positively to nitrogen (N) fertilization. Nitrogen often promotes shoot and root growth and, consequently, increase carbon (C) inputs into the soil via above- and below-ground biomass. The objective of this 2-yr field study was to assess the short-term effects of increased N levels on soil C dynamics of a Tifton 85 bermudagrass pasture grown in a tropical soil. Treatments consisted of five levels of N fertilization (0, 60, 120, 180 and 240 kg ha−1 N) applied at each harvest for a total of four harvest events per year. Soil samples were collected at the 0 to 0.1 and 0.1 to 0.2 m depths for determination of soil C content. The latter was also fractionated into free-light (FLF), particulate organic carbon (POC), and mineral-associated organic carbon (C-min) fractions. Results indicated that N levels showed no effect on total C content and distribution among the various size-density fractions. The top layer (0–0.1 m) was more sensitive to changes in soil C for more recalcitrant fractions (POC and C-min) relative to 0.1–0.2 m layer. Our findings suggest that acceleration of the decomposition rate induced by N fertilization may have offset the potential accumulation of soil C associated with high inputs of above- and below-ground biomass, but additional research is warranted to better elucidate long-term impacts of nitrogen fertilization on soil C dynamics in grassland of tropical regions.

Forage Characteristics of Bermudagrass Pastures Overseeded with Pintoi Peanut and Grazed at Different Stubble Heights

Overseeding warm‐season legumes into warm‐season perennial grass pastures may increase productivity and nutritive value of pastures in tropical and subtropical regions. The objective of this study was to investigate the effects of overseeding ‘Amarillo’ pintoi peanut (Arachis pintoi Krapov. &amp; W.C. Greg.) into Jiggs bermudagrass [Cynodon dactylon (L.) Pers.] pastures grazed at different stubble heights. The experiment was conducted in Ona, FL, from June to October in 2014 and 2015. Treatments were a split‐plot design of two sward types (bermudagrass monocultures or overseeded with pintoi peanut, main plots) and two postgrazing stubble heights (15 or 25 cm [SH15 and SH25], subplots) arranged in a randomized complete block design with four replicates. Pastures were mob stocked, with 28‐d resting periods between grazing events. There was no effect of stubble height on pintoi peanut plant density (5.8 plants m−2), ground cover (5.8%), or proportion in the herbage mass (HM, 5.2%); however, proportion in the HM increased from 1.1 to 8.2% over 2 yr. There was no effect of sward type on weed ground cover; however, SH25 had greater weed ground cover than SH15 (53.4 vs. 18.2%). Herbage accumulation rate, crude protein, and in vitro digestible organic matter were not affected by sward type (23.4 kg ha−1 d−1, 101 g kg−1, and 431 g kg−1, respectively). Pintoi peanut proportion in the HM increased over time; however, it may take &gt;2 yr to have a significant presence of pintoi peanut in the mixed sward.

Effects of grazing different ergovaline concentrations on vasoactivity of bovine lateral saphenous vein.

Previous research has demonstrated that exposure to ergot alkaloids reduces vasoactivity of serotonin (5HT) receptors. Chemical suppression of tall fescue seedhead production is a tool to reduce the level of exposure to ergot alkaloids by a grazing animal. Therefore, the objective was to evaluate contractility of lateral saphenous veins biopsied from mixed breed steers following a 87- to 101-d grazing period on 3-ha pastures of bermudagrass (Cynodon dactylon; n = 5 steers; BW = 340 ± 9 kg), or toxic endophyte-infected tall fescue (Lolium arundinaceum) that was not treated (n = 5 steers; BW = 300 ± 6; 0.56 ppm ergovaline) or was treated (n = 5 steers; BW = 294 ± 9 kg; 0.24 ppm ergovaline) with herbicide containing aminopyralid and metsulfuron-methyl. To evaluate contractility, biopsied veins were mounted in a multimyograph and exposed to increasing concentrations of a tall fescue seed extract (EXT; ergovaline source) and 5HT1B (CP 93129), 5HT1D (L-694,247), and 5HT2A (TCB2) agonists. All contractility data were normalized to a maximal response of 1 × 10-4 M norepinephrine and were analyzed as a split plot treatment design using SAS for effects of pasture treatment, agonist concentration, and the interaction. There was no contractile response to any concentration of 5HT1B agonist in any of the pasture treatments. There were pasture × concentration interactions for contractile responses to 5HT2A agonist (P < 0.01) and EXT (P < 0.01). For both EXT and TCB2, veins from bermudagrass steers were more vasoactive to the higher concentrations of these compounds (P < 0.05), and there were no differences between veins collected from the unsuppressed or seedhead-suppressed treatments (P = 0.66). There was also a pasture × concentration interaction for the contractile responses to 5HT1D agonist (P < 0.01). However, these responses were not sigmoidal and reached a zenith at 5 × 10-7 and 1 × 10-6 M. At these concentrations, the response was greatest for veins from the unsuppressed treatment (P < 0.05) and did not differ between veins from suppressed and bermudagrass treatments (P = 0.41). Although reduced levels of ergovaline in seedhead-suppressed pastures did not alter vasoactivity of 5HT2A or 5HT1B receptors in the lateral saphenous vein, elevated vasoactivity of 5HT1D in veins from unsuppressed tall fescue pasture treatment suggests that lower ergovaline levels in seedhead-suppressed pastures can influence the vascular effects of ergot alkaloids.

Including Legumes in Bermudagrass Pastures

Including Legumes in Bermudagrass Pastures

Fixed versus variable rest period effects on herbage accumulation and canopy structure of grazed 'Tifton 85' and 'Jiggs' Bermuda grass

Abstract: The objective of this work was to evaluate the effects of variable and fixed rest periods on the forage production, plant-part composition, and canopy structural characteristics of 'Tifton 85' and 'Jiggs' Bermuda grass (Cynodon spp.) pastures under rotational stocking. The treatments were two grass cultivars (Jiggs and Tifton 85) and two rest periods (grazing starting whenever the canopy reached 25 cm or every 28 days, regardless of canopy height). A completely randomized experimental design, with a 2×2 factorial arrangement (two grass cultivars and two managements), was used with three replicates. The experiment was carried out during the summer growing season in Piracicaba, SP, Brazil. Pre- and post-grazing forage mass chacteristics were evaluated. 'Jiggs' and 'Tifton 85' canopies had similar light interception (96.8%) at pre-grazing, for fixed and variable rest periods; however, they showed different canopy structural characteristics. 'Jiggs' had greater stem proportion, greater canopy height during pre-grazing, and lower leaf area index. There were no differences between strategies and between grass cultivars for total yield, which averaged 16.8 Mg DM ha-1. Fixed and variable rest periods can be used for 'Tifton 85' and 'Jiggs' Bermuda grass.