Gary E. Bates

Forage Availability for White-Tailed Deer Following Silvicultural Treatments in Hardwood Forests

ABSTRACT Closed-canopy upland hardwood stands often lack diverse understory structure and composition, limiting available nutrition for white-tailed deer (Odocoileus virginianus) as well as nesting and foraging structure for other wildlife. Various regeneration methods can positively influence understory development; however, non-commercial strategies are needed to improve available nutrition in many stands, as some contain timber that is not ready to harvest and others are owned by landowners who are not interested in harvesting timber. Applications of herbicide and prescribed fire have improved availability of food and cover for deer and other wildlife in pine (Pinus spp.) systems. However, this strategy has not been evaluated in hardwood systems. To evaluate the influence of fire and herbicide treatments on available deer forage in upland hardwood systems, we measured forage availability and calculated nutritional carrying capacity (NCC) at 14% crude protein mixed diet, following 7 silvicultural treatments, including controls, in 4 mixed upland hardwood stands July–September 2007 and 2008. We compared NCC among forest treatments and within 4 paired warm-season forage food plots to evaluate the usefulness of food plots in areas where forests are managed. Nutritional carrying capacity estimates (deer days/ha) were greatest following canopy reduction with prescribed fire treatments in both years. Understory herbicide application did not affect species composition or NCC 1 year or 2 years post-treatment. Production of forage plantings exceeded that of forest treatments both years with the exception of early-maturing soybeans and retention cut with fire 2 years post-treatment. We encourage land managers to use canopy reducing treatments and low-intensity pre-scribed fire to increase available nutrition and improve available cover where needed in upland hardwood systems. In areas where deer density may limit understory development, high-quality forage food plots may be used to buffer browsing while strategies to reduce deer density and stimulate the forest understory are implemented.

Horsenettle (Solanum carolinense) Control in Tall Fescue (Festuca arundinacea) and Clover (Trifolium sp.) Pastures with Mixtures of 2,4-D and Picloram1

Herbicide treatments (4:1 ratio of 2,4-D amine:picloram) at 0.7 and 1.4 kg ae/ha at early postemergence (10- to 15-cm horsenettle height), midpostemergence (early flower), and late postemergence (fruit initiation) applied both early and late in the growing season provided >80% horsenettle control. Horsenettle density at seasons end in all treated plots was less than 0.25 stems/m2, whereas untreated plots contained about 5 stems/m2. Horsenettle control the next spring was between 47 and 66% for all rates and application timings, and horsenettle density in treated plots was less than 3 stems/m2 as opposed to about 6 stems/m2 in the untreated plots. Clover drilled into the treated area the year after herbicide application was injured, indicating clover establishment the season after application of this package mixture would be difficult. Nomenclature: 2,4-D; picloram; clover sp., Trifolium sp.; horsenettle, Solanum carolinense L. #3 SOLCA. Additional index words: Crop tolerance. Abbreviations: EPOST, early postemergence; LPOST, late postemergence; MPOST, midpostemergence.

Biomass and integrated forage/biomass yields of switchgrass as affected by intercropped cool- and warm-season legumes

Switchgrass (Panicum virgatum L.) has potential as a biofuel feedstock for ethanol production on marginal soils not suitable for row crop production. Further, it is hypothesized that legumes may be interseeded into switchgrass to increase available soil nitrogen (N) and enhance switchgrass yields. Therefore the primary objective was to identify compatible legume species for intercropping with lowland switchgrass and determine if biomass yields and forage quality can be improved. Four cool- and two warm-season legume species were compared to application of 67 and 134 kg N ha−1 (59.8 and 119.6 lb N ac−1) during 2009 and 2010 over a range of soils at three research and education centers in Tennessee. Cool-season legumes were alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), crimson clover (Trifolium incarnatum L.), and hairy vetch (Vicia villosa L.), and warm-season legumes included Illinois bundle flower (Desmanthus illinoensis L.) and partridge pea (Chamaechrista fasciculata L.). Legumes were evaluated for establishment (plant densities) and their effects on switchgrass yield and forage quality under a one-cut biomass (single, postdormancy biofuel) and an integrated two-cut (biomass/forage [preanthesis]) system. In the one-cut system, switchgrass yields (16.6 Mg ha−1 [6.7 tn ac−1]) from the current recommended rate (67 kg N ha−1 [59.8 lb N ac−1]) exceeded (p < 0.05) legume treatment yields (average 13.5 Mg ha−1 [5.5 tn ac−1]). In the integrated harvest system, switchgrass yields from red (13.4 Mg ha−1 [5.4 tn ac−1]) and crimson clover (12.8 Mg ha−1 [5.2 tn ac−1]) intercrops were not different from 67 kg N ha−1 (14.5 Mg ha−1 [5.9 tn ac−1]). Crude protein levels were greater (p < 0.05) for 134 kg N ha−1 (119.6 lb N ac−1), compared to legume intercrops (except red clover). Partridge pea showed promise as a warm-season legume that can be grown compatibly with switchgrass for up to two years. Therefore, compatible legume-intercrop candidates, such as partridge pea and red clover, may enhance switchgrass yield and forage quality while displacing synthetic N in integrated biofuel/forage systems, but need to be further investigated in efforts to reduce nitrate (NO3) leaching and emissions from fertilizing.

Avian Habitat Following Grazing Native Warm-Season Forages in the Mid-South United States

ABSTRACT Native warm-season grasses (NWSG) currently are being promoted for livestock forage and biofuels feedstock in the Mid-South. However, there are no published data on how NWSG managed with livestock in the Mid-South may affect habitat for wildlife. We conducted a study to evaluate habitat for grassland songbirds and northern bobwhite (Colinus virginianus) in response to two cattle grazing treatments in NWSG pastures across three sites in Tennessee, 2010 and 2011. We evaluated vegetation composition and structure along with invertebrate availability during the primary nesting season for grassland songbirds and the typical brood-rearing season for the northern bobwhite. Grazing treatments included full-season (May to August) grazing and early-season (30 days beginning in May) grazing, after which subsequent growth was taken as a biofuel harvest postdormancy. Forage treatments included big bluestem/indiangrass mixture, switchgrass, and eastern gamagrass. Vegetation composition was dominated by the planted forages in all pastures. All forage types and both grazing treatments provided suitable structure for grassland songbirds and bobwhite during the primary nesting season. Full-season grazing maintained suitable structure through the brooding period, with greater openness at the ground level and angle of obstruction, as well as optimal vegetation height (<60 cm). Structure within early-season grazing treatments became dense after cattle were removed with less openness at ground level than what brooding bobwhites typically use. Invertebrate biomass was sufficient in all forage types and grazing treatments to support bobwhite broods. We recommend livestock producers in the Mid-South use full-season grazing that maintains grass height of approximately 40 cm in production stands of NWSG to maximize benefits for grassland birds and northern bobwhite.

The cost of feeding bred dairy heifers on native warm-season grasses and harvested feedstuffs

Heifer rearing is one of the largest production expenses for dairy cattle operations, which is one reason milking operations outsource heifer rearing to custom developers. The cost of harvested feedstuffs is a major expense in heifer rearing. A possible way to lower feed costs is to graze dairy heifers, but little research exists on this topic in the mid-south United States. The objectives of this research were to determine the cost of feeding bred dairy heifers grazing native warm-season grasses (NWSG), with and without legumes, and compare the cost of grazing with the cost of rearing heifers using 3 traditional rations. The 3 rations were corn silage with soybean meal, corn silage with dry distillers grain, and a wet distillers grain-based ration. Bred Holstein heifers between 15- and 20-mo-old continuously grazed switchgrass (SG), SG with red clover (SG+RC), a big bluestem and Indiangrass mixture (BBIG), and BBIG with red clover (BBIG+RC) in Tennessee during the summer months. Total grazing days were calculated for each NWSG to determine the average cost/animal per grazing day. The average daily gain (ADG) was calculated for each NWSG to develop 3 harvested feed rations that would result in the same ADG over the same number of grazing day as each NWSG treatment. The average cost/animal per grazing day was lowest for SG (

Effects of Aminocyclopyrachlor Plus Metsulfuron on Tall Fescue Yield, Forage Quality, and Ergot Alkaloid Concentration

0.48/animal/grazing d) and highest for BBIG+RC (

Effects of endophyte infected tall fescue seed and red clover isoflavones on rumen microbial populations, fiber fermentation, and volatile fatty acids in vitro

1.10/animal/grazing d). For both BBIG and SG, legumes increased the average cost/animal per grazing day because grazing days did not increase enough to account for the additional cost of the legumes. No difference was observed in ADG for heifers grazing BBIG (0.85 kg/d) and BBIG+RC (0.94 kg/d), and no difference was observed in ADG for heifers grazing SG (0.71 kg/d) and SG+RC (0.70 kg/d). However, the ADG for heifers grazing SG and SG+RC was lower than the ADG for heifers grazing either BBIG or BBIG+RC. The average cost/animal per grazing day was lower for all NWSG treatments than the average cost/animal per day for all comparable feed rations at a low, average, and high yardage fee. Results of this study suggest that SG was the most cost-effective NWSG alternative to harvested feeds for bred dairy heifer rearing.

Effects of red clover isoflavones on tall fescue seed fermentation and microbial populations in vitro

Most tall fescue in the United States is infected with a fungal endophyte which imparts certain advantages to the plant, such as drought tolerance, insect feeding deterrence, and enhanced mineral uptake. However, the endophyte also produces ergot alkaloids that are harmful to livestock and contribute to fescue toxicosis. Because the alkaloids are concentrated in seed and stems, a potential way to reduce the likelihood of fescue toxicosis is by suppressing seedhead formation with herbicides. Research was conducted from 2012 to 2014 using metsulfuron applied alone and in combination with other herbicides in spring to determine the growth response of tall fescue, effects on forage quality, and ergot alkaloid concentration. Clipping or metsulfuron applied alone or in combination with aminocyclopyrachlor or aminopyralid reduced seedhead density by 36 to 55% compared to the nontreated control. Treatments containing metsulfuron reduced spring harvest yield 35 to 61%, but no differences were observed in the summer or year-after harvests. The same treatments increased crude protein levels by 1.03 to 2.14% and reduced acid detergent fiber levels by 1.60 to 2.76% compared to the nontreated control at spring harvest. Treatments containing metsulfuron reduced ergot alkaloid concentration 26 to 34% at the spring harvest, but no differences were observed in summer-harvested forage. Results from this study indicate metsulfuron applied alone or in combination with aminocyclopyrachlor or aminopyralid can potentially reduce the severity of fescue toxicosis and improve forage quality. Nomenclature: Aminocyclopyrachlor; aminopyralid; metsulfuron; tall fescue, Schedonorus arundinaceus (Schreb.) Dumort., nom. cons. La mayoría del pasto Schedonorus arundinaceus, en los Estados Unidos, está infectado con un hongo endófito lo que le brinda ciertas ventajas a la planta, tales como tolerancia a la sequía, repelencia de insectos plaga, y una absorción de nutrientes mejorada. Sin embargo, el endófito también produce esclerocios con alkaloids que son dañinos para el ganado y contribuyen a la toxicosis con S. arundinaceus. Debido a que los alkaloids están concentrados en las semillas y los tallos, una forma potencial de reducir la probabilidad de la toxicosis con S. arundinaceus es el suprimir la formación de inflorescencias con herbicidas. Se realizó una investigación desde 2012 a 2014 usando metsulfuron aplicado solo y en combinación con otros herbicidas en la primavera para determinar la respuesta del crecimiento de S. arundinaceus, los efectos en la calidad del forraje, y la concentración de alkaloids de esclerocios. La poda o la aplicación de metsulfuron solo o en combinación con aminocyclopyrachlor o aminopyralid redujeron la densidad de inflorescencias en 36 a 55% al compararse con el testigo sin tratamiento. Los tratamientos que contenían metsulfuron redujeron los rendimientos de cosecha en la primavera 35 a 61%, pero no se observaron diferencias en la cosecha de verano o cosechas en años posteriores. Los mismos tratamientos aumentaron los niveles de proteína cruda de 1.03 a 2.14% y redujeron los niveles de fibra detergente ácida de 1.6 a 2.76% al compararse con el testigo sin tratamiento en la cosecha de primavera. Los tratamientos que contenían metsulfuron redujeron la concentración de alkaloids de esclerocios de 26 a 34% en la cosecha de primavera, pero no se observaron diferencias en la cosecha de forraje de verano. Los resultados de este estudio indican que metsulfuron aplicado solo o en combinación con aminocyclopyrachlor o aminopyralid pueden potencialmente reducir la severidad de la toxicosis con S. arundinaceus y mejorar la calidad del forraje.

Management of native warm-season grasses for beef cattle and biomass production in the Mid-South USA1

Negative impacts of endophyte-infected Lolium arundinaceum (Darbyshire) (tall fescue) are responsible for over

The effect of spike-tooth aeration on tall fescue yield.

2 billion in losses to livestock producers annually. While the influence of endophyte-infected tall fescue has been studied for decades, mitigation methods have not been clearly elucidated. Isoflavones found in Trifolium pretense (red clover) have been the subject of recent research regarding tall fescue toxicosis mitigation. Therefore, the aim of this study was to determine the effect of ergovaline and red clover isoflavones on rumen microbial populations, fiber degradation, and volatile fatty acids (VFA) in an in vitro system. Using a dose of 1.10 mg × L−1, endophyte-infected or endophyte-free tall fescue seed was added to ANKOM fiber bags with or without 2.19 mg of isoflavones in the form of a control, powder, or pulverized tablet, resulting in a 2 × 3 factorial arrangements of treatments. Measurements of pH, VFA, bacterial taxa, as well as the disappearance of neutral detergent fiber (aNDF), acid detergent fiber (ADF), and crude protein (CP) were taken after 48 h of incubation. aNDF disappearance values were significantly altered by seed type (P = 0.003) and isoflavone treatment (P = 0.005), and ADF disappearance values were significantly different in a seed x isoflavone treatment interaction (P ≤ 0.05). A seed x isoflavone treatment interaction was also observed with respect to CP disappearance (P ≤ 0.05). Seventeen bacterial taxa were significantly altered by seed x isoflavone treatment interaction groups (P ≤ 0.05), six bacterial taxa were increased by isoflavones (P ≤ 0.05), and eleven bacterial taxa were altered by seed type (P ≤ 0.05). Due to the beneficial effect of isoflavones on tall fescue seed fiber degradation, these compounds may be viable options for mitigating fescue toxicosis. Further research should be conducted to determine physiological implications as well as microbiological changes in vivo.