Soil Bacterial Diversity Responds to Long-Term Establishment of Perennial Legumes in Warm-Season Grassland at Two Soil Depths.

The introduction of rhizoma peanut (RP Arachis glabrata Benth) into bahiagrass (Paspalum notatum Flüggé) may require time to develop stable plant-soil microbe interactions as the microbial legacy of the previous plant community may be long-lasting. A previous study showed that <2 years of introducing rhizoma peanut into bahiagrass pastures minimally affected soil bacterial diversity and community composition. In this study, we compared the effects of the long-term inclusion of rhizoma peanut (>8 years) into bahiagrass on soil bacterial diversity and community composition against their monocultures at 0 to 15 and 15 to 30 cm soil depths using next-generation sequencing to target bacterial 16S V3-V4 regions. We observed that a well-established RP-bahiagrass mixed stand led to a 36% increase in bacterial alpha diversity compared to the bahiagrass monoculture. There was a shift from a soil bacterial community dominated by Proteobacteria (~26%) reported in other bahiagrass and rhizoma peanut studies to a soil bacterial community dominated by Firmicutes (39%) in our study. The relative abundance of the bacterial genus Crossiella, known for its antimicrobial traits, was enhanced in the presence of RP. Differences in soil bacterial diversity and community composition were substantial between 0 to 15 and 15 to 30 cm soil layers, with N2-fixing bacteria belonging to the phylum Proteobacteria concentrated in 0 to 15 cm. Introducing RP into bahiagrass pastures is a highly sustainable alternative to mineral N fertilizer inputs. Our results provide evidence that this system also promotes greater soil microbial diversity and is associated with unique taxa that require further study to better understand their contributions to healthy pastures.

Effects of providing artificial shade to pregnant grazing beef heifers on vaginal temperature, growth, activity, and behavior.

This experiment evaluated the effects of providing artificial shade during summer on activity, behavior, and growth performance of pregnant grazing beef heifers. Thirty-six black-hided Angus and Angus crossbred pregnant heifers [418 ± 9 kg body weight (BW); approximately 90 d of gestation] were stratified by breed, blocked by BW, and allocated to 12 "Pensacola" bahiagrass pastures (Paspalum notatum Flüggé; 1.3 ha, n = 3 heifers/pasture) with or without access to artificial shade (SHADE vs. NO SHADE; 6 pastures each) for 7 wk during summer. The shade structures were composed of shade cloth (11 × 7.3 m length, 2.4 m height: 26.8 m2 of shade per heifer). Shrunk BW was recorded on enrollment (day 0) and week 7 (day 47), whereas full BW was obtained on week 2 (day 14), 4 (day 28), and 6 (day 42) to assess average daily gain (ADG). Vaginal temperature was recorded for five consecutive days during weeks 1, 3, 5, and 7 using an intravaginal digital thermo-logger, and individual GPS devices were used to quantify the use of shade for an 8-h period. Activity was monitored using automated monitoring devices (HR-LDn tags SCR Engineers Ltd., Netanya, Israel) through the experimental period. Vaginal temperature was lower (P < 0.01) for heifers in the SHADE compared with heifers in the NO SHADE treatment from 1200 to 1600 h and 1100 to 1900 h for weeks 1 and 3, respectively. Heifers in the SHADE treatment spent 70% of the 8-h period evaluated under the shaded structure. Provision of shade increased (P < 0.01) daily lying time (11.4 ± 0.2 vs. 10.3 ± 0.2 h/d) and standing bouts per day (P < 0.01; 12.6 ± 0.4 vs. 10.8 ± 0.4 bouts/d), whereas it reduced (P < 0.01) standing bout duration (61.6 ± 3.0 vs. 82.9 ± 3.0 min/bout) relative to heifers without access to shade. The interaction between treatment and hour affected (P < 0.01) daily rumination time because heifers with access to SHADE had greater rumination between 1000 and 1200 h. Although ADG tended (P = 0.08) to be greater for the heifers in the SHADE treatment (0.20 vs. -0.02 kg, respectively), the access to shade did not (P = 0.79) affect the final BW. In conclusion, providing artificial shade during summer to pregnant grazing beef heifers was effective in reducing vaginal temperatures and exerted changes in heifer behaviors that translated into slight improvements in growth performance.

Dwarf and Tall Elephantgrass Genotypes under Irrigation as Forage Sources for Ruminants: Herbage Accumulation and Nutritive Value.

This two-year study evaluated the effect of Pennisetum purpureum genotypes under rainfed or irrigated conditions, during the dry and rainy seasons, on herbage, leaf, and stem dry matter (DM) accumulation rates, nutritive value, and carbohydrate and protein fractionation. Treatments were tall (Iri 381 and Elefante B) or dwarf (Mott and Taiwan A-146 2.37) genotypes under rainfed or irrigated conditions. Taiwan A-146 2.37 (146 kg DM ha per day) showed similar herbage accumulation rate (HAR) to tall genotypes during the rainy season (124 and 150 kg DM/ha per day, respectively). Dwarf genotypes showed differences in leaf accumulation rate (LAR) (66 and 49 kg DM/ha per day). Mott leaf had less neutral detergent fiber (NDF) (589 g/kg DM) than Taiwan A-146 2.37 (598 g/kg DM), and tall genotypes had generally greater NDF (668 g/kg DM) than the dwarf genotypes. Irrigation increased fiber deposition in the leaf. Stems of all genotypes had lower in vitro digestible dry matter (IVDDM) (378 g/kg DM) under rainfed conditions in the rainy season. Leaf from irrigated plots had 23% more carbohydrate C fraction (160 g/kg CHO) than those from rainfed plots (122 g/kg CHO). Dwarf genotypes had generally greater nutritive value than tall genotypes. These genotypes show promise under irrigation to fill forage gaps during dry periods.

Characterization of Forage Utilization and Pasture Management Practices on Florida Horse Operations.

This study used an online survey to gather information on forage utilization and pasture management practices implemented on horse farms in Florida. We hypothesized that pastures were inadequately managed and underutilized, resulting in greater reliance on hay. Data from 80 complete responses were submitted to descriptive analysis and Fisher's exact test. Significantly associated variables were also evaluated using multiple correspondence analysis. The primary function of the facility most reported was recreational horse use (62%). Nearly all operations (n = 79) had pasture available, with 57% reporting housing horses on pasture full time (24 hr/d) and 48% reporting implementation of rotational stocking. Most respondents reported using a combination of hay and pasture (57.5%) as their primary source of forage, followed by pasture only (32.5%) and hay only (10%). Pasture maintenance was performed by 82% of respondents, and 6% did not implement any type of pasture management. Primary forage fed to the horses was related to the type of pasture management implemented (P = .0313) and turnout practices (P = .0003). The multiple correspondence analysis showed that relying on hay as the primary source of forage was associated with a shorter duration of pasture access and lack of pasture management. Most operations did not have their hay (89%) or pasture (94%) analyzed for nutrient composition. Despite pasture availability, lack of adequate pasture management appeared to contribute to a greater dependence on hay feeding. Pasture management practices and forage analysis are potential areas for horse owner education in Florida.