Larry A. Redmon

Nutritive value, fermentation characteristics, and in situ disappearance kinetics of sorghum silage treated with inoculants

Fibrolytic enzymes and microbial inoculants have the potential to improve the value of sorghum feedstuff and feedstock. An experiment was conducted to determine nutritive value, ensiling characteristics, and in situ disappearance kinetics of 4 sorghum (Sorghum bicolor L.) silage varieties: Dairy Master BMR (DBMR; brown midrib; Richardson Seed, Vega, TX), PS 747 (PS; photoperiod sensitive; Pogue Seed, Kenedy, TX), Silo 700D (S700D; conventional forage type; Richardson Seed), and MMR 381/73 (MMR; conventional forage type; Richardson Seed) pretreated with fibrolytic enzyme (xylanase plus cellulase, XC; 50:50 mixture of Cellulase Plus and Xylanase Plus; Dyadic, Juniper, FL) or microbial [Promote ASB (Lactobacillus buchneri and Lactobacillus plantarum); Cargill Animal Nutrition, Indianapolis, IN; PRO] inoculants. The greatest yield was for cultivar PS and the least for MMR. Neutral detergent fiber (NDF) concentration was least for XC-treated silage, and acid detergent fiber (ADF) concentration was least for XC- and PRO-treated silage. When silage was treated with XC, concentrations of NDF concentrations decreased, on average, 4.81% across all cultivars and ADF concentrations decreased, on average, 3.23% in all cultivars except MMR. Inoculant PRO reduced the NDF concentration of DBMR by 6.47%. The ADF concentrations of DBMR and PS treated with PRO were decreased by 3.25%. Treating sorghum silage with XC or PRO reduced the NDF and ADF fractions, which increased cell wall degradability. In vitro true digestibility was greatest for PRO-treated DBMR, whereas acid detergent lignin was least for PRO-treated DBMR. Aerobic stability was not improved by PRO; however, aerobic stability of XC-treated MMR was 63 h greater than that of the control. Acetate concentrations were greatest for XC-treated MMR, which explains the 63-h improvement in aerobic stability due to the inhibition of fungi. However, inoculant PRO did not improve yeast and mold counts or aerobic stability of sorghum silage compared with the control, which may be due to the lesser acetate concentrations, especially of PRO-treated S700D silage. Generally, in situ disappearance kinetics were improved with the application of XC and PRO, and XC had the greatest effect on silage with greater NDF and ADF concentrations.

Broomsedge (Andropogon virginicus) Response to Herbicides and Burning1

Broomsedge control studies were conducted on six broomsedge-infested pastures in southeastern Oklahoma from 1995 to 1997. Glyphosate applied in spring at 2.24 kg ai/ha decreased broomsedge plant density by 58% 3 mo after treatment (MAT), on areas where the previous years forage was grazed, and by 95% 3 MAT, where spring fire had removed the old top-growth before glyphosate application. Broomsedge plant density was not affected where glyphosate was applied in spring to sites with old-standing top-growth. Paraquat applied in spring at 0.56 kg ai/ha and spring burning without a herbicide treatment had no effect on broomsedge plant density. Glyphosate at 0.56 and 1.12 kg ai/ha applied in late summer reduced the number of broomsedge stems 1 yr after treatment (YAT) by an average of 65 and 80%, respectively. Paraquat at 0.56 kg/ha applied in late summer of 1995, followed by burning 1 wk after treatment (WAT), decreased broomsedge stem density by more than 60% 1 YAT at four of six locations when compared with mowing in late summer. Burning in November after an October frost decreased broomsedge stem density by more than 47% 1 YAT at four locations. Two consecutive years of burning after frost and paraquat applied in late summer followed by burning 1 WAT reduced broomsedge dry matter production by 68 and 96%, respectively, when compared with mowing in late summer. These data suggest that good to excellent control of established broomsedge is possible with herbicides alone, with a combination of herbicides and late-summer burning, and with fall burning after an early frost in a dry fall. However, broomsedge control was short-lived with all the treatments because of the establishment of new broomsedge seedlings. Thus, it will be important to integrate the destruction of broomsedge plants with proper fertility and grazing management in order to provide satisfactory broomsedge control. Nomenclature: Glyphosate; paraquat; broomsedge, Andropogon virginicus L. #3 ANOVI. Additional index words: CYNDA, Cynodon dactylon, mowing, prescribed fire. Abbreviations: DM, dry matter; MAT, months after treatment; WAT, weeks after treatment; YAT, years after treatment.

Nonriparian Shade as a Water Quality Best Management Practice for Grazing-Lands: A Case Study

On the Ground Cattle within riparian zones can negatively impact water quality and riparian health, which are important environmental concerns for grazing lands. Best management practices (BMPs) help mitigate agricultural pollution. Since BMPs are primarily voluntary, stakeholder acceptance is critical, and agricultural producers need BMPs that are relevant to their operation and will not negatively impact production. Alternative shade has been suggested as a water quality BMP, with both environmental and agricultural benefits. After implementing the nonriparian shade structure, a 30% average reduction was observed in the time cattle spent within the riparian zone.

Inoculants to Enhance the Ruminal Degradation of Small-Grain Forage

Abstract Fibrolytic enzymes and microbial inoculants have the potential to improve fiber degradability. A 2 × 2 × 2 factorial experiment was conducted to determine the nutritive value, ruminal degradability, and degradation rates of wheat ( Triticum aestivum L.) and oat ( Avena sativa L.) pretreated with fibrolytic enzyme (xylanase plus cellulase: XC) or bacterial [Promote ASB ( Lactobacillus buchneri and L. plantarum ); PRO] inoculants at two maturities. Forage was harvested twice during the tillering stage (H1 and H2) and a third time as stover (H3). Forage from H1 had less neutral detergent fiber (NDF; 43.8% dry-matter [DM] basis) and acid detergent fiber (ADF; 31.2% DM basis) and greater in vitro true digestibility (IVTD; 78.5%) concentrations than H3 (69.0 and 45.3% DM basis, and 51.9%, respectively). The IVTD was greater for oat (55.0%) than wheat (50.7%). Chemical composition was not affected by inoculant; however, inoculant did affect ruminal degradability and degradation rates. Potentially degradable DM, NDF, and ADF and effective ruminal degradability were greater for wheat and oat at tillering. Treatment of oat or wheat with XC or PRO enhanced potential degradability and reduced undegradable fractions. Both XC and PRO may be used to degrade the fiber fractions of small-grain forage.