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Creating ensiled forage on a laboratory-scale is a tedious and cumbersome process. One must ensure an anaerobic environment for the success of the fermentation while also striving to replicate field-scale conditions. The objective of this experiment was to determine the effect of laboratory-scale silo type on nutritive value and fermentation profiles of grass-legume silage. This experiment was conducted as a generalized complete block design. There was one treatment factor (silo type) with 11 levels: field-scale baleage control (CON), miniature wrapped baleage (MINI), large fermentation bucket (6GAL), small fermentation bucket (2GAL), miniature silo (PVC), pint-sized Mason-type jar with "BurpLid" (BURP), pint-sized Mason-type jar with Ball-brand fermentation lid (BALL), pint-sized Mason-type jar with an airlock lid (LOCK), single-layered vacuum-sealed bag using a chamber-style sealer (CHMB), double-layered vacuum-sealed bag using a chamber-style sealer (HCHMB), single-layered vacuum-sealed bag using a suction-style sealer (FOOD), or double-layered vacuum-sealed bag using a suction-style sealer (HFOOD). Harvest served as the random blocking factor. Forage was harvested from a single alfalfa-bermudagrass pastures at the Wiregrass Research and Extension Center in Headland, AL. Forage was cut 24 h before collection and allowed to sun-cure. After allocation to treatment, samples were allowed to ferment for 56 d. Following fermentation, samples were assayed for NDF, ADF, ADL, CP, pH, mold, and yeast. Dunnett's test revealed a difference (P < 0.05) from CON for NDF, ADF, and pH. Samples from PVC had 26% greater NDF and 45% greater ADF than CON (58 and 37%, respectively). Samples from BALL were 3 units greater and samples from LOCK were 2 units greater in pH than CON (4.8). When comparing alternative treatments exclusive of CON, there were differences (P ≤ 0.01) in NDF, ADF, ADL, pH, and mold counts among treatments. Results are interpreted to mean that BALL and LOCK are not effective representatives of field-scale silage production due to lack of pH drop, while PVC alters the fiber profiles. All other methods showed promise as prospects for laboratory silage procedures. [ABSTRACT FROM AUTHOR]

Though much effort has been made to characterize the in vivo (IV) and in situ (IS) dry matter digestibility (DMD) of southeastern forages, there is a lack of information identifying methods that best represent the in vivo digestibility of these forages. Thus, the objective of our study was to compare IV and IS methods to determine which technique best represents the in vivo DMD of four bermudagrass (Cynodon dactylon [L.] Pers.) cul-tivars. In an IV experiment, ruminally fistulated heifers (n = 4) were randomly assigned to one of four bermudagrass cultivars (Coastal [COS], Russell [RUS], Tifton 44 [T44], or Tifton 85 [T85]) for four 30-d in vivo periods (21-d adaptation and 9-d collection) in a Latin square design. On d 28 of each period, rumen fluid was collected 4 h post-feeding for an accompanying IV experiment using a completely randomized design with a 4 x 2 factorial treatment structure. Factors in the IV experiment included bermudagrass cultivar (COS, RUS, T44, and T85) and digestibility method (Tilley and Terry [TT] or Goering and Van Soest [GVS]). On d 31 of in vivo periods 3 and 5, an accompanying IS experiment was conducted as a randomized complete block design with three treatment factors (in vivo diet [previous described], bermudagrass cultivar [previously described], and incubation timepoint [0, 0.25, 0.50, 0.75, 1, 2, 3, 4, 8, 12, 16, 20, 24, 48, 72, 96, 120, 144, and 168 h]). Correlations were computed between in vivo DM disappearance and each of the IV (TT and GVS) and IS (24, 48, and 72 h) methods. Regressions were calculated for each of the individual IV and IS measurements, and a stepwise regression was used to determine the predictive value of linear combinations of the measurements. None of the IV or IS DMD values were correlated with in vivo DMD (P ≥ 0.18). Individual IV and IS DMD values did not yield significant models through linear regression (P ≥ 0.18), though the best model (based on AIC) was TT IVDMD (r² = 0.09; P = 0.26). Stepwise regression revealed that there was no linear combination of IV or IS DMD that improved prediction beyond single predictor models. While both IV and IS experiments remain viable tools to screen forages and make relative comparisons, results from this experiment are interpreted to mean that neither of these methods is suitable for prediction of in vivo performance. [ABSTRACT FROM AUTHOR]

Buffers are an essential component in various biochemical and biophysical assays, enabling the control of pH shifts in the environment. The Tilley and Terry (1963) and Goering Van Soest (1970) methods dominate in vitro forage digestibility research with equally viable results. However, the methods utilize distinct buffer solutions to control the in vitro environment. Given this divergence, it is of interest whether differences in estimates are a factor of the methodology, or the buffer solutions employed in the method. The objective of this study was to determine the effects of in vitro DM digestibility (IVDMD) methodology and buffer solution on digestibility estimates of four bermudagrass cultivars. We conducted our experiment as a randomized complete block design with a 2 × 2 × 4 factorial treatment structure. Approximately 1,000 mL of rumen content (solid and liquid fractions) were collected from two ruminally fistulated heifers in each of two periods (blocks). The samples were separated into two 500-mL aliquots; the first aliquot was subjected to the procedures of Tilley and Terry (1963), and the second aliquot was subjected to the Goering and Van Soest (1970) procedure. Duplicate samples of four bermudagrass cultivars (Coastal, Russell, Tifton 44, Tifton 85) were placed in 125-mL Erlenmeyer flasks and incubated according to the assigned in vitro method. One-half of the samples in each method received the methodologically prescribed buffer solution, and the other one-half in each method received the opposite buffer. There was no effect of in vitro method (P = 0.78), buffer solution (P = 0.53), or bermudagrass cultivar (P = 0.46), or their interactions (P = 0.23) on IVDMD estimates in this experiment. Results are interpreted to mean that buffer type is not pivotal to methodological success, and both methods will yield similar estimates of digestibility. [ABSTRACT FROM AUTHOR]

"The vine that ate the South," also known as kudzu (Pueraria montana [Lour.] Merr.) is a droughttolerant perennial leguminous vine that was introduced from Asia to the United States as an ornamental crop. It was quickly recognized and favored as a solution to soil erosion during the Dust Bowl. However, due to its ability to quickly overtake existing vegetation, it was ultimately labeled as an invasive species by the USDA. Given current sustainability efforts, interest has renewed in ways to incorporate this invasive species for productive agricultural purposes. The goal of this study was to investigate how preservation (i.e., haying) would affect the nutritive value and digestibility of kudzu forage. Kudzu was harvested from a private property in Auburn, Alabama. Two independent plots on the property were utilized; half of thefresh biomass was immediately removed, and the remaining half was removed at 20% moisture for the sun-cured sample. Samples were collected from each plot and assayed for NDF, ADF, ADL, and CP. Samples were also assayed for in vitro true and NDF disappearance (IVTD and IVNDFD, respectively) as well as in situ ruminal disappearance. Data were analyzed using SAS v. 9.4. There was no effect of preservation on NDF, ADF, ADL, and CP concentrations (P =0.39). However, kudzu samples subjected to sun-curing had greater IVTD (64.3%, P < 0.01) and IVTDOM (63.0%; P < 0.01) and tended to have greater IVNDFD (35.6%; P = 0.06) thanfresh kudzu (59.4, 57.8, and 31.3%, respectively). There was no effect (P = 0.12) of preservation on the potentially degradable fraction, lag time, or rate of digestion of kudzu samples. However, fresh samples had a greater (P < 0.01) undegradable residue than did sun-cured samples (49.3 vs.38.8%). The improvements in digestibility are interpreted to mean that preservation methods, such as sun-curing, may be valuable for increasing the value of kudzu as a roughage source for ruminant livestock production systems. [ABSTRACT FROM AUTHOR]

For in vitro digestibility experiments addressing both horses and cattle, feces have long been thought to be an equivalent surrogate for ruminal or cecal inoculum that would eliminate the need for fistulated animals. However, this assumption requires similar microbial and chemical properties among inoculum sources. Validation of the relationship of fecal to ruminal metabolic properties would allow for more readily accessible information on fermentation across nutrition experiments. Thus, the purpose of this study was to compare ruminal and fecal VFA production from heifers fed four bermudagrass (Cynodon dactylon [L.] Pers.) cultivars. Ruminally-fistulated heifers (n = 4) were assigned randomly to one of four bermudagrass cultivars (Coastal [COS], Russell [RUS], Tifton 44 [T44], or Tifton 85 [T85]) for four 30-d in vivo periods (21-d adaptation and 9-d collection). On d 28, rumen fluid (RF) samples were collected at 13 timepoints (0, 0.25, 0.5, 0.75, 1, 2, 3, 4, 8, 12, 16, 20, 24 h) and rectal fecal samples were collected at 7 timepoints (0, 0.5, 1, 2, 4, 8, 12 h). Samples were acidified with meta-phosphoric acid, and 2-ethylbutyric acid was included as an internal standard. Samples were assayed for acetic (A), propionic (P), isobutyric (IB), butyric (B), isovaleric (IV), valeric (V), 4-methylvalteric (4MV), and caproic (C) acids by gas-liquid chromatography. Data were analyzed using SAS v. 9.4. Heifers receiving COS produced less (P < 0.05) RF concentrations of A (25.01 mM), P (5.21 mM), and total VFA (34.2 mM) than T85 (43.4, 8.9, and 58.0 mM, respectively), T44 (42.0, 9.0, and 57.3 mM, respectively), and RUS (39.8 8.9, and 55.3 mM, respectively), which were all similar. Ruminal B was greatest (P < 0.05) from RUS (5.4 mM) and least from COS (3.1 mmol/L), with T44 and T85 intermediate (4.9 and 4.4 mM, respectively). There was no effect of cultivar (P = 0.10) on RF IB, IV, V, or 4MV concentrations. Fecal IB was correlated (P < 0.05) with RF IV (r = 0.59) and tended to be correlated (P = 0.09) with RF A (r = 0.39), P (r = 0.39), C (r = 0.37), and total VFA (r = 0.38). Fecal P was correlated (P < 0.05) with RF IV (r = 0.51). No other fecal VFA were correlated with RF VFA. Results are interpreted to mean that COS results in decreased ruminal fermentation relative to the other cultivars tested. However, there is little indication that fecal VFA can serve as an indicator for ruminal fermentation. [ABSTRACT FROM AUTHOR]

While much effort has been devoted to both the characterization of ruminal fermentation dynamics and the evaluation of bermudagrass production, independently, there is a lack of information regarding ruminal digestive kinetics using beef cattle in southern forage systems. Thus, the objective of our study was to evaluate in situ digestive kinetics of four bermudagrass (Cynodon dactylon [L.] Pers.) cultivars in heifers consuming typical southern forages. (Coastal, Tifton 44, Tifton 85, and Russell). Ruminally fistulated heifers (n = 4) were assigned randomly to one of four bermudagrass cultivars (Coastal [COS], Russell [RUS], Tifton 44 [T44], or Tifton 85 [T85]) for four 30-d in vivo periods (21-d adaptation and 9-d collection). On d 31 of periods 2 and 3, an in-situ experiment was conducted as a randomized complete block design with a 3-factor factorial treatment structure. The first factor (n = 4) was diet consumed by the animal (described above). The second factor (n = 4) was the incubated forage (same cultivars as the in vivo experiment). The third factor was incubation timepoint (n = 19; 0, 0.25, 0.50, 0.75, 1, 2, 3, 4, 8, 12, 16, 20, 24, 48, 72, 96, 120, 144, and 168 h). Four in situ bags were incubated in each animal at each timepoint; two were used for NDF, ADF, and ADL, and two were used for CP determination. Data were analyzed using SAS v. 9.4. There was a decreased (P < 0.05) potentially degradable fraction from COS (30.0%) compared with T85 (55.1%), T44 (48.1%), or RUS (47.1%). Similarly, COS presented the greatest (P < 0.05) undegradable fraction (37.0%) and T85 the least (15.9%), with RUS and T44 intermediate (25.0 and 21.9%, respectively). There was no effect of bermudagrass cultivar, however, on the rate constant of digestion (0.94%/h; P = 0.26) or lag time (3.2 h; P = 0.38). A visual appraisal of the degradation curve suggests that the asymptote of digestion was not reached at the measured 168 h. Results are interpreted to mean that T44 is the preferable bermudagrass cultivar, followed by T85 and RUS, while COS is the least favorable. Further, given the lack of visible asymptote, we speculate that bermudagrass likely passes the rumen before full digestion is realized. [ABSTRACT FROM AUTHOR]

Maintenance of pastures for grazing accounts for $132.50/animal in the United States (23% of operating costs), and pasture nutrient input represents the single greatest influence in productivity per unit area. Cultivar differences in the forage offered to cattle have the potential to manifest differences in digestive efficiency, resulting in different nutrient excretion profiles. The objective of this study was to assess the growth potential and incorporation of N, P, and K into forage material from manure from cattle fed one of four bermudagrass (Cynodon dactylon [L.] Pers.) cultivars. Ruminally fistulated heifers (n = 4) were assigned randomly to one of four bermudagrass cultivars (Coastal, Russell, Tifton 44, or Tifton 85) for four 30-d in vivo periods (21-d adaptation and 9-d collection). On d 23, total fecal collections were subsampled from each heifer. As a hierarchical addition, a controlled greenhouse experiment was conducted for each period [15 pots per period; 5 manure treatments (four bermudagrass diets plus a negative control) × 3 replications]. Manure was added to 4.58 L pots based on stocking rate estimates for Central Alabama (1,110 kg/ha). The pots were seeded with bermudagrass (cv. Giant) as an indicator for forage nutrient uptake. At harvest (d 70), herbage, root, and soil samples were collected. Herbage and root samples were assayed for CP. Soil samples were assayed for pH, N, P, K, Mg, and Ca. Data were analyzed using SAS v. 9.4. There was no effect of manure treatment on herbage (P = 0.88) or root DM yield (P =.00;.54 and.73 g/pot, respectively). Similarly, there was no effect of manure treatment on soil pH (P = 0.18; 5.5), P (P = 0.78; 24.2 kg/ha), or K (P = 0.42;56.7 kg/ha). Results are interpreted to mean that, regardless of the cultivar effects on ruminal digestive dynamics, there is little to no effect of the resulting manure on subsequent forage production and nutrient uptake. [ABSTRACT FROM AUTHOR]

Dried distillers grains with solubles (DDGS) is commonly used as supplemental feed in cattle rations. However, the systemic effects of overfeeding DDGS, especially to potential fertilizer benefits of passthrough nitrogen, are widely unknown. Therefore, our objective was to evaluate plant and soil response to fertilization with manure from steers supplemented with titrated levels of DDGS. Manure utilized was collected from steers supplemented with DDGS (0%, 0.25%, 0.5%, and 1% BW) during a 2-yr experiment. The experimental design was a randomized complete block design with an augmented factorial treatment structure wherein benches represented blocks. The factorial was made up of manure treatment (0, 0.25, 0.5, or 1% BW DDGS, chemical fertilizer, or none) soil type (Windthorst or Purves), and plant species (none, crimson clover, or rye). Pots were sown (5 seeds/pot) and grown in a greenhouse for 35 d. Water was applied daily at 90% evapotranspiration. After harvest, soils were sifted, dried for 72 h at 55°C, then assayed for C, N, NO3-N, P, K, Ca, Mg, Na, and S. There was an interaction of manure and soil type for soil C (P < 0.01). Purves soils amended with any manure had a greater (P < 0.05) concentration of C (1.8%) than did the negative control (1.3%). From Windthorst, soil C was greatest from 1% BW DDGS manure (1.9%), and least from 0% DDGS manure (1.5%), with 0.25 and 0.5% manures and the negative control intermediate. There was an interaction of manure, soil type, and forage for soil N (P < 0.01). Manures with higher levels of supplementation had greater (P < 0.05) soil N than lower levels of supplementation or the negative control. Legumes had greater soil N than grasses. Results are interpreted to mean that moderate supplementation of steers with DDGS may yield soil nutrient benefits through nutrient deposition. [ABSTRACT FROM AUTHOR]