Concentration and chemical constituents of lignin are factors that may influence cell‐wall (CW) digestibility of forages. This study was conducted to determine the apparent effect of lignin concentration on extent of CW digestion in immature and mature stems of grasses and legumes and to estimate and relate monomeric products of saponification and nitrobenzene oxidation of lignin to CW digestion. The basal 150 mm of stem from cultivars of field‐grown alfalfa (Medicago sativa L.), birdsfoot trefoil (Lotus corniculatus L.), smooth bromegrass (Bromus inermis Leyss.), orchardgrass (Dactylis glomerata L.), and red clover (Trifolium pratense L.) were harvested during spring growth. Laboratory evaluations included CW digestibility after 72 h of fermentation, neutral‐detergent fiber (to estimate CW concentration), permanganate lignin, alkali‐labile phenolic acids in CW, and nitrobenzene oxidation products (NBO). The apparent inhibition of CW digestion by lignin was 62% greater in grasses than in legumes. In grass stems, ferulic acid was positively correlated with arabinose [r = 0.58 (arabinose determined for another study)], whereas p‐coumaric acid was positively associated with lignin (r = 0.52). The syringaldehyde proportion in NBO increased 61% in grasses and 31% in legumes with stem maturity. The NBO as a proportion of lignin was closely related to CW digestion (r = −0.86) when both grasses and legumes were correlated. The syringaldehyde proportion in NBO was closely related to CW digestion in grass stems (r = −0.93), but not in the legumes (r = −0.23). Thus, there was close agreement between lignin concentration and CW digestibility within grass and legume stems, and the results indicate lignin chemical constituents can be important in accounting for differences in inhibition to digestion between grass and legume lignins.

The regenerative capacity of Schwann cells in the PNS underlies functional repair after injury. In this study, Mindos et al. show a new function for the tumor suppressor Merlin and Hippo/YAP signaling in the generation of repair-competent Schwann cells after injury.

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The most accurate method for determining canopy biomass of pastures for forage availability is by cutting and weighing forage from known areas. Faster methods that require less time and labor would help producers to monitor forage availability in pastures on a daily or weekly basis. Indirect methods rely on calibrations performed on pure or evenly distributed plant compositions to determine forage biomass. However, microclimates developed by varying landscape positions and soil morphological characteristics of pastures may cause uneven plant and species distributions. This study was performed to compare the ability of a modified Robel pole, rising plate meter, canopy height stick, and Li‐Cor LAI 2000 leaf canopy analyzer to determine forage availability in pastures with varying species composition from four areas. Swards consisted of pure warm‐season grass stands, cool‐season grass stands, legume stands, and grass‐legume mixtures. Instrument readings were compared with forage availability determined by clipping and were measured for accuracy, or closeness to clipped weight. For all observations, coefficients of determination (r2), were 0.63, 0.59, 0.55, and 0.32 for the modified Robel pole, rising plate meter, canopy height stick, and leaf canopy analyzer, respectively. For modified Robel pole readings, r2 was highest for observations in red clover (Trifolium pratense L.) (r2 = 0.83), smooth bromegrass (Bromus inermis Leyss.) (r2 = 0.82), and alfalfa (Medicago sativa L. (r2 = 0.76) swards, whereas the rising plate meter r2 values were highest for observations in tall fescue (Festuca arundinacea Schreb.) (r2 = 0.85), alfalfa (r2 = 0.84), and red clover (r2 = 0.73) swards. Grass observations also had their highest r2 values with the modified Robel pole and rising plate meter at 0.63 and 0.59, respectively. The modified Robel pole proved to be the most accurate method used over a variety of species.

Ammonia emission is a major concern for the poultry industry and can be lowered by dietary inclusion of fibrous ingredients and by lowering the dietary CP content. The objectives of this research were to determine the effects of dietary fiber and reduced-CP diets, which may lower NH(3) emission, on egg production and N balance in laying hens. A total of 256 Hy-Line W-36 hens were fed diets with 2 contents of CP (normal and reduced) and 4 fiber treatments in a 2 x 4 factorial arrangement from 23 to 58 wk of age. The fiber treatments included a corn and soybean meal-based control diet and diets formulated with either 10.0% corn dried distillers grains with solubles (DDGS), 7.3% wheat middlings (WM), or 4.8% soybean hulls (SH) added to contribute equal amounts of neutral detergent fiber. The CP contents of the reduced-CP diets were approximately 1 percentage unit lower than that of the normal-CP diets. All diets were formulated on a digestible amino acid basis to be isoenergetic. There were no effects (P > 0.05) of including corn DDGS, WM, or SH in the diet on egg production, egg weight, egg mass, yolk color, feed consumption, feed utilization, or BW gain. Although the corn DDGS and WM diets resulted in an increase (P < 0.001) in N consumption, N excretion was not affected (P > 0.10) compared with hens fed the control diet. The reduced-CP diets did not affect egg weight, feed consumption, or BW gain (P > 0.05); however, egg production, egg mass, feed utilization, N consumption, and N excretion were lower than that from the hens fed the normal-CP diets (P < 0.05). The results of this study show that the diets containing 10% corn DDGS, 7% WM, or 5% SH did not affect egg production or N excretion. However, the 1% lower CP diets caused a lower egg production and lower N excretion.

We evaluated the effects of cellulase (from Trichoderma longibrachiatum) application rates on neutral detergent fiber (NDF) concentration and fermentation products of orchardgrass (Dactylis glomerata L.) and alfalfa (Medicago sativa L.) silages harvested with decreasing dry matter (DM) digestibility. Additionally, the impacts of inoculant (Lactobacillus plantarum and Pediococcus cerevisiae), pectinase (from Aspergillus niger), or formic acid on silage composition were studied. Forages wilted to a DM content of about 320 g/kg were ensiled in laboratory silos for 60 d. Cellulase, combined with inoculant, was applied at 2, 10, and 20 ml/kg of herbage (at least 2500 IU/ml). Cellulase at 10 ml/kg was also applied alone or in combination with pectinase and inoculant or formic acid. The NDF concentration of orchardgrass silage decreased with increasing cellulase up to 20 ml/kg, at which NDF content was decreased by 30%. The NDF concentration of alfalfa silage decreased with increasing cellulase application up to 10 ml/kg, at which NDF content was decreased by 13%. Immature plants were more responsive to cellulase treatment than mature plants. Cellulase at 2 ml/kg combined with inoculant improved fermentation characteristics of the silages but generally, there was no effect on silage fermentation by higher cellulase applications, resulting in an accumulation of sugar. The improved fermentation of orchardgrass treated with cellulase and inoculant was mostly related to the effect of inoculant, whereas cellulase alone improved fermentation characteristics of alfalfa silage and this effect was enhanced by addition of inoculant. Decreased NDF and increased sugar concentrations did not improve the in vitro DM digestibility of cellulase-treated silages.

Complete information on forage quality characteristics of amaranth is unavailable. This study evaluated the forage quality of various amaranth accessions at different harvest dates. Seven accessions from the North Central Plant Introduction Station were established in June 1997 and June 1998 near Boone, IA. Subplots were harvested six times at 2‐wk intervals beginning 42 d after planting (DAP). In vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF), crude protein (CP), nitrate‐nitrogen, acid detergent fiber (ADF), acid detergent lignin (ADL), protein and fiber digestion, and undegradable intake protein (UIP) were determined. Averaged over accessions, IVDMD decreased (P < 0.05) from 780 g kg−1 at 42 DAP to 680 g kg−1 at 112 DAP. Digestibility ranged from 590 to 790 g kg−1 Averaged over accessions at 42 DAP, CP was 270 g kg−1 then decreased to 100 g kg−1 at 112 DAP. Neutral detergent fiber increased from 310 g kg−1 at 42 DAP to 430 g kg−1 at 112 DAP. Averaged over harvest date, Amaranthus cruentus (Zimbabwe) had the highest NDF (390 g kg−1), and A. hybrid (Puebla, Mexico) had the lowest (330 g kg−1). Amaranthus cruentus (Zimbabwe), A. cruentus (Rwanda), and A. hybrid (Puebla, Mexico) had UIP averaging 25, 22, and 16%, respectively, of total crude protein after 16 h of digestion. Forage quality of the accessions at most harvest dates was consistent with what would be expected for relatively good quality forage, although high nitrate levels are a concern.

The pH optimum of pancreatic alpha-amylase from grain-fed steers was determined to be 6.9, while that of intestinal maltase was established at 5.8. Both assays were found to be linear up to 1 hr of incubation. The V max of pancreatic amylase was determined to be pancreatic amylase was determined to be 1.15 mg of maltose monohydrate produced/hr. Activities of pancreatic and intestinal maltase were not reduced (P greater than .05) during the interval from sample collection from the animal until analysis 4 hr later when tissues were kept on ice. Twenty-four yearling Holstein steers fed either alfalfa hay at a maintenance level of metabolizable energy (ME) intake or corn at one, two or three times the maintenance ME intake level were slaughtered after being fed 106 days. The pancreas was removed alone with sections of the intestine. Specific activity of pancreatic amylase for steers fed the high level of corn was 129% of that for steers fed the alfalfa diet (P greater than .05). Intestinal maltase activity was highest in the jejunum and decreased toward the ileum. Increasing dietary starch intake resulted in no response (P greater than .05) in maltase activity at 10, 30, 50, 70, or 90% of the small intestine length. The effect of dietary starch level on dieesta pH was dependent on sampling location within the small intestine. There were no dietary effects (P greater than .05) on digesta pH for the first 10% segment of intestine distal to the pylorus. However, in all subsequent sections, digesta pH was higher steers fed the alfalfa diet than for those fed the two higher levels of grain. A calculation for estimating th amount of pancreatic amylase needed to hydrolyze starch presented to small intestine is discussed.