D. J. R. Cherney

Potential of Brown-Midrib, Low-Lignin Mutants for Improving Forage Quality

Publisher Summary Brown-midrib (bmr) mutants differing in quality and quantity of lignin from normal genotypes offer an opportunity to increase the overall digestion of plant fiber. It is a simple recessive trait that phenotypically produces a reddish-brown pigmentation associated with lignified tissues. Several different genes have been identified in both maize and sorghum, which produce the characteristic bmr phenotype. Lignin concentrations in bmr genotypes are consistently lower than their normal counterparts. Besides differences between bmr and normal alkali-labile phenolics, the nitrobenzene oxidation of the two lignins yields different ratios of products. In vitro digestibility of bmr genotypes has been consistently higher than normal, but in vitro rate of digestion does not appear to be consistently affected by the mutation. Animal performance on bmr forage has not always produced better results than with normal genotypes but the tendency is for improved animal performance with bmr genotypes. Activities of several enzymes involved in lignification differed between bmr and normal genotypes. Differences in activities are not consistent across species, indicating that several different modifications of the lignifications pathway may result in a similar phenotypic bmr response. This chapter concludes that bmr provide an excellent system for examining and possibly modifying the lignifications process in plants.

Botanical composition, soil and forage quality under different management regimes in Russian grasslands

Little is known on how management of Russian native grasslands affects botanical composition, soil and forage properties. Three fields were sampled in the V.V. Alekhin Central-Chernozem Biosphere State Reserve in the Kursk region of Russia: a native grassland (not cultivated for at least 300 years), a grazed/hay field with 4 years of annual harvest followed by 1 year of rest (periodically-cut grazed/hay field), and a yearly-cut grazed/hay field. Soil samples were collected from the top 10 cm and analyzed. Plant species were identified at the sampling sites and this plant material was used to determine total elemental analysis of forage, crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), in vitro true digestibility (IVTD) and lignin concentrations. Above-ground live and dead plant material and roots were analyzed for C, N and lignin. Soil sample analysis showed that fields were comparable in terms of soil chemical and physical properties. SOC and N contents were not statistically different in the native and yearly grazed/hay fields. Soil bulk density significantly increased as a result of utilization, from 0.800.09 Mg m 3 for the native grassland to 0.970.06 Mg m 3 for the yearly grazed/hay field. A total of 107 different plant species were recorded at the three fields. There were changes in plant composition among the fields. The native grassland field had the least number of plant species (41) followed by the yearly-cut grazed/hay field (68), and the periodically-cut grazed/hay field (87). There was a greater proportion of grass species (20%) in the native grassland field. Dead plant biomass and roots from the grazed/hay fields were higher in N and lignin concentrations. Forage mineral concentration was highest in the periodically-cut hay field. No significant differences were observed in terms of forage properties.

Low Intensity Harvest Management of Reed Canarygrass

forage K concentration was 12 g kg 1 (Brown et al., 1969). Timothy stands should persist over time with a High K grass forage increases risk of animal metabolic disorders, concentration of 15 to 18 g K kg 1 in headed spring and forage management of perennial grass grown under K-limiting soil conditions needs further study. Our objective was to evaluate growth and 12 to 16 g K kg 1 in regrowth, according to forage nutritive value, yield, and stand persistence of reed canarygrass Grant and MacLean (1966). Nitrogen fertilization of (Phalaris arundinaceae L.) under two-harvest management and low grasses initially increases forage K concentration if there availability of soil K. Three N and three K fertilizer treatments were is sufficient available soil K, but prolonged N fertilizaapplied to reed canarygrass for 5 yr at two sites in central New York tion of a grass stand will quickly deplete soil K and state with Niagara silt loam (fine-silty, mixed, active, mesic Aeric result in decreased forage K concentration (Cherney et Epiqualfs) and Williamson silt loam (coarse-silty, mixed, active, mesic al., 1998). Typic Fragiudepts) soil types. Reed canarygrass persisted under all Management systems that result in low forage K contreatments throughout the experiment, although K deficiency sympcentration are a prerequisite for grass forage fed to toms appeared in the high N, low K fertilizer combination. At the nonlactating dairy cows (Cherney et al., 1998). Based high N fertilizer rate, dry matter (DM) yield increased linearly (P 0.05) with increased K fertilizer rate, while K fertilizer did not influon results of Goff and Horst (1997), animal scientists ence yield in the absence of N fertilizer. Recovery of K fertilizer was generally suggest that forage for nonlactating dairy cows low and increased linearly (P 0.05) with increased N fertilizer rate contain less than 25 g K kg 1 DM to reduce the risk of from 6 to 42%. Soil test K increased to 59.9 mg kg 1 with no N high dietary K on animal health. High dietary K can fertilization and decreased to 34.9 mg kg 1 with 224 kg N ha 1. Under predispose pregnant cows to a number of disorders, high N fertilization with no K fertilization, grass forage K concentraincluding ketosis, metritis, retained placenta, and distion averaged 12 g kg 1 in the spring and 8 g kg 1 in the fall. placed abomasums (Beede, 1996). Our objective was to Sufficient yields of grass forage with reasonable quality and low conevaluate the effects of extensive harvest management centrations of K were possible through high N, low K fertility manageand low availability of soil K on reed canarygrass forage ment in a two-harvest system. yield, nutritive value, and stand persistence. MATERIALS AND METHODS P grasses will absorb K in excess of plant requirements, depending on the quantity of availReed canarygrass was established in 1992 on a Niagara silt loam (fine-silty, mixed, active, mesic Aeric Epiqualfs) soil with able soil K and the availability of other elements, partic0 to 2% slope in Ithaca, NY (Site 1). A second site was ularly N. Regions of the world, such as Europe, that established in 1993 on a Williamson silt loam (coarse-silty, rely heavily on grazing appear to have few concerns mixed, active, mesic Typic Fragiudepts) soil with 0 to 6% regarding plant K, and K often is not discussed in their slope in Ithaca, NY (Site 2). Both soils are classified as having literature concerning grass management (Beever et al., medium K supplying power, based primarily on their clay 2000). In contrast, in the USA, where stored forage is content. the primary dairy forage source, concerns regarding K Site 1 was fertilized with three rates of N fertilizer: 0, 168, content of dairy cattle diets are high (Horst et al., 1997). or 336 kg N ha , split applied before each of three harvests Incidence of milk fever in dairy cows fed a low calcium in 1993 and 1994. Site 2 received the same fertilization/harvest (Ca) diet was 0% for a diet containing 11 g K kg 1 dry regime in 1994 and 1995. Both sites were fertilized with P and K during the first 2 yr following the establishment year matter (DM), 36% for a diet containing 21 g K kg 1 according to soil test recommendations. DM, and 80% for a diet containing 31 g K kg 1 DM In 1995 previous N fertilized plots were split into three (Goff and Horst, 1997). High concentrations of soil-test subplots (2.13 by 6.08 m), with 0, 56 and 112 kg K ha 1 applied K in perennial grass fields are common on many dairy annually from 1995 to 2000. Previous N-fertilized plots refarms in the northern USA owing to preferential appliceived 0, 112 or 224 kg N ha 1 annually from 1995 to 2000, cation of animal manure on these fields. split applied at spring greenup and immediately after first On prairie soil with low available soil K concentraharvest. The same management sequence was applied to Site tion, no yield increase resulted from K fertilization of 2, starting 1 yr later than Site 1. Potassium fertilizer was applied smooth bromegrass (Bromus inermis Leyss.) (George as one annual early spring application from 1995 through et al., 1979). Timothy (Phleum pratense L.) yield was 1997, and then applied to both sites as one annual application following spring harvest in 1998 through 2000. significantly reduced under a 2-cut management when Broadleaf weeds were controlled by annual applications of either 2,4-D [(2,4-dichlorophenoxy) acetic acid] at 0.14 kg J.H. Cherney, Dep. of Crop and Soil Sci., 503 Bradfield Hall, Cornell a.i. ha 1 in the spring or dicamba [(3,5-dichloro-2-methoxy) Univ., Ithaca, NY 14853; D.J.R. Cherney, Dep. of Animal Sci., Cornell benzoic acid] at 0.11 kg a.i. ha 1 in the fall. From 1995 to 2000 Univ., Ithaca, NY 14853; and M.D. Casler, USDA-ARS, U.S. Dairy for Site 1 and from 1996 to 2000 for Site 2, plots were harvested Forage Research Center, Madison, WI 53706-1108. Contribution from Cornell Univ. Agric. Exp. Stn. Received 10 May 2002. *Corresponding Abbreviations: Ca, calcium; CP, crude protein; DM, dry matter; IVTD, author (jhc5@cornell.edu). in vitro true digestibility; K, potassium; N, nitrogen; NDF, neutral detergent fiber; OM, organic matter. Published in Agron. J. 95:627–634 (2003).

In vitro ruminal fiber digestion as influenced by phenolic-carbohydrate complexes released from sorghum cell walls

Abstract Objectives were to isolate groups of phenolic-carbohydrate complexes from brown-midrib 6 and normal ‘Redlan’ sorghum ( Sorghum bicolor (L.) Moench) and to investigate the influence of isolated complexes on in vitro fiber digestion. Three field replicates of brown-midrib 6 and normal sorghum stem were harvested 1 week after physiological maturity of grain. Extracts of cellulase-digested neutral detergent fiber (NDF) of both sorghums inhibited in vitro dry matter digestion when added to in vitro ruminal incubations at quantities equivalent to 0.5, 1.0, and 2.0 g sorghum stem NDF. Cellulase extracts separated by size exclusion Chromatograph y (Sepharose CL-6B) yielded two major peaks that absorbed at 320 nm. Phenolic-carbohydrate complexes isolated in Peak 2 were lower in p -coumaric (PCA): ferulic acid (FA) ratios and higher in xylose: arabinose ratios than complexes isolated in Peak 1. When concentrated solutions of isolated fractions were added to in vitro ruminal incubations of sorghum leaf blade (0.25 g) at quantities equivalent to 0.5, 1.0, 2.0, and 3.0 g of sorghum stem NDF, in vitro NDF digestibility of sorghum leaf blade was reduced more by addition of Peak 2 than Peak 1 for both sorghums, but the effect on digestibility was greater for brown-midrib 6 . The pH of resulting solutions did not influence in vitro dry matter digestibility. Further separation of Peak 2 by size exclusion chromatography (Sephadex LH-20, for separation of compounds with lower molecular weights) yielded several major peaks that absorbed at 320 nm. One of these peaks, with a low molar p -coumaric: ferulic acid ratio, inhibited fiber digestion when added at quantities equivalent to 5.0 g of sorghum stem NDF. Results suggest that phenolic-carbohydrate complexes low in PCA: FA molar ratio acid and high in xylose: arabinose ratio may inhibit ruminal fiber digestion, although the mode of action is not yet clear.

TETANY POTENTIAL OF ORCHARDGRASS AND TALL FESCUE AS INFLUENCED BY FERTILIZATION WITH DAIRY MANURE OR COMMERCIAL FERTILIZER

ABSTRACT The main objective of this study was to compare potassium (K), calcium (Ca), and magnesium (Mg) utilization and grass tetany potential of orchardgrass (Dactylis glomerata L.) and tall fescue (Festuca arundinaceae Schreb.) fertilized with dairy manure or commercial fertilizer. The study was conducted from 1994 through 2000 in Willsboro, NY on a Kingsbury clay soil (very-fine, illitic, mesic Aeric Ochraqualf) of somewhat poor drainage. The design was a split-plot in a randomized complete block with two manure rates (16.8 Mg ha−1 and 33.6 Mg ha−1) and one fertilizer treatment (84 kg N ha−1 at spring greenup and 56 kg N ha−1 prior each regrowth harvest) as the main plots and grass species as subplots replicated six times. Potassium concentration and uptake increased after two years of manure application compared to commercial fertilizer treatment and residual effects of manure were large at least three years following manure application. Calcium concentration and uptake decreased after two years of manure application compared to the commercial fertilizer treatment, but there were no differences in treatments three years after manure application had ceased. Magnesium concentration and uptake at the high manure rate did not differ from fertilizer treatment in all years. Orchardgrass was more grass tetany prone than tall fescue as a result of dairy manure application. The K/(Ca+Mg) ratio in plant tissue was as high as 3.26 for orchardgrass and as high as 2.11 for tall fescue for spring harvests at the highest manure rate. The K/(Ca+Mg) ratio in plant tissue was in the range of 0.34–1.74 (below the 2.20 critical level) for all three years with no manure application. Soil K increased in manure treatments from an initial 76.8 kg ha−1 (1993) to 171.7 kg ha−1 (1997) in the highest manure treatment. After three years of no manure applications, soil K had been reduced to the initial level.

Short communication: Antioxidant activity of calf milk replacers

A calf milk replacer (CMR) is designed to replace whole, saleable milk as a lower cost nutrient source for calves while striving to nourish a newborn calf, reduce calf mortality, strengthen immunity, and increase animal life span and productivity. Antioxidants (AO) can enhance immune defense by reducing oxidative damage, but CMR are traditionally not formulated for AO activity. The objective of this study was to compare total AO activities of bovine milk and 6 CMR (A to F) that vary in the amount and source of fat and protein. Calf milk replacers were donated by Milk Products LLC (Chilton, WI). Milk was obtained from the Cornell Dairy Research Farm bulk tank, representing milk produced within 24h by 455 cows. Milk replacers were mixed to 150 g/L with 40°C purified water. All samples were extracted in triplicate. Following hexane lipid extraction, both milk and CMR samples were extracted 5 times with ethyl acetate and then evaporated and reconstituted with 70% methanol:water. Samples were assessed for total AO activity using the peroxyl radical scavenging capacity assay where each sample was diluted to 5 descending concentrations, plated in triplicate. Ascorbic and gallic acids were standards for each plate. Type of protein (soy) had a positive effect on AO activity for CMR A, which exhibited the highest total AO activity. Natural bovine milk had the second highest AO activity. Many factors may explain the difference in AO activity between natural milk and formulated CMR, including fat, vitamin, and mineral contents, enzymatic AO, phenolics, flavonoids, fatty acid profile, and AA composition. When comparing AO activity of CMR, it is important to consider the diversity in feeding recommendations, which will alter the vitamin and mineral content, thus influencing AO activity. The opportunity exists to enhance AO activity of CMR to more closely mimic that of bovine milk. Future research is warranted to compare a broader range of CMR using methods that account for total lipophilic and hydrophilic AO activities, as well as to investigate the effect of additional compounds in milk that may affect AO activity.

Milk Production in High Producing Dairy Cows as Influenced by Corn Silage Quality

Greater milk production is the promised outcome for selecting corn hybrids with various traits that impact forage quality. Our objective was to select a set of hybrids most likely to exhibit differences in forage quality and evaluate milk production of cows fed a high forage diet. Four hybrids were selected for the feeding trial: a leafy hybrid (Mycogen TMF 100; Mycogen Seeds, Indianapolis, IN), a brown midrib (BMR) hybrid (Mycogen BMR F407), and two conventional hybrids varying in fiber digestibility (Pioneer 36B08 [Conventional 1 {CONV1}] and Pioneer 35P12 [Conventional 2 {CONV2}]; Pioneer Hybrid International, Inc., Des Moines, IA). Diets were formulated to provide 1.0% BW as forage NDF (approximately 32% NDF) and were balanced to meet or exceed NRC requirements. Fifty-six cows were fed for 56 d. The DMI of cows fed the BMR and the leafy hybrid total mixed rations (TMR) were greater than those of cows fed the other hybrids. Differences in milk production reflected the differences in intake. Cows fed the BMR (41.7 kg/d) and leafy hybrid (42.1 kg/d) TMR were not different from each other in milk production, but had greater (P≤0.05) milk

Protein solubility and degradation in vitro as influenced by buffer and maturity of alfalfa

Abstract Factors influencing the extraction of proteins and protein degradation of alfalfa ( Medicago sativa L.) in vitro were compared with other forages. Kansas State buffer, a phosphate buffer, and McDougalls artificial saliva, a carbonate buffer, (both commonly used as in vitro digestion buffers) extracted more buffer-soluble proteins than did N-2-Hydroxyethylpiperazine-N′-ethanesulfonic acid, 2[N-Morpholino] ethanesulfonic acid, piperazine-N, N′-bis [2-ethane-sulfonic acid] and imidazole-HCl. Protein solubilities and sodium dodecylsulfate-polyacrylamiden gel electrophoresis (SDS-PAGE) indicated that Kansas State buffer and McDougalls artificial saliva extracted more high molecular weight proteins than did the other buffers. Proteins soluble in Kansas State buffer were extensively degraded by ruminal microorganisms within 12 h in both stem and leaf tissues; several high molecular weight proteins in leaf tissues did, however, survive 12 h in rumen fluid. Alfalfa initially contained more buffer-soluble protein than other forages, but, similar amounts of undegraded protein remained in all forages after 12 h of digestion. Protein profiles (SDS-PAGE) of birdsfoot trefoil ( Lotus corniculatus L.) contained two distinct bands of protein that were apparently unaffected by 12 h of incubation, while alfalfa profiles contained several polypeptides that ‘escaped’ ruminal fermentation. In contrast, proteins in orchardgrass ( Dactylis glomerata L.) were rapidly and completely degraded in 12 h with no identifiable surviving proteins. Identification and characterization of proteins capable of surviving ruminal degradation and factors influencing their accumulation in forages may allow for introduction of forages or management practices which could potentially improve the nitrogen status of the ruminant.

Split Application of Nitrogen on Temperate Perennial Grasses in the Northeast USA

Timing of N applications on grasses can impact agronomic forage traits as well as the environment. We studied the impact of split N applications on yield, quality, and N recovery in orchardgrass, reed canarygrass, and tall fescue. Nitrogen fertilizer was applied at 200 lb N per acre at spring greenup, or 100 lb N fertilizer per acre at spring greenup followed by 100 lb N per acre after first cut, or 100 lb N fertilizer/acre at spring greenup followed by 50 lb N per acre after first cut and 50 lb N per acre after second cut. Plots were harvested three times per season for three years at two locations in central New York. There was about a 12% yield increase associated with split application of N in the spring and after first cut, but no yield advantage to using a three-way split of N over the season. Nitrogen yield and apparent N recovery were not influenced by timing of N application. Highest N fertilizer rates prior to the first and second cuts resulted in increased crude protein and reduced neutral detergent fiber, but fertilization after second cut had no impact on third cut quality. Fertilization with a split application of N will maximize yield, most of which is suitable forage for lactating dairy cows.

Free ferulic acid uptake in lactating cows

Ferulic acid (FRA), a phenolic compound with antioxidant and anticancer activities, naturally occurs in plants as a lignin precursor. Many veins of research have been devoted to releasing FRA from the lignin complex to improve digestibility of ruminant feeds. Thus, the objective of this research was to investigate the transfer of a given dosage of the free form of FRA into the milk of dairy cattle. Six mid- to late-lactation Holstein cows at the Cornell Research Farm (Harford, NY) were given 14-d adaptation to diet and stall position. Ad libitum access to a total mixed ration based on haylage and maize silage (31.1% neutral detergent fiber containing 5.52 mg of FRA/g) was provided during the study. A crossover design was implemented so that each cow alternated weekly between FRA-dosed and control. On d 1, jugular cannulas and urine catheters were placed in all cows. On d 2, FRA-dosed cows received a single dosage of 150 g of pure FRA powder at 0830 h via their fistula (n=4) or a balling gun for nonfistulated cows (n=2). Plasma, urine, feces, feed, orts, milk, and rumen fluid were sampled intensively for the next 36 h and analyzed for FRA concentration. On d 8, the cows crossed over and the experiment was repeated. When compared with the control, FRA administration did not have an effect on dry matter intake, milk yield, milk fat yield, milk protein yield, somatic cell count, or neutral detergent fiber content of orts and feces. The concentration of FRA in the feces did not change as a result of FRA dosage. As expected, FRA concentration increased dramatically upon FRA dosage and decreased over time until returning to basal levels in rumen fluid (4 h after dosage), plasma (5.5 h after dosage), urine (10 h after dosage), and milk (14 h after dosage). Baseline values for FRA in urine and rumen fluid were variable among cows and had an effect on FRA concentration in FRA-dosed cows. From this study, it is observed that orally ingested FRA can be transported into the milk and that the physiological transfer of FRA occurs from rumen to milk within 6.5 h or the first milking after dosage. Ferulic acid may affect the functionality of milk due to its antioxidant, anticancer, and antibacterial activities. Future research will be required to elucidate whether FRA in milk is bioavailable and bioactive, and to evaluate the complete sensory and microbiological effects of increased FRA and FRA degradation products in milk.