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Browsing by Author "Buttrey, Sherri A."

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    Effect of sulfur fertilization on yield and chemical composition of corn forage and utilization of corn silage by sheep
    Buttrey, Sherri A. (Virginia Polytechnic Institute and State University, 1985)
    Sulfur (S) deficiencies have become an increasing problem in the United States. A field experiment, in a latin square design, was conducted to investigate effects of S fertilization as 0 and 67 kg/ha as a single or split application on corn (Zea mays L.) forage yield and chemical composition. Sulfur fertilization by either method increased yield of whole plant and grain 7% and increased number of plants with two ears. Total S and sulfate-S concentration in whole corn plants, leaf, stem, and grain were increased with S fertilization. Corn forages were ensiled at harddent stage (35% dry matter). Sulfur fertilized corn silages (N/ S=42 and 43) and non-S fertilized silage (N/ S=62) supplemented at two rates with sodium sulfate (N/ S=l2 and 45) were fed to sheep in metabolism and palatability trials. Both experiments were conducted as a randomized block design with six replications per treatment. All silages were supplemented with urea (6.7 g/ d). Digestibility of dry matter and cell wall components and apparent absorption of Sand N were increased with S fertilization and S supplementation. Nitrogen retention was increased 14% by S supplementation (N/S=l2) and 31% by S fertilization. Sheep fed N/ S=12 silage had lower blood hematocrit and hemoglobin levels then those fed S fertilized or N/ S=45 silages. Blood urea-N levels were higher in sheep fed S fertilized silages. Increasing dietary S by fertilization or supplementation had no measurable effect on dry matter intake.
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    Influence of Acremonium coenophialum on Festuca arundinacea growth, chemical composition, digestibility and tall fescue toxicosis
    Buttrey, Sherri A. (Virginia Polytechnic Institute and State University, 1989)
    Infection of tall fescue (Festuca arundinacea Schreb.) with the endophyte fungus (Acremonium coenophialum, Morgan-Jones and Gam) has been associated with toxicity symptoms observed in cattle. The overall objective was to investigate the influence of endophyte infection on growth and chemical composition of tall fescue and the toxicity of endophyte-infected (EI) tall fescue to cattle. In a greenhouse study with pairs of genetically identical EI and non-infected (NI) ‘Kenhy’ tall fescue clones, concentration of N, Ca, Mg, Al, B, Mn and Zn was higher and K and S was lower in NI, compared to EI tall fescue. Insect resistance was higher in EI, compared to NI. Yield and chemical composition of high and low EI tall fescue were measured at four growth stages (stockpiled, prebloom, bloom and regrowth after harvest at bloom), two sites (Glade Spring and Blackstone) and three rates of N fertilization (0, 40 and 80 kg/ha) in a field study. Tall fescue grown at Glade Spring was higher in N, Mg, Al, Cu, Fe and Mn, compared to Blackstone. Nitrogen fertilization increased N, Mg, Ca, B, Cu, Na, Zn and decreased NDF, ADF, cellulose, P and S concentration in tall fescue. Neutral detergent fiber, ADF, cellulose, lignin, Fe and Na were higher in low, compared to high EI tall fescue. Concentrations of Cu, Na and Zn in stockpiled and Ca, Cu, Na and Zn in bloom-cut tall fescue hay were below dietary requirements for 227-kg steers. A disc meter was also evaluated for use in predicting yield of tall fescue. The meter is useful for non-destructive estimation of yield. Three feeding studies were conducted with steers (6/treatment/year). Diets were orchardgrass/alfalfa hay, spring-cut EI tall fescue hay, spring-cut EI tall fescue silage and fall-cut EI tall fescue silage. Serum prolactin and cholesterol were depressed in steers fed fescue hay and silages, compared to steers fed orchardgrass/alfalfa hay. Differences in mineral composition of hay and silage were reflected in serum minerals in steers. Ergopeptine alkaloids in EI tall fescue may have contributed to the depression of serum prolactin. The spring-cut silage contained the highest concentration of ergopeptine alkaloids, compared to other diets. Steers fed the spring-cut tall fescue silage had the lowest basal and thyrotropin-releasing hormone stimulated prolactin compared to steers fed the other diets.