Arkansas - Agricultural Communication Services - University of ...

More documents

Recommendations

Info

Arkansas Animal Science Department Report 2001 Forage Preparation and Analysis. All forage samples were dried to a constant weight under forced air at 122°F. Dry forage samples were ground through a Wiley mill (Arthur H. Thomas, Philadelphia, PA) equipped with a 1-mm screen before analysis. Total plant N was determined by rapid combustion (850°C); conversion of all N-combustion products to N 2 ; and subsequent measurement by thermoconductivity cell (LECO Model FP-428; LECO Corp., St. Joseph, MI). Neutral (NDF) and acid detergent (ADF) fiber analyses were conducted by the batch procedures outlined by ANKOM Technology Corp. (Fairport, NY). No sulfite was included in the neutral detergent solution. The concentrations of N in NDF and ADF residues (NDIN and ADIN, respectively) were determined as described previously. Cell-soluble N was calculated as 100 - NDIN, where NDIN was expressed as a percentage of total plant N. Statistical Analysis. For each individual harvest, orthogonal contrasts (PROC GLM; SAS Inst., Inc., Cary, NC) were used to test each N fraction for linear, quadratic, and cubic responses to N fertilization. For each individual plot, fertilization rate (0, 50, 100, or 150 lb N/acre) was not necessarily the same on both application dates; therefore, for the first and second harvest, contrast statements were constructed based on the initial (April 28) application of ammonium nitrate. For the third harvest, contrast statements were based on the second application of fertilizer N on July 19. A combined analysis of all data from all three harvests at each site was conducted by similar methods. This analysis included seven N fertilization rates (0, 50, 100, 150, 200, 250, and 300 lb N/acre) and a test for quartic effects was included in the model. Results and Discussion Nitrogen. At both sites, forages from the initial harvest on May 30 and the third harvest on August 18 exhibited a strong positive linear relationship (P < 0.0001) between N fertilization rate and the concentration of N in the forage (Table 2). This is a commonly observed response to N fertilization. The increases observed in forages fertilized with 150 lb N/acre compared with those receiving no fertilization ranged from 0.56 to 1.11 percentage units, which corresponds to 3.5 to 6.9 percentage units of CP. The effects of the first application of N fertilizer on forages harvested on the second date (July 7) were not significant (P > 0.05) at either site, indicating that the residual effects of the first application were not sufficient to affect concentrations of N in forages harvested on the second date. When all data for the year was combined, strong positive linear effects (P < 0.0001) were found at both sites (Table 3). The higher concentrations of N generally observed for forages grown at the Latta site probably reflects the more recent applications of poultry waste during the preceding year that did not occur at the Stephens site. Cell-soluble N (NDSN). The percentage of total plant N found in the cell-soluble portion of the plant ranged from 55.5 to 75.6% over the study and was affected by N fertilization in a manner similar to that described for total plant N (Table 4). Positive linear effects (P = 0.001 and 0.033 for the Stephens and Latta sites, respectively) were observed for the first harvest; however, no effects (P > 0.05) were observed for the second harvest date across both sites. On the third harvest date, linear (P = 0.047) and quadratic (P = 0.022) effects were observed at the Stephens and Latta sites, respectively. The overall analysis for the entire year indicated that the concentration of NDSN was related to N fertilization rate in a positive linear manner at both sites (P ≤ 0.023; Table 3). Cell-wall associated N (NDIN). Concentrations of NDIN in these bermudagrass forages ranged from 24.4 to 44.5% of total N on individual harvest dates (Table 5). At both sites, concentrations of NDIN declined (P ≤ 0.047) with N fertilization on the first and third harvest dates, but not on the second harvest date (P > 0.05). Apparently, the residual or carryover effects of the first application of N fertilizer were not sufficient to affect the relative percentages of N partitioned into the cell wall and cell solubles. The overall analysis for the entire year indicated that the concentration of NDIN was inversely related to N fertilization rate in a linear manner at both sites (P ≤ 0.023; Table 3). Acid-detergent insoluble N (ADIN). The N fraction that is insoluble in acid detergent (ADIN) is generally assumed to be indigestible; therefore the effects of N fertilization on this fraction are of particular interest to nutritionists. Normally, this fraction is of considerable interest when spontaneous heating has occurred during the storage of dry hay or during the silage fermentation process. Unlike the other N fractions discussed in this study, substantive differences in concentrations of ADIN were observed between sites. On the first harvest date, ADIN decreased linearly (P < 0.0001) with N fertilization rate from 11.48 to 8.32% of the total N pool at the Stephens site (Table 6); however, concentrations of ADIN and fertilization rate were not related (P > 0.05) at the Latta site (overall mean = 4.69% of N). There was no relationship (P > 0.05) between ADIN and N fertilization rate at either site for the second harvest date. Linear declines in concentrations of ADIN were observed with N fertilization rate at both the Stephens (P = 0.002) and Latta (P = 0.011) sites on the final harvest date. The overall analysis for the entire year indicated that concentrations of ADIN were inversely related to N fertilization rate in a linear manner at both sites (P ≤ 0.001; Table 3). Implications The results of this study suggest that fertilization with N may result in lower percentages of the total plant N pool being associated with the cell wall. Theoretically, this should increase the degradability of N in the rumen; additional studies are being planned to verify this hypothesis. Literature Cited National Research Council. 2000. 8th rev. ed. Natl. Acad. Press, Washington, DC. Sniffen, C. J., et al. 1992. J. Anim. Sci. 70:3562. 108
AAES Research Series 488 Table 1. Application scheme for fertilization of bermudagrass with ammonium nitrate (34-0-0) at the Stephens and Latta sites during 2000. Total N applied 1 1st application 2 2nd application 3 ------------------------------------------ lb N/acre --------------------------------------------- 0 0 0 50 50 0 100 50 50 150 100 50 200 100 100 250 150 100 300 150 150 1 Total application for the entire growing season. 2 April 28, 2000. 3 July 19, 2000. Table 2. Effects of N fertilization on concentrations of N in bermudagrass harvested at two sites near Lincoln, AR. --------------------- Stephens site ---------------------- --------------------------- Latta site -------------------------- Fertilization rate May 30 July 7 August 18 May 30 July 7 August 18 lb N/acre ---------------------------------------------------------- % of DM ------------------------------------------------------------- 0 1.78 1.94 1.81 2.97 2.56 2.11 50 2.26 1.99 2.11 3.19 2.65 2.45 100 2.47 2.08 2.33 3.33 2.65 2.75 150 2.89 2.10 2.63 3.53 2.79 2.68 SEM 1 0.097 0.056 0.052 0.048 0.089 0.052 Effect 2 L< 0.0001 NS L < 0.0001 L < 0.0001 NS L < 0.0001 Q = 0.002 1 Standard error of the mean. 2 NS, not significant (P > 0.05); L, linear effect; Q, quadratic effect. Table 3. Cumulative effects of N fertilization in split applications on concentrations of N, cell-soluble N (NDSN), cell-wall associated N (NDIN), and acid-detergent insoluble N (ADIN) in bermudagrass harvested at two sites near Lincoln, AR during 2000. --------------------- Stephens site -------------------------- -------------------------- Latta site ------------------------- Fertilization rate N NDSN NDIN ADIN N NDSN NDIN ADIN lb N/acre % of DM ------------------ % of N ------------------ % of DM ------------------ % of N ------------------ 0 1.84 60.3 39.7 8.92 2.52 65.7 34.3 6.48 50 2.05 62.8 37.2 8.07 2.65 64.6 35.4 5.88 100 2.08 63.2 36.8 7.95 2.75 65.7 34.3 6.06 150 2.25 63.9 36.1 7.74 2.91 64.7 35.3 5.63 200 2.30 62.3 37.7 7.41 2.81 68.7 31.3 5.90 250 2.50 64.6 35.4 7.09 3.07 67.5 32.5 5.23 300 2.46 64.0 36.0 6.95 2.98 68.6 31.4 5.40 SEM 1 0.062 1.06 1.06 0.330 0.046 1.22 1.22 0.211 Effect 2 L< 0.0001 L = 0.023 L = 0.023 L = 0.0001 L < 0.0001 L = 0.014 L = 0.014 L = 0.001 1 Standard error of the mean. 2 NS, not significant (P > 0.05); L, linear effect. 109
Page 1 and 2:
Arkansas Animal Science Department
Page 3:
spine copy ARKANSAS ANIMAL SCIENCE
Page 6 and 7:
INTRODUCTION The faculty and staff
Page 8 and 9:
COMMON ABBREVIATIONS Abbreviation T
Page 10 and 11:
The Effects of Nitrogen Fertilizati
Page 12 and 13:
Page 14 and 15:
Demographics and Academic Success o
Page 16 and 17:
Page 18 and 19:
Page 20 and 21:
Page 22 and 23:
Efficacy of Mannan Oligosaccharide
Page 24 and 25:
Page 26 and 27:
Effects of Dietary Magnesium and Ha
Page 28 and 29:
Page 30 and 31:
Page 32 and 33:
Page 34 and 35:
Page 36 and 37:
Effect of Feather Meal on Live Anim
Page 38 and 39:
Page 40 and 41:
Page 42 and 43:
Maternal Effects for Performance Te
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Supplementation of Beef Cows and He
Page 62 and 63: Arkansas Animal Science Department
Page 70 and 71: Influence of Supplementing Cobalt i
Page 80 and 81: Long-Term Immune Response of Beef H
Page 92 and 93: Small Grain Forage for Stocker Catt
Page 100 and 101: Economics of Production Systems Inv
Page 118 and 119: Influence of Moisture Concentration
Page 126 and 127: Impact of Spontaneous Heating Durin
Page 134 and 135: Effects of Tall Fescue Inoculated w
Page 142 and 143: Yield and Nutritive Value of Easter
Page 154 and 155: 2000 Dairy Herd Improvement Herds i
Page 162 and 163:
Page 164 and 165:
The Impact of Multiple Antimicrobia
Page 166 and 167:
Page 168 and 169:
The Impact of Multiple Antimicrobia
Page 170 and 171:
Page 172 and 173:
The Use of Hurdle Technology to Red
Page 174 and 175:
Page 176 and 177:
Consumer Acceptability of Forage Fe
Page 178 and 179:
Page 180:
show all

Arkansas - Agricultural Communication Services - University of ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?