Influence of maturity on alfalfa hay nutritional fractions and indigestible fiber content.

This study focused on changes in fibrous and protein fractions, changes in fiber digestibility and amount of indigestible neutral detergent fiber (NDF) as a consequence of increased maturity in alfalfa. A total area of 720 m(2) was divided in 18 blocks randomly assigned to 3 treatments, differing in cutting intervals. Treatment 1 was harvested with a 21-d cutting schedule, at a prebloom stage; treatment 2 with a 28-d schedule, at about first-bloom stage; whereas a full bloom was observed in treatment 3, harvested with a 35-d cutting schedule. Treatments were replicated 4 times through the spring-summer period for 2 subsequent years, 2011 and 2012. Statistical differences were observed for crude protein [treatment 1: 20.8%, treatment 2: 17.3%, and treatment 3: 17.0%; standard error of the mean (SEM)=0.83], soluble protein, and nonprotein nitrogen among treatments on a dry matter basis. Similar results were observed for acid detergent lignin (6.3, 6.9, and 7.3%, respectively; SEM=0.39), lower in treatment 1 compared with others, and in vitro NDF digestibility at 24 or 240 h. Indigestible NDF at 240 h resulted in lower values for treatment 1 compared with treatments 2 and 3 (15.5, 17.2, and 18.3%, respectively; SEM=1.54). Moreover, the indigestible NDF:acid detergent lignin ratio varied numerically but not statistically among treatments, being as much as 9% greater than the 2.4 fixed value applied for rate of digestion calculation and Cornell Net Carbohydrate Protein System (Cornell University, Ithaca, NY)-based model equations. Assuming the diet composition remained unchanged, treatment 3 (35-d cutting interval) would be expected to yield 1.4 kg less milk per day based on energy supply, and 2.8 kg less milk daily based on protein supply than treatment 1.

[1]  L. G. Jones,et al.  Effect of cutting interval and stage of maturity on the digestibility and yield of alfalfa. , 1960 .

[2]  J. M. A. Tilley,et al.  A TWO-STAGE TECHNIQUE FOR THE IN VITRO DIGESTION OF FORAGE CROPS , 1963 .

[3]  H. Goering,et al.  Forage fiber analyses (apparatus, reagents, prcedures, and some applications) , 1970 .

[4]  D. J. Minson,et al.  The digest1bility of temperate and tropical grasses. , 1970 .

[5]  W. Horwitz.  Official Methods of Analysis , 1980 .

[6]  J. B. Robertson,et al.  Predicting methane fermentation biodegradability , 1980 .

[7]  W. P. T. James,et al.  The Analysis of dietary fiber in food , 1981 .

[8]  Chemical composition and in-vitro degradability of major chemical constituents of red clover harvested at different stages of maturity , 1983 .

[9]  P. Åman,et al.  Changes during growth in anatomical and chemical composition and in-vitro degradability of lucerne , 1986 .

[10]  W. F. Wedin,et al.  Cell-wall composition and digestibility of alfalfa stems and leaves , 1987 .

[11]  D. R. Buxton,et al.  Lignin constituents and cell-wall digestibility of grass and legume stems , 1988 .

[12]  D. E. Akin.  Histological and Physical Factors Affecting Digestibility of Forages , 1989 .

[13]  D. Combs,et al.  Effect of alfalfa maturity on fiber utilization by high producing dairy cows. , 1990, Journal of dairy science.

[14]  D. Buxton,et al.  Digestibility of structural carbohydrates in cool-season grass and legume forages , 1991 .

[15]  P. V. Soest,et al.  A net carbohydrate and protein system for evaluating cattle diets: II. Carbohydrate and protein availability. , 1992, Journal of animal science.

[16]  R. F. Lucey,et al.  In Vitro Digestion Kinetics and Quality of Perennial Grasses as Influenced by Forage Maturity , 1993 .

[17]  O. Hesterman,et al.  Alfalfa maturity and cultivar effects on chemical and in situ estimates of protein degradability , 1994 .

[18]  J. Cherney,et al.  Forage Quality and Harvest Index of Corn Hybrids Under Different Growing Conditions , 1994 .

[19]  P. V. Soest.  Nutritional Ecology of the Ruminant , 1994 .

[20]  M. Allen,et al.  Characteristics of plant cell walls affecting intake and digestibility of forages by ruminants. , 1995, Journal of animal science.

[21]  Giuseppe Licitra,et al.  Standardization of procedures for nitrogen fractionation of ruminant feeds , 1996 .

[22]  C. Sheaffer,et al.  Early spring clipping and herbicide treatments delay alfalfa maturity , 1996 .

[23]  W. G. Glasser,et al.  Lignin Impact on Fiber Degradation. 3. Reversal of Inhibition of Enzymatic Hydrolysis by Chemical Modification of Lignin and by Additives , 1997 .

[24]  Richard A. Dixon,et al.  Lignin Impact on Fiber Degradation: Increased Enzymatic Digestibility of Genetically Engineered Tobacco (Nicotiana tabacum) Stems Reduced in Lignin Content , 1997 .

[25]  D. Lanna,et al.  Predicting forage indigestible NDF from lignin concentration. , 1998, Journal of animal science.

[26]  D. Faulkner,et al.  Fractionation of fiber and crude protein in fresh forages during the spring growth. , 1999, Journal of animal science.

[27]  D. Faulkner,et al.  In situ dry matter and crude protein degradation of fresh forages during the spring growth. , 1999, Journal of dairy science.

[28]  Raymond C. Boston,et al.  The Conversion of a Scientific Model Describing Dairy Cow Nutrition and Production to an Industry Tool: the CPM Dairy Project , 2000 .

[29]  D. E. Beever,et al.  Modelling Nutrient Utilization in Farm Animals , 2000 .

[30]  Alfalfa Stem Tissues , 2002 .

[31]  F. M. Engels,et al.  Alfalfa Stem Tissues: Cell Wall Deposition, Composition, and Degradability , 2002 .

[32]  D. Mertens.  Gravimetric determination of amylase-treated neutral detergent fiber in feeds with refluxing in beakers or crucibles: collaborative study. , 2002, Journal of AOAC International.

[33]  J. Markert,et al.  Effect of variety and maturity stage on chemical composition, carbohydrate and protein subfractions, in vitro rumen degradability and energy values of timothy and alfalfa , 2003 .

[34]  W. Knaus,et al.  Validation of the 2,4 times lignin factor for ultimate extent of NDF digestion, and curve peeling rate of fermentation curves into pools. , 2008 .