The use of internal markers to predict total digestibility and duodenal flow of nutrients in cattle given six different diets.

Six ruminally and duodenally cannulated cattle were used in a 6 × 6 Latin square experiment with a 2 × 3 factorial arrangement of treatments. The cattle were fed diets based on silage or dried grass cut simultaneously from the same sward, each fed with 250, 500 or 750 g concentrate dry matter (DM) kg−1 total DM. The feed components investigated as potential markers to determine total DM digestibility (DMD) were acid insoluble ash (AIA) and acid detergent lignin (ADL), indigestible DM (IDM41), neutral detergent fibre (INDF41) and acid detergent fibre (IADF41) determined by a 288 h ruminal incubation in nylon bags with a pore size of 41 μm, and corresponding indigestible fractions determined by using bags with a pore size of 6 μm were IDM6, INDF6 and IADF6. INDF and IADF were also determined by a 96 h in vitro incubation in rumen fluid (IVINDF, IVIADF). If the criterion of an ideal marker is to predict the digestibility and the differences between the diets, none of the markers met this criterion. Of the markers evaluated, the most suitable was AIA, followed by INDF6, INDF41 and IADF41. ADL was the least acceptable marker. Three double-marker systems were used to calculate duodenal flows of organic matter (OM), non-ammonia N (NAN), microbial N and NDF. Cr-mordanted straw, INDF41 and IADF41 were used as particulate markers in conjunction with Co-EDTA as a liquid phase marker. Duodenal OM flows were also estimated using a single-marker system. Double-marker systems reduced variability in duodenal OM flow estimates compared with single-marker systems. The choice of the particulate marker affected (P < 0.001) duodenal flow estimates but there were no indications of marker × diet interactions. Neither was the statistical significance of dietary effects changed. When compared with the values obtained with Cr as a particulate marker, INDF estimated a greater relative increase in NDF flow (0.143) than in OM (0.062) or NAN flow (0.018). This suggests that there may be differences in the distribution of solid phase markers in various particle size fractions. In such cases, if the digesta sample contains different proportions of large and small particles compared with the true digesta, then a double-marker system may not be sufficient to correct unrepresentativeness of digesta sampled from a simple T-shaped cannula.

[1]  G. Waghorn,et al.  Feed comminution, particle composition and distribution between the four compartments of the stomach in sheep fed chaffed lucerne hay at two feeding frequencies and intake levels , 1986, The Journal of Agricultural Science.

[2]  M. Courtenay,et al.  A comparison between ytterbium acetate, ruthenium phenanthroline and indigestible acid detergent fibre in a double-marker system for intestinal flow measurements in steers , 1990, The Journal of Agricultural Science.

[3]  P. Doyle,et al.  A comparison of particulate markers for the estimation of digesta flow from the abomasum of sheep offered chopped oaten hay , 1984 .

[4]  P. V. Soest,et al.  The determination of digesta particle size in some herbivores , 1982 .

[5]  B. A. Young,et al.  Evaluation of Acid-Insoluble Ash as a Natural Marker in Ruminant Digestibility Studies1 ,2 , 1977 .

[6]  W. C. Ellis,et al.  Recovery of Indigestible Fiber from Feces of Sheep and Cattle on Forage Diets , 1986 .

[7]  P. Huhtanen,et al.  The effects of forage preservation method and proportion of concentrate on digestion of cell wall carbohydrates and rumen digesta pool size in cattle , 1993 .

[8]  P. Huhtanen,et al.  The effects of forage preservation method and proportion of concentrate on nitrogen digestion and rumen fermentation in cattle , 1993 .

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

[10]  C. F. Hanson,et al.  External and internal markers for appraising site and extent of digestion in ruminants. , 1992, Journal of dairy science.

[11]  R. Muntifering.  Evaluation of various lignin assays for determining ruminal digestion of roughages by lambs. , 1982, Journal of animal science.

[12]  P. H. Robinson,et al.  Feed Components as Internal Markers in Digestion Studies with Dairy Cows , 1989 .

[13]  W. Flatt,et al.  the Evaluation of Feeds through Digestibility Experiments , 1975 .

[14]  R. H. Smith,et al.  Factors influencing the digestion of dietary carbohydrates between the mouth and abomasum of steers , 1983, British Journal of Nutrition.

[15]  D. Ross,et al.  Sources of Variation of Dry Matter Digestibility Measured by the Acid Insoluble Ash Marker , 1985 .

[16]  J. D. Wallace,et al.  Predicting Digestibility of Different Diets with Internal Markers: Evaluation of Four Potential Markers , 1986 .

[17]  D. J. Minson,et al.  The validity of the critical size theory for particles leaving the rumen , 1980, The Journal of Agricultural Science.

[18]  G. Faichney.  The use of markers to measure digesta flow from the stomach of sheep fed once daily , 1980, The Journal of Agricultural Science.

[19]  P. V. Van Soest,et al.  Investigation of chromium, cerium and cobalt as markers in digesta. Rate of passage studies. , 1980, Journal of the science of food and agriculture.

[20]  H. Goering.  Forage Fiber Analyses , 1970 .

[21]  G. Fahey,et al.  Lignin as a Marker in Digestion Studies: a Review , 1983 .

[22]  J. T. Reid,et al.  Acid Insoluble Ash and Permanganate Lignin as Indicators to Determine Digestibility of Cattle Rations , 1979 .

[23]  B. Wilkins.  The potential digestibility of cellulose in forage and faeces , 1969, The Journal of Agricultural Science.

[24]  M. Dhanoa,et al.  The effect of digestibility and forage species on the removal of digesta from the rumen and the voluntary intake of hay by sheep , 1986, British Journal of Nutrition.

[25]  R. Barton,et al.  Estimating diet digestibility: a comparison of 11 techniques across six different diets fed to rams. , 1990, Journal of animal science.

[26]  P. Penning,et al.  The use of internal markers to estimate herbage digestibility and intake: 2. Indigestible acid detergent fibre , 1983, The Journal of Agricultural Science.

[27]  G. Moseley,et al.  The physical digestion of perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) in the foregut of sheep , 1984, British Journal of Nutrition.

[28]  A. Warner,et al.  Digestion and metabolism in the ruminant. , 1975 .

[29]  É. Grenet.  A comparison of the digestion and reduction in particle size of lucerne hay (Medicago sativa) and Italian ryegrass hay (Loliurn italicurn) in the ovine digestive tract , 1989, British Journal of Nutrition.

[30]  E Block,et al.  Acid insoluble ash as a marker of digestibility for sheep fed corn plants or hay and for lactating dairy cattle fed hay. , 1981, Journal of animal science.

[31]  T. DelCurto,et al.  Evaluation of internal markers isolated by alkaline hydrogen peroxide incubation and acid detergent lignin extraction. , 1988, Journal of Animal Science.

[32]  G. J. Faichney,et al.  Behaviour of solute and particle markers in the stomach of sheep given a concentrate diet , 1978, British Journal of Nutrition.

[33]  D. Beever,et al.  Ytterbium acetate as a particulate-phase digesta-flow marker , 1985, British Journal of Nutrition.

[34]  P. Penning,et al.  The use of internal markers to estimate herbage digestibility and intake: 1. Potentially indigestible cellulose and acid insoluble ash , 1983, Journal of Agricultural Sciences.

[35]  J. Finley,et al.  Ash-free indigestible acid detergent fiber as an internal marker to estimate digestibility with grazing ruminants. , 1990 .

[36]  P. Huhtanen,et al.  Composition, digestibility and particle-associated enzyme activities in rumen digesta as influenced by particle size and time after feeding , 1992 .

[37]  L. Krysl,et al.  Estimating digestibility and faecal output in lambs using internal and external markers , 1988, The Journal of Agricultural Science.