Prediction of Ruminal Volatile Fatty Acids and pH Within the Net Carbohydrate and Protein System

Journal of Animal Science

Volumn 74, Issue 1, 1996, Pages 226-244

  Pitt, R E ^a,b   Van Kessel, J S ^a   Fox, D G ^a   Pell, A N ^a   Barry, M C ^a   Van Soest, P J ^a  

^a Cornell University ^*  (United States)

^b 318 Riley Robb Hall ^*

Author keywords

Effective Fiber; Model; pH; Rumen; VFA

Indexed keywords

BACTERIA (MICROORGANISMS);

ACETIC ACID DERIVATIVE; BUTYRIC ACID DERIVATIVE; LACTIC ACID DERIVATIVE; METHANE; PROPIONIC ACID DERIVATIVE; PROTEIN; VOLATILE FATTY ACID;

ANIMAL; BIOLOGICAL MODEL; CARBOHYDRATE METABOLISM; CATTLE; CHEMISTRY; DIGESTION; METABOLISM; MICROBIOLOGY; PH; PHYSIOLOGY; PREDICTION AND FORECASTING; REVIEW; RUMINANT STOMACH;

ACETATES; ANIMALS; BUTYRATES; CARBOHYDRATE METABOLISM; CATTLE; DIGESTION; FATTY ACIDS, VOLATILE; HYDROGEN-ION CONCENTRATION; LACTATES; METHANE; MODELS, BIOLOGICAL; PREDICTIVE VALUE OF TESTS; PROPIONATES; PROTEINS; RUMEN;

EID: 0029690406     PISSN: 00218812     EISSN: None     Source Type: Journal    
DOI: 10.2527/1996.741226x     Document Type: Article

References (123)

1. Argyle, J. L., and R. L. Baldwin. 1988. Modeling of rumen water kinetics and effects of rumen pH changes. J. Dairy Sci. 71:1178.
2. 2 in steers and the effects of monensin on volatile fatty acid kinetics. J. Nutr. 113:1265.
3. Ash, R. W., and A. Dobson. 1963. The effect of absorption on the acidity of rumen contents. J. Physiol. (Lond.) 169:39.
4. Atkins, K. B., R. A. Erdman, and J. H. Vandersall. 1988. Dietary choline effects on milk yield and duodenal choline flow in dairy cattle. J. Dairy Sci. 71:109.
5. Bailey, C. B. 1961. Saliva secretion and its relation to feeding in cattle. 3. The rate of secretion of mixed saliva in the cow during eating, with an estimate of the magnitude of the total daily secretion of mixed saliva. Br. J. Nutr. 15:443.
6. Baldwin, R. L., L. J. Koong, and M. J. Ulyatt. 1977. A dynamic model of ruminant digestion for evaluation of factors affecting nutritive value. Agric. Syst. 2:255.
7. Baldwin, R. L., H. L. Lucas, and R. Cabrera. 1970. Energetic relationships in the formation and utilization of fermentation end-products. In: A. T. Phillipson (Ed.) Physiology of Digestion and Metabolism in the Ruminant. p 319. Oriel Press, Newcastle upon Tyne, U.K.
8. Barry, M. C., D. G. Fox, T. R. Tylutki, A. N. Pell, J. D. O'Connor, C. J. Sniffen, and W. Chalupa. 1994. A manual for using the Cornell net carbohydrate and protein system for evaluating cattle diets. Cornell Univ., Ithaca, NY.
9. Beauchemin, K. A. 1991. Ingestion and mastication of feed by dairy cattle. Vet. Clin. North Am. 7:439.
10. Beauchemin, K. A., and L. M. Rode. 1994. Compressed baled alfalfa hay for primiparous and multiparous cows. J. Dairy Sci. 77:1003.
11. Ben-Ghedalia, D., E. Yosef, J. Miron, and Y. Est. 1989. The effects of starch- and pectin-rich diets on quantitative aspects of digestion in sheep. Anim. Feed Sci. Technol. 24:289.
12. Bergman, E. N. 1990. Energy contributions of volatile fatty acids from the gastrointestinal tract in various species. Physiol. Rev. 70:567.
13. Cameron, M. R., T. H. Klusmeyer, G. L. Lynch, J. H. Clark, and D. R. Nelson. 1991. Effects of urea and starch on rumen fermentation, nutrient passage to the duodenum, and performance of cows. J. Dairy Sci. 74:1321.
14. Casper, D. P., and D. J. Schingoethe. 1986. Evaluation of urea and dried whey in diets of cows during early lactation. J. Dairy Sci. 69:1346.
15. Casper, D. P., D. J. Schingoethe, and W. A. Eisenbeisz. 1990. Response of early lactation cows to diets that vary in ruminal degradability of carbohydrates and amount of fat. J. Dairy Sci. 73:425.
16. Cassida, K. A., and M. R. Stokes. 1986. Eating and resting salivation in early lactation dairy cows. J. Dairy Sci. 69:1282.
17. Chalupa, W., C. J. Sniffen, D. G. Fox, and P. J. Van Soest. 1991. Model generated protein degradation nutrition information. In: Proc. Cornell Nutr. Conf. Feed Manuf. p 44. Cornell Univ., Ithaca, NY.
18. Colucci, P. E. 1984. Comparative digestion and digesta kinetics in sheep and cattle. Ph.D. Dissertation, Cornell Univ., Ithaca, NY.
19. Colucci, P. E., G. K. MacLeod, W. L. Grovum, L. W. Cahill, and I. McMillan. 1989. Comparative digestion in sheep and cattle fed different forage to concentrate ratios at high and low intakes. J. Dairy Sci. 72:1774.
20. Cone, J. W., and M.G.E. Wolters. 1990. Some properties and degradability of isolated starch granules. Starch 42:298.
21. Coppock, C. E., G. T. Schelling, F. M. Byers, and C. E. Gates. 1986. A naturally occurring mineral as a buffer in the diet of lactating dairy cows. J. Dairy Sci. 69:111.
22. 13C]lactate in the rumen of dairy cattle. Appl. Environ. Microbiol. 42:649.
23. Danielli, J. F., M.W.S. Hitchcock, R. A. Marshall, and A. T. Phillipson. 1945. The mechanism of absorption from the rumen as exemplified by the behaviour of acetic, propionic, and butyric acids. J. Exp. Biol. 22:75.
24. Davis, C. L. 1967. Acetate production in the rumen of cows fed either control or low-fiber, high-grain diets. J. Dairy Sci. 50:1621.
25. Dijkstra, J., H. Boer, J. V. Bruchem, M. Bruining, and S. Tamminga. 1993. Absorption of volatile fatty acids from the rumen of lactating dairy cows as influenced by volatile fatty acid concentration, pH and rumen liquid volume. Br. J. Nutr. 69:385.
26. Dijkstra, J., H.D. St.C. Neal, D. E. Beever, and J. France. 1992. Simulation of nutrient digestion, absorption, and outflow in the rumen: Model description. J. Nutr. 122:2239.
27. Dirksen, G., H. G. Liebich, G. Brosi, H. Hagemeister, and E. Mayer. 1985. Morphology of the ruminal mucosa and fatty acid absorption in cattle - significant factors for health and productivity. Anim. Res. Dev. 21:7.
28. Erasmus, L. J., P. M. Botha, and A. Kistner. 1992. Effect of yeast culture supplement on production, rumen fermentation, and duodenal nitrogen flow in dairy cows. J. Dairy Sci. 75:3056.
29. Erdman, R. A. 1988. Dietary buffering requirements of the lactating dairy cow: A review. J. Dairy Sci. 71:3246.
30. Feng, P., W. H. Hoover, T. K. Miller, and R. Blauwiekel. 1993. Interactions of fiber and nonstructural carbohydrates on lactation and ruminal function. J. Dairy Sci. 76:1324.
31. Fischer, J. M., J. G. Buchanan-Smith, C. Campbell, D. G. Grieve, and O. B. Allen. 1994. Effects of forage particle size and long hay for cows fed total mixed rations based on alfalfa and corn. J. Dairy Sci. 77:217.
32. Fox, D. G., M. C. Barry, R. E. Pitt, D. K. Roseler, and W. C. Stone. 1995. Application of the Cornell net carbohydrate and protein model for cattle consuming forages. J. Anim. Sci. 73:267.
33. Fox, D. G., C. J. Sniffen, J. D. O'Connor, J. B. Russell, and P. J. Van Soest. 1990. The Cornell Net Carbohydrate and Protein System for Evaluating Cattle Diets. Search: Agriculture 34, Cornell Univ. Agric. Exp. Stn., Ithaca, NY.
34. Fox, D. G., C. J. Sniffen, J. D. O'Connor, J. B. Russell, and P. J. Van Soest. 1992. A net carbohydrate and protein system for evaluating cattle diets: III. Cattle requirements and diet adequacy. J. Anim. Sci. 70:3578.
35. France, J., J.H.M. Thornley, and D. E. Beever. 1982. A mathematical model of the rumen. J. Agric. Sci. 99:343.
36. Ghorbani, G. R., J. A. Jackson, and R. W. Hemken. 1989. Effects of sodium bicarbonate and sodium sesquicarbonate on animal performance, ruminal metabolism, and systemic acid-base status. J. Dairy Sci. 72:2039.
37. Grant, R. J., V. F. Colenbrander, and D. R. Mertens. 1990a. Milk fat depression in dairy cows: Role of particle size of alfalfa hay. J. Dairy Sci. 73:1823.
38. Grant, R. J., V. F. Colenbrander, and D. R. Mertens. 1990b. Milk fat depression in dairy cows: Role of silage particle size. J. Dairy Sci. 73:1834.
39. Grant, R. J., and D. R. Mertens. 1992. Influence of buffer pH and raw corn starch addition on in vitro fiber digestion kinetics. J. Dairy Sci. 75:2762.
40. Grant, R. J., and S. J. Weidner. 1992. Digestion kinetics of fiber: Influence of in vitro buffer pH varied within observed physiological range. J. Dairy Sci. 75:1060.
41. Gray, F. V. 1947. The absorption of volatile fatty acids from the rumen. J. Exp. Biol. 24:1.
42. Haaland, G. L., and H. F. Tyrell. 1982. Effects of limestone and sodium bicarbonate buffers on rumen measurements and rate of passage in cattle. J. Anim. Sci. 55:935.
43. Haaland, G. L., H. F. Tyrell, P. W. Moe, and W. E. Wheeler. 1982. Effect of crude protein level and limestone buffer in diets fed at two levels of intake on rumen pH, ammonia-nitrogen, buffering capacity and volatile fatty acid concentration of cattle. J. Anim. Sci. 55:943.
44. Huhtanen, P., H. Mietinen, and M. Ylinen. 1993. Effect of increasing ruminal butyrate on milk yield and blood constituents in dairy cows fed a grass silage-based diet. J. Dairy Sci. 76:1114.
45. Hungate, R. E. 1966. The Rumen and Its Microbes. Academic Press, New York.
46. Johnson, R. B. 1951. The relative rates of absorption of the volatile acids from the rumen and their relationship to ketosis. Cornell Vet. 41:115.
47. Johnson, M. A., T. F. Sweeney, and L. D. Muller. 1988. Effects of feeding synthetic zeolite A and sodium bicarbonate on milk production, nutrient digestion, and rate of digesta passage in dairy cows. J. Dairy Sci. 71:946.
48. Klusmeyer, T. H., G. L. Lynch, J. H. Clark, and D. R. Nelson. 1991. Effects of calcium salts of fatty acids and protein source on ruminal fermentation and nutrient flow to duodenum of cows. J. Dairy Sci. 74:2206.
49. Rung, L., Jr., R. S. Tung, and B. R. Carmean. 1992. Rumen fermentation and nutrient digestion in cattle fed diets varying in forage and energy source. Anim. Feed Sci. Technol. 39:1.
50. Leibensperger, R. Y., and R. E. Pitt. 1987. A model of clostridial dominance in ensilage. Grass Forage Sci. 42:297.
51. Leonard, M., and E. Block. 1988. Effect of ration protein content and solubility on milk production of primiparous Holstein heifers. J. Dairy Sci. 71:2709.
52. Lescoat, P., and D. Sauvant. 1995. Development of a mechanistic model for rumen digestion validated using duodenal flux of amino acids. Reprod. Nutr. Dev. 35:45.
53. Mansfield, H. R., and M. D. Stern. 1994. Effects of soybean hulls and lignosulfonate-treated soybean meal on ruminal fermentation in lactating dairy cows. J. Dairy Sci. 77:1070.
54. Masson, M. J., and A. T. Phillipson. 1951. The absorption of acetate, propionate and butyrate from the rumen of sheep. J. Physiol. (Lond.) 113:189.
55. McAllister, T. A., R. C. Phillippe, L. M. Rode, and K.-J. Cheng. 1993. Effect of the protein matrix on the digestion of cereal grains by ruminal microorganisms. J. Anim. Sci. 71:205.
56. McBurney, M. I., P. J. Van Soest, and L. E. Chase. 1983. Cation exchange capacity and buffering capacity of neutral-detergent fibres. J. Sci. Food Agric. 34:910.
57. McCarthy, R. D., Jr., T. H. Klusmeyer, J. L. Vicini, J. H. Clark, and D. R. Nelson. 1989. Effects of source of protein and carbohydrate on ruminal fermentation and passage of nutrients to the small intestine of lactating cows. J. Dairy Sci. 72:2002.
58. McDonald, P., R. A. Edwards, and J.F.D. Greenhalgh. 1981. Animal Nutrition (3rd Ed.). Longman Press, London.
59. McDonald, P., A. R. Henderson, and S.J.E. Heron. 1991. The Biochemistry of Silage (2nd Ed.). Chalcombe Publ., Marlow, U.K.
60. Mertens, D. R. 1992. Nonstructural and structural carbohydrates. In: H. H. Van Horn and C. J. Wilcox (Ed.) Large Dairy Herd Management, p 219. Am. Dairy Sci. Assoc., Champaign, IL.
61. Moran, J. B., and T. E. Trigg. 1989. Feed intake and utilization of maize silage-based complete diets by Australian Friesian cows and heifers at various stages of lactation. Livest. Prod. Sci. 23:275.
62. Murphy, M. R., R. L. Baldwin, and L. J. Koong. 1982. Estimation of stoichiometric parameters for rumen fermentation of roughage and concentrate diets. J. Anim. Sci. 55:411.
63. Nagel, S. A., and G. A. Broderick. 1992. Effect of formic acid or formaldehyde treatment of alfalfa silage on nutrient utilization by dairy cows. J. Dairy Sci. 75:140.
64. Nakamura, T., and F. G. Owen. 1989. High amounts of soyhulls for pelleted concentrate diets. J. Dairy Sci. 72:988.
65. Neal, H.D.St.C., J. Dijkstra, and M. Gill. 1992. Simulation of nutrient digestion, absorption, and outflow in the rumen: Model evaluation. J. Nutr. 122:2257.
66. Nelson, W. F., and L. D. Satter. 1992. Impact of stage of maturity and method of preservation of alfalfa on digestion in lactating dairy cows. J. Dairy Sci. 75:1571.
67. Newbold, J. R., and S. R. Rust. 1990. Effects of protein degradability and source on rumen function, food intake and growth in Holstein cattle given high-moisture maize grain. Anim. Prod. 50:399.
68. Nocek, J. 1992. Feeding sequence and strategy effects on ruminal environment and production performance in first lactation cows. J. Dairy Sci. 75:3100.
69. Nocek, J. E., and S. Tamminga. 1991. Site of digestion of starch in the gastrointestinal tract of dairy cows and its effect on milk yield and composition. J. Dairy Sci. 74:3598.
70. O'Connor, J. D., C. J. Sniffen, D. G. Fox, and W. Chalupa. 1993. A net carbohydrate and protein system for evaluating cattle diets: IV. Predicting amino acid adequacy. J. Anim. Sci. 71:1298.
71. Oliviera, J. S., J. T. Huber, D. Ben-Ghedalia, R. S. Swingle, C. B. Theurer, and M. Pessarakli. 1993. Influence of sorghum grain processing on performance of lactating dairy cows. J. Dairy Sci. 76:575.
72. Olumeyan, D. B., T. G. Nagraja, G. W. Miller, R. A. Frey, and J. E. Boyer. 1986. Rumen microbial changes in cattle fed diets with or without salinomycin. Appl. Environ. Microbiol. 51:340.
73. Pell, A. N., and P. Schofield. 1993. Computerized monitoring of gas production to measure forage digestion in vitro. J. Dairy Sci. 76:1063.
74. Peters, J. P., R.Y.W. Shen, and J. A. Robinson. 1992. Disappearance of acetic acid from the bovine reticulorumen at basal and elevated concentrations of acetic acid. J. Anim. Sci. 70:1509.
75. Peters, J. P., R.Y.W. Shen, J. A. Robinson, and S. T. Chester. 1990. Disappearance and passage of propionic acid from the rumen of the beef steer. J. Anim. Sci. 68:3337.
76. Peters, R. H. 1986. The Ecological Implications of Body Size. Cambridge Univ. Press, Cambridge, U.K.
77. Petit, H. V., and D. M. Veira. 1991. Effect of grain level and protein source on ruminal fermentation, degradability, and digestion in milking cows fed silage. J. Dairy Sci. 74:2256.
78. Pfander, W. H., and A. T. Phillipson. 1953. The rates of absorption of acetic, propionic, and n-butyric acids. J. Physiol. (Lond.) 122:102.
79. Pirt, S. J. 1965. The maintenance energy of bacteria in growing cultures. Proc. R. Soc. Lond. B Biol. Sci. 163:224.
80. Pitt, R. E., R. E. Muck, and R. Y. Leibensperger. 1985. A quantitative model of the ensilage process in lactate silages. Grass Forage Sci. 40:279.
81. Robinson, P. H., G. de Boer, and J. J. Kennelly. 1991. Influence of source of rumen-degraded nitrogen on ruminal and whole tract digestion, plasma hormone and metabolite concentrations as well as milk yield and composition in dairy cows. Can. J. Anim. Sci. 71:417.
82. Robinson, P. H., and J. J. Kennelly. 1991. Influence of degradability of supplemental protein and time post-partum in early lactation dairy cows. 1. Rumen fermentation and milk production. Livest. Prod. Sci. 28:121.
83. Robinson, P. H., and R. E. McQueen. 1992. Influence of rumen fermentable neutral detergent fiber levels on feed intake and milk production of dairy cows. J. Dairy Sci. 75:520.
84. Rogers, J. A., and C. L. Davis. 1982a. Effects of intraruminal infusions of mineral salts on volatile fatty acid production in steers fed high-grain and high-roughage diets. J. Dairy Sci. 65:953.
85. Rogers, J. A., and C. L. Davis. 1982b. Rumen volatile fatty acid production and nutrient utilization in steers fed a diet supplemented with sodium bicarbonate and monensin. J. Dairy Sci. 65:944.
86. Rosenberg, L. A., and R. W. Rinne. 1987. Changes in seed constituents during germination and seedling growth of precociously matured soybean seeds (Glycine max). Ann. Bot. 60:705.
87. Russell, J. B., and M. S. Allen. 1984. Physiological basis for interactions among rumen bacteria: Streptococcus bovis and Megasphaera elsdenii as a model. In: M. J. Klug and C. A. Reddy (Ed.) Current Perspectives in Microbial Ecology. p 239. Am. Soc. Microbiol., Washington, DC.
88. Russell, J. B., and R. L. Baldwin. 1979. Comparison of maintenance energy expenditures and growth yields among several rumen bacteria grown on continuous culture. Appl. Environ. Microbiol. 37:537.
89. Russell, J. B., and J. M. Chow. 1993. Another theory for the action of ruminal buffer salts: Decreased starch fermentation and propionate production. J. Dairy Sci. 76:826.
90. Russell, J. B., and D. B. Dombrowski. 1980. Effect of pH on the efficiency of growth by pure cultures of rumen bacteria in continuous culture. Appl. Environ. Microbiol. 39:604.
91. Russell, J. B., J. D. O'Connor, D. G. Fox, P. J. Van Soest, and C. J. Sniffen. 1992. A net carbohydrate and protein system for evaluating cattle diets: I. Ruminal fermentation. J. Anim. Sci. 70:3551.
92. Russell, J. B., W. M. Sharp, and R. L. Baldwin. 1979. The effect of pH on maximum bacterial growth rate and its possible role as a determinant of bacterial competition in the rumen. J. Anim. Sci. 48:251.
93. Sarwar, M., J. L. Firkins, and M. L. Eastridge. 1992. Effects of varying forage and concentrate carbohydrates on nutrient digestibilities and milk production by dairy cows. J. Dairy Sci. 75:1533.
94. Schoenherr, W. D., T. S. Stahly, and G. L. Cromwell. 1989. The effects of dietary fat or fiber addition on energy and nitrogen digestibility in lactating, primiparous cows housed in a warm or hot environment. J. Anim. Sci. 67:473.
95. Sharp, W. M., R. R. Johnson, and F. N. Owens. 1982. Ruminal VFA production with steers fed whole or ground corn grain. J. Anim. Sci. 55:1505.
96. Shi, Y., and P. J. Weimer. 1992. Response surface analysis of the effects of pH and dilution rate on Ruminococcus flavefaciens FD-1 in cellulose-fed continuous culture. Appl. Environ. Microbiol. 58:2583.
97. Shockey, W. L., and A. L. Barta. 1991. Effect of salt on fermentation of alfalfa. 1. Treatment with potassium chloride. J. Dairy Sci. 74:155.
98. Shriver, B. J., W. H. Hoover, J. P. Sargent, R. J. Crawford, Jr., and W. V. Thayne. 1986. Fermentation of a high concentrate diet as affected by ruminal pH and digesta flow. J. Dairy Sci. 69:413.
99. Siddons, R. C., J. V. Nolan, D. E. Beever, and J. C. MacRae. 1985. Nitrogen digestion and metabolism in sheep consuming diets containing contrasting forms and levels of N. Br. J. Nutr. 54:175.
100. Sniffen, C. J. 1988. Balancing rations for carbohydrates for dairy cattle. In: The Application of Nutrition in Dairy Practice. p 25. American Cyanamid, Raleigh, NC.
101. Sniffen, C. J., J. D. O'Connor, P. J. Van Soest, D. G. Fox, and J. B. Russell. 1992. A net carbohydrate and protein system for evaluating cattle diets: II. Carbohydrate and protein availability. J. Anim. Sci. 70:3562.
102. Stokes, M. R., L. L. Vandemark, and L. S. Bull. 1986. Effects of sodium bicarbonate, magnesium oxide, and a commercial buffer mixture in early lactation cows fed hay crop silage. J. Dairy Sci. 69:1595.
103. Stokes, S. R., W. H. Hoover, T. K. Miller, and R. Blauweikel. 1991. Ruminal digestion and microbial utilization of diets varying in type of carbohydrate and protein. J. Dairy Sci. 74:871.
104. Strobel, H. J., and J. B. Russell. 1986. Effect of pH and energy spilling on bacterial protein synthesis by carbohydrate-limited cultures of mixed rumen bacteria. J. Dairy Sci. 69:2941.
105. Sutton, J. D. 1985. Digestion and absorption of energy substrates in the lactating cow. J. Dairy Sci. 68:3376.
106. Sutton, J. D., I. C. Hart, W. H. Broster, R. J. Elliott, and E. Schuller. 1986. Feeding frequency for lactating cows: Effects on rumen fermentation and blood metabolites and hormones. Br. J. Nutr. 56:181.
107. Therion, J. J., A. Kistner, and J. H. Kornelius. 1982. Effect of pH on growth rates of rumen amylolytic and lactilytic bacteria. Appl. Environ. Microbiol. 44:428.
108. Theurer, C. B. 1986. Grain processing effects on starch utilization by ruminants. J. Anim. Sci. 63:1649.
109. Thorlacius, S. O., and G. A. Lodge. 1973. Absorption of steam-volatile fatty acids from the rumen of the cow as influenced by diet, buffers, and pH. Can. J. Anim. Sci. 53:279.
110. Tsuda, T. 1956. Studies on the absorption from the rumen. II. Absorption of several organic substances from the miniature rumen of the goat. Tohoku J. Agric. Res. 7:241.
111. Tucker, W. B., G. A. Harrison, and R. W. Hemken. 1988. Influence of dietary cation-anion balance on milk, blood, urine, and rumen fluid in lactating dairy cattle. J. Dairy Sci. 71:346.
112. Valdez, F. R., J. H. Harrison, and S. C. Fransen. 1989. Effect of feeding silage of early and late maturing corn planted at two population densities to lactating dairy cows. J. Dairy Sci. 72:2081.
113. Van Soest, P. J. 1994. Nutritional Ecology of the Ruminant (2nd Ed.). Cornell Univ. Press, Ithaca, NY.
114. Vanzant, E. S., R. C. Cochran, K. A. Jacques, A. A. Beharka, T. DelCurto, and T. B. Avery. 1990. Influence of level of supplementation and type of grain in supplements on intake and utilization of harvested, early-growing-season, bluestem-range forage by beef steers. J. Anim. Sci. 68:1457.
115. Voelker, H. H., D. P. Casper, F. C. Ludens, and D. J. Schingoethe. 1989. High moisture corn preserved with esters of propionic acid for lactating dairy cows. J. Dairy Sci. 72:89.
116. Waybright, T. R., and G. A. Varga. 1991. Effect of water-filled bags in the rumen of wethers on ruminal digesta kinetics and total tract nutrient digestibility. J. Anim. Sci. 69:2157.
117. Weiss, W. P., G. R. Fisher, and G. M. Erickson. 1989. Effect of source of neutral detergent fiber and starch on nutrient utilization by dairy cows. J. Dairy Sci. 72:2308.
118. Welch, J. G. 1982. Rumination, particle size and passage from the rumen. J. Anim. Sci. 54:885.
119. West, J. W., C. E. Coppock, D. H. Nave, and G. T. Schelling. 1986. Effects of potassium buffers on feed intake in lactating dairy cows and on rumen fermentation in vivo and in vitro. J. Dairy Sci. 69:124.
120. Wester, T. J., S. M. Gramlich, R. A. Britton, and R. A. Stock. 1992. Effect of grain sorghum hybrid on in vitro rate of starch disappearance and finishing performance of ruminants. J. Anim. Sci. 70:2866.
121. Wilks, D. L., C. E. Coppock, K. N. Brooks, and C. E. Gates. 1991. Effects of differences in starch content of diets with whole cottonseed or rice bran on milk casein. J. Dairy Sci. 74:1314.
122. Williams, V. J., and D.D.S. MacKenzie. 1965. The absorption of lactic acid from the reticulo-rumen of the sheep. Aust. J. Biol. Sci. 18:917.
123. Wolin, M. J. 1960. A theoretical rumen fermentation balance. J. Dairy Sci. 43:1452.