1- Bartley, E. E., and C. W. Deyoe. 1975. Starea as a protein replacer for ruminants. A review of 10 years of research. Journal of Feedstuffs, 47: 42–51.
2- Blummel M., H. P. S Makkar, and K. Becker. 1997. In vitro gas production: a technique revisited. Journal of Animal Nutrition, 77: 24–34.
3- 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. Journal of Dairy Science, 74: 1321.
4- Caneque, V., S. Velasco., and J. L., Sancha. 1998. Nutritional value and use of ligno-cellulosic feed treated with urea in the ruminant diet. Options Mediterraneennes. 17–31.
5- Casper, D. P., and D. J. Schingoethe. 1986. Evaluation of urea and dried whey in diets of cows during early lactation. Journal of Dairy Science, 69: 13-46.
6- Chahil, S. M., Lohan, O. P. and Rathee, C. S. 1986. In vitro evaluation of urea-lignocellulose complex. Indian Journal of Animal Nutrition, 56: 280–282.
7- Chanjula. P., M. Wanapat, C. Wachirapakorn, and P. Rowlinson. 2004. Effect of synchronizing starch sources and protein (NPN) in the rumen on feed intake, rumen microbial fermentation, nutrient utilization and performance of lactating dairy cows. Asian- Australia Journal of Animal Science, 17: 1400–1410.
8- Chen, X. B., Y. K. Chen, M. F. Franklin, E. R. Orskov, and W. J. Shand. 1992. The effect of feed intake and body weight on purine derivative excretion and microbialt protein supply in sheep. Journal of Animal Science, 70: 1534-1542.
9- Cherdthong, A., and M.Wanapat. 2010. Development of urea products as rumen slow-release feed on ruminant production: a review. Australlia Journal Basic Applly Science, 4: 2232–2241.
10- Dijkstra, J. 2011. Effects of nutritional strategies on simulated nitrogen excretion and methane emission in dairy cattle Modelling nutrient digestion and utilisation in farm animals. In: Faverdin and N. Friggens Wageningen Academic Publishers. 394-402.
11- Forero, O., F.N. Owens, K.S. Lusby. 1980. Evaluation of slow-release urea for winter supplementation of lactating range cows. Journal of Animal Science, 50: 532-538.
12- Forman, L., J. Tuma, and M. Dedek. 1982. A feeding stuff constituent made of whey and containing lactosylurea. XXI International Dairy Congress. Mir Publishers Moscow. USSR. 638–639.
13- Galo, E., S. M. Emanuele, C.J. Sniffen, J.H. White, and J. R. Knapp. 2003. Effects of a polymer-coated urea product on nitrogen metabolism in lactating Holstein dairy cattle. Journal of Dairy Science, 86: 2154–2162.
14- Getachew, G., M. Blümmel, H. P .S. Makkar, and K. Becker. 1998. In vitro gas measuring techniques for assessment of nutritional quality of feeds: a review. Journal of Animal feed Science Technology, 72: 261-281.
15- Golombeski, G. L., K. F. Kalscheur, A. R. Hippen., and D. J. Schingoethe. 2006. Slow-release urea and highly fermentable sugars in diets fed to lactating dairy cows. Journal of Dairy Science, 89: 4395-4403.
16- Griswold, K. E., G. A. Apgar, J. Bouton, and J. L. Firkins. 2003. Effects of urea infusion and ruminal degradable protein concentration on microbial growth, digestibility and fermentation in continuous culture. Journal of Animal Science, 81: 329-336.
17- Harrison, G. A., and T. p. Karnezos. 2005. Can we improve the efficiency of nitrogen utilization in the lactating dairy cows? Recent Advances in Animal Nutrition in Australia. School of Rural and Agriculture, University of New England, 15: 146-154.
18- Highstreet, A., P. H. Robinson, J. Robison, and J. G. Garrett. 2010. Response of Holstein cows to replacing urea with with a slowly rumen released urea in a diet high in soluble crude protein. Livestock Science, 129: 179-185.
19- Hristov, A. N., M. Ivan, and T. A. McAllister. 2000. In vitro effects of common fatty acids on fermentation and protozoal numbers and activity in rumen fluid from cattle fed a barley-based diet. Journal of Animal Science, 78: 27-35.
20- Huber, J. T. 1976. Use of non-protein nitrogen by lactating cows. Journal of Feedstuffs, 48: 6-13.
21- Hungate, R. E. 1950. The anaerobic mesophilic cellulolytic bacteria. Bacteriol Revolotion, 14: 1–49.
22- Huntington, G. B., D. L. Harmon, N. B. Kristensen, K. C. Hanson, J. W. Spears. 2006. Effects of a slow-release urea source on absorption of ammonia and endogenous production of urea by cattle. Animal Feed Science Technology, 130: 225–241.
23- Huston, J. E., M. Shelton, and L. H. Breuer. 1974. Effect of rate of release of urea on its utilization by sheep. Journal of Animal Science, 39: 618–628.
24- Kandylis, K., and A. C. Bray. 1986. Effects of variation of dietary sulfur on movement of sulfur. Journal of Dairy Science, 70: 40–49.
25- Karabulut, A., O. Canbolat, H. Kalkan, F. Gurbuzol, E. Sucu, I. Filya. 2007. Comparison of in vitro gas production, metabolizable energy, organic matter digestibility and microbial protein production of some legume hays. Asian-Australia Journal Animal Science, 20: 517–522.
26- Lorenzo, N., and A. Costanzo. 2007. In vitro release of ammonia nitrogen from various nitrogen sources in batch culture. Technical Research Report.
27- Malik, N. S., P. N. Langar, and A. K. Chopra. 1978. Uromol as a source of dietary nitrogen for ruminants: metabolic and rumen fermentation studies on buffalo calves. Journal of Agricultur Science, 91: 309–316.
28- Mathison, G. W., S. R. Soofi. and M. Worsley. 1994. The potential of isobutyraldehyde monourea (propanal, 2-methyl- monourea) as a nonprotein nitrogen source for ruminant animals. Journal of Animal Science, 74: 665–674.
29- Menke, K. H., and H.Steingass. 1988. Estimation of the energetic feed value obtained from chemical analysis and gas production using rumen fluid. Animal Research Development, 28: 7–55.
30- Ørskov, E. R., and I. McDonald. 1979. The estimation of protein degradability in the rumen from incubation measurements weighted according to rate of passage. Journal of Agricultur Science, 92: 499–503.
31- Pinos-Rodriguez, J. M., L. Y. Peña, S. S. Gonzalez-Muñoz, R. Barcena, and A. Salem. 2010. Effects of a slow-release coated urea product on growth performance and ruminal fermentation in beef steers. Italian Journal of Animal Science, 9: 16–19.
32- Prokop, M. J., and T. J. Klopfenstein. 1977. Slow ammonia release urea. Nebraska Beef Cattle Report Nebraska. 77-218.
33- Shahidi, F., and X. Q. Han. 1993. Encapsulation of food ingredients. Critical Review in Food Science and Nutrition.
34- Sommer, A., J. Szakacs, and L. Chrastinova. 1985. Effect of treated urea on the digestion of nutrients and the dynamics of releasing ammonia in the rumen of fattening cattle. Journal of Agricultur Science, 31: 718–726.
35- Taylor-Edwards, C. C. 2009. Influence of slow-release urea on nitrogen balance and portal-drained visceral nutrient flux in beef steers. Journal of Animal Science, 87: 209-221.
36- Tedeschi, L. O., A. Cannas, and D. G. Fox. 2010. A nutrition mathematical model to account for dietary supply and requirements of energy and nutrients for domesticated small ruminants: The development and evaluation of the Small Ruminant Nutrition System. Small Ruminant Research, 89: 174-184.
37- Valkeners, D., A. Thewis, S. Amant, and Y. Beckers. 2006. Effect of various levels of imbalance between energy and nitrogen release in the rumen on microbial protein synthesis and nitrogen metabolism in growing double-muscled Belgian Blue bulls fed a corn silage-based diet. Journal of Animal Science, 84: 877-885.
38- Van Horn, H. H., C. F. Foreman, and J. E. Rodriguez. 1967. Effect of high-urea supplementationon feed intake and milk productionof dairy cows. Journal of Dairy science, 50: 70-89.
39- Virk, A. S., H.Steingass, and K. H. Menke. 1989. Studies on in vitro degradation and in vivo digestion of a slow ammonia releasing urea product. Journal of Animal Nutrition, 39: 167–176.
40- Waite, R., and A. G Wilson. 1968. Biuret and urea in concentrates for milking cows. Journal of Dairy Research, 35: 203–212.
41- Xin, H. S., D. M. Schaefer, Q. P. Liu, D. E. Axe, and Q. X. Meng. 2010. Effects of polyurethane coated ureasupplement on in vitro ruminal fermentation, ammonia release dairy cows fed a steam-flaked corn-based diet. Asian-Australia Journal Animal Science, 23: 491-500.
42- Yu, P., L. Boon-ek, B.J. Leury, A. R. Egan. 2001. Effect of dietary protein variation in terms of net truly digested intestinal protein (DVE) and rumen degraded protein balance (OEB) on the concentrations and excretion of urinary creatinine, purine derivatives, and microbial N supply in sheep: Comparison with the prediction from the DVE/OEB model. Animal Feed Science Technology, 93: 71–91.