Determination of coated urea releasing in ruminant’s rumen through in vivo and in vitro studies

Document Type : Ruminant Nutrition




Introduction Urea is a small organic compound that is very rich in N (44.96% N) and is used to supply degradable intake protein (DIP) for ruminants. Urea is broken down to ammonia in the rumen under the action of urease bacteria. Using urea over other sources of DIP is cheaper according to per N basis than any other feedstuffs. However, urea is used rather inefficiently by ruminants compared with other sources that contain true protein, and this is due to the fact that the rate of urea degradation in the rumen is more rapid than the rate of utilization of the resulting ammonia by rumen bacteria. One strategy for improving the utilization of urea by ruminants is reducing the degradation rate of urea. A number of slow release urea products were developed for this purpose. Coated urea is a urea product design to reduce the rate of ruminal degradation of urea. The objective of this research was to investigate the effects of coated urea on N metabolism and determine this Effect in ruminant feed.
Materials and Methods to characterize the ruminal behavior of coated urea three experimental studies were designed. Two in vitro studies were designed to determine NH3-N release and gas production difference in treatments. NH3-N release of each Optigen and coated urea was tested in sex liquid phase included: distilled water, TCA (Ph = 6.2), buffer solution, buffered rumen fluid, Free cell rumen fluid (centrifugation at 7000 rpm), Free cell buffered rumen fluid. Each of the two N-sources was isonitrogenous (equivalent 20mg urea) and added to a 100-ml glass syringe. Then 30 ml of solution (consisting distilled water, TCA, buffer solution, buffered rumen fluid, free cell rumen fluid or free cell buffered rumen fluid) was pipetted into each syringe followed by incubated in a water bath at 39°C. Three syringes for each treatment diet were incubated for 0, 30 min and 2, 4 and 6 h time points. The syringes were taken out and Residual solid parts were taken for determination of NH3-N release using the Kjeldahl N methods (AOAC, 2005). The gas production of each N-Sources (four N-Sources in triplicate) was tested in 4 different feed mixtures (straw + 3% N-Sources, barley flour + 3% N-Sources, barley flour + molasses as additives + 3% N-Sources, a dairy ration formulated to + 3% N-Sources). The in vivo experiment was conducted using sixteen dairy Sannen goats with an average body weight of 38.85 kg, 73 days of lactation and 1979g milk production. The experimental design was a completely randomized design. The experiment consisted of 21-day periods each consisting of 14 days adaptation and 7 days of sampling. The experimental rations were: 1) control (canola), 2) urea (urea % 0.5), 3) Optigen (Optigen %0.55), 4) coated urea (% 0.7 coated urea).
Results and Discussion Based on these results, urea is often degraded rapidly in the rumen by the action of urease and the resulting ammonia supply may exceed the capacity of rumen bacteria to assimilate it into amino acids. This rapid release of ammonia may result in inefficient N utilization in the rumen. Therefore coated urea improves ammonia assimilation in the rumen. The cumulative gas production (96 hours) influenced by diet and N-source treatments, which was higher in formulated TMR diets for the dairy cow and least gas production in wheat straw. The result indicated that Optigen (90.82) and then coated urea (90.81) were the highest gas producer in the formulated TMR diets for the dairy cow and the canola meal (69.04) and urea (69.43) had the least gas production in wheat straw (P<0.05). The results showed that treatments had no significant effect on milk compositions, rumen fermentation and synthesis of microbial protein (p> 0.05). The impact on the most blood metabolites except BUN, Cholesterol and ALT were also no significant (p> 0.05). As a result, no significant differences observed between coated urea with control (canola) treatments.
Conclusion it was concluded that little difference was observed in gas production results between coated urea and Optigen treatments with control (canola). And therefore to reducing feed costs and increasing the efficiency of the rumen microorganism, we can use NPN sources as a replacement for part of dietary protein.


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.