All India dairy business directory. 2001. 2nd Ed. Sadana Publishers and distributors, SA-104, Shastrinagar, Ghaziabad, India.
AOAC. 1995. Official methods for analysis. Association of Official Analytical Chemists, Washington, DC, USA.
Bector, B. S., M. Ram and O. P. Singhal. 1998. Rapid platform test for the detection/determination of added urea in milk. Indian Dairyman 50:59-62.
Broderick, G. A. and M. K. Clayton. 1997. A statistical evaluation of animal and nutritional factors influencing concentrations of MU nitrogen. J. Dairy Sci., 80:2964-2971.
Butler, W. R., J. J. Calaman and S. W. Beam. 1996. Plasma or milk urea nitrogen in relation to pregnancy rate in lactating dairy cattle. J. Anim. Sci. 74:858-865.
Canfield, D. A., C. J. Sniffen and W. Butler. 1990. Effects of excess degradable protein on postpartum reproduction and energy balance in dairy cattle. J. Dairy Sci. 73:2342-2349.
Carlsson, J., J. Bergstrom and B. Pehrson. 1995. Variations and breed, age, season, yield, stage of lactation and herd in the concentration of urea in bulk milk and individual cow's milk. Acta Veterinaria Scandinavica 36:245-254.
Chalupa, W. 1984. Discussion of protein symposium. J. Dairy Sci. 67: 1134-1146.
Coustumier, J. L. E. 1996. The balance of ration is not the whole story. Production Laitiere Moderne 261:96-97 (Cited: Dairy Sci. Abst., 59: 347).
Dhali, A. 2001. Studies on the effect of feeding management systems on blood and milk urea concentration in dairy cattle. Ph.D thesis. National Dairy Research Institute (Deemed University), Karnal, India.
Diab Ismail, A. K. and J. K. Hillers. 1996. Effect of selection for milk yield and dietary energy on yield traits, bovine somatotropin and plasma urea nitrogen in dairy cows. J. Dairy Sci. 79:682-688.
Erbersdobler, H. F., S. Braasch and E. A. Trautwein. 1990. Concentrations of taurine, urea and free amino acids in milk as influenced by stage of lactation and breed of the cows. J. Anim. Physiol. Anim. Nutri., 63:1-7 (Cited: Dairy Sci. Abst. 54:1061).
Ferguson, J. D. and W. Chalupa. 1989. Symposium: Interactions of nutrition and reproduction. Impact of protein nutrition on reproduction in dairy cows. J. Dairy Sci. 72:746-766.
Gooden, S. M., D. F. Kelton, K. D. Lisssemore, J. S. Walton, K. E. Leslie and J. H. Lumsden. 2001. Milk urea testing as a tool to monitor reproductive performance in Ontario dairy herds. J. Dairy Sci. 84:1397-1406.
Gustafsson, A. H. and D. L. Palmquist. 1993. Diurnal variation of rumen ammonia, serum urea and milk urea in dairy cows at high and low yields. J. Dairy Sci. 76:475-484.
Harvey, W. B. 1987. User's Guide for LSMLMW, mixed model least-squares and maximum likelihood computer program, PC-1 Version, Mimeograph, Ohio State University, Ohio, USA.
Hof, G., M. D. Vervoorn, P. J. Lenacrs and S. Tamminga. 1997. Milk urea nitrogen as a tool to monitor the protein nutrition of dairy cows. J. Dairy Sci. 80:3333-3340.
Hwang, S. Y., M. J. Lee and P. W. Chiou. 2000. Monitoring nutritional status of dairy cows in Taiwan using milk protein and milk urea nitrogen. Asian-Aust. J. Anim. Sci. 13(12):1667-1673.
Kaim, M., Y. Folman and H. Neumark. 1983. The effect of protein intake and lactation number on post-partum body weight loss and reproductive performance of dairy cows. Ani. Prod. 37: 229-235.
Kalchreuter, R. 1990. Advantages of urea estimation in milk. Tierzuchter 42: 352-354 (Cited: Dairy Sci. Abst. 55:913).
Kramer, C. Y. 1957. Extension of multiple range tests to group correlated adjusted means. Biometrics 13:13-18.
McDonald, P., R. A. Edwards, J. F. D. Greenhalgh and C. A. Morgan. 1995. Animal Nutrition, 5th Ed. Addison Wesley Lonman, Edinburgh Gate, Harlow, Essex CM202JE, United Kingdom.
Moore, D. A. and G. Verga. 1996. BUN and MUN: Urea nitrogen testing in dairy cattle. Comp. Cont. Edu. Pract. Vet. 18:712-721.
Ndibualonji, B. B. and J. M. Godeau. 1993. Changes in plasma amino acids, urea and glucose in relation to the end of gestation and the onset of lactation in low yielding dairy cows. Mededelingen Vande Faculteit Land bouwwetenschappen, Universitiet Gent 58:1713-1717 (Cited: Dairy Sci. Abst. 58:7).
Oltner, R., M. Emanuelson and H. Wiktorsson. 1985. Urea concentrations in milk in relation to milk yield, live weight, lactation number and amount and composition of feed given to dairy cows. Livest. Prod. Sci. 12:47-57.
Pecorari, M., M. S. Mariani, M. G. Calzolari and G. Tedeschi. 1993. Urea content in milk: Variations and relationships with technological parameters. Scienzae Tecnica Lattiero-Casearia 44:144-154 (Cited: Dairy Sci. Abst. 55:1001).
Pestevsek, U., D. Likosar, J. Zust and A. Vengust. 1990. Use of Milk Urea test to detect malnutrition in dairy cows. Zbornik Veterinarske Fakultete Univerza Ljubljana 27:139-148 (Cited: Dairy Sci. Abst. 54:5).
Qureshi, S. M., G. Habib, H. A. Samad, M. M. Siddiqui, N. Ahmad, and M. Syed. 2002. Reproduction-Nutrition relationship in dairy buffaloes. I. Effect of intake of protein, energy and blood metabolites levels. Asian-Aust. J. Anim. Sci. 15(3):330-339.
Rajcevic, M., I. Jazbec and M. Ponikvas. 1993. Urea in milk and blood as indicator of nutritive matter supply in high-yielding dairy cows. Zbornik Biotehniske Fakultete Univerze Edvasda Kardelja V Ljubljani, Kmetijstvo 62:179-184 (Cited: Dairy Sci. Abst. 57:498).
Reinartz, M. and W. Hofmann. 1989. Serum urea estimation in dairy herds. Praktische Tierarzt 70:22-28 (Cited: Dairy Sci. Abst. 52: 752).
Roseler, D. K., J. D. Ferguson, C. J. Sniffen and J. Heremma. 1993. Dietary protein degradability effects on plasma and Milk Urea nitrogen and milk non-protein nitrogen in Holstein cows. J. Dairy Sci. 76:525-534.
Sauvant, D., P. Bas, M. F. Mahe, P. Morand-Fehr and N. Mandran. 1992. Relationship between the type of $\alpha_S1$
-casein and the urea content of blood and milk of goat. Annales de Zootechnie 41:103-104 (Cited: Dairy Sci. Abst., 54: 933).
Schepers, A. J. and R. G. M. Meijer. 1998. Evaluation of the utilization of dietary nitrogen by dairy cows based on urea concentration in milk. J. Dairy Sci. 81:579-584.
Whitaker, D. A., J. M. Kelly and H. F. Eayros. 1995. Assessing dairy cow diets through milk urea tests. Vet. Rec., 136: 179-180.
Zadnik, T., M. V. Nemec, Cadonic-Spelic and M. Klinkon. 1993. Urea concentration in samples of bulk tank milk. In: Prvi Slovenski Veterinarski Kongres. Portoroz 18-20 November 1993 (Cited: Dairy Sci. Abst. 57: 223).