AOAC. (1994). Official Methods of Analysis.15th Ed., Association of Official Analytical Chemists, Inc., Arlington, Virginia, USA.
Bequette B.J., Backwell F.R.C., Crompton L.A. (1998). Current concepts of amino acid and protein metabolism in the mammary gland of the lactating ruminant. J. Dairy Sci. 81, 2540-2559.
Boguhn J., Kluth H., Stenhofel O., Peterhansel M. and Rodehutscord M. (2003). Nutrient digestibility and prediction of metabolizable energy in total mixed ration for ruminants. Arch. Anim. Nutr. 57, 253-266.
Chaturvedi O.H. and Walli T.K. (2001). Effect of feeding graded levels of undegraded dietary protein on voluntary intake, milk production and economic return in early lactating crossbred cows. Asian-australas J. Anim. Sci. l14, 1118-1124.
Emery R.S. (1978). Feediing for increased milk protein. J. Dairy Sci. 61, 825-828.
Evans E., Buchanan-Smith J.G., Macleod G.K. and Stone J.B. (1975). Glucose metabolism in cows fed low and high roughage diets. J. Dairy Sci. 58, 672-677.
Gordon F.J. (1977). The effect of protein content on the response of lactating cows to level of concentrate feeding. Anim. Prod. 25, 181-191.
Gordon F.J. and Forbes T.J. (1970). The associate effect of level of energy and protein intake in the dairy cow. J. Dairy Res. 37, 481-491.
Grainger C. and Wilhelms G. (1979). Effect of duration and pattern of underfeeding in early lactation on milk production and reproduction of dairy cows. Australian J. Exp. Agric. Anim. Husb. 19, 395-401.
Grieve D.G., Korver S., Rijpkema Y.S. and Hof G. (1986). Relationship between milk composition and some nutritional parameters in early lactation. Livest. Prod. Sci. 14, 239-254.
Holter J.B., Byrne J.A. and Schwab C.G. (1982).Crude protein for high milk production. J. Dairy Sci. 65, 1175-1188.
Kennedy J., Dillon P., Delaby L., Faverdin P., Stakelum G. and Rath M. (2003). Effect of genetic merit and concentrate supplementation on grass intake and milk production with Holstein-Friesian dairy cows. J. Dairy Sci. 86, 610-621.
Kennedy J., Dillon P., Faverdin P., Delaby L., Buckley F. and Rath M. (2002). The influence of cow genetic merit on response to concentrate supplementation in a grass based system. J. Anim. Sci. 75, 433-446.
Macleod G.K., Grieve D.G. and McMillan I. (1983). Performance of first lactation dairy cows fed complete rations of several ratios of forage to concentrate. J. Dairy Sci. 66, 1668-1674.
Roche J.R., Berry D.P. and Kolver E.S. (2006). Holstein-Friesian strain and feed effects on milk production, body weight and body condition score profiles in grazing dairy cows. J. Dairy Sci. 89, 3532-3543.
Roffler R.E., Satter L.D., Hardie A.R. and Tyler W.J. (1978). Influence of dietary protein concentration on milk production by dairy cattle during early lactation. J. Dairy Sci. 61, 1422-1428.
Rook J.A.F. (1961). Variations in the chemical composition of the milk of the cow. Dairy Sci. Abstr. 23, 251.
Sporndly E. (1989). Effects of diet on milk composition and yield of dairy cows with special emphasis on milk protein content. Swed. J. Agric. Res. 19, 99-106.
SPSS. (2007). SPSS for Windows, Version 16.0, SPSS Inc., Chicago.
Stata. (2009). Stata Statistical Software, Version 11C, TX: Stata Corp LP., College Station, USA.
Sutton J.D., Bines J.A., Morant S.V., Napper D.J. and Givens D.I. (1987). A comparison of starchy and fibrous concentrates for milk production, energy utilization and hay intake by Friesian cows. J. Agric. Sci. 109, 375-386.
Thomas P.C. and Chamberlain D.G. (1984). Manipulation of milk composition to meet market needs. Pp. 219-244 in Recent Advances in Animal Nutrition. W. Haresign and D.J.A. Cole, Eds. Buttenvorths, London.
Wu Z. and Huber J.T. (1994). Relationship between dietary fat supplementation and milk protein concentration in lactating cows: a review. Livest. Prod. Sci. 39, 141-155.
Yousef M., Huber J.T. and Emery R.S. (1970). Milk protein synthesis as affected by high grain, low fiber rations. J. Dairy Sci. 53, 734-739.