{"references": ["J. B.Andersen, T. G. Madsen, T. Larsen, K. L. Ingvartsen, and M. O.\nNielsen. The effects of dry period versus continuous lactation on\nmetabolic status and performance in periparturient cows. J. Dairy\nSci. 88:3530-3541. 2005.", "E. L.Annen, R. J. Collier, M. A. McGuire, J. L. Vicini, J. M. Ballam,\nand M. J. Lormore. Effect of modified dry period lengths and bovine\nsomatotropin on yield and composition of milk from dairy cows. J.\nDairy Sci. 87:3746-3761. 2004.", "K. C. Bachman. Milk production of dairy cows treated with estrogen\nat the onset of a short dry period. J. Dairy Sci. 85:797-803. 2002.", "K. C. Bachman and M. L. Schairer. Invited review: Bovine studies\non optimal lengths of dry periods. J. Dairy Sci. 86:3027-3037. 2003.", "A. V. Capuco, R. M. Akers, and J. J. Smith. Mammary growth in\nHolstein cows during the dry period: Quantification of nucleic acids\nand histology. J. Dairy Sci. 80:477-487. 1997.", "C. E. Coppock, R. W. Everett, R. P. Natzke, and H. R. Ainslie. Effect\nof dry period length on Holstein milk production and selected\ndisorders at parturition. J. Dairy Sci. 57:712-718. 1974.", "M. A. De Feu, A. C. O. Evans, p. Lonergan, and S. t. Butler. The\neffect of dry period duration and dietary energy density on milk\nproduction, bioenergetic status, and postpartum ovarian function in\nHolstein-Friesian dairy cows. J. Dairy Sci. 92: 6011-6022. 2009.", "J. K. Drackley. Biology of dairy cows during the transition period:\nThe final frontier. J. Dairy Sci. 82:2259-2273. 1999.", "A. J. Edmonson, I. J. Lean, L. D. Weaver, T. Farver, and G. Webster.\nA body condition scoring chart for Holstein Dairy Cows. J. Dairy\nSci. 72:68-78. 1989.\n[10] E. Farries and S. Hoheisel. The influence of reduced dry periods on\nsome performance and metabolism traits in dairy cows. J. Dairy Sci.\n72(Suppl.1):565. (Abstr.) 1989.\n[11] D. A. Funk, A. E. Freeman, and P. J. Berger. Effects of previous days\nopen, previous days dry and present days open on lactation yield. J.\nDairy Sci. 70:2366-2373. 1987.\n[12] R. R. Grummer. Strategies to improve fertility of high yielding dairy\nfarms: Management of the dry period. Theriogenology 68s: s281-\ns288. 2007.\n[13] R. R. Grummer and R. R. Rastani. Why reevaluate dry period length?\nJ. Dairy Sci. 87(E-Suppl.):E77-E85. 2004.\n[14] M. S. Gulay, M. J. Hayen, H. H. Head, C. J. Wilcox, and K. C.\nBachman. Milk production from Holstein half udders after\nconcurrent thirty- and seventy-day dry periods. J.Dairy. Sci. 88:\n3953_3962. 2005.\n[15] M. S. Gulay, M. J. Hayen, K. C. Bachman, T. Belloso, M. Liboni,\nand H. H. Head. Milk production and feed intake of Holstein cows\ngiven short (30-d) or normal (60-d) dry periods. J. Dairy Sci.\n86:2030-2038. 2003.\n[16] R. N. Heitmann and J. M. Fernandez. Autoregulation of Alimentary\nand Hepatic Ketogenesis in Sheep. J. Dairy Sci. 69:1270-1281. 1986.\n[17] K. L. Ingvartsen and J. B. Andersen. Integration of metabolism and\nintake regulation: A review focusing on periparturient animals. J.\nDairy Sci. 83:1573-1597. 2000.\n[18] J. W. Klein and T. E. Woodward. Influence of length of dry period\nupon the quantity of milk produced in the subsequent lactation. J.\nDairy Sci. 26:705-713. 1943.\n[19] E. Lotan and J. H. Adler. Observations on the effect of shortening the\ndry period on milk yield, body weight, and circulating glucose and\nFFA levels in dairy cows. Tijdsch. Diergeneeskd. 101:77-82. 1976.\n[20] T. G. Madsen, M. O. Nielsen, J. B. Andersen, and K. L. Ingvartsen.\nContinuous lactation in dairy cows: Effect on milk production and\nmammary nutrient supply and extraction J. Dairy Sci. 91:1791-1801.\n2008.\n[21] D. Mashek, K. L. Ingvartsen, J. B. Andersen, M. Vestergaard, and T.\nLarsen. Effects of a four-day hyperinsulinemic-euglycemic clamp in\nearly and mid-lactation dairy cows on plasma concentrations of\nmetabolites, hormones, and binding proteins. Domest. Anim.\nEndocrinol. 21:169-185. 2001.\n[22] A. Pezeshki, J. Mehrzad, G. R. Ghorbani, H. R. Rahmani, R. J.\nCollier, and C. Burvenich. Effect of short dry periods on\nperformance and metabolic status in Holstein dairy cows. J. Dairy\nSci. 90:5531-5541. 2007.\n[23] R. R. Rastani, R. R.Grummer, S. J. Bertics.A. Gumen, M.C.\nWiltbank, D. G. Mashek, and M. C. Rich. Effects of varying dry\nperiod length and prepartum diet on metabolic profiles and lactation\nof periparturient dairy cattle. J. Dairy Sci. 86(Suppl. 1):154. (Abstr.)\n2003.\n[24] R. R. Rastani, , R. R. Grummer, S. J. Bertics, A. Gumen, M. C.\nWiltbank, D. G. Mashek, and M. C. Schwab. Reducing dry period\nlength to simplify feeding transition cows: Milk production, energy\nbalance, and metabolic profiles. J. Dairy Sci. 88:1004-1014. 2005.\n[25] B. Remond, J. Kerouanton, and V. Brocard. The effect of reducing or\nomitting the dry period on the performance of dairy cows. Prod.\nAnim. 10:301-315. 1997.\n[26] SAS Institute. User-s Guide: Statistics. Version 8 ed. SAS Institute,\nCary, NC. 1999.\n[27] H. Seifi, M. Gorji-Dooz, M. Mohri, B. Dalir-Naghadeh, and N.\nFarzaneh. Variations of energy-related biochemical metabolites\nduring transition period in dairy cows. Comp. Clin. Pathol. 16:253-\n258. 2007.\n[28] L. R. Schaeffer and C. R. Henderson. Effects of days dry and days\nopen on Holstein milk production. J. Dairy Sci. 55:107-112. 1972.\n[29] M. L. Schairer. Estrogen treatments for the initiation of dry off in\ndairy cows. M.S. Thesis. Univ. Florida, Gainesville. 2001.\n[30] A. Smith, , J. V. Wheelock, and F. H. Dodd. Effect of milking\nthroughout pregnancy on milk secretion in the succeeding lactation.\nJ. Dairy Res. 34:145-150. 1967.\n[31] J. T. Sorensen and C. Enevoldsen. Effect of dry period length on\nmilk production in subsequent lactation. J. Dairy Sci. 74:1277-1283.\n1991.\n[32] E. W. Swanson. Comparing continuous milking with sixty-day dry\nperiods in successive lactations. J. Dairy Sci. 48:1205-1209. 1965.\n[33] R. D. Watters, , J. N. Guenther, A. E. Brickner, R. R. Rastani, P. M.\nCrump, P. W. Clark, and R. R. Grummer. Effects of Dry Period\nLength on Milk Production and Health of Dairy Cattle. J. Dairy Sci.\n91:2595-2603. 2008.\n[34] J. W. Wilton, E. B. Burnside, and J. C. Rennie. The effects of days\ndry and days open on the milk and butterfat production of Holstein-\nFriesian cattle. Can. J. Anim. Sci. 47:85-90. 1967.\n[35] D. A. Whitaker, W. J. Goodger, M. Garcia, B. Perera, and F.\nWittwer. Use of metabolic profiles in dairy cattle in tropical and\nsubtropical countries on smallholder dairy farms. Prev. Vet. Med.\n38:119-131. 1999."]}

Twenty - nine Holstein cows were used to evaluate the effects of different dry period (DP) lengths on milk yield and composition, some blood metabolites, and complete blood count (CBC). Cows were assigned to one of 2 treatments: 1) 60-d dry period, 2) 35-d DP. Milk yield, from calving to 60 days, was not different for cows on the treatments (p =0.130). Cows in the 35-d DP produced more milk protein and SNF compare with cows in treatment 1 (p ≤ 0.05). Serum glucose, non-esterified fatty acids (NEFA), beta hydroxyl butyrate acid (BHBA), blood urea nitrogen (BUN), urea, and glutamic oxaloacetic transaminase (GOT) were all similar among the treatments. Body condition score (BCS), body weight (BW), complete blood count (CBC) and health problems were similar between the treatments. The results of this study demonstrated we can reduce the dry period length to 35 days with no problems.