摘要
本试验针对东北寒区高产奶牛日粮配制中存在的营养不平衡,特别是在围产期和泌乳盛期日粮蛋白质水平过低或过高给奶牛健康和生产性能造成不利影响的关键问题,采用对比实验设计,将年龄、体重、胎次、预产期及上一个泌乳期校正泌乳量相近的72头中国荷斯坦牛,随机分成3组,每组24头,分别在围产期和泌乳盛期饲喂9.8%( A1)和13.8%(A2 )、12.6%(B1)和16.2%(B2)、14.1%(C1)和17.8%(C2)不同蛋白质水平日粮。即A组(A1,A2)、B组(B1,B2)和C组(C1,C2)。进行研究日粮蛋白质水平与奶牛体内尿素氮的关系及其对相关繁殖性能指标的影响。通过试验结果分析,确定日粮适宜蛋白质水平,为奶牛高效日粮配制及健康高产提供依据。试验结果表明:
1.日粮蛋白质水平与奶牛体内尿素氮的关系及对泌乳性能的影响
乳中尿素氮(MUN)和血浆尿素氮(PUN[0])浓度随着日粮蛋白质水平的升高极显著上升(P﹤0.01);MUN与PUN显著线性正相关(P﹤0.001),MUN=0.79×PUN+1.02(R2=0.91);围产期和泌乳盛期不同蛋白质水平日粮对乳成分未产生显著的影响(P﹥0.05);泌乳盛B组产奶量显著高于A组(P﹤0.05),与C组差异不显著(P﹥0.05)。
2.日粮蛋白质水平对奶牛生殖激素的影响
B组和C组产后10d和15d外周血浆中LH和E2浓度差异不显著,均显著高于A组(P﹤0.05);B组和C组奶牛产后5d、10d、15d外周血浆中P4浓度差异不显著,均显著低于A组(P﹤0.05);在奶牛产后5d、10d、15d,B组和C组外周血浆中E2浓度差异不显著,均显著高于A组(P﹤0.05);在发情周期第20d,B组外周血浆中E2浓度显著高于C组(P﹤0.05);在发情周期第15d和20d,A组和B组血浆中P4浓度差异不显著,均显著高于C组(P﹤0.05)。
3.日粮质水平对奶牛产后繁殖性能指标的影响
产后A组奶牛胎衣排出时间和恶露排放历期均比B组和C组延迟并差异显著(P﹤0.05);C组奶牛产后卵巢恢复活动时间、首次发情时间和第一次配种时间显著早于A组(P﹤0.05),与B组比较差异不显著;B组奶牛产后情期受胎率最高,为57.14%,比A组高11.31%,比C组高10.08%;B组奶牛的配种指数最低,为1.75,比A组低0.43,比C组低0.38;B组奶牛产后空怀期显著短于C组(P﹤0.05),与A组差异不显著。
According to the problem of the preparation of the nutritional imbalances of ration compound, particularly in the perinatal and peak lactateion too low or too high dietary protein levels had a adverse effect on dairy cow healthy and performance,the test used the contract test design, milk urea nitrogen, milk yield and milk composition by using contrast test of 72 Chinese-Holstein with similar age, weight, birth order, parturition date and correction lactation yield randomly divided into 3 groups, 24 in each group in north frigid area. respectively fed different protein levels diet 9.8%(A1)和13.8%(A2 )、12.6%(B1)和16.2%(B2)、14.1%(C1)和17.8%(C2),that was A group(A1,A2)、B group(B1,B2)和C group(C1,C2)in perinatal and peak lactation,studied the relation of dietary protein levels and BUN and the effect on related reproductive traits. Analysising for the testing results ,the test determined the appropriate dietary protein levels, and provided the basis for efficient ration compound and healthy highyield.
1. The relation of dietary protein levels and BUN and the effect on milk performance
The concentration of MUN and PUN rose significantly((P﹤0.01) with dietary protein levels rosed, A significant linear positive correlation between MUN与PUN(P﹤0.001), MUN=0.79×PUN+1.02(R2=0.91);dietary protein levels had no significant effecton milk composition(P﹥0.05)in perinatal and peak lactation;B group milk yield was significantly higher than A group (P﹤0.05), had no obvious difference with C group (P﹥0.05)in peak lactation.
2. Effect of dietary protein levels on reproductive hormones of dairy cow
The concentration of LH和E2 in plasma of B and C group was significantly higher thanA group(P﹤0.05),but had no obvious difference between B and C group on 10day and 15day after delivery;the concentration of P4 in plasma of B and C group had no significant difference,but was lower than A group(P﹤0.05)5day, 10day and 15day after delivery; the concentration of E2 in plasma of B group was higher than C group(P﹤0.05)on the 20th day of estrous cycle; the concentration of P4 in plasma of A and B group had no significant difference,but was higher than C group(P﹤0.05)on the 15th and 20th day of estrous cycle.
3. Effect of dietary protein levels on reproductive performance index after delivery of dairy cow
The expulsion period of afterbirth and lochia of A group was later than B and C group and difference was significant(P﹤0.05);The period of ovarian reactivation、the first estrusand the first service of C group was earlier than A group(P﹤0.05) and; the sexual period pregnancy rate of B group was highest,57.14%,respectively higher than those of A and C group 11.31% and 10.08%;the mating index of B group was lowest, 1.75%, respectively lower than those of A and C group 0.43% and 0.38%;the open period of afterbirth was significantly shorter compared with C group(P﹤0.05)and had no significant difference compared with A group.
引文
[1] Santos J.P.E., Theurer B.C. and Huber J.T. Effects of rumen undegradable protein on dairy cows performance: a 12-year reviw[J]. Dairy Sci, 1998, (81): 3123-3182.
[2] Hwang,S.Y., Lee M.J. and Chiou P.W.S. Mnitoring nutritional status of dairy cows in Taiwan using milk protein and milk urea nitrogen[J]. Asian-Aust. Anim. Sci, 2000, (13): 1667-1673.
[3] Baker LD, Ferguson JD and Ramberg CF. Kinetic analysis of urea transport from plasma to milk in dairy cows. [J]. Dairy Sci, 1992, 75 (1) : 181.
[4] Roseler DK, Ferguson JD, Sniffen CJ, et al. Dietary protein degradability effects on plasma and milk urea nitrogen and milk nonprotein nitrogen in Holstein cows[J]. Dairy Sci, 1993, (76): 525-534.
[5] Reynal,S.M. and Broderick GA. Effect of dietary level of Rumen-degraded protein on production and nitrogen metabolism in lactating diary cows[J]. Dairy Sci. 2005, (88): 4045-4064.
[6] Promkot,C. and Wanapat M. Effect of level of crude protein and use of cottonseed meal in diets containing cassava chips and rice straw for lactating dairy cows[J]. Asian-Aust.J.Sci., 2005,(18): 502-511.
[7] Hof G., M.D. Vervoorn, P.J. Lenaers, et al. Milk Urea Nitrogen as aTool to Monitor the Protein Nutrition of Dairy Cows[J]. Dairy Sci. 1997,( 80): 3333-3340.
[8] Broderick Glen A. and Murray k. Clayton. A Statisti-cal Evaluation of Animal and Nutritional Factors Influencing Concentrations of Milk Urea Nitrogen[J]. Dairy Sci 1997, (80): 2964-2971.
[9] Hwang, SY, MJ Lee and HC Peh. Diurnal variations in milk and blood urea nitrogen and whole blood ammonia nitrogen in dairy cows. Asian-Aus[J]. Anim. Sci. 2001,14(12):1683-1689.
[10] Hristov, AN and Ropp J.k. Effect of dietary carbohydrate composition and availability on utilization of ruminal ammonia nitrogen for milk protein synthesis in dairy cows[J] Dairy Sci., 2003, (86): 2416-2427.
[11] Dvidson,S., Hopkins BA. and Diaz D.E., et al. Effects of amounts and degradability of dietary protein on lactation, nitrogen utilization, and excretion in early Holstein cows[J]. Dairy Sci., 2003, (86): 1681-1679.
[12] Baker, L.D., Ferguson J.D. and Chalupa W. Responses in urea and true protein of milk to different protein feeding schemes for dairy cows[J]. Dairy Sci.1995, (78): 2424-2434.
[13] Wattiaux, M.A. and Karg K.L. Protien level for alfalfa and corn silage-Based diets:I. lactational response and Milk Urea Nitrogen [J]. Dairy Sci., 2004b, (81): 3480~3491.
[14] Promkot, C. and Wanapat M. Effect of level of crude protein and use of cottonseed meal in diets containing cassava chips and rice straw for lactating dairy cows[J]. Asian-Aust[J]. Sci., 2005, (18): 502-511.
[15] Broderick, G.A. Effect of varying dietary protein and energy levels on the production of lactatingdairy cows[J]. Dairy Sci. 2003, (86): 1370-1381.
[16]Kalscheur K.f., Baldwin R.L. and Glenn VI, B.P., et al. Milk production of dairy cows fed differing concentrations of rumen-degraded protein [J]. Dairy., 2006, (89): 249-259.
[17] Flis, S. A. and Wattiaux M.A. Effects of Parity and Supply of Rumen-Degraded and Undegraded Protein on Production and Nitrogen Balanc in Holsteins[J]. Dairy Sci. 2005, (88): 2096-2106.
[18] M’hmaed,D., P. Faverdin and R.Verite. Eeffets of the level and source dietary protein on int ake and milk yield in dairy cows[J] Anim.Res. 2001,(50): 205-211.
[19] Wittwer FG, Gallardo P and Reyes J, et al. Bulk milk urea concentrations and their relation-ship with cow fertility in grazing dairy herds in southern Chile[J]. Prev Vet Med, 1999, (38): 159-166.
[20] Jordan,E.R., Chapman T.E.and Holtan D.W., et al. Relationship of dietary crude protein to composition of uterine secretions and blood in high–producing dairy cows[J]. Dairy Sci. 1983,(66):1854-1862.
[21] Elord,C.C., and Butler W.R. Reduction of fertility and alteration of uterine pH in heifers fedexcess ruminally degrsdable protein[J]. Anim.Sci. 1993, (71): 694-701.
[22] Butler W.R. Effect of protein nutrition on ovarian and uterine physiology in dairy cattle[J]. Dairy Sci. 1998, (81): 2533-2539.
[23] Gustadsson, A H, Palmquist, DC. Diural Variation of rumen ammonia, serum urea, and milk urea in dairy cows at high and low yields[J]. Dairy Sci, 1993, (76):475-484.
[24] Bulter WR, Calaman J, Beam SW, Plasma and milk urea nitrogen in relation to pregnancy rate in lactating dairy herds[J]. Dairy Sci, 1996, (74): 858-865.
[25] Ferguson JD, Chalupa W. Impact of protein nutrition on reproduction in dairy cows[J]. Dairy Sci, 1989, (72): 746-766.
[26] Ferguson JD, Galligan DT and Blanchard T, et al. Serum urea nitrogen and conception rate: the usefulness of test information[J]. Dairy Sci, 1993, (76): 3742-3746.
[27] Rajala-Schultz P J,Saville W J A and Frazer G S, et al. Association Between Milk urea Nitrogen and Fertility in Ohio Dairy Cows[J].Dairy Sci,2001,(84): 482-489.
[28] Staples CR, Garcia-Bojalil CM and Oldick BS, et al. Protein intake and reproductive performance of dairy cows: a review, a suggested mechanism, and blood and milk urea measurements[J]. Florida Ruminant Nutr Symp, 1993, (4): 37-51.
[29] Hojman D, Kroll O and AdinG, et al. Relationship between milk urea and production, nutrition, and fertility traits in Israeli dairy herds[J]. Dairy Sci. 2004, (87): 1001-1011.
[30] Larson F, Butle WR and Currie WB. Reduced fertility associated with low progesteronepostbreeding and increased milk urea nitrogen in lactating cows[J].Dairy Sci. 1997, (80): 288-1295.
[31] Canfield RW, Sniffen CJ and Bulter WR. Effects of excess degradable protein on postpartum reproduction and energy balance in dairy cattle[J]. Dairy Sci, 1990, (73): 2342-2349.
[32] Barton BA, Rosario HA and Anderson GW, et al. Effects of dietary crude protein breed, parity, and health status on the fertility of dairy cows[J]. Dairy Sci, 1996, (79): 2225-2236.
[33] Anderson GW, Barton B. Reproductive efficiency: potential nutrition management interactions[M]. NEW England Feed Dealers Conf, Univ. Maine. Orono. 1987.
[34] Oldick BS, Firkins JL. Imbalanced, inadequate diets effect reproduction performance, bottom line[J]. Feedstuffs. 1996, (51): 12-25.
[35] Garcia-Bojalil CM, Staples CR and Risco CA, et al. Protein degradability and calcium salts of long-chain fatty acids in the diets of lactating dairy cows: reproductive reposes[J]. Dairy Sci. 1988, (81): 1385-1395.
[36]叶日松.奶牛营养对繁殖性能的影响[J].中国奶牛. 2003,(6): 36-37
[37]丛智慧,谭支良,周传社,汤少勋,孙志洪.影响奶牛繁殖性能的营养因素及其调控[J].家畜生态学报.2006, 27(6): 14-18
[38]张拴林,黄应祥,岳文斌.蛋白质对奶牛繁殖力的影响[J].中国奶牛. 2004, (6): 38-40.
[39]张永根,番军.营养与体况对母牛繁殖性能的影响及作用机理[J].黑龙江畜牧兽医. 1994,(2): 35-39
[40]周虚.营养对奶牛繁殖的影响[J].中国奶牛. 2001, (4): 32-34.
[41]胡海彦,张宇明.影响母牛繁殖力的营养因素[J].中国奶牛. 2001, (6): 34-36.
[42]翟少伟,刘建新,徐英男.过量蛋白质对奶牛卵巢和子宫生理的影响[J].饲料研究.2005, (1): 27-31.
[43] Dliri M,Appa Rao KBC. Expression of growth factor ligand and receptor genes in preimplantation stage water buffalo Bubalus bubalis embryos and oviduct epithelial cells[J]. Journal of Reproduction Fertility. 1999, (177l): 61-70.
[44] Royal MD, Darwash AD and Flint AP, et al. Declining fertility in dairy cattle: changes in traditional and endocrine parameters of fertility[J]. Animal Science, 2000, (70): 487-501.
[45] Jordan ER, Swanson LV. Serum progesterone and luteinizing hormone in dairy cattle fed varying levels of crude protein[J]. Anim Sci. 1979, (48): 1154-1158.
[46] Carroll, D. J., Barton B. A. and Anderson G.W., et al. Influence of protein intake and feeding strategy on eproductive peformance of dairy cows[J]. Dairy Sci. 1988, (71): 3470-3481.
[47] Howard H.J., Aalseth E.P., and Adama G.D., etal. Influence of Dietary Protein on Reproductive Performance of Dairy Cows[J]. Dairy Sci. 1987, (70):1563-1571.
[48] Ohajuruka.O.A., Wu Z. and D.L.Palmquist. Ruminal metabolism, fiber, and protein digestion by lactating cows fed calcium soap or animal-vegetable fat[J] Dairy Sci. 1991, (74): 2601-2609
[49] Stegeman G.A, Casper D.P. andSchingoethe D.J.. Lactational responses of dairy cows fedunsaturated dietary fat and receiving bovine somatotropin. J. Dairy Sci.1992,(75):1936-1945.
[50] Serge-alain Wandji,Michel A. Fortier and Marc-andre Sirard. Differential response to gonadotropins and prostaglandin E2 in ovarian tissue during prenatal and postnatal development in cattle. Biology of reproduction 1992,(46): 1034-1041.
[51] Carroll, D.J., Hossain F.R. and Keller M.R. Effect of supplemental fish meal on the lactation and reproductive performance of dairy cows[J]. Dairy Sci. 1994, (77): 3058~3072.
[52] Ducker M.J., Rosemary A. and Fisher W.J., et al. The effect of level of feeding in late pregnancy and around time of insemination on the productive performance of first lactation dairy heifers.Anim.Prod.1985, (41): 1-12
[53] Staples C.R., Burke J.M., and Thatcher W.W. Influence of supplemental fats on reproductive tissues and performance of lactating cows[J] Dairy Sci. 1998,(81):856-871.
[55] McNamara, J. P. Integrating genotype and nutrition on utilization of body reserves during lactation of dairy cattle. Pages in Symposium on Ruminant Physiology[J]. P. B. Cronje, ed. CAB Int, London, UK. 2000, (46): 353-370.
[56] Haraszti,J.G. Huszenicza, L. and Fekete J. Studies on the postpartum sexual function of“fatty”cows in the dry period (so-called“fat cow syndrome”). MagyarAllatorv[J]. Lapja 1982,(37): 199~209. (In Hungarian; abstract in English).
[57] Heinonen. K. Y. Grohn, L. A. Lindberg, and M. Alanko. The effect of mild fat infiltration in the liver on the fertility of Finnish Ayrshire cows. Acta Vet[J]. Scand. 1987, (28): 151-155.
[58] Sheldon, I.M, D.E.Noakes, A. N. Rycroft, D. U. Pfeiffer, and H. Dobson. Influence of uterine bacterial contamination after parturition on ovarian dominant follicle selection and follicle growth and function in cattle[J]. Reprod. Fertil. 2002, (123): 837-845.
[59] Zerbe, H.N. Schneider, W. Leibold, T. Wensing,T. A. M. Kruip, and H. J. Schuberth Altered functional and immune phenotypical properties of neutrophilic granulocytes in postpartum cows associated with fatty liver[J]. Theriogenology 2000, (54): 771-786.
[60] Herdt, T. H. Relationship of fat metabolism to health and performance in dairy cattle.Bovine Pract[J]. 1991, (26): 92-95
[61] Comin, A.D. Gerin, A. and Cappa, V. et al. The effect of an acute energy deficit on the hormone profile of dominant follicles in dairy cows[J]. Theriogenology 2002, (58): 899-910.
[62] Jorritsma, R. T. Wensing, T. A. M. Kruip, P. L. A. M. Vos, et al. Metabolic changes in early lactation and impaired reproductive performance in dairy cows[J]. Vet. Res.2003, (34): 11-26.
[63] Wentink, G. H.V. P. M. G. Rutten,T. S. G. A. M. and van den Ingh, A. et al. Wensing. Impaired specific immunoreactivity in cows with hepatic lipidosis[J]. Vet.Immunol. Immunopathol. 1997, (56): 77-83.
[64] Johnson.J.C.J.R,P.R.Utley,and B.G.Mullinix.Effects of adding fat and lasalocid to diets of dairy cows[J]. Dairy Sci.1988,(71): 2151-2165.
[65] Breukink,HJ,and Wensing T. Patho physiology of the liver in high yielding dairy cows and its consequences for health and production.Isr[J]. Vet.Med. 1997,(52): 66-72.
[66] Butler, W.R., Smith, R.D. Interrelationships between energy balance on postpartum reproductive function in dairy cattle[J]. Dairy Sci. 1989, (7): 767-783.
[67] Staples, C.R., Thatcher, W.W., Clark, J.H. Relationship between ovarian activity and energy status during the early postpartum period of high producing dairy cows[J]. Dairy Sci. 1990, (73): 938-47.
[68] Garnsworthy, P.C., Topps, J.H. The effect of body condition of dairy cows at calving on their food intake and performance when given complete diets[J]. Anim. Prod. 1982, (35): 113-119.
[69] Rukkwamsuk, T., Wensing, T., Kruip, T.A.M. Relationship between triacylglycerol concentration in the liver and first ovulation in postpartum dairy cows[J]. Theriogenology.1999, (51): 1133-1142.
[70] Beam, S.W., Butler, W.R. Energy balance and ovarian follicle development prior to the first ovulation postpartum in dairy cows receiving three levels of dietary fat[J]. Biol. Reprod. 1997, (56): 133-142.
[71] Jolly, P.D., McDougall, S., and Fitzpatrick, L.A., et al. Physiological effects of undernutrition on postpartum anestrous in cows[J]. Reprod. Fertil., Suppl. 1995,(49): 477-492.
[72] Butler, W.R. Nutritional effects on resumption of ovarian cyclicity and conception rate in postpartum dairy cows. Anim. Sci. 2000, in press.
[73] Spicer, L.J., Alpizar, E., Echternkamp, S.E. Effects of insulin, insulin-like growth factor I, and gonadotropins on bovine granulosa cell proliferation, progesterone production, estradiol production and orinsulin-like growth factor-I production[J]. Anim. Sci. 1993, (71): 1232-1241.
[74] Impson, R.B., Chase, C.C., and Spicer, L.J., et al. Effect of exogenous insulin on plasma and follicular insulin-like growth factor I, insulin-like growth factor binding protein activity, follicular oestradiol and progesterone, and follicular growth in superovulated Angus and Brahman cows[J]. Reprod. Fertil. , 1994, (102): 483-92.
[75] Beam, S.W., Butler, W.R. Energy balance, metabolic hormones, and early postpartum follicular development in dairy cows fed prilled lipid.[J]. Dairy Sci. 1998, (81): 121-131.
[76] Beam, S.W., Butler, W.R. Effects of energy balance on follicular development and first ovulation in postpartum dairy cows[J]. Reprod. Fertil., Suppl. 1999,(54): 411-24.
[77] Cohick, W.S., Armstrong, J.D., and et al. Ovarian expression of insulin-like growth factor-I ?IGF-I , IGF binding proteins, and growth hormone ?GH. receptor in heifers actively immunized against GH-Releasing factor[J]. Endocrinology. , 1996,(137): 1670-677.
[78] Perks, C.M., Peters, A.R., Wathes, D.C. Follicular and luteal expression of insulin-like growth factors I and II and the type 1 IGF receptor in the bovine ovary[J]. Reprod. Fertil. 1999, (116): 156-165.
[79] Wildman,E.E., Jones G.M. and Wanger P.E., et al. A dairy cow body condition scoring system and itsrelationship to standard production characteristics[J]. Dairy.Sci.1982,(65): 495-501
[80] Rhodes F. M. Invited Review:Treatment of Cows with an Extended Postpartum Anestrous Interval[J]. Dairy Sci.1982,(86):1876-1894.
[81] Villa-Godoy, A., Hughes, T.L., and Emery, R.S., et al. Association between energy balance and luteal function in lactating dairy cows[J] Dairy Sci. 1988, (71): 1063-1072.
[82] Rawlings N C. Some endocrine changes associat-ed with the postpartum period of the suckling beef cow[J]. Reprod. Fertil.1980,(60): 301.
[83] Bazer F W, Ferst N L. Pregnancy and parturition[J]. Anim. Sci. 1983, (57) : 425.
[84]杨胜.饲料分析及饲料质量检测技术[M].北京农业大学出版社. 1993, 124-141.
[85] Kauffman A J, St-pierre N R. The relationship of milk urea nitrogen to urine nitrogen excretion in Holstein and Jersey cows[J]. Dairy Sci, 2001,(84): 2284-2294.
[86] Galo, E., Emanuele S.M. and Sniffen C.J., et al. Effects of a polymer-coated urea product on nitrogen metabolism in lactaring Holstein dairy cows[J]. Dairy Sci. 2003,(85): 1829-1838.
[87] Higginbotham, G.E. andHuber J.T. Influence of protein percentage and degradability on performance of lactating cows during moderate temperature[J]. Dairy Sci.1989b,(72): 1818-1823.
[88] Kalscheur, K.F., Vandersall J.H. and Erdman R.A., et al. Russek-Cohen. Effects of dietary crude protein concentration and degradability on milk production responses of early, mid and late lactation dairycows[J]. Dairy Sci. 1999, (82): 545-554.
[89] Park A. F., Shirley J. E., Titgemeyer E. C., et al. Effect of Protein Level in Prepartum Diets on Metabolismand Performance of Dairy Cows[J]. Dairy Sci. 2002, (85): 1815-1828
[90]刘崇立,王运亨,周玉云.高产奶牛产后乳汁中孕酮含量变化与卵巢机能恢复和子宫复旧的关系[J].中国畜牧杂志.1992, 32 (6) : 36-37.
[91]吴姜文,杨培新.影响奶牛产后卵巢恢复的几个因素[J].浙江农业大学学报.1997, 23(5): 573~576.
[92]陈海燕,傅衍.牛奶中孕酮含量变化与奶牛的卵巢机能[J].核农学报.2005, 19 (5):390-392.
[93]田元波.奶牛产后卵巢周期重建[J].北京奶牛.1989 (3):3-5.
[94] Schollo K K. Effects luteinizing hormone of dietary energy on control of secretion in cattle and sheep[J]. Anim.Sci., (70): 1271
[95]罗晓林, J.G.Gong.代谢激素及营养对牛卵泡发育的影响[J].青海畜牧兽医杂志.2003, 33 (2):20-22.
[96]刘广振,唐冬生,陈红玲等.高产奶牛繁殖力低的原因分析及解决措施[J].黑龙江畜牧兽医, 2007, (3):29-30.
[97]吴新.奶牛胎衣不下的病因分析[J].中国畜牧兽医, 2009, 36 (8): 112-14.
[98]曹述彬.母牛产后生殖器官的复旧[J].中国奶牛. 1997, (3):30-31.
[99]大成清.周产期营养与乳热(1)(2)[J].畜产の研究. 2001, 55 (7):3-6,5(8):43-48.
[100] Julien, W. E., Conrad H. R., and Redman D.R.. Influence of dietary on susceptibility to alert downer syndrome[J]. 1976a, Dairy Sci. (60): 210-215
[101] Maas,J.P. Prevention of retained fetal membranes in dairy cattle[J]. Compend. Contin. Educ.1982,(4):s519-s527.
[102]周虚.营养对奶牛繁殖的影响[J].中国奶牛. 2001, (4): 32-34
[103] Santos J.E.P., DePeters E. J. and Jardon P. W. et al. Effect of Prepartum Dietary Protein Level on Performance of Primigravid and Multiparous Holstein Dairy Cows[J]. Dairy Sci. 2001, (84): 213-224
[104] Bruckental,I.D., Oori, M. Effect of source and level of protein oil milk yield and reproductive performance of high-producing primiparous and multiparous dairy cows[J]. Anim.Prod.,1989, (48): 319- 329.
[105] Kaim, M., Y. Folman, H. Neumark, and W. Kaufmann. The effect of protein intake and lactation number on postpartum body weight loss and reproductive performance of dairycows[J]. Anim. Prod. 1983, (37): 229-235.
[106] Rakestraw JK. postpartum Weight and body condition loss and performance of fall-calvingcows[J]. Theriogenology.1986, (26): 461.
[107] Jordan E. R. and Swanson L. V.. Effect of Crude Protein on Reproductive Efficiency Serum Total Protein, and Albumin in the High-producing Dairy Cow[J]. Dairy Sci. 1979, (62):58-63.
[108] Bruckental,I.D., Oori, M. Effect of source and level of protein oil milk yield and reproductive performance of high-producing primiparous and multiparous dairy cow Y.Folman,H.Neumark,Mkaim, et al.Preformance,Rumen and Blood Metabolites in High-Yielding Cows Fed Varying Protein Percents and Protected Soybean[J]. Dairy Sci. 1981, (64): 759-768.
[109] Butler W R.Nutritional interactions with reproductive performance in dairy cattle[J].Animal Reproduction Science. 2000, (60): 449-457
[110] Westwood, C.T., Lean, I.J., Kellaway, R.C. Indications and implications for testing of milk urea in dairy cattle: a quantitative review Part 2. Effect of dietary protein on reproductive performance[J]. N. Z. Vet. 1998, (46): 123-140.