Association between Plasma and Milk Urea on the Insemination Day and Pregnancy Rate in Early Lactation Dairy Cows

Document Type: Research Articles


1 1.Department of Agrarian Science,Animal Reproduction, Universityof Azores, 9701-851 Angra Do Heroísmo, Portugal 2 CITA-A, University of Azores, 9701-851 Angra Do Heroísmo, Portugal

2 Department of Agrarian Science,Animal Reproduction, Universityof Azores, 9701-851 Angra Do Heroísmo, Portugal

3 1.Department of Agrarian Science,Animal Reproduction, Universityof Azores, 9701-851 Angra Do Heroísmo, Portugal 2.CITA-A, University of Azores, 9701-851 Angra Do Heroísmo, Portugal


Lactatingdairy cows (n=177) fed with grass and corn silage ad libitum kept in pasture, were randomly assigned to evaluate how urea nitrogen in plasma and milk can be related to their pregnancy rate. Blood and milk samples were collected on the artificial insemination (AI) day to evaluate plasma urea nitrogen (PUN) and milk urea nitrogen (MUN) as well as progesterone levels, excluding cows with progesterone higher than 0.5 ng/mL. Cows were considered pregnant if six weeks after artificial insemination did not return to estrus.Concentrations of PUN or MUN greater than the average (16 mg/dL) were associated with decreased pregnancy rates (13% and 14%, respectively) (P<0.05) compared with the cows with urea levels less than this value on the insemination day. As PUN and MUN increased to greater than 16 mg/dL, the likelihood ratio for pregnancy decreased. There was a high correlation between PUN and MUN concentrations (r2= 0.97, P≤0.001). The results of this study indicate that an increase in PUN or MUN can exert director indirect effects in reproduction, impairing the conception of grazing dairy cows.


Barton B.A., Rosario H.A., Anderson G.W., Grindle B.P. and Carroll D.J. (1996). Effects of dietary crude protein, breed, parity, and health status on the fertility of dairy cows. J. Dairy Sci. 79, 2225-2236.
Blanchard T., Ferguson J., Love L., Takeda T., Henderson B., Hasler J. and Chalupa W. (1990). Effect of dietary crude-protein type on fertilization and embryo quality in dairy cattle. Am. J. Vet. Res. 51, 905-908.
Borba A. (1992). Estudo do valor nutritivo e da qualidade da proteína de algumas forragens açorianas. Department of Agrarian Sciences. Angra do Heroísmo: University of the Azores. 455 Pp.
Broderick G.A. and Clayton MK. (1997). A statistical evaluation of animal and nutritional factors influencing concentrations of milk urea nitrogen. J. Dairy Sci. 80, 2964-2971.
ButlerW.R., Calaman J.J. and Beam S.W. (1996). Plasma and milk urea nitrogen in relation to pregnancy rate in lactating dairy cattle. J. Anim. Sci. 74, 858-865.
Canfield R.W., Sniffen C.J. and Butler W.R. (1990). Effects of excess degradable protein on postpartum reproduction and energy balance in dairy cattle. J. Dairy Sci. 73, 2342-2349.
Carrol D.J., Barton B.A., Anderson G.W. and Smith R.D. (1988). Influence of protein intake and feeding strategy on reproductive performance of dairy cows. J. Dairy Sci. 71, 3470-3481.
Dawuda P.M., Scaramuzzi R.J., Leese H.J., Hall C.J., Peters A.R., Drew S.B. and Wathes D.C. (2002). Effect of timing of urea feeding on the yield and quality of embryos in lactating dairy cows. Theriogenology. 58, 1443-1455.
De Wit A.A., Cesar M.L. and Kruip T.A. (2001). Effect of urea during in vitro maturation on nuclear maturation and embryo development of bovine cumulus-oocyte-complexes. J. Dairy Sci. 84, 1800-1804.
Donnay I., Partridge R.J. and Leese H.J. (1999). Can embryo metabolism be used for selecting bovine embryos before transfer? Reprod. Nutr. Dev. 39, 523-533.
Duinkerken G., André G., Smits M.C.J., Monteny G.J. and Šebek L.B.J. (2005). Effect of rumen-degradable protein balance and forage type on bulk milk urea concentration and emission of ammonia from dairy cow houses. J. Dairy Sci, 88, 1099-1112.
Elrod C.C. and Butler W.R. (1993). Reduction offertility and alteration of uterine pH in heifers fed excess ruminally degradable protein. J. Anim. Sci. 71, 694-701.
Fahey J., Boland M.P. and Callaghan D.O. (2001). The effects of dietary urea on embryo development in superovulated donor ewes and on early embryo survival and development in recipient ewes. J. Anim. Sci. 72, 395-400.
FergusonJ.D., Blanchard T., Galligan D.T., Hoshall D.C. and Chalupa W. (1988). Infertility in dairy cattle fed a high percentage of protein degradable in the rumen. J. Amer. Vet. Med. Assoc. 192, 659-662.
FergusonJ.D. and Chalupa W. (1989). Impact of protein nutrition on reproduction in dairy cows. J. Dairy Sci. 72, 746-766.
FergusonJ.D., Galligan D.T., Blanchard T. and Reeves M. (1993). Serum urea nitrogen and conception rate: the usefulness of test information. J. Dairy Sci. 76, 3742-3746.
Geerts N.E., De Brabander D.L., Vanacker J.M., De Boever J.L. and Botterman S.M. (2004). Milk urea concentration as affected by complete diet feeding and protein balance in the rumen of dairy cattle. Livest. Prod. Sci. 85, 263-273.
Gustafsson A.H. and Palmquist D.L. (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.
Hammon H.M., Zanker I.A. and Blum J.W. (2000). Delayed colostrum feeding affects IGF-I and insulin plasma concentrations in neonatal calves. J. Dairy Sci. 83, 85-92.
Howard H.J., Aalseth E.P., Adams G.D., Bush L.J., McNew R.W. and Dawson L.J. (1987). Influence of dietary protein on reproductive performance of dairy cows. J. Dairy Sci. 70, 1563-1571.
Jordan E.R. and Swanson L.V. (1979). Effect of crude protein on reproductive efficiency, serum total protein, and albumin in t-he high-producing dairy cows. J. Dairy Sci. 62(1), 58-63.
Jordan E.R., Chapman T.E., Holtan D.W. and Swanson L.V. (1983). Relationship of dietary crude protein to composition of uterine secretions and blood in high-producing postpartum dairy cows. J. Dairy Sci. 66, 1854-1862.
Kaim M., Folman Y., Neumark H. and Kaufmann W. (1983). The effect of protein intake and lactation number on postpartum body weight loss and reproductive performance of dairy cows. Anim. Prod. 37, 229-235.
Kenny D.A., Humpherson P.G,. Leese H.J,. Morris D.G., Tomos A.D., Diskin M.G. and Sreenan J.M. (2002). Effect of elevated systemic concentrations of ammonia and urea on the metabolite and ionic composition of oviductal fluid in cattle. Biol. Reprod. 66, 1797-1804.
Kwong W.Y., Wild A.E., Roberts P., Willis A.C. and Fleming T.P. (2000). Maternal under nutrition during the preimplantation period of rat development causes blastocyst abnormalities and programming of postnatal hypertension. Reprod. Nutr. Dev. 127, 4195-4202.
McDonald P., Edwards R.A., Greenhalgh J.F.D. and Morgan C.A. (1995). Protein concentrates, 5th Ed. Longman Scientific and Technical, New York.
McEvoy T.G., Robinson J.J., Aitken R.P., Findlay P.A. and Robertson I.S. (1997). Dietary excesses of urea influence the viability and metabolism of preimplantation sheep embryos and may affect fetal growth among survivors. Anim. Reprod. Sci. 47, 71-90.
Ocon O.M. and Hansen P.J. (2003). Disruption of bovine oocytes and preimplantation embryos by urea and acidic pH. J. Dairy Sci. 86, 1194-1200.
Oltner R. and Wiktorsson H. (1983). Urea concentration in milk and blood as influenced by feeding varying amounts of protein and energy to dairy cows. Livest. Prod. Sci. 10, 457-467.
Papadopoulos S., Lonergan P., Gath V., Quinn K.M., Evans A.C., O'Callaghan D. and Bolan M.P. (2001). Effect of diet quantity and urea supplementation on oocyte and embryo quality in sheep. Theriogenology. 55, 1059-1069.
Partridge R.J. and Leese H.J. (1996). Consumption of amino acids by bovine preimplantation embryos. Reprod. Fert. Dev. 8, 945-950.
Rhoads M.L., Gilbert R.O., Lucy M.C. and ButlerW.R. (2004). Effects of urea infusion on the uterine luminal environment of dairy cows, J. Dairy Sci. 87, 2896–2901.
Rhoads M.L., Rhoads R.P., Gilbert R.O., Toole R. and ButlerW.R. (2006). Detrimental effects of high plasma urea nitrogen levels on viability of embryos from lactating dairy cows. Anim. Reprod. Sci. 91, 1-10.
Roseler D.K., Fergunson J.D., Sniffen C.J. and Herrema J. (1993). Dietary protein degradability effects on plasma and milk urea nitrogen and milk nonprotein nitrogen in Holstein cows. J. Dairy Sci. 76, 525-534.
Sauer M.J., Foulkes J.A., Worsfold A. and Morris B.A. (1986). Use of progesterone 11-glucuronide-alkaline phosphatase conjugate in a sensitive microtitre-plate enzymeimmunoassay of progesterone in milk and its application to pregnancy testing in dairy cattle. J. Reprod. Fert. 76, 375-391.