Review Article
Anna Kurpińska 
, Wiesław Skrzypczak
Department of Physiology, Cytobiology and Proteomics, West Pomeranian University of Technology Szczecin, Janickiego 29, 71-270 Szczecin, Poland
Abstract. In the last month of pregnancy and the first weeks of lactation, intensive adaptations processes, both morphological and functional, take place in the cow's body. An organism adapts through changes in the intensity of metabolic processes and the activity of its regulatory mechanisms. Maintaining the homeostasis of an organism in prepartum and postpartum periods is the key condition in health maintaining of the mother and the foetus/calf. This paper presents studies on changes in the levels of progesterone, estrogens, androgens, placental lactogen, relaxin, pregnancy glycoproteins, prostaglandin F2α, cortisol, oxytocin, prolactin, GnRH, LH, FSH, thyroid hormones, insulin and growth hormone, significantly associated with the growth and development of the foetus, preparation of the mammary glands for lactation, and, after parturition, with reproductive system regeneration and preparation for new fertilization and pregnancy.
Keywords: dairy cows, periparturient period, hormonal status
Hormonal changes during periparturient period are abrupt. Optimal concentration of hormones is crucial for maintaining health of mother, fetus and calf, course of parturition without complications, initiation of lactation and preparation of mother’s organism for new pregnancy [Kornmatitsuk et al. 2003Kornmatitsuk, B., Franzen, G., Gustafsson, H., Kidahl, H. (2003). Endocrine measurements and calving performance of Swedish Red and White and Swedish Holstein dairy cattle with special respect to stillbirth. Acta Vet. Scand., 44, 21–33. https://doi.org/10.1186/1751-0147-44-21, Kindahl et al. 2002Kindahl, H., Kornmatitsuk, B., Königsson, K., Gustaffson, H. (2002). Endocrine changes in late bovine pregnancy with special emphasis on fetal well-being. Domest. Anim. Endocrinol., 23, 321–328. https://doi.org/10.1016/S0739-7240(02)00167-4, 2004; Skrzypczak et al. 2005Skrzypczak, W.F., Ożgo, M., Dratwa, A. (2005). The level of melatonin and somatotropin in chosen points of 24-hour period in calves. Acta Sci. Pol., Med. Vet., 4, 65–72. Google Scholar, Herosimczyk et al. 2013Herosimczyk, A., Lepczyński, A., Ożgo, M., Dratwa-Chałupnik, A., Michałek, K., Skrzypczak, W.F. (2013). Blood plasma protein and lipid profile changes in calves during the first week of life. Pol. J. Vet. Sci., 16, 425–434. https://doi.org/10.2478/pjvs-2013-0060, Kurpińska et al. 2014Kurpińska, A., Jarosz, A., Skrzypczak, W.F. (2014). Proteomic studies in pregnant and lactating cows. A review. J. Anim. Feed Sci., 23, 203–211. https://doi.org/10.22358/jafs/65680/2014, 2015, 2016; Wankhade et al. 2017Wankhade, P.R., Manimaran, A., Kumaresan, A., Jeyakumar, S., Ramesha, K.P., Sejian, V., Rajendran, D., Varghese, M.R. (2017). Metabolic and immunological changes in transition dairy cows: A review. Vet. World, 10(11), 1367–1377. https://doi.org/10.14202/vetworld.2017.1367-1377, Mikuła et al. 2018Mikuła, R., Pruszyńska-Oszmałek, E., Maćkowiak, P., Nowak, W. (2018). Effect of different pre-calving feeding strategies on the metabolic status and lactation performance of dairy cows. J. Anim. Feed Sci., 27, 292–300. https://doi.org/10.22358/jafs/99003/2018, Kurpińska et al. 2019Kurpińska, A., Jarosz, A., Skrzypczak, W. (2019). Parameters of protein and iron metabolism in dairy cows during periparturient period. Acta Sci. Pol. Zootechnica, 18(3), 3–10. Google Scholar, Lucy 2019Lucy, M.C. (2019). Stress, strain, and pregnancy outcome in postpartum cows. Proceedings of the 33rd Annual Meeting of the Brazilian Embryo Technology Society (SBTE); Ilha de Comandatuba, BA, Brazil. https://doi.org/10.21451/1984-3143-AR2019-0063]. The most important hormones involved in the regulation of pregnancy are: progesterone, estrogens, androgens, placental lactogen, relaxin, PAGs (pregnancy-associated glycoproteins). Hormones characterized by dynamic changes connected with parturition are: progesterone, estrogens, prostaglandin F2α, cortisol, oxitocin, prolactin, relaxin. In postpartum period further changes are observed in the concentration of all above-mentioned hormones. During pregnancy and lactation abrupt changes are also noted for GnRH (gonadotropin-releasing hormone), LH (luteinizing hormone), FSH (folicle-stimulating hormone), hormones of the hypothalamic-pituitary axis (prolactin, growth hormone – GH) and the hormones of ovaries, adrenals, thyroid a well as insulin [Convey 1973Convey, E.M. (1973). Serum hormone concentrations in ruminants during mammary growth, lactogenesis and lactation: a review. J. Dairy Sci., 57, 905–917. https://doi.org/10.3168/jds.S0022-0302(74)84986-6, Ceriani 1974Ceriani, R.L. (1974). Hormones and other factors controlling growth in the mammary gland: a review. J. Invest. Dermatol., 63, 93–108. https://doi.org/10.1111/1523-1747.ep12678104, Desrivières et al. 2003Desrivières, S., Prinz, T., Castro-Palomino, T., Meyer, L.M., Boehm, G., Bauer, U., Schäfer, J., Neumann, T., Shemanko, C., Groner, B. (2003). Comparative proteomic analysis of proliferating and functionally differentiated mammary epithelial cells. Moll. Cell. Proteomics, 2, 1039–1054. https://doi.org/10.1074/mcp.M300032-MCP200].
Progesterone is produced in cows by the corpus luteum, adrenal glands and placenta. Its purpose is primarily to maintain pregnancy. Progesterone is involved in the development of the mammary gland and the onset of lactation [Convey 1973Convey, E.M. (1973). Serum hormone concentrations in ruminants during mammary growth, lactogenesis and lactation: a review. J. Dairy Sci., 57, 905–917. https://doi.org/10.3168/jds.S0022-0302(74)84986-6, Kindahl et al. 2002Kindahl, H., Kornmatitsuk, B., Königsson, K., Gustaffson, H. (2002). Endocrine changes in late bovine pregnancy with special emphasis on fetal well-being. Domest. Anim. Endocrinol., 23, 321–328. https://doi.org/10.1016/S0739-7240(02)00167-4, 2004].
According to Lopes et al. [2007]Lopes, A.S., Butler, S.T., Gilbert, R.O., Butler, W.R. (2007). Relationship of the pre-ovulatory follicle size, estradiol concentration and season to pregnancy to pregnancy outcome in dairy cows. Anim. Reprod. Sci., 99, 34–43. https://doi.org/10.1016/j.anireprosci.2006.04.056 the concentration of progesterone in Holstein cows on the day of insemination was on average 0.225 ng · ml–1. According to Edqvist et al. [1978]Edqvist, L.E., Kindahl, H., Stabenfeldt, G. (1978). Release of prostaglandin F2α during the bovine peripartal period. Prostaglandins, 16, 111–119. https://doi.org/10.1016/0090-6980(78)90207-1 high progesterone levels are observed during the entire pregnancy in cows, however a gradual decrease is observed starting from the 60th day before calving. The average concentration of progesterone in the blood plasma of primiparous and multiparous Holstein cows a month before calving was 3.69 ng · ml–1 [Ożgo and Skrzypczak 2000Ożgo, M., Skrzypczak, W.F. (2000). Preliminary studies on progesterone contribution in water-electrolyte balance regulation in cows in perinatal period. 51th Annual Meeting of the EAAP (Hague), p. 137. Google Scholar]. Abrupt changes were noted 24–48 h before calving [Edqvist et al. 1978Edqvist, L.E., Kindahl, H., Stabenfeldt, G. (1978). Release of prostaglandin F2α during the bovine peripartal period. Prostaglandins, 16, 111–119. https://doi.org/10.1016/0090-6980(78)90207-1].
The day before parturition concentration of progesterone in cows blood was 0.7 ng · ml–1, and on the day of calving 0.05 ng · ml–1 [Henricks et al. 1972Henricks, D.M., Dickey, J.F., Hill, J.R., Johnston, W.E. (1972). Plasma estrogen and progesterone levels after mating, and during late pregnancy and postpartum in cows. Endocrinol., 90, 1336–1342. https://doi.org/10.1210/endo-90-5-1336, Ożgo and Skrzypczak 2000Ożgo, M., Skrzypczak, W.F. (2000). Preliminary studies on progesterone contribution in water-electrolyte balance regulation in cows in perinatal period. 51th Annual Meeting of the EAAP (Hague), p. 137. Google Scholar]. The decrease in the concentration of progesterone before calving is necessary for uterine contractions, contributes to the onset of lactation, allows mammary epithelial to respond to lactogen complex (glucocorticoids and ACTH) [Convey 1973Convey, E.M. (1973). Serum hormone concentrations in ruminants during mammary growth, lactogenesis and lactation: a review. J. Dairy Sci., 57, 905–917. https://doi.org/10.3168/jds.S0022-0302(74)84986-6, Bernal 2001Bernal, A.L. (2001). Overview of current research in parturition. Exp. Physiol., 86, 213–222. https://doi.org/10.1113/eph8602178, Mastorakos and Ilias 2003Mastorakos, G., Ilias, I. (2003). Maternal and fetal hypothalamic-pituitary-adrenal axes during pregnancy and postpartum. Ann. N. Y. Acad. Sci., 997, 136–149. https://doi.org/10.1196/annals.1290.016, Kindahl et al. 2004Kindahl, H., Kornmatitsuk, B., Gustaffson, H. (2004). The cow in endocrine focus before and after calving. Reprod. Dom. Anim., 39, 217–221. https://doi.org/10.1111/j.1439-0531.2004.00506.x]. Decrease in the concentration of progesterone at the end of pregnancy in cows is associated with cortisol-induced fetal enzyme activity – 17α-hydroxylase and C17–20 lyase – which catalyze the conversion of progesterone to androgens, which in turn is converted to estrogen. In addition, 2–3 days before calving luteolysis is also observed [Bernal 2001Bernal, A.L. (2001). Overview of current research in parturition. Exp. Physiol., 86, 213–222. https://doi.org/10.1113/eph8602178, Mastorakos and Ilias 2003Mastorakos, G., Ilias, I. (2003). Maternal and fetal hypothalamic-pituitary-adrenal axes during pregnancy and postpartum. Ann. N. Y. Acad. Sci., 997, 136–149. https://doi.org/10.1196/annals.1290.016, Kindahl et al. 2004Kindahl, H., Kornmatitsuk, B., Gustaffson, H. (2004). The cow in endocrine focus before and after calving. Reprod. Dom. Anim., 39, 217–221. https://doi.org/10.1111/j.1439-0531.2004.00506.x].
Kindahl et al. [2004]Kindahl, H., Kornmatitsuk, B., Gustaffson, H. (2004). The cow in endocrine focus before and after calving. Reprod. Dom. Anim., 39, 217–221. https://doi.org/10.1111/j.1439-0531.2004.00506.x reported that postpartum increase in the concentration of progesterone in cows is observed after the first ovulation. Cernescu et al. [2010]Cernescu, H., Onita, P., Knop, R., Ionescu, C., Zarcula, S., Groza, E. (2010). The metabolic and hormonal profile on peripartal periode in cow. Lucrǎri Ştiinţifice Medicinǎ Veterinarǎ, 43, 1–8. Google Scholar reported that until day 26 after calving, progesterone levels in the blood of Holstein-Friesian cows gradually increased from 0.48 to 1.61 ng · ml–1, on the day 29 after calving reached similar values as on the day of calving (0.54 ng · ml–1) and subsequently rising again until day 44 postpartum. According to Corah et al. [1974]Corah, L.R., Quealy, A.P., Dunn, T.G., Kaltenbach, C.C. (1974). Prepartum and postpartum levels of progesterone and estradiol in beef heifers fed two levels of energy. J. Anim. Sci., 39, 380–385. https://doi.org/10.2527/jas1974.392380x a significant increase in progesterone levels was observed in postpartum beef cows, 3–5 days before the first heat, as a result of luteinization of maturing follicles, and/or progesterone synthesis in the adrenal glands. According to Stevenson and Britt [1979]Stevenson, J.S., Britt, J.H. (1979). Relationship among luteinizing hormone, estradiol, progesterone, glucocorticoids, milk yield, body weight and postpartum ovarian activity in Holstein cows. J. Anim. Sci., 48, 570–577. https://doi.org/10.2527/jas1979.483570x lower concentration of progesterone was noted during the first estrous cycle in cows after calving in comparison to later cycles – which in turn may result in a shorter first estrous cycle.
The non-bound estrogens present in the blood of cows during pregnancy, parturition and lactation are represented by 17β-estradiol, estrone (in the maternal circulation mainly in the form of estrone sulfate) and estriol. They are synthesized in the placenta, ovaries and fetal membranes. Estrogens contribute to the growth of, inter alia, the myometrium, the actomyosin synthesis necessary for uterine contractions during parturition. The local increase in the concentration of estrogens (especially in the amniotic fluid), subsequently shifts the ratio of estrogen to progesterone and contributes to the initiation of the uterus contraction. Estrogens interact with relaxin and prepare the reproductive tissues for calving, additionally they stimulate the release of PGF2α from endometrium [Mastorakos and Ilias 2003Mastorakos, G., Ilias, I. (2003). Maternal and fetal hypothalamic-pituitary-adrenal axes during pregnancy and postpartum. Ann. N. Y. Acad. Sci., 997, 136–149. https://doi.org/10.1196/annals.1290.016, Kindahl et al. 2004Kindahl, H., Kornmatitsuk, B., Gustaffson, H. (2004). The cow in endocrine focus before and after calving. Reprod. Dom. Anim., 39, 217–221. https://doi.org/10.1111/j.1439-0531.2004.00506.x].
An increase in the concentration of estrogens during the perinatal period in cattle is associated with the preparation of the mammary gland for lactation and increased enzymatic activity of the mammary gland [Convey 1973Convey, E.M. (1973). Serum hormone concentrations in ruminants during mammary growth, lactogenesis and lactation: a review. J. Dairy Sci., 57, 905–917. https://doi.org/10.3168/jds.S0022-0302(74)84986-6].
Takahashi et al. [1997]Takahashi, T., Hirako, M., Takahashi, H., Patel, O.V., Takenouchi, N., Domeki, I. (1997). Maternal plasma estrone sulfate profile during pregnancy in the cow; comparison between singleton and twin pregnancies. J. Vet. Med. Sci., 59, 287–288. https://doi.org/10.1292/jvms.59.287 reported that twin pregnancy in cows result in higher concentration of estrone sulfate compared to singleton pregnancy in cows. This parameter increased rapidly in the third trimester of pregnancy and reached its peak on the day of calving (16.7 ng · ml–1). Singleton pregnancy was characterized by gradual increase in the concentration of estrone sulphate, reaching its maximum 10 days before calving (7.1 ng · ml–1) followed by a period of declining.
Higher concentration of estrone sulfate and other estrogens was noted from mid-pregnancy until the expulsion of placenta [Kindahl et al. 2002Kindahl, H., Kornmatitsuk, B., Königsson, K., Gustaffson, H. (2002). Endocrine changes in late bovine pregnancy with special emphasis on fetal well-being. Domest. Anim. Endocrinol., 23, 321–328. https://doi.org/10.1016/S0739-7240(02)00167-4]. Convey [1973]Convey, E.M. (1973). Serum hormone concentrations in ruminants during mammary growth, lactogenesis and lactation: a review. J. Dairy Sci., 57, 905–917. https://doi.org/10.3168/jds.S0022-0302(74)84986-6 stated that the rapid increase was observed in the last 2 weeks of pregnancy. In early lactation a rapid decline was noted.
Between day 14 before calving and the day of calving the estrogens concentration increased from 0.5 to 2.66 ng · ml–1. In the last 5 days of pregnancy estrogens concentration increased gradually at a rate of 0.248 ng per day [Henricks et al. 1972Henricks, D.M., Dickey, J.F., Hill, J.R., Johnston, W.E. (1972). Plasma estrogen and progesterone levels after mating, and during late pregnancy and postpartum in cows. Endocrinol., 90, 1336–1342. https://doi.org/10.1210/endo-90-5-1336]. The highest estrogen levels were recorded on the day of calving and during postpartum their concentration decreased [Kindahl et al. 2004Kindahl, H., Kornmatitsuk, B., Gustaffson, H. (2004). The cow in endocrine focus before and after calving. Reprod. Dom. Anim., 39, 217–221. https://doi.org/10.1111/j.1439-0531.2004.00506.x]. After calving the highest concentrations are observed during the heat as a result of follicular development [Corah et al. 1974Corah, L.R., Quealy, A.P., Dunn, T.G., Kaltenbach, C.C. (1974). Prepartum and postpartum levels of progesterone and estradiol in beef heifers fed two levels of energy. J. Anim. Sci., 39, 380–385. https://doi.org/10.2527/jas1974.392380x, Stevenson and Britt 1979Stevenson, J.S., Britt, J.H. (1979). Relationship among luteinizing hormone, estradiol, progesterone, glucocorticoids, milk yield, body weight and postpartum ovarian activity in Holstein cows. J. Anim. Sci., 48, 570–577. https://doi.org/10.2527/jas1979.483570x].
Androgens are involved, inter alia, in the regulation of the ovarian follicle growth, regulation of the hypothalamic-pituitary axis and are precursor of estrogens. The androgens and estrogens are involved in the stimulation of prolactin secretion from the pituitary gland. The concentration of androgens in cows increases in the periparturient period. It is suggested that androgens increase during this period is associated with increased levels of estrogen [Wise et al. 1982Wise, T.H., Caton, D., Thather, W.W., Rami Lehrer, A., Fields, M.J. (1982). Androstenedione, dehydroepiandrosterone and testosterone in ovarian vein plasma and androstenedione in peripheral arterial plasma during the bovine oestrous cycle. J. Reprod. Fert., 66, 513–518. https://doi.org/10.1530/jrf.0.0660513].
Gaiani et al. [1984]Gaiani, R., Chiesa, F., Mattioli, M., Nannetti, G., Galeati, G. (1984). Androstenedione and testosterone concentrations in plasma and milk of the cow throughout pregnancy. J. Reprod. Fertil., 70, 55–59. https://doi.org/10.1530/jrf.0.0700055 reported that the concentration of androstenedione during the first trimester of pregnancy in Holstein-Friesian cows was approximately 0.1–0.2 ng · ml–1 on 200 day of pregnancy reached 1.4 ng · ml–1 and on this level was stable until the end of pregnancy. The concentration of testosterone until day 90 of pregnancy was approximately 0.02–0.05 ng · ml–1, then steadily increases reaching the value of 0.22 ng · ml–1 on day 270 of gestation. Möstl et al. [1981]Möstl, E., Möstl, K., Choi, H.S., Dreier, H.K., Stöckl, W., Bamberg, E. (1981). Plasma levels of androstenedione, epitestosterone, testosterone and oestrogens in cows at parturition. J. Endocrinol., 89, 251–255. https://doi.org/10.1677/joe.0.0890251 reported that in the last week of pregnancy in cows androstendion, epitestosterone and testosterone concentrations were relatively stable (0.92; 0.40; 0.90 ng · ml–1, respectively). After calving their concentration rapidly decreases.
Safonov [2008]Safonov, V.A. (2008). Hormonal Status of Pregnant and Infertile High Producing Cows. Russian Agri. Sci., 34, 273–275. https://doi.org/10.3103/S1068367408040198 stated that the mean concentration of testosterone in Red Pied cows within the first month of lactation was approximately 2.6 ng · ml–1 with the highest value one day before estrus. The increase in the concentration of testosterone was also noted in the middle of the reproductive cycle. The increase in the concentration of androgens affects the occurrence of estrous behavior [Nessan and King 1981Nessan, G.K., King, G.J. (1981). Relationship of peripheral estrogens and testosterone concentrations to sexual behavior in normal and cystic cows. Can. Vet. J., 22, 9–11. Google Scholar]. According to Kesler et al. [1979]Kesler, D.J., Garvericka, H.A., Caudlea, A.B., Bierschwala, C.J., Elmorea, R.G., Youngquista, R.S. (1979). Testosterone Concentrations in Plasma of Dairy Cows with Ovarian Cysts. J. Dairy Sci., 62, 1825–1828. https://doi.org/10.3168/jds.S0022-0302(79)83506-7 during the heat testosterone concentration in dairy cows was appriximatelly 0.0463 ng · ml–1, on the day 13 of the cycle, 0.0851 ng · ml–1. On the other hand Kanchev and Dobson [1976]Kanchev, L.N., Dobson, H. (1976). Plasma concentration of androstenedione during the bovine oestrous cycle. J. Endocrinol., 71, 351–354. https://doi.org/10.1677/joe.0.0710351 reported that the concentration of androstenedione levels in cows in the reproductive cycle does not increase and ranges from 0.08–0.1 ng · ml–1.
Placental lactogen, a glycoprotein hormone of lactogenic and somatogenic activity, is synthesized by the placenta. The process of transcription of mRNA for placental lactogen occurs in binuclear giant cells from day 30 until the end of pregnancy in cows. Its concentration in blood depends on the stage of pregnancy, placental weight, fetal weight, race, nutritional status. In cows during pregnancy this hormone is involved in the regulation of ovarian steroidogenesis, mammogenesis, lactogenesis, has luteotrophic action and is involved in the supply of the fetus with nutrients. It is believed that its action also increases milk productivity and mass in cows and promotes greater weight of the fetus/calves.
Concentration of placental lactogen increases during pregnancy, peaking during the third trimester, then falls from the day of calving. Placental lactogen can be detected in the blood plasma of the cows from 60 days of pregnancy and its concentration is maintained from 1.3 to 2.0 ng · ml–1. After calving a steep decline in its concentration within 24 hours was noted [Schuler et al. 1988Schuler, L.A., Shimomura, K., Kessler, M.A., Zieler, C.G., Bremel, R.D. (1988). Bovine placental lactogen: molecular cloning and protein structure. Biochemistry, 27, 8443–8448. https://doi.org/10.1021/bi00422a022, Byatt et al. 1992Byatt, J.C., Warren, W.C., Eppard, P.J., Staten, N.R., Krivi, G.G., Collier, R.J. (1992). Ruminant placental lactogens: structure and biology. J. Anim. Sci., 70, 2911–2923. https://doi.org/10.2527/1992.7092911x, Wallace 1993Wallace, C.R. (1993). Concentration of bovine placental lactogen in dairy and beef cows across gestation. Dom. Anim. Endocrinol., 10, 67–70. https://doi.org/10.1016/0739-7240(93)90009-Z, Patel et al. 1996Patel, O.V., Takahashi, T., Takenouchi, N., Hirako, M., Sasaki, N., Domeki, I. (1996). Peripheral cortisol levels throughout gestation in the cow: effect of stage of gestation and foetal number. Br. Vet. J., 152, 425–432. https://doi.org/10.1016/S0007-1935(96)80036-4, Ollivier-Bousquet and Devinoy 2005Ollivier-Bousquet, M., Devinoy, E. (2005). Physiology of lactation: old questions, new approaches. Livestock Production Sci., 98, 163–173. https://doi.org/10.1016/j.livprodsci.2005.10.012, Alvarez-Oxiley et al. 2008Alvarez-Oxiley, A.V., Sousa, N.M., Beckers, J.F. (2008). Native and recombinant bovine placental lactogens. Reprod. Biol., 8, 85–106. https://doi.org/10.1016/S1642-431X(12)60006-0].
The relaxin was isolated from cows corpus luteum in the third trimester of pregnancy, suggesting that the corpus luteum is the main source of relaxin in pregnant cows [Fields et al. 1980Fields, M.J., Fields, P.A., Castro-Hernandez, A., Larkin, L.H. (1980). Evidence for relaxin in corpora lutea of late pregnant cows. Endocrinol., 107, 869–876. https://doi.org/10.1210/endo-107-4-869]. Relaxin is necessary for expanding the cervix and pelvic canal during calving, also inhibits the uterine contractions. Relaxin is involved in the process of luteolysis, affecting the concentration of progesterone, estrogen, oxytocin, prostaglandins F2α. In beef cows a few days before the calving the relaxin concentration was 0.29 ng · ml–1, on the day of calving was greater than 0.8 ng · ml–1 [Anderson et al. 1982Anderson, L.L., Perezgrovas, R., O'Byren, E.M., Steinetz, B.G. (1982). Biological actions of relaxin in pigs and beef cattle. Ann. N Y Acad. Sci., 380, 131–150. https://doi.org/10.1111/j.1749-6632.1982.tb18036.x, Smith et al. 1997Smith, K.H., Musah, A.I., Cho, S.J., Schwabe, C., Anderson, L.L. (1997). Continuous infusion of relaxin on periparturient progesterone, oxytocin and relaxin plasma concentrations and time of parturition in beef heifers. Anim. Reprod. Sci., 46, 15–25. https://doi.org/10.1016/S0378-4320(96)01616-8].
PAGs are produced by mono-and-binuclear giant cells of placenta in cows. It was observed that they affect maternal recognition of pregnancy, trophoblast adhesion and implantation. Furthermore, they are a good indicator of embryo viability. It was reported that they may have local immunosuppressive effect, while maintaining a histological heterogeneity of feto-maternal tissues. They are involved in the formation and remodeling of placenta, as well as in the ecpulsion of the placenta after calving. They have an luteotropic, and luteopreventive action.
PAGs may be involved in postnatal growth of ovarian follicles, they induce the release of prostaglandin E2 from the corpus luteum and endometrium and progesterone release from the corpus luteum. Their greater concentrations are recorded in twin pregnancies [Zoli et al. 1992Zoli, A.P., Guilbault, L.A., Delahaut, P., Ortiz, W.B., Beckers, J.F. (1992). Radioimmunoassay of a bovine pregnancy-associated glycoprotein in serum: its application for pregnancy diagnosis. Biol. Reprod., 46, 83–92. https://doi.org/10.1095/biolreprod46.1.83, Kiracofe et al. 1993Kiracofe, G.H., Wright, J.M., Schalles, R.R., Ruder, C.A., Parish, S., Sasser, R.G. (1993). Pregnancy-specific protein B in serum of postpartum beef cows. J. Anim. Sci., 71, 2199–2205. https://doi.org/10.2527/1993.7182199x, Austin et al. 1999Austin, K.J., King, C.P., Vierk, J.E., Sasser, R.G., Hansen, T.R. (1999). Pregnancy-specific protein B induces release of an alpha chemokine in bovine endometrium. Endocrinology, 140(1), 542–455. https://doi.org/10.1210/endo.140.1.6608].
PAGs synthesis begins after the tight connection formation between the trophoblast and the uterus. Their concentration is gradually increasing, with low levels (below 500 ng · ml–1) noted until the second week before parturition in cows. In the last 10 days before calving their concentration triples, reaching the highest values between 1–5 days before calving, During postpartum gradual decrease was noted [Patel et al. 1997Patel, O.V., Sulon, J., Beckers, J.F., Takahashi, T., Hirako, M., Sasaki, N., Domeki, I. (1997). Plasma bovine pregnancyassociated glycoprotein concentrations throughout gestation in relationship to fetal number in the cow. Eur. J. Endocrinol., 137, 423–428. https://doi.org/10.1530/eje.0.1370423, Kindahl et al. 2002Kindahl, H., Kornmatitsuk, B., Königsson, K., Gustaffson, H. (2002). Endocrine changes in late bovine pregnancy with special emphasis on fetal well-being. Domest. Anim. Endocrinol., 23, 321–328. https://doi.org/10.1016/S0739-7240(02)00167-4, Kornmatitsuk et al. 2003Kornmatitsuk, B., Franzen, G., Gustafsson, H., Kidahl, H. (2003). Endocrine measurements and calving performance of Swedish Red and White and Swedish Holstein dairy cattle with special respect to stillbirth. Acta Vet. Scand., 44, 21–33. https://doi.org/10.1186/1751-0147-44-21, Kindahl et al. 2004Kindahl, H., Kornmatitsuk, B., Gustaffson, H. (2004). The cow in endocrine focus before and after calving. Reprod. Dom. Anim., 39, 217–221. https://doi.org/10.1111/j.1439-0531.2004.00506.x].
80–90 days after calving PAGs are not detectable in maternal blood [Haugejorden et al. 2006Haugejorden, G., Waage, S., Dahl, E., Karlberg, K., Beckers, J.F., Ropstad, E. (2006). Pregnancy associated glycoproteins (PAG) in postpartum cows, ewes, goats and their offspring. Theriogenology, 66, 1976–1984. https://doi.org/10.1016/j.theriogenology.2006.05.016]. PAG’s changes in concentration may be helpful in monitoring the health of the fetus in animals in which there is a risk that they may give birth to dead calves [Kornmatitsuk et al. 2004Kornmatitsuk, B., Dahl, E., Ropstad, E., Beckers, J.F., Gustafsson, H., Kindahl, H. (2004). Endocrine Profiles, Haematology and Pregnancy Outcomes of Late Pregnant Holstein Dairy Heifers Sired by Bulls Giving a High or Low Incidence of Stillbirth. Acta Vet. Scand., 45, 47–68. https://doi.org/10.1186/1751-0147-45-47]. Kindahl et al. [2004]Kindahl, H., Kornmatitsuk, B., Gustaffson, H. (2004). The cow in endocrine focus before and after calving. Reprod. Dom. Anim., 39, 217–221. https://doi.org/10.1111/j.1439-0531.2004.00506.x emphasized that PAG concentration is higher in fetus blood compared to the mother. According to Haugejorden et al. [2006]Haugejorden, G., Waage, S., Dahl, E., Karlberg, K., Beckers, J.F., Ropstad, E. (2006). Pregnancy associated glycoproteins (PAG) in postpartum cows, ewes, goats and their offspring. Theriogenology, 66, 1976–1984. https://doi.org/10.1016/j.theriogenology.2006.05.016, this compound also enters the bloodstream of neonatal ruminants in the uterus and is provided with colostrum.
PGF2α is unstable prostaglandin and is metabolized to 15-keto- 13,14-dihydro-PGF 2α [Bernal 2001Bernal, A.L. (2001). Overview of current research in parturition. Exp. Physiol., 86, 213–222. https://doi.org/10.1113/eph8602178]. Maternal concentration of prostaglandins in cows is regulated by changes in the concentration of cortisol. The increasing estrogen to progestins ratio also stimulates the production of prostaglandins in the uterine tissues, and as a result, sensitizes the myometrium to the action of oxytocin.
The release of prostaglandins is necessary for luteolysis and onset of parturition. 10 days before calving average concentration of PGF2α metabolites in cows was 500 ng · ml–1 and subsequently increased contributing to prepartum luteolysis. The highest value is observed on the day of birth [Edqvist et al. 1978Edqvist, L.E., Kindahl, H., Stabenfeldt, G. (1978). Release of prostaglandin F2α during the bovine peripartal period. Prostaglandins, 16, 111–119. https://doi.org/10.1016/0090-6980(78)90207-1].
After calving, the release of PGF2α is higher for a period of about 2–3 weeks, but their concentration gradually decreases. The presence of PGF2α is essential for the involution of the uterus. Until it is released in large quantities, the cow is not ovulating [Kornmatitsuk et al. 2003Kornmatitsuk, B., Franzen, G., Gustafsson, H., Kidahl, H. (2003). Endocrine measurements and calving performance of Swedish Red and White and Swedish Holstein dairy cattle with special respect to stillbirth. Acta Vet. Scand., 44, 21–33. https://doi.org/10.1186/1751-0147-44-21, 2004; Kindahl et al. 2004Kindahl, H., Kornmatitsuk, B., Gustaffson, H. (2004). The cow in endocrine focus before and after calving. Reprod. Dom. Anim., 39, 217–221. https://doi.org/10.1111/j.1439-0531.2004.00506.x].
Prolactin is necessary for the secretion of milk during lactation, is involved in the development, differentiation and function of mammary tissue, supports the function of the corpus luteum. It is related to the supply of nutrients and their disposal in the fetus [Knight 2001Knight, C.H. (2001). Overview of prolactin's role in farm animal lactation. Livestock Production Sci., 70, 87–93. https://doi.org/10.1016/S0301-6226(01)00200-7, Soares 2004Soares, M.J. (2004). The prolactin and growth hormone families: Pregnancy-specific hormones/cytokines at the maternal-fetal interface. Reprod. Biol. Endocrinol., 2, 1–15. https://doi.org/10.1186/1477-7827-2-51, Ollivier-Bousquet and Devinoy 2005Ollivier-Bousquet, M., Devinoy, E. (2005). Physiology of lactation: old questions, new approaches. Livestock Production Sci., 98, 163–173. https://doi.org/10.1016/j.livprodsci.2005.10.012]. It was reported that prolactin is not involved in the regulation of the reproduction cycle in cattle [Bevers et al. 1988Bevers, M.M., Dieleman, S.J., Kruip, T.A. (1988). The role of prolactin during the estrus cycle of cattle. Tijdschr. Diergeneeskd., 113, 1227–1236 [in Dutch]. Google Scholar].
Higher concentration of prolactin during pregnancy were observed in cows with male fetus [Oxender et al. 1972Oxender, W.D., Hafs, H.D., Ederton, L.A. (1972). Serum growth hormone, LH and prolactin in the pregnant cow. J. Anim. Sci., 35, 51–55. https://doi.org/10.2527/jas1972.35151x]. The concentration of prolactin 2–4 weeks before calving was 50 ng · ml–1, in the last 5 days of pregnancy an increase was noted. On the day of calving prolactin concentration was 234 ng · ml–1. During the first 6 weeks of lactation decreased to 69 ng · ml–1. [Edgerton and Hafs 1973Edgerton, L.A., Hafs, H.D. (1973). Serum luteinizing hormone, prolactin, glucocorticoid, and progestin in dairy cows from calving to gestation. J. Dairy Sci., 56, 451–458. https://doi.org/10.3168/jds.S0022-0302(73)85199-9]. Convey [1973]Convey, E.M. (1973). Serum hormone concentrations in ruminants during mammary growth, lactogenesis and lactation: a review. J. Dairy Sci., 57, 905–917. https://doi.org/10.3168/jds.S0022-0302(74)84986-6 reported that in the first 90 days of lactation the prolactin concentration was 9 ng · ml–1.
Somatotropin (GH) in cows affects laktopoesis and contributes, among other things, to increased hepatic gluconeogenesis, increased amino acid uptake and release of urea from liver, it also increases the deposition of proteins in the liver. The concentration of somatotropin increases before calving, reaching its peak on the day of calving, and then steadily decreases [Bell 1995Bell, A.W. (1995). Regulation of organic nutrient metabolism during transition from late pregnancy to early lactation. J. Anim. Sci., 73, 2804–2819. https://doi.org/10.2527/1995.7392804x, Grummer 1995Grummer, R.R. (1995). Impact of changes in organic nutrient metabolism on feeding the transition dairy cow. J. Anim. Sci., 73, 2820–2833. https://doi.org/10.2527/1995.7392820x, Etherton and Bauman 1998Etherton, T.D., Bauman, D.E. (1998). Biology of somatotropin in growth and lactation of domestic animals. Physiol. Rev., 78, 745–761. https://doi.org/10.1152/physrev.1998.78.3.745]. The concentration of growth hormone one month prior to calving was 3.5 ng · ml–1 [Leury et al. 2003Leury, B.J., Baumgard, L.H., Block, S.S., Segoale, N., Ehrhardt, R.A., Rhoads, R.P., Bauman, D.E., Bell, A.W., Boisclair, Y.R. (2003). Effect of insulin and growth hormone on plasma leptin in periparturient dairy cows. Am. J. Physiol. Regul. Integr. Comp. Physiol., 285, 1107–1115. https://doi.org/10.1152/ajpregu.00320.2003]. Between 9 and 5 days before parturition an increase was observed with a significant increase during and immediately after calving, then a gradual decrease was noted [Convey 1973Convey, E.M. (1973). Serum hormone concentrations in ruminants during mammary growth, lactogenesis and lactation: a review. J. Dairy Sci., 57, 905–917. https://doi.org/10.3168/jds.S0022-0302(74)84986-6]. Leury et al. [2003]Leury, B.J., Baumgard, L.H., Block, S.S., Segoale, N., Ehrhardt, R.A., Rhoads, R.P., Bauman, D.E., Bell, A.W., Boisclair, Y.R. (2003). Effect of insulin and growth hormone on plasma leptin in periparturient dairy cows. Am. J. Physiol. Regul. Integr. Comp. Physiol., 285, 1107–1115. https://doi.org/10.1152/ajpregu.00320.2003 reported that GH concentration in cows on day 7 after calving was 4.6 ng · ml–1. According to Bell et al. [2000]Bell, A.W., Burhans, W.S., Overton, T.R. (2000). Protein nutrition in late pregnancy, maternal protein reserves and lactation performance in dairy cows. Proc. Nutr. Soc., 59, 119–126. https://doi.org/10.1017/S0029665100000148 an increase in the concentration of growth hormone was observed in the early stages of lactation. According to Gabai et al. [2004]Gabai, G., Testoni, S., Piccinini, R., Marinelli, L. Howard, C.M., Stradaioli, G. (2004). Oxidative stress in primiparous cows in relation to dietary starch and the progress of lactation. Anim. Sci., 79, 99–108. https://doi.org/10.1017/S1357729800054576 the concentration of GH in primiparous cows on the day 37 of lactation was 7.5 ng · ml–1, on the day 50 of lactation – 11 ng · ml–1, on day 60 of lactation – 7.8 ng · ml–1.
Oxytocin is synthesized by the hypothalamus and released from the posterior pituitary. It is also synthesizeded by the large cells of the corpus luteum and luteal cells of uterus placnetoma. Oxytocin is, inter alia, necessary for the secretion of milk during lactation, stimulates the production of lipids, involved in osmoregulation, stimulates the synthesis of prostaglandins in uterus tissues. It is involved in the control of ovarian cycle – contributes to the regression of the corpus luteum. During sexual cycle in cows changes in the concentration of oxytocin are similar to progesterone. During pregnancy oxytocin is released intermittently and in small quantities [Flint et al. 1986Flint, A.P., Sheldrick, E.L., Theodosis, D.T., Wooding, F.B. (1986). Ovarian peptides: role of luteal oxytocin in the control of estrous cyclicity in ruminants. J. Anim. Sci., 62, 62–71. https://doi.org/10.1093/ansci/62.2.62, Fuchs et al. 2001Fuchs, A.R., Ivell, R., Ganz, N., Fields, M.J., Gimenez, T. (2001). Secretion of oxytocin in pregnant and parturient cows: corpus luteum may contribute to plasma oxytocin at term. Biol. Reprod., 65, 1135–1141. https://doi.org/10.1095/biolreprod65.4.1135, Ollivier-Bousquet and Devinoy 2005Ollivier-Bousquet, M., Devinoy, E. (2005). Physiology of lactation: old questions, new approaches. Livestock Production Sci., 98, 163–173. https://doi.org/10.1016/j.livprodsci.2005.10.012].
Before calving the frequency and the amount of oxytocin increases. A gradual increase in the concentration of oxytocin (The highest concentration was noted 5 minutes before calving), followed by the decrease in the concentration after the expulsion of placenta [Williams et al. 2001Williams, G.L., Gazal, O.S., Leshin, L.S., Stanko, R.L., Anderson, L.L. (2001). Physiological regulation of maternal behavior in heifers: roles of genital stimulation, intracerebral oxytocinrelease, and ovarian steroids. Biol. Reprod., 65, 295–300. https://doi.org/10.1095/biolreprod65.1.295, Perumamthadathil et al. 2014Perumamthadathil, C.S., Johnson, W.H., LeBlanc, S.J., Foster, R.A., Chenier, T.S. (2014). Persistence of oxytocin receptors in the bovine uterus during the first 7 d after calving: An immunohistochemical study. Can. J. Vet. Res., 78, 72–77. Google Scholar].
GnRH is a hormone produced in the hypothalamus. It stimulates the synthesis and release of LH and FSH, thus indirectly is involved in steroidogenesis and gametogenesis. GnRH is produced in response to increased concentrations of estrogen in the blood, in turn, increase the concentration of progesterone inhibits its secretion [Jadav et al. 2010Jadav, P.V., Patel, D.M., Kavani, F.S., Dhami, A.J. (2010). GnRH and its Applications in Bovine Reproduction. J. Adv. Dev. Res., 1, 74–80. Google Scholar]. Macmillan et al. [1986]Macmillan, K., Taufa, V.K., Day, A.M. (1986). Effects of an agonist of gonadotrophin releasing hormone (Buserelin) in cattle. III. Pregnancy rates after a post-insemination injection during metoestrus or dioestrus. Anim. Reprod. Sci., 11, 1–10. https://doi.org/10.1016/0378-4320(86)90096-5 reported that GnRH has the luteotropic effect.
GnRH concentration before calving is very low which and associated with the negative feedback between gonadotropins and high concentration of estrogen and progesterone [Rhodes et al. 2003Rhodes, F.M., McDougall, S., Burke, C.R., Verkerk, G.A., Macmillan, K.L. (2003). Treatment of cows with an extended postpartum anestrous interval. J. Dairy Sci., 86, 1876–1894. https://doi.org/10.3168/jds.S0022-0302(03)73775-8]. After calving at first GnRH is secreted rarely and in small quantities [Peters and Lamming 1990Peters, A.R., Lamming, G.E. (1990). Lactational anoestrus in farm animals. Oxf. Rev. Reprod. Biol., 12, 245–288. Google Scholar]. According to Jadav et al. [2010]Jadav, P.V., Patel, D.M., Kavani, F.S., Dhami, A.J. (2010). GnRH and its Applications in Bovine Reproduction. J. Adv. Dev. Res., 1, 74–80. Google Scholar cows pituitary is able to respond to GnRH from day 20 after calving.
LH is primarily luteotropic hormone which stimulates the ovulation. The concentration of LH in late pregnant cows is subject to dynamic changes under the influence of GnRH [Little et al. 1982Little, D.E., Rahe, C.H., Fleeger, J.L., Harms, P.G. (1982). Episodic release of LH during gestation in the cow. J. Reprod. Fertil., 66, 687–690. https://doi.org/10.1530/jrf.0.0660687]. Very high levels of estrogen during pregnancy in cows suppresses the LH release. Before calving LH concentration is high, during postpartum LH concentration changes are characteristic for the sexual cycle in cows [Cernescu et al. 2010Cernescu, H., Onita, P., Knop, R., Ionescu, C., Zarcula, S., Groza, E. (2010). The metabolic and hormonal profile on peripartal periode in cow. Lucrǎri Ştiinţifice Medicinǎ Veterinarǎ, 43, 1–8. Google Scholar].
During the estrous cycle in cows LH release is associated with a reduction in the concentration of progesterone. The decrease in progesterone concentration is also observed before calving, which stimulates the secretion of LH [Edgerton and Hafs 1973Edgerton, L.A., Hafs, H.D. (1973). Serum luteinizing hormone, prolactin, glucocorticoid, and progestin in dairy cows from calving to gestation. J. Dairy Sci., 56, 451–458. https://doi.org/10.3168/jds.S0022-0302(73)85199-9]. It is worth noting that negative energy balance in cows contribute to the inhibition of LH secretion [Roche et al. 2000Roche, J.F., Mackey, D., Diskin, M.D. (2000). Reproductive management of postpartum cows. Anim. Reprod. Sci., 60–61, 703–712. https://doi.org/10.1016/S0378-4320(00)00107-X].
LH concentration during pregnancy in cows ranges between 0.7–1 ng · ml–1 and statistically significant changes were observed between the different trimesters of pregnancy [Oxender et al. 1972Oxender, W.D., Hafs, H.D., Ederton, L.A. (1972). Serum growth hormone, LH and prolactin in the pregnant cow. J. Anim. Sci., 35, 51–55. https://doi.org/10.2527/jas1972.35151x]. Edgerton and Hafs [1973]Edgerton, L.A., Hafs, H.D. (1973). Serum luteinizing hormone, prolactin, glucocorticoid, and progestin in dairy cows from calving to gestation. J. Dairy Sci., 56, 451–458. https://doi.org/10.3168/jds.S0022-0302(73)85199-9 reported that LH concentration in the last month of pregnancy in cows was maintained at 0.5 ng · ml–1, after calving increased up to 5–6 weeks to 1.5 ng · ml–1. On the other hand Cernescu al. [2010] reported that the concentration of LH in Holstein-Friesian cows eight days before calving was 7.75 ng · ml–1, at the day of calving – 0.41 ng · ml–1, on day 7 of lactation – 0.84 ng · ml–1, on day 14 of lactation – 0.82 ng · ml–1, on day 32 of lactation 0.86 ng · ml–1.
During estrus in cows (about a day before ovulation) a high concentration of luteinizing hormone (42 ng · ml–1) was noted, with subsequent decrease to a value of 0.5–1.7 ng · ml–1 at the peak of estrus [Arije et al. 1974Arije, G.R., Wiltbank, J.N., Hopwood, M.L. (1974). Hormone levels in pre- and posparturient beef cows. J. Anim. Sci., 39, 338–347. https://doi.org/10.2527/jas1974.392338x]. Stevenson and Britt [1979]Stevenson, J.S., Britt, J.H. (1979). Relationship among luteinizing hormone, estradiol, progesterone, glucocorticoids, milk yield, body weight and postpartum ovarian activity in Holstein cows. J. Anim. Sci., 48, 570–577. https://doi.org/10.2527/jas1979.483570x reported that there is a positive correlation between the increase in the concentration of estrogens in postpartum and stimulation of the production and secretion of LH, however GnRH-dependent release of LH is partially inhibited to about 10 days postpartum. The reduced secretion of LH during this period may be associated with a high milk production. According to Rhodes et al. [2003]Rhodes, F.M., McDougall, S., Burke, C.R., Verkerk, G.A., Macmillan, K.L. (2003). Treatment of cows with an extended postpartum anestrous interval. J. Dairy Sci., 86, 1876–1894. https://doi.org/10.3168/jds.S0022-0302(03)73775-8 The increase in the concentration of LH in postpartum cows was observed between 10 and 20 days after calving.
FSH is a hormone that stimulates follicular maturation. The concentration of FSH in the blood of cows during pregnancy s cycling subsidiary the follicle maturation cycles (0.1–1.2 ng · ml–1) [Ginther et al. 1996Ginther, O.J., Kot, K., Kulick, L.J., Martin, S., Wiltbank, M.C. (1996). Relationships between FSH and ovarian follicular waves during the last six months of pregnancy in cattle. J. Reprod. Fertil., 108, 271–279. https://doi.org/10.1530/jrf.0.1080271]. Cernescu et al. [2010]Cernescu, H., Onita, P., Knop, R., Ionescu, C., Zarcula, S., Groza, E. (2010). The metabolic and hormonal profile on peripartal periode in cow. Lucrǎri Ştiinţifice Medicinǎ Veterinarǎ, 43, 1–8. Google Scholar reported that the concentration of FSH in Holstein-Friesian cows 8 days before calving was 2 · 41 ng · ml–1, on the day of calving – 2.21 ng · ml–1, on day 7 of lactation 3.12 ng · ml–1, day 14 of lactation – 2.26 ng · ml–1, day 32 of lactation – 0.86 ng · ml–1, day 44 of lactation – 0.78 ng · ml–1. The authors reported that the concentration changes are related to the maturation of ovarian follicles (characteristic for ovarian activity in estrous cycle).
Thyroid hormones are essential for the differentiation, growth and proper metabolism of the cells. Among other things, they have a significant impact on the regulation of the mammary gland, lactopoesis. They are involved in the initiation and stimulation of ovarian activity – in steroidogenesis in the follicles. Their high concentration is observed in late pregnancy. In cows exhibiting postpartum negative energy balance, lower concentrations of T3 and T4 hormones was noted. Low levels of these hormones were observed during the first three months of lactation, due to the fact that the concentration of T3 and T4 is negatively correlated with milk productivity [Capuco et al. 2001Capuco, A.V., Wood, D.L., Elsasser, T.H., Kahl, S., Erdman, R.A., Van Tassell, C.P., Lefcourt, A., Piperova, L.S. (2001). Effect of somatotropin on thyroid hormones and cytokines in lactating dairy cows during ad libitum and restricted feed intake. J. Dairy Sci., 84, 2430–2439. https://doi.org/10.3168/jds.S0022-0302(01)74693-0, Huszenicza et al. 2002Huszenicza, G.Y., Kulcsar, M., Rudas, P. (2002). Clinical endocrinology of thyroid gland function in ruminants. Vet. Med. – Czech, 47, 199–210. https://doi.org/10.17221/5824-VETMED, Jorritsma et al. 2003Jorritsma, R., Wensing, T., Kruip, T.A., Vos, P.L., Noordhuizen, J.P. (2003). Metabolic changes in early lactation and impaired reproductive performance in dairy cows. Vet. Res., 34, 11–26. https://doi.org/10.1051/vetres:2002054, Klimienė et al. 2008Klimienė, I., Mockeliūnas, R., Špakauskas, V., Černauskas, A., Sakalauskienė, R. (2008). Metabolic changes of thyroid hormones in cattle. Veterinarija ir Zootechnika, 42(64), 3–13. Google Scholar,
Djoković et al. 2010Djoković, R., Šamanc, H., Bojkovski, J., Fratrić, N. (2010). Blood concentrations of thyroid hormones and lipids of dairy cows in transitional period. Lucrări Ştiinłifice Medicină Veterinară, 43(2), 34–40. Google Scholar,
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2015]. According to Meikle et al. [2004]Meikle, A., Kulcsar, M., Chilliard, Y., Febel, H., Delavaud, C., Cavestany, D., Chilibroste, P. (2004). Effects of parity and body condition at parturition on endocrine and reproductive parameters of the cow. Reproduction, 127, 727–737. https://doi.org/10.1530/rep.1.00080 in the period from 30 days before to 60 days after calving a higher concentration of T3 in multiparous Holstein cows (0.89 ng · ml–1) compared to primiparous (0.8 ng · ml–1) was noted. T4 concentration also remained at a higher level in multiparous cows (33.41 ng · ml–1) compared to primiparous cows (30.61 ng · ml–1). The authors bind the fact with the observed metabolic problems in multiparous cows.
About a month before calving triiodothyronine concentration in cows was 2.42 nM · L-1 [Safonov 2008Safonov, V.A. (2008). Hormonal Status of Pregnant and Infertile High Producing Cows. Russian Agri. Sci., 34, 273–275. https://doi.org/10.3103/S1068367408040198]. The concentration of T3 in Holstein-Friesian cows eight days before calving was 0.75 ng · ml–1, on the day of calving – 0.98 ng · ml–1, on day 7 of lactation – 1.05 ng · ml–1, on day 14 of lactation 1.04 ng · ml–1, on day 32 of lactation – 0.96 ng · ml–1, on day 44 of lactation – 1. ng · ml–1 [Cernescu et al. 2010Cernescu, H., Onita, P., Knop, R., Ionescu, C., Zarcula, S., Groza, E. (2010). The metabolic and hormonal profile on peripartal periode in cow. Lucrǎri Ştiinţifice Medicinǎ Veterinarǎ, 43, 1–8. Google Scholar].
The concentration of thyroxine in Holstein-Friesian cows eight days before calving was 21.75 ng · ml–1, on the day of calving 25.75 ng · ml–1, on day 7 of lactation – 24.56 ng · ml–1, on day 14 of lactation – 21.08 ng · ml–1, on day 32 of lactation – 24.58 ng · ml–1, on day 44 of lactation – 21.10 ng · ml–1 [Cernescu et al. 2010Cernescu, H., Onita, P., Knop, R., Ionescu, C., Zarcula, S., Groza, E. (2010). The metabolic and hormonal profile on peripartal periode in cow. Lucrǎri Ştiinţifice Medicinǎ Veterinarǎ, 43, 1–8. Google Scholar] .
The cortisol concentration reflects the stress during calving [Kindahl et al. 2002Kindahl, H., Kornmatitsuk, B., Königsson, K., Gustaffson, H. (2002). Endocrine changes in late bovine pregnancy with special emphasis on fetal well-being. Domest. Anim. Endocrinol., 23, 321–328. https://doi.org/10.1016/S0739-7240(02)00167-4]. Cortisol is, inter alia, an endogenous inhibitor of the effects of progesterone, it contributes to the conversion of progesterone to estrogens, affects progesterone-inactivating enzymes, which contributes to increase in the number of receptors for oxytocin and release of prostaglandins, which affects the date of parturition. The average concentration of cortisol during pregnancy in Holstein cows was maintained at 2–4 ng · ml–1, the increase in the concentration was observed in the last days of pregnancy [Patel et al. 1996Patel, O.V., Takahashi, T., Takenouchi, N., Hirako, M., Sasaki, N., Domeki, I. (1996). Peripheral cortisol levels throughout gestation in the cow: effect of stage of gestation and foetal number. Br. Vet. J., 152, 425–432. https://doi.org/10.1016/S0007-1935(96)80036-4]. Two days before parturition cortisol level in cattle was 6.2 ng · ml–1. The concentration of cortisol during calving was 19.2 ng · ml–1, one hour after calving – 11.2 ng · ml–1. Three days postpartum cortisol returned to levels observed before pregnancy [Hudson et al. 1976Hudson, S., Mullford, M., Whittlestone, W.G., Payne, E. (1976). Bovine plasma corticoids during parturition. J. Dairy Sci., 169, 500–506. https://doi.org/10.3168/jds.S0022-0302(76)84267-1, Mastorakos and Ilias 2003Mastorakos, G., Ilias, I. (2003). Maternal and fetal hypothalamic-pituitary-adrenal axes during pregnancy and postpartum. Ann. N. Y. Acad. Sci., 997, 136–149. https://doi.org/10.1196/annals.1290.016, Kindahl et al. 2004Kindahl, H., Kornmatitsuk, B., Gustaffson, H. (2004). The cow in endocrine focus before and after calving. Reprod. Dom. Anim., 39, 217–221. https://doi.org/10.1111/j.1439-0531.2004.00506.x, Djoković et al. 2014Djoković, R., Cincović, M., Kurćubić, V., Petrović, M., Lalović, M., Jašović, B., Stanimirovic, Z. (2014). Endocrine and metabolic status of dairy cows during transition period. Thai. J. Vet. Med., 44(1), 59–66. Google Scholar].
Tauck et al. [2010]Tauck, S.A., Olsen, J.R., Wilkinson, J.R., Wedlake, R.J., Davis, K.C., Berardinelli, J.G. (2010). Characteristics of temporal patterns of cortisol and luteinizing hormone in primiparous, postpartum, anovular, suckled, beef cows exposed acutely to bulls. Reprod. Biol. Endocrinol., 8(89), 1–8. https://doi.org/10.1186/1477-7827-8-89 reported that on the second day after calving, the concentration of cortisol in the blood of primiparous beef cows was about 2 ng · ml–1. In cows in lactation average cortisol concentration was 5.67 ng · ml–1 [Roussel et al. 1983Roussel, J.D., Clement, T.J., Aranas, T.J., Seybt, S.H. (1983). Changes in circulating plasma levels of cortisol in lactating and non-lactating dairy cattle during the estrous cycle. Theriogenology, 19, 535–539. https://doi.org/10.1016/0093-691X(83)90174-7].
Insulin is a hormone associated with the metabolism of nutrients. It is inter alia necessary for the production of milk proteins. The concentration of insulin before calving is higher than in the lactation and is negatively correlated with the milk productivity [Sano et al. 1991Sano, H., Nakai, M., Kondo, T., Terashima, Y. (1991). Insulin responsiveness to glucose and tissue responsiveness to insulin in lactating, pregnant, and nonpregnant, nonlactating beef cows. J. Anim. Sci., 69, 1122–1127. https://doi.org/10.2527/1991.6931122x, Menzies et al. 2009Menzies, K.K., Lefèvre, C., Macmillan, K.L., Nicholas, K.R. (2009). Insulin regulates milk protein synthesis at multiple levels in the bovine mammary gland. Funct. Integr. Genomics, 9, 197–217. https://doi.org/10.1007/s10142-008-0103-x]. Insulin, together with FSH and LH, stimulates steroidogenesis and proliferation of granulosa cells and thecal cells [Rhodes et al. 2003Rhodes, F.M., McDougall, S., Burke, C.R., Verkerk, G.A., Macmillan, K.L. (2003). Treatment of cows with an extended postpartum anestrous interval. J. Dairy Sci., 86, 1876–1894. https://doi.org/10.3168/jds.S0022-0302(03)73775-8].
After calving the concentration of insulin is essential for the occurrence of estrus and ovulation in cows. The reduced concentration of insulin after calving is caused by the following factors: reduced energy consumption, low energy reserves, increased energy expenditure to produce milk, and diseases of the perinatal period [Rhodes et al. 2003Rhodes, F.M., McDougall, S., Burke, C.R., Verkerk, G.A., Macmillan, K.L. (2003). Treatment of cows with an extended postpartum anestrous interval. J. Dairy Sci., 86, 1876–1894. https://doi.org/10.3168/jds.S0022-0302(03)73775-8]. Bell et al. [2000]Bell, A.W., Burhans, W.S., Overton, T.R. (2000). Protein nutrition in late pregnancy, maternal protein reserves and lactation performance in dairy cows. Proc. Nutr. Soc., 59, 119–126. https://doi.org/10.1017/S0029665100000148 reported that perinatal decrease in insulin concentration helps to enhance mobilization of amino acids from peripheral tissues.
Starting from 3 weeks before calving insulin concentration in cows gradually decreased from 0.3 to 0.05 ng · ml–1. The concentration of insulin one month before calving was 1.8 ng · ml–1 [Leury et al. 2003Leury, B.J., Baumgard, L.H., Block, S.S., Segoale, N., Ehrhardt, R.A., Rhoads, R.P., Bauman, D.E., Bell, A.W., Boisclair, Y.R. (2003). Effect of insulin and growth hormone on plasma leptin in periparturient dairy cows. Am. J. Physiol. Regul. Integr. Comp. Physiol., 285, 1107–1115. https://doi.org/10.1152/ajpregu.00320.2003]. Two weeks before the parturition its concentration in primiparous cows was 0.45 ng · ml–1, postpartum decrease in the concentration was observed until the fourth week postpartum (approximately 0.32 ng · ml–1), then a gradual increase was noted [Taylor et al. 2003Taylor, V.J., Beever, D.E., Bryant, M.J., Wathes, D.C. (2003). Metabolic profiles and progesterone cycles in first lactation dairy cows. Theriogenology, 59, 1661–1677. https://doi.org/10.1016/S0093-691X(02)01225-6]. According to Meikle et al. [2004]Meikle, A., Kulcsar, M., Chilliard, Y., Febel, H., Delavaud, C., Cavestany, D., Chilibroste, P. (2004). Effects of parity and body condition at parturition on endocrine and reproductive parameters of the cow. Reproduction, 127, 727–737. https://doi.org/10.1530/rep.1.00080 and Djoković et al. [2014]Djoković, R., Cincović, M., Kurćubić, V., Petrović, M., Lalović, M., Jašović, B., Stanimirovic, Z. (2014). Endocrine and metabolic status of dairy cows during transition period. Thai. J. Vet. Med., 44(1), 59–66. Google Scholar there were no differences in the profiles of changes in the concentrations of insulin in primiparous and multiparous cows.
In conclusion, morphological and functional changes that occur in a cows body during the last period of pregnancy and the first weeks of lactation require constant adjustments of several mechanisms that regulate their metabolism. This article addresses one of the above- mentioned alterations i.e. hormonal changes attempted at maintaining the homeostasis of pregnant cows. The efficiency of these processes depend on further health, and therefore the milk yield of cows and the regeneration of the reproductive system as well as preparation for new fertilization and pregnancy. Maintaining the cow homeostasis is also critical for proper fetal growth and development. The efficiency of neonatal adaptation, and in the longer term its productivity depends on the health of the newborn. Comprehensive knowledge of these issues is important not only for researchers, but also for breeding and veterinary practice.
This work was supported by scientific grants from the Ministry of Science and Higher Education, Poland (Project No. N311 112538).
Received: 26 Oct 2019
Accepted: 31 Dec 2019
Published online: 17 Jan 2020
Accesses: 3320
Kurpińska, A., Skrzypczak, W., (2019). Hormonal changes in dairy cows during periparturient period. Acta Sci. Pol. Zootechnica, 18(4), 13–22. DOI: 10.21005/asp.2019.18.4.02.