Reproduction in Domestic Animals

162 J de Gier, NJ Beijerink, HS Kooistra and AC Okkens2–3 years. For that reason, the manufacturer does notrecommend using MPA intended for breeding at a laterdate. Medroxyprogesterone acetate 3 can also be administeredorally, 5 mg once daily (10 mg for large dogsduring the first 5 days) for a maximum of 21 days. Thereturn of oestrus may vary from 2 to 9 months.Use of progestagens for oestrus prevention may leadto the following side-effects:• Development of cystic endometrial hyperplasia(CEH)-endometritis (Sokolowski and Zimbelman1974).• Prolonged pregnancy. This occurs if progestagensare administered subcutaneously at the onset of thefollicular phase and the bitch becomes pregnant. Thegestation will be prolonged, and a caesarian sectionmay be needed.• Hypersecretion of growth hormone, which maylead to diabetes mellitus (Selman et al. 1997). Thishypersecretion of growth hormone as a result ofprogestagen administration can be successfully treatedby the progesterone receptor blocker aglepristone(Bhatti et al. 2006).• An increased risk of neoplastic transformation ofmammary tissue. This may range from hyperplasia,adenomatous hyperplasia and adenomas to malignanttumours. The progestagen-induced neoplastic transformationof mammary tissue starts with the proliferationof undifferentiated terminal ductal structures,so-called terminal end buds (Russo and Russo 1991).This proliferation increases the susceptibility of themammary tissue to malignant transformation.The occurrence of these side-effects is, with theexception of ‘prolonged pregnancy’, largely dependentupon the total progestagen exposure. With the adviseddosage regimens, the exposure may be higher with MPAand MA than with proligestone, the latter being a ratherweak progestagen.3 ProveraÒ, Upjohn, Ede, The Netherlands; OvuconÒ, Intervet,Boxmeer, The NetherlandsReferencesBeck W, Hancke JL, Wuttke W, 1978: Increased sensitivity ofdopaminergic inhibition of luteinizing hormone release inimmature and castrated female rats. Endocrinology 102,837–843.Beijerink NJ, 2007: Endocrinology of physiological andprogestin-induced canine anoestrus. Ch. 8 Pulsatile plasmaprofiles of FSH and LH before and during medroxyprogesteroneacetatetreatment in the bitch. PhD Thesis, UtrechtUniversity.Beijerink NJ, Dieleman SJ, Kooistra HS, Okkens AC, 2003:Low doses of bromocriptine shorten the interestrous intervalin the bitch without lowering plasma prolactin concentration.Theriogenology 60, 1397–1386.Beijerink NJ, Kooistra HS, Dieleman SJ, Okkens AC, 2004:Serotonin-antagonist-induced lowering of prolactin secretiondoes not affect the pattern of pulsatile secretion offollicle-stimulating hormone and luteinizing hormone in thebitch. Reproduction 128, 181–188.Beijerink NJ, Bhatti SFM, Okkens AC, Dieleman SJ, Mol JA,Duchateau L, van Ham LML, Kooistra HS, 2007: Adenohypophysealfunction in bitches treated with medroxyprogesteroneacetate. Domest Anim Endocrinol 32, 63–78.Besognet B, Hansen S, Daels PF, 1997: Induction of reproductivefunction in anestrous mares using a dopamineantagonist. Theriogenology 47, 467–480.Bevers MM, Willemse AH, Kruip TAM1983: The effect ofbromocriptine on luteinizing hormone levels in the lactatingsow: evidence for a suppressive action by prolactin and thesuckling stimulus. Acta Endocrinol 104, 261–265.Bhatti SFM, Duchateau L, Okkens AC, van Ham LML, MolJA, Kooistra HS, 2006: Treatment of growth hormoneexcess in dogs with the progesterone receptor antagonistaglépristone. Theriogenology 66, 797–803.Chowdhury M, Steinberger E1975: Biosynthesis and secretionof follicle-stimulating hormone. Endocr Rev 4, 369–374.Colon J, Kimball M, Hansen B, Concannon PW, 1993: Effectsof contraceptive doses of the progestagen megestrol acetateon luteinizing hormone and follicle-stimulating hormonesecretion in female dogs. J Reprod Fertil Suppl 47, 519–521.Concannon PW, 1993: Biology of gonadotrophin secretion inadult and prepubertal female dogs. J Reprod Fertil Suppl47, 3–27.Concannon PW, Temple M, 1988: Periovulatory decline andlate anestrus increase in naloxone-inducible LH release inadult domestic bitches. Biol Reprod Suppl 36, 101.Concannon PW, Whaley S, Anderson SP, 1986: Increased LHpulse frequency associated with termination of anestrusduring the ovarian cycle of the dog. Biol Reprod Suppl 34,119 (Abstract).Galac S, Kooistra HS, Dieleman SJ, Cestnik V, Okkens AC,2004: Effects of aglépristone, a progesterone receptorantagonist, administered during the early luteal phase innon-pregnant bitches. Theriogenology 66, 494–500.de Gier J, Kooistra HS, Djajadiningrat-Laanen SC, DielemanSJ, Okkens AC, 2006: Differential regulation of the secretionof luteinizing hormone and follicle-stimulating hormonearound the time of ovulation in the bitch. Theriogenology66, 1419–1422.Gobello C, Castex G, Corrada Y, 2002: Use of cabergoline totreat primary and secondary anestrus in dogs. J Am VetMed Assoc 11, 1653–1654.van Haaften B, Dieleman SJ, Okkens AC, Bevers MM,Willemse AH, 1989: Induction of oestrus and ovulation indogs by treatment with PMSG and ⁄ or bromocriptine.J Reprod Fertil Suppl 39, 330–331.van Haaften B, Bevers MM, van den Brom WE, Okkens AC,van Sluijs FJ, Willemse AH, Dieleman SJ, 1994: Increasingsensitivity of the pituitary to GnRH from early to lateanoestrus in the beagle bitch. J Reprod Fertil 101, 221–225.Haisenleder DJ, Dalkin AC, Ortolano GA, Marshall JC,Shupnik MA, 1991: A pulsatile gonadotropin-releasinghormone stimulus is required to increase transcription ofthe gonadotropin subunit genes: evidence for differentialregulation of transcription by pulse frequency in vivo.Endocrinology 128, 509–517.Havern RL, Whisnant CS, Goodman RL, 1994: Dopaminergicstructures in the ovine hypothalamus mediating estradiolnegative feedback in anestrous ewes. Endocrinology 134,1905–1914.Inaba T, Namura T, Tani H, Matsuyama S, Torii R, KawataN, Tamada H, Hatoya S, Kumagai D, Sugiura K, SawadaT, 2002: Enhancement of aromatase gene expression in themediobasal hypothalamus during anestrus in the beaglebitch. Neurosci Lett 333, 107–110.Jeffcoate IA, 1993: Endocrinology of anoestrous bitches.J Reprod Fertil Suppl 47, 69–76.Kooistra HS, Okkens AC, 2001: Secretion of prolactin andgrowth hormone in relation to ovarian activity in the dog.Reprod Domest Anim 36, 115–119.Ó 2008 The Authors. Journal compilation Ó 2008 Blackwell Verlag