Reproduction in Domestic Animals

Reprod Dom Anim 43 (Suppl. 2), 144–149 (2008); doi: 10.1111/j.1439-0531.2008.01154.xISSN 0936-6768Updates on Reproductive Physiology, Genital Diseases and Artificial Insemination inthe Domestic CatE Axne´rDivision of Reproduction, Department of Clinical Sciences, Swedish University of Agricultural Sciences, Uppsala, SwedenContentsReproduction in the domestic cat is characterized by largeindividual variations in the female oestrous cycle and in malesemen quality. The female cat reproduction is stronglyinfluenced by season, and new data suggest that it is possiblethat season also affects male fertility. Repeated periods ofoestrus and spontaneous ovulation may lead to degenerativeendometrial changes causing infertility. For artificial insemination(AI), induction of ovulation is necessary in the absenceof the mating stimuli. The large variation in the relationshipbetween follicular growth and timing of expression of oestruscomplicates, however, timing of ovulation induction. Stressmay lead to progesterone secretion by the adrenal glands andpossibly have a negative impact on early pregnancy. The largeindividual variation in semen quality makes fertility evaluationand feline semen conservation a challenge. For AI, the semencan be deposited in the cranial vagina, the uterus or in theuterine tubes. Intrauterine insemination results in higherpregnancy rates than intravaginal but is more complicated.Surgical intrauterine or intratubal insemination has resulted inthe birth of kittens, but is an invasive procedure that is notallowed in all countries. Transcervical intrauterine inseminationwith frozen-thawed semen has, however, recently resultedin the birth of kittens.IntroductionThe domestic cat has been shown to be an interestingmodel for the development of reproductive biotechnologiesin wild felids with the aim to conserve geneticvariation in small populations. There is, however, also apotential for the use or semen preservation and artificialinsemination (AI) in the breeding of domestic cats. Inthe dog, these techniques can be considered routinetoday. In contrast, more research is necessary before AI,and semen conservation can be considered routineprocedures in the domestic cat. To be able to successfullyuse reproductive biotechnologies, a thoroughknowledge about reproductive physiology and pathologyis necessary.Physiology of the Female CatThe oestrous cycleThe female cat is seasonally polyoestrous with changesin daylength (increasing number of light hours) regulatingthe seasonality (Leyva et al. 1989; Tsutsui et al.2004a). Characteristic for reproduction in the domesticcat is the large normal variation in the length of theoestrous cycle, the length of the reproductive season andthe number of cycles ⁄ year between queens (Shille et al.1979; Tsutsui et al. 2004a). The presence of matureoocytes in the ovaries and the effect of ovulationinduction seem to be dependent on the day of the onsetof physiological oestrus during the follicular phase(Banks and Stabenfeldt 1982; Glover et al. 1985).Because there is a variation between queens in whichday during the follicular phase they will start to showoestrous behaviour, the day of oestrous behaviour inrelation to the progress of oocyte maturation is likely todiffer between queens (Shille et al. 1979; Malandainet al. 2002). Most queens will respond with an LHrelease,leading to ovulation of good quality oocytesafter a mating in midoestrus, while mating in earlyoestrus is not always followed by ovulation (Banks andStabenfeldt 1982; Glover et al. 1985). Expression ofFSH- and LH receptors in the ovarian follicles variesdepending on the stage of follicular growth or atresia(Saint-Dizier et al. 2007).Cyclical changes in the female tubular genitalia in relationto hysterographic appearance and cervical patencyThe outer diameter of the uterus and the appearance ofthe endometrial lining will vary depending on the stageof the oestrous cycle. During inactive stages, a singlelayer of cuboidal cells lines the endometrium, andthe endometrial glands are inactive. When the queenenters the follicular stage, the endometrial and myometrialdiameters increase and the endometrial glandsproliferate. The luteal phase endometrium is characterizedby a high number of elongated and active glands(Chatdarong et al. 2005). The shape of the uterine cavitycan be studied with hysterography. In the healthy cat,the endometrial outlining is smooth. During the inactivephase of the cycle, the uterine horns are straight.Because of the endometrial growth and increasedmuscular activity, the uterine horns become curved witha wavy luminal cavity during the follicular phase. Theluminal shape during the luteal phase varies fromstraight to irregular, wavy and coiled (Chatdarong et al.2005). The cervix is normally only patent (physiologicallyopen cervical canal) during oestrus and theduration of cervical patency does not depend onwhether or not the queen ovulates (Chatdarong et al.2002, 2006a). The period of cervical patency usuallycoincides with the period when the vaginal smear iscornified (Chatdarong et al. 2002).Sperm distribution after matingSperm deposition during mating is vaginal. Initial spermtransport in the female reproductive tract is very rapid.Spermatozoa can be found in the uterine tube 30 minafter mating. The uterotubal junction and uterine cryptsserve as initial sperm reservoirs but spermatozoa areÓ 2008 The Author. Journal compilation Ó 2008 Blackwell Verlag