Clinical, Ovulatory and Histological Effect of a Postnatal Testosterone Treatment in Female Dogs.

It has been described in some female mammalian species that postnatal androgenization causes reproductive structural and functional abnormalities. The objective of this study was to describe the clinical, ovulatory and genital effects of postnatal androgens in female dogs. Ten newborn female crossbred puppies were randomly assigned to: testosterone enanthate 18 mg/100 g sc (TE; n = 5) or placebo sc (PL; n = 5). The puppies were physically followed up until puberty when ovulation was tested by serum progesterone. Then, ovariohysterectomies were performed, and genital tracts were grossly and histomorphometrically examined. At puberty, all the females had normal estrous behavior and ovulated without age and body weight differences. All TE puppies presented mild clitoris enlargement. Gross and microscopical ovarian examination did not reveal differences. Conversely, the endometrial area occupied by uterine glands as well as the height of the glandular and luminal epithelium were higher in the TE than in the PL group (<0.01). The height of the endometrium and myometrial thickness did not differ between groups. It was concluded that a supraphysiological postnatal dose of testosterone did not affect ovulatory capacity, nor did it provoke gonadal histological alterations, although it caused an increased area of endometrial glands and a higher uterine epithelium.

Effect of a GnRH Antagonist on Anti-Müllerian Hormone and Follicular Population in Anestrous Bitches.

The objective of this study was to describe the effect of the third-generation GnRH antagonist, acyline, on ovarian follicular population and serum anti-Müllerian hormone (AMH) concentrations in female dogs. Four late anestrous bitches were administered 330 µg/kg SC acyline every 10 days for 60 days and followed up for 45 days. Blood samples were drawn on days -1, 15, 30, 45, 60, 75, 90 and 105 for AMH determination. Then, the females were ovariectomized and the excised ovaries were gross and histologically evaluated. The total ovarian follicles were counted. None of the female dogs presented estrus during treatment. Only one bitch presented an ovulatory estrus 20 days after treatment. The total number of ovarian follicles in these bitches was 96,200.10 ± 26,125.12, with 84.13%, 11.36%, 7.8% and 0.01% corresponding to primordial, primary, secondary and antral structures, respectively. Pretreatment AMH concentrations were 0.62 ± 0.17 ng/mL. This hormone varied throughout the study period (p < 0.01), diminishing to nadir values during treatment to then rapidly recover after its effect (0.2 ± 0.05 vs. 0.67 ± 0.22 ng/mL; p < 0.01). Acyline rapidly and reversibly prevented the initiation of cycling without affecting follicle count but diminishing serum AMH concentrations.

Effect of artificial light in the female domestic cat reproduction: What we know so far?

Domestic felids (Felis catus) have been traditionally categorized as seasonal polyestrous with induced ovulation. Thus, the ability to augment or distribute the number of litters born throughout the year would offer a desirable advantage. Artificial-light regimens have been used to overcome seasonal variations in this species. Understanding the mechanisms that underlie photoperiodicity might enable the development of improved and sustainable breeding schemes. The aim of this article was therefore to summarize the present knowledge on the effect of artificial light on female-cat reproduction. To that end a systematic review of the literature from 1940 to the present was performed. International original articles and scientific abstracts were also included, and at the conclusion we emphasized areas that require further research.

Evaluation of Long-Term Effects of the Gonadotrophin-Releasing-Hormone Antagonist Acyline on Domestic-Cat Growth.

Acyline contraception has been described in cats, but few data are available on the drug's long-term effect on growth. The relevant data cover until puberty with no radiographic description. We investigated the radiographic parameters throughout bone growth in order to more completely determine the drug's safety. Thirteen male and 12 female cats were studied, with the kittens being randomly assigned to one of the following groups within the first 24 hours of birth: ACY, subcutaneous acyline, 33 µg/100 g, which injection was repeated weekly until age 3 months; or CO, untreated control. Body measurements were recorded weekly and radiographic parameters obtained from monthly radiographs of the antebrachium. In the ACY and CO male and female kittens, the body weight, withers height, and body length plus the age at the end of body growth and radial growth remained similar throughout the study (P> .05). Both female groups finished radial growth before the males (P< .05). The ACY females evidenced a longer radial length between the eighth and 28th weeks (P< .05). All groups closed their proximal and distal physes within the normal ranges described for the species. The bone-cortex width was lower in the ACY vs. the CO animals at weeks 52 and 60 in the males and at weeks 24, 48, 52, and 56 in the females (P< .05) The transient greater radial length and lower bone-cortex thickness observed in the treated cats were compensated for at the end of growth with no adverse clinical effects being observed. In conclusion, acyline as a contraceptive did not evidence a permanent or severe effect on domestic-cat growth.

Doppler ultrasonographic evaluation of medically treated female dogs with cystic endometrial hyperplasia-pyometra complex.

Monitoring the treatment outcome of canine cystic endometrial hyperplasia-pyometra complex (CEH-P) is essential to identify nonresponding patients who might require a rapid intervention to avoid life-threatening conditions. Uterine artery Doppler characterization may contribute to monitoring medically treated CEH-P, but published studies are currently lacking. Therefore, the aim of this longitudinal prospective observational study was to evaluate uterine artery resistance changes in the medical treatment of female dogs with CEH-P. Twelve diestrous female dogs suffering from CEH-P were treated with a combined protocol of cabergoline, cloprostenol, and antibiotics. The animals were clinically and ultrasonographically evaluated before the beginning of treatment (day 0) and on days 3, 7, 14, 21, and 28. The widest transverse diameter and luminal diameter of uterine horns were measured, as well as the peak systolic velocity (PSV) and end diastolic velocity (EDV) of uterine arteries. The resistance index (RI), pulsatility index (PI), and notch deep index (NDI) were calculated. On day 3, nine of 12 animals showed clinical improvement. In all these female dogs, the widest transverse sectional diameter (P < 0.01), luminal diameter (P < 0.01), PSV (P < 0.01), and EDV (P < 0.01) progressively decreased, while RI (P < 0.01), PI (P < 0.01), and NDI (P < 0.01) increased up to day 21. In nonresponding dogs (3/12), Doppler parameters remained unchanged. Although comparisons of PSV, EDV, and NDI were significantly different, these results should be cautiously interpreted due to the low statistical power. female dogs that responded to this treatment showed an increase in uterine artery resistance, along with clinical and ultrasonographic improvement.

Key aspects of domestic cat spermatogenesis.

In mammals, spermatogenesis is a complex and cyclic process in which a spermatogonia turns into a highly differentiated cell: the spermatozoa. Spermatogenesis comprises proliferation of spermatogonia (spermatocytogenesis), meiosis of spermatocytes and finally differentiation of spermatids into spermatozoa (spermiogenesis). This review summarizes the current knowledge on domestic cat spermatogenesis including its physiology, development, efficiency and pathologies as well as their novel non-invasive diagnostic methods. This information will provide a resource for further studies to achieve precise fundamental knowledge of key aspects that will facilitate breeding, management and contraception in this popular species.

Ovarian and uterine two-dimensional and Doppler ultrasonographic changes in the feline peri-estrus period.

OBJECTIVES: The aim of this study was to evaluate two-dimensional and Doppler ultrasonographic changes of the ovary and uterus during estrus and the early post-estrus period in domestic cats. METHODS: Two-dimensional and Doppler ultrasonographic evaluations of the ovaries and uterus were performed in seven queens on days 1, 3 and 5 of estrus, and 5 days after estrus (AE5). RESULTS: On day 1, 5.4 ± 0.5 follicles of 2.1 ± 0.1 mm were detected progressively increasing in number and size up to day 5 and then decreased on AE5 (P <0.05). A maximum follicular diameter of 4.1 ± 0.1 mm was achieved on day 5. Both during and after estrus, the uterus was generally hypoechoic compared with the surrounding tissues and delineated by a thin hyperechoic line corresponding to the serosa. In some animals, the uterine layers were distinguished during and after estrus. The blood flow waveforms of the intraovarian and uterine arteries were characterized by a systolic peak and diastolic flow extending throughout the remainder of the cardiac cycle to the next systole. In the uterine artery waveforms, the early diastolic notch was mild or absent during most estrous observations. The resistance index of the intraovarian arteries decreased up to day 5, and then increased on AE5 (P <0.05). The resistance index of the uterine arteries was lower during estrus than in the post-estrus period (P <0.05). CONCLUSIONS AND RELEVANCE: It is concluded that in the domestic cat, follicular number and diameter as well as ovarian and uterine blood flow changed during and immediately after estrus. Doppler ultrasound proved suitable to evaluate the hemodynamic changes involved in the cyclic remodeling of ovarian and uterine tissues that occurs during and after follicular growth in domestic cats.

Testicular effects of a postnatal GnRH antagonist in domestic cats.

The aim of this study was to describe the histological effects of two high postnatal doses of the potent third-generation GnRH antagonist, acyline in the domestic cat testicle. Secondly, the physical, endocrine, and steroidogenic findings of this pharmaceutical protocol are also reported. Twelve postnatal littermate male kittens were administered acyline in a dose of 2.2 mg/100 g SC weekly for 2 weeks (ACY; n = 6), or placebo (PL; n = 6). All the animals were followed up until puberty when they were castrated. Serial faecal samples were collected until the age of 10 weeks for testosterone (T) measurement. The kittens achieved puberty without either age (236.5 ± 19.7 vs. 221.7 ± 23.7 days) or body weight (3.05 ± 0.15 vs. 2.78 ± 0.28 kg, P > 0.05) differences between ACY and PL, respectively. Acyline suppressed faecal T concentrations for 3 weeks (P < 0.01). From the fourth week on, both groups had low concentrations up to the end of the follow-up period (P > 0.05). Histological assessment of the testes showed that ACY cats presented a reduced height of the epithelium (P < 0.01) due to the diminished number of germinal cells accompanied by an enlarged luminal area (P < 0.01) with cellular debris (P < 0.01). The immunostaining of P450c17 also appeared partially diminished in ACY testes.

Revisiting canine pseudocyesis.

Canine (Canis familiaris) pseudocyesis, pseudopregnancy, false pregnancy or nervous lactation is a frequent syndrome observed in non-pregnant, late diestrous or early anestrous females that is characterized by different degrees of mammary gland enlargement, maternal behavior and lactation. Further education about this frequent canine physiological event is still necessary to ensure optimal diagnosis and treatment strategies. Thus, the aim of this article was to review and update the physiopathology, physical and behavioral signs, diagnosis, treatment and prevention of pseudocyesis in bitches in which it is a clinical problem.

Fecal Progestins Differentiate Pregnant From Nonpregnant Early Luteal Bitches.

Considering the high perimplantation progesterone (P4) secretion that occurs in female domestic dogs, we hypothesize that fecal P4 concentrations distinguishes pregnant from nonpregnant early luteal bitches. The objective of this study was to compare fecal P4 metabolites in early pregnant vs. nonpregnant early luteal bitches. Eighteen 2-6 years of age, 5-15 kg, pure-bred bitches, that were followed up for breeding management, and 2 ovariectomized (OVX) bitches were included in this study. On pregnancy day 18-28, a single fecal sample was collected from each animal. Fecal samples were frozen at -20°C until analysis. Pregnancy diagnosis was carried out by ultrasonography on day 21. Fecal samples were also collected from the 2 OVX bitches. Fecal P4 metabolites were extracted as based on methods described by Brown et al. (2008) and, then, measured by an electrochemiluminescence immunoassay. Eleven bitches were pregnant (PREG) while 7 were non-pregnant (N-PR). Fecal P4 metabolites concentrations were 283.9 ± 60.4 and 102.7 ± 19.1 (ng/g; P < .05) for PREG and N-PR, respectively. Both values were higher than those of the OVX bitches (9.9±1.1; P < .05). This noninvasive technique to measure P4 metabolites in feces appears as a simple and noncostly alternative for early pregnancy diagnosis in the domestic dog. Further large scale studies are necessary before this test could be widely recommended.

Uterine and umbilical resistance index and fetal heart rate in pregnant bitches of different body weight.

The aim of this study was to compare uterine and umbilical artery blood flow and fetal heart rate (FHR) in small, medium and large body weight (BW) dogs during the second half of pregnancy. Purebred pregnant bitches were assigned to one of the following groups according to their BW: small (S; ≤10 kg), medium (M; 11-25 kg) and large (L; >25-45 kg). Uterine and umbilical Doppler and M-mode ultrasonography was conducted every 10 days from Day 30-60 (Day 0 = first day of gestation). From Day 40, uterine and umbilical artery resistance index (RI) progressively and differentially decreased in the three groups (P < 0.01) being less in L than S bitches (P < 0.01). Litter size but not maternal BW (P > 0.1) affected uterine RI on Days 40 (r = 0.39; P < 0.01) and 50 (r = 0.41; P < 0.01). Conversely, on Day 60, maternal BW (r = 0.61; P < 0.01) had an effect on uterine RI while litter size did not (P > 0.1). Fetal heart rate increased from Day 30-50 and decreased to the time of parturition (P < 0.01) without differences among groups at any time point (P > 0.1). Uterine and umbilical blood flow differentially increased throughout mid- and late-pregnancy in breeds with large and small BW. These differences were affected by litter size on Days 40 and 50, and by maternal BW on Day 60. Conversely, during this same period, FHR did not vary among BW groups. Physiological variations should be considered when gestational ultrasonic examination is interpreted in different BW bitches.

Ultrasonographic evaluation of ovarian morphology and blood flow in prepubertal and pubertal cats.

The aim of this study was to evaluate two-dimensional and Doppler ultrasonographic changes of feline ovaries before and during puberty. Nine, 3-month-old female cats were followed until puberty (Day 1). Two-dimensional and Doppler ultrasound evaluations of the ovaries were carried out on Days -50, -20, -7 and 1. Longitudinal and transverse sections of the ovaries were measured and all anechoic spherical structures were considered to be follicles. The number of follicles >1 mm and the maximum diameter of the largest follicle were recorded. Peak systolic velocity and end diastolic velocity of intraovarian arteries were also measured to automatically calculate the resistive index (RI). The mean ovarian longitudinal diameter increased gradually throughout the study from 8.6 to 10.7 mm (p < 0.05). While four cats presented multiple anechoic spherical structures <1 mm diameter throughout the study, the remaining five animals had these structures only on Days -50 and -20. On Days -20, -7 and 1, the mean number of follicles were 1.4 ± 0.7, 2.5 ± 0.8 and 4.8 ± 1 respectively (p < 0.01). The largest follicles at the same time points were 1.1 ± 0.2 mm, 1.9 ± 0.3 mm and 2.6 ± 0.5 mm respectively (p < 0.05). The RI of the intraovarian arteries declined throughout the study period (p < 0.01). It is concluded that, in female cats, ovarian dimensions, follicle number and intraovarian blood flow increased from 3 months of age to puberty.

Uterine two-dimensional and Doppler ultrasonographic evaluation of feline pyometra.

The aim of this study was to compare uterine two-dimensional and Doppler ultrasonographic parameters in queens suffering from pyometra from those in early pregnancy. Secondly, the effect of the presence of clinical signs of systemic illness on these parameters was also described. Fourteen post-oestrous queens, with uterine luminal content in the absence of embryos were included. According to their outcome (pyometra surgery or parturition), the queens were retrospectively assigned to one of the following groups: Pyometra (PYO; n = 7) or pregnant (PRG; n = 7). In all the queens, two-dimensional and Doppler ultrasound examinations of the uterus were performed. The presence or absence of clinical signs of systemic illness was recorded. The widest cross-sectional diameter (UD), uterine wall thickness (WT), uterine lumen contents (LC) and uterine artery resistance index (RI) were measured. Uterine horn diameter was higher in PYO group than in PRG group (p < 0.05), while WT (p > 0.1) and LC (p = 0.09) did not differ between groups. Values of RI for PYO and PRG groups were 0.61 ± 0.03 vs 0.53 ± 0.09 (p < 0.05), respectively. PYO cats suffering from clinical signs of systemic illness showed larger UD than those without signs (p < 0.01). It is concluded that two-dimensional and Doppler ultrasound might be useful to distinguish queens suffering from pyometra from those in early pregnancy. Secondly, the clinical signs of systemic illness were associated with a larger UD.

Development and proliferation of feline endometrial glands from fetal life to ovarian cyclicity.

In this study it was determined the progression of uterine gland development from late gestation to puberty in domestic felids. Cell proliferation patterns for luminal (LE), glandular epithelium (GE) as well as stroma (S) were also described. Twenty-four uteri from female kittens: 45 and 65 days of gestation and 1 to 5, 8, 12, 16, 20 and 24 weeks postnatally were obtained. Uterine cross-sections were submitted for routine histological and immunohistochemical quantification of proliferating cell nuclear antigen (PCNA) techniques. Although prenatal uteri presented no indication of adenogenesis, 1 week old uteri revealed an incipient budding of the LE. During the second week budding increased and a mild degree of tubulogenesis of the GE into the stroma was detected. From the third to fifth weeks coiling, branching and cross-sections of glands appeared. These latter findings were more evident in week 8 when GE began to penetrate through much of the S to week 24. PCNA immunostaining revealed that DNA synthesis decreased throughout the study in the 3 cell compartments; (P < 0.01). Luminal proliferation began prenatally, it maintained up to postnatal week 8 to markedly decrease to puberty (P < 0.01). From postnatal week 3 up to week 8, GE mitotic activity was elevated becoming low thereafter (P < 0.01). Stroma actively proliferated prenatally (P < 0.01), diminishing up to week 8 (P < 0.01) and again during the last weeks (P < 0.01) of the study. It was concluded that, in domestic felids, proliferation of LE begins prenatally, histological uterine adenogenesis commenced during the first postnatal week and both events concluded by postnatal weeks 5-8.

Disrupting effect of androgens in postnatal female domestic cats.

To test the hypothesis that in domestic cats, postnatal androgens induce sterility, the aims of this study were to describe the reproductive effects and the clinical safety of a postnatal administration of a long term release androgen in this species. Thirteen newborn littermate female kittens were randomly assigned to one of the following treatment groups within the first 24h of birth: testosterone enanthate 12.5mg sc (TE; n=8) or Placebo (PL; n=5). The animals were subsequently assessed for fecal sexual hormones until puberty was attained and subsequently when matings occurred. After 21 days, ovulation and gestation were diagnosed. All queens were subsequently ovario-hysterectomized. Fecal testosterone concentrations differed between the treatment groups throughout the study period (P<0.05) being greater during the first 2 postnatal weeks in those of the TE group (P<0.01). Fecal estradiol was not affected by treatment (P>0.1). While all the females were receptive during the pubertal estrus (P>0.1), two TE (2/8) compared with all (5/5) females of the PL group had ovulations (P<0.05). Only one (1/2) compared with three (3/5) of the queens of the TE and PL groups, respectively became pregnant. All kittens of the TE group had transient clitoral enlargement. Anovulatory TE-treated cats had no corpus luteum, and a significant diminution of the endometrial glands as well as of the height of the uterine epithelium. It is concluded that, in domestic cats, a single postnatal supra-physiological dose of testosterone caused a large proportion of queens to be anovulatory and there were also histological endometrial abnormalities that also occurred with this treatment that were accompanied by mild and transient side effects.

Postnatal exposure to a progestin does not prevent uterine adenogenesis in domestic dogs.

To assess the effects of a single supraphysiological postnatal administration of a progestogen on uterine glands in dogs, 10 females were randomly assigned to a medroxyprogesterone acetate 35 mg (MPA; n = 6) or placebo (n = 4) group within the first 24 h of birth. The safety of the treatment was also evaluated. A transient mild clitoris enlargement appeared in MPA-treated females. Microscopic postpubertal uterine assessment revealed the presence of uterine glands in all cases without significant differences in the area occupied by the glands per µm(2) of endometrium nor in the height of the uterine epithelium.

Treatment of canine pyometra with the gonadotropin-releasing hormone antagonist acyline: a case series.

To describe the effect of the third-generation gonadotropin-releasing hormone antagonist acyline in the treatment of 4 diestrous bitches with the cystic endometrial hyperplasia-pyometra complex. The 4 bitches were treated with 330 µg/kg of subcutaneous acyline on day 0 and antibiotics, and followed up for 2 weeks. One closed-cervix case showed cervical dilatation 36 hours after treatment, and all the 4 animals showed resolution of clinical signs starting on day 3 posttreatment. Ultrasonographic uterine diameters and luminal contents decreased in the bitches having high progesterone serum concentrations before treatment but not in those with low levels. Serum progesterone importantly decreased from high to basal concentrations in the 3 "ultrasonographically cured" animals. No local or systemic side effects related to the treatment were observed. The gonadotropin-releasing hormone antagonist acyline may have a promising place for the medical treatment of cystic endometrial hyperplasia-pyometra complex in dogs.

Ejaculation training, seminal alkaline phosphatase and semen preservation through cooling in a milk-based extender in domestic cats.

The purpose of this report is to describe (1) the training of domestic cats in ejaculation into an artificial vagina (AV), (2) alkaline phosphatase (AP) concentrations in whole ejaculates, and (3) the in vitro effect of a skimmed-milk plus egg yolk (SM-Y) extender on feline spermatozoa incubated at 4ºC. Five post-pubertal cats were trained to ejaculate into an AV three times a week for 20 mins in the presence of a teaser queen. Fifty AV-obtained ejaculates were macro- and microscopically assessed, and the AP therein measured by optimized colorimetry. Eighty AV-obtained ejaculates were pooled, diluted in SM-Y extender [80% (v/v) skimmed milk, 20% (v/v) egg yolk, and antibiotics], stored at 4°C and evaluated daily for 6 days. All the animals could be trained to ejaculate, although the interval up to the first AV ejaculation varied from 1.5 to 5.5 months (mean 3.9 months). The final performance at collection ranged from excellent to poor and was inversely related to the training period required in all cases. The mean AP concentration in whole ejaculates was 20,645.6 ± 4405U/l, which was not correlated with the concentration of spermatozoa. Most seminal parameters [(%); total (77 ± 2.3) and progressive (62.7 ± 3.4) motility, live sperm (91.8 ± 1.2), intact plasmalemma (83.5 ± 2.6), normal acrosomes (83.5 ± 2.6), pH (6.6 ± 0.0) and osmolarity (mOsm/l; 321 ± 5.2)], though decreasing during storage in the cold, remained within values compatible with in vivo fertilization for 2 days.

Effect of adjuvant perioperative desmopressin in locally advanced canine mammary carcinoma and its relation to histologic grade.

Desmopressin (DDAVP) is a vasopressin peptide analog with hemostatic properties that has been successfully used during surgery in patients with bleeding disorders. Recently published experimental and clinical data indicate that perioperative administration of DDAVP can minimize spread and survival of residual mammary cancer cells. The central aim of this study was to explore the effect of perioperative DDAVP and its relation to histologic grade in bitches with locally advanced mammary carcinoma. Of the 32 dogs initially recruited, 28 intact bitches with mammary carcinoma tumors stage III or IV were ultimately included. These dogs were randomized to receive DDAVP at intravenous doses of 1 µg/kg (n=18) or saline solution as placebo (n=10). En bloc mastectomy of the affected gland(s) was performed. Tumor malignancy was graded by the method of Elston and Ellis into well-differentiated (grade 1), moderately differentiated (grade 2), or poorly differentiated (grade 3). DDAVP therapy significantly prolonged the disease-free survival (P<0.001) and overall survival (P<0.01) in bitches with grade 2 or 3 carcinomas compared with bitches in the control group. No significant difference in disease-free period or overall survival was found between treatment groups in bitches with grade 1 tumors. The present data suggest that DDAVP may be an excellent candidate as a surgical adjuvant in the management of aggressive cancers in small animals. More research in this field is warranted.