Abstract
A 13-month-old Persian queen was presented for infertility. She had been bred on two consecutive oestrous cycles on day 1 of oestrus, and on both occasions had developed a purulent vulvar discharge shortly after breeding. Treatment by the private veterinarian had included parenteral antibiotics and vaginal medications. Upon presentation to the Small Animal Reproduction Service, a complete clinical, diagnostic imaging and laboratory investigation failed to demonstrate evidence of a reproductive tract disease. Therefore, at a subsequent cycle breeding was attempted on day 3 of oestrus. The queen conceived and delivered six kittens by caesarean section. The initial inability of this queen to conceive appears to have resulted from inappropriate management practice.
Tres Joli, a 13-month-old, 3.2 kg body weight Persian queen, was presented to the Small Animal Reproduction Service of the University of Pisa for reproductive failure. The queen had been purchased by her current owner 3 months previously (Fig 1). She was observed to be in heat on December 19, and the same day was bred to an adult Persian tom cat of proven fertility (who had sired his last litter 6 months previously). Breeding was reported to occur once and was characterised by a post-coital type after reaction (vocalisation, rolling, vulvar licking) by the female. Eight days later the owner took the queen to the veterinarian because of a yellowish sticky mucoid vulvar discharge, which was diagnosed as a purulent vaginitis and treated with a twice daily course of 250 mg ceftriaxone (Rocefin; Roche) subcutaneously for 7 days. The purulent vulvar discharge disappeared within 2 days and the queen was normal thereafter. On January 12–13, the queen was taken to a cat show, where she developed a cough for which she was treated with 250 mg bid cefazoline (Totacef; Bristol-Myers Squibb) subcutaneously for 5 days. Pregnancy status was not assessed.
Tres Joli.
On January 25 the queen was in heat again and was mated four times on the first day by the same male, with a post-coital reaction being confirmed after each encounter. On the evening of the same day the owner observed the perivulvar area of the queen being wet and dirty due to a purulent vulvar discharge. The following day the queen was taken again to the veterinarian who took a vaginal smear observing a high percentage of cornified as well as polymorphonuclear cells, and performed an abdominal ultrasound observing what the owner reported as an enlarged and fluid filled uterus. Treatment consisted of a twice daily course of cefotaxime (Zariviz; Aventis Pharma, 250 mg) subcutaneously, vaginal flushing twice daily with an iodine based human vaginal medication (Betadine Ginecologico, Asta Medica S.p.A.) and methylergometrine (Methergin; Novartis, five drops orally, the compound has 0.025 mg/ml), for 5 days.
On January 30 the queen was referred to the Small Animal Reproduction Service of the University of Pisa for purulent vulvar discharge and failure to conceive. Upon presentation she was normal on physical examination, had a normal temperature, heart and respiration rate and showed no abnormal findings. A complete blood count and serum chemistry run on a 1.5 cc blood sample drawn from the left jugular vein showed no abnormality. A vaginal smear collected using a sterile human urethral cotton swab and stained with Leishman blue showed mostly intermediate cells, <10% cornified cells, occasional polymorphonuclear cells and no red blood cells. Serum progesterone (P4), assayed using a commercial kit for serum P4 radioimmunoassay (PROG-CTK; Sorin Biomedica, Italy) validated for the feline (data not published) was 0.4 ng/ml (reference range: anoestrus/follicular phase=0.0–0.6 ng/ml; dioestrus≥2.0 ng/ml). Abdominal ultrasound performed with a 5.0 MHz probe revealed no uterine enlargement and absence of fluids within the uterine lumen. Presence of uterine or vaginal pathology at the time of presentation was ruled out based on clinical and ultrasonographic findings. The owner was asked not to breed her at the next heat but bring her in for a recheck.
The following day (January 31) the queen was in heat again. On February 6 she was taken to the Small Animal Reproduction Service of the University of Pisa for a recheck, which showed no abnormal findings on physical examination as well as on uterine ultrasound. Her vaginal smear showed more than 90% cornified cells. Based on the above findings it was decided to wait until the following heat and breed her on day 3.
The next heat began on February 13. She was taken to the same male and left with him from February 15 until February 17 during which time multiple copulations were observed to occur. The last day of her heat was February 19. Although the need for confirmation of pregnancy at day 30 after breeding had been thoroughly discussed at time of initial presentation to the Small Animal Reproduction Service, the owner elected not to have her evaluated and called on April 14 reporting indirect signs of pregnancy (abdominal enlargement, weight increased to 3.8 kg, excellent health, good appetite). On the evening of April 22 (day 66) parturition started progressing very slowly and uterine contractions stopped on the evening of day 67. The veterinarian performed a caesarean section on the morning of day 68, delivering six live kittens. One of them, a female, was euthanased because of the presence of an oral lesion suggestive of cleft palate. The five remaining kittens were dyspnoeic at birth because of the prolonged parturition process, but after being treated accordingly grew normally until and beyond weaning age. Tres Joli recovered uneventfully from the caesarean section but did not come in heat for the remaining of the breeding season. She was bred again to the same tom cat during the month of February the following year, on day 3 of oestrus, conceived and gave birth (through a planned caesarean section on day 66) to six kittens, all of which had lesions indicative of palatoschisis. The kittens were all euthanased and the queen was ovariectomised 2 months later.
In a cycling queen that accepts breeding by a tom cat, infertility can be due to failure to ovulate (due to incomplete breeding, errors in breeding management, stress), failure to conceive (due to lack of patency or infection of the reproductive tract, poor semen quality, inbreeding, stress) or failure to carry a pregnancy to term (due to embryonic/fetal chromosomal anomalies, immune mediated disease, use of drugs in pregnancy, luteal insufficiency) (Johnston et al 2001). Considering the final outcome of this case (parturition of six kittens), one can rule out anatomical abnormalities of Tres Joli's reproductive tract as well as incomplete breeding or poor semen quality. Also, immune-mediated disease, stress and luteal insufficiency can be considered less relevant or highly unlikely in such a case. Therefore, the most likely causes of Tres Joli's infertility at the two breedings of December 19 and January 25 should be failure to ovulate (due to errors in breeding management), failure to conceive (due to infection of the reproductive tract, inbreeding, stress) or failure to carry a pregnancy to term (due to embryonic/fetal chromosomal anomalies, inbreeding).
When considering the interval between Tres Joli's subsequent heats it appears that she probably ovulated after breeding on December 19 as shown by an interoestrus interval of 37 days (Table 1). An interoestrus interval of 35–45 days in the queen is generally indicative of occurrence of ovulation, suggesting development of corpora lutea and progesterone secretion (Wildt et al 1980, 1981, Schmidt et al 1983) whether or not breeding occurred (Lawler et al 1993, Gudermuth et al 1997).
First days of consecutive heats, length of interoestrus intervals, time of natural breeding/s and their outcome in a 13-month-old Persian queen referred for infertility and purulent vulvar discharge
Assuming that ovulation occurred, infertility at the first breeding (December 19) is likely to be due to failure to conceive because of an acute endometrial infection as shown by development of purulent vulvar discharge 1 week after breeding. However, infertility due to failure to carry a pregnancy to term or failure to ovulate cannot be ruled out. Although unlikely, Tres Joli might have conceived regardless of the purulent vulvar discharge occurring shortly thereafter, with pregnancy being subsequently lost through resorption due to chronic uterine infection, embryonic/fetal abnormalities, use of drugs in pregnancy or luteal insufficiency. Conception at this cycle cannot be ruled out as pregnancy diagnosis was not performed. Furthermore, occurrence of cleft palate in both litters (in 1/6 kittens in the first litter and in 6/6 kittens in the second litter) suggests a high degree of inbreeding as this oral lesion is transmitted in kittens and puppies as a simple recessive or irregular dominant trait (Hawkins 2001). Inbreeding may cause failure to conceive or early embryonic death, both of which might have been responsible for infertility at the breeding of December 19. The queen was treated with cefazoline from day 24 through day 29 after breeding, a time when feline organogenesis may still be taking place. However, although cephalosporin drugs are known to cross the placenta, they are reported to cause no harmful effects to feline fetuses (Papich 1989). The lack of information on this queen's serum progesterone concentration makes it impossible to rule out luteal insufficiency as a cause of fetal death, as well as failure to ovulate as being a cause of infertility. Although unlikely, a long interoestrus (37 days) following lack of ovulation might be due to the fact that the queen developed a health problem when she was taken to a cat show at approximately the time when she should have been in heat (January 12–13), potentially postponing onset of oestrus.
Tres Joli obviously did not ovulate after breeding on January 25 as shown by an interoestrus interval of only 7 days (Table 1). A short interval (on average 8–10 days) between consecutive heats in the queen, known as postoestrus, indicates failure to ovulate and lack of corpora lutea development (Lofstedt 1982). Occurrence of postoestrus (and therefore lack of ovulation) was also evident in early February, when the queen was not bred and her interoestrus interval was again short (12 days, Table 1). Infertility at the breeding of January 25 is therefore due to failure to ovulate as evidenced by an early return to heat on January 31. Failure to ovulate following breeding during oestrus may result from an incomplete breeding or from an error in breeding management. Incomplete breeding may result from lack of experience, persistence of the penile frenulum, phimosis or presence of a penile hair-ring, all of which may prevent the tom cat from achieving a complete intromission, therefore causing insufficient or no luteinising hormone (LH) peak in the queen. The tom cat who mated Tres Joli on the first two breedings was never checked for presence of a hair ring, phimosis or persistence of a penile frenulum. However, he was a proven sire who subsequently managed to obtain two litters from Tres Joli and, most importantly, Tres Joli showed evidence of post-coital reactions at each breeding, which proves that complete intromission occurred on most, if not all, occasions.
Therefore, the only possible cause of failure to ovulate at the breeding of January 25 is an error in breeding management. In the majority of queens, ovulation occurs following a copulation-induced pituitary LH peak whose magnitude is directly proportional to the number of breedings; ovulation occurred in only 50% of queens bred just once, while it occurred in 100% of queens bred four times or less (Concannon et al 1980). Clinical and experimental evidence suggest that more than 1 day of exposure to increasing oestrogen stimulation is necessary before the feline pituitary can release an ovulatory surge of LH in response to a coital stimulus. The threshold of oestradiol-17β concentrations indicating active hormonal secretion by growing follicles is generally considered to be 20 pg/ml with >20 pg/ml indicating oestrus and <20 pg/ml indicating anoestrus or interoestrus (Shille et al 1979). However, significantly higher concentrations of oestradiol-17β (51±4.8 pg/ml) are reported on the day of the ovulatory LH surge than on the previous day (34±4.2 pg/ml) (Banks 1981). Therefore, breeding too early (such as on the first day of heat) may not induce ovulation as the pituitary may not be ready to release LH or the follicles may not be mature enough to rupture in the presence of an LH surge. An LH response was not elicited when 2/12 queens were bred three times during the first day of oestrus (Wildt et al 1981), when 4/24 queens were bred three times during the first or second day of oestrus (Wildt et al 1980) or when 5/14 queens were bred twice during the first and second day of oestrus (Banks and Stabenfeldt 1982). In this case, breeding on day 3 instead of day 1 produced a good ovulation rate as demonstrated by the birth of six kittens.
Presence of vulvar discharge shortly after the two breedings of December 19 and January 25 is difficult to interpret. When the queen was initially seen by the Small Animal Reproduction Service there was no clinical or laboratory evidence of any abnormality at the vaginal, cervical or uterine level. Occurrence of vulvar discharge shortly after breeding could be due to bacteria originating either from the male reproductive system or from the female perivulvar area gaining access to the queen's reproductive tract during copulation. Unfortunately, this was impossible to investigate as in Tres Joli's case the antibiotic therapy had already been used. Despite the lack of evidence of reproductive disease, the decision not to breed her at the heat following January 25 was taken in order to let her go through an oestrogenic phase to allow increased uterine blood flow to help the endometrium eliminate any potential subclinical infection.
This is the first report documenting a clinical case of failure to ovulate through wrong breeding management in a privately owned queen. Despite the common perception that cats can reproduce well even without (or regardless of) human intervention, it is evident that the choice of time for breeding in the oestrous queen can be crucial to fertility. Veterinarians should advice a careful monitoring of the sequence of events in oestrous cats in order to help cat breeders and owners maximise the reproductive potential of their queens. Breeding on the first or second day of heat should be discouraged as fertility can be very low.