Heat stress and sperm production in the domestic cat.

This study aimed to assess 1) the effect of high environmental temperatures on sperm production and 2) the effectiveness of a temperature-humidity index (THI) to predict the degree of thermal stress in a cat model. Semen collection was performed by electroejaculation for 18 mo in 20 tomcats maintained under controlled photoperiod. Still, temperature and humidity were not experimentally manipulated to describe the effect of natural climate conditions on seminal samples. Ejaculates (n = 512) were then grouped according to temperature records of the sampling day and compared by temperature and THI index. Significant lower sperm parameters and increase sperm tail abnormalities were observed during warm environments (temperature and THI). Concentration and total sperm count were the most affected parameters. Environmental temperatures of 28.5 °C with 54% relative humidity (THI = 77.07) and 27.9 °C with 66% humidity (THI = 77.84) were upper thresholds of moderate thermal stress. Moreover, days with relative humidity near 90% led to severe thermal stress with temperatures as low as 26.6 °C (THI = 78.88). The current study demonstrates the detrimental effect of high environmental temperatures on sperm quality in the domestic cat. This effect is observed at lower temperatures when high relative humidity is present. In this sense, the THI was a reliable predictor of the magnitude of thermal stress experienced by cats. Thus, cats from reproductive programs should be maintained under controlled photoperiod cycles with temperatures around 20 °C and humidity around 70% to avoid semen detrimental effects.

Effect of cat seminal plasma and purified llama ovulation-inducing factor (ß-NGF) on ovarian function in queens.

The present study aimed to determine the effect of cat seminal plasma and purified llama ovulation-inducing factor (ß-NGF) on ovarian activity in queens. Queens (n = 6) were used for all the treatments in a crossover design with an interval time between treatments of three interestrus intervals. Forty-eight hours after the detection of an estrus vaginal cytology, queens were given cat seminal plasma (subcutaneous or intramuscular), purified llama ovulation-inducing factor (15 or 35 µg), hCG (75 UI), saline, or were mated with a male. A total of 192 estrous cycles were observed. Estrus length and serum estradiol concentration were 6 ± 1 days (range 2-10 d) and 38 pg/mL (range 10-75 pg/mL), respectively. Queens mated and given hCG showed higher serum progesterone concentration and longer interestrus interval (47 ± 5 d) than that of controls (10 ± 3 d). Sixty-seven percent of queens (4/6) treated with subcutaneous cat seminal plasma, and 17% of those treated with purified llama ß-NGF showed high serum progesterone concentrations along with prolonged interestrus. However, intramuscular administration of cat seminal plasma produced interestrus intervals similar to controls (15 ± 5 d) and basal serum progesterone concentration (<0.50 ng/mL). This study demonstrates that the subcutaneous administration of cat seminal plasma induced ovulation in queens. Therefore, molecules present in cat seminal plasma, contribute to the induction of ovulation in queens. Identifying those molecules will improve the knowledge of queen's reproductive physiology. Also, it could offer a physiologic alternative to induce ovulation in queens when reproductive biotechnologies are used.

Uterine endometrial cytology, biopsy, bacteriology, and serum C-reactive protein in clinically healthy diestrus bitches.

The aim of this work was to assess the agreement between endometrial cytology and uterine biopsy for the diagnosis of endometritis (END), the bacterial populations isolated from the vagina and uterus of bitches having END, and the measurement of C- reactive protein as a diagnostic tool for diagnosis of END in clinically healthy bitches. Fifty privately-owned intact, clinically healthy bitches, in diestrus, without a history of progestin administration, aged between 8 months and 6 years old and weighing between 5 and 28 kg were used in this study. Bitches were included in a program for breeding control at a municipal pet public shelter. Before ovariohysterectomy (OVX) samples for vaginal cytology and bacteriology, and blood samples were taken. After OVX endometrial cytology, bacteriological samples and biopsy were collected. Histologic examination was performed to confirm the uterine condition. Blood samples were centrifuged and stored at -20 °C until progesterone (P4) and C-reactive protein was measured. Samples for bacteriological culture were collected, and swabs were placed into Stuart's transport medium and transported to the laboratory. On histopathologic examination, the most common observation was END (27/50), followed by normal endometrium (NE; 18/50), cystic endometrial hyperplasia (CEH; 2/50), atrophy (2/50) and fibrosis with degeneration of the endometrial glands (1/50). Low degree of agreement was observed between results obtained by endometrial cytology samples and results obtained by biopsy in endometrial diagnosis (Kappa Coefficient: -0.19). In vaginal samples, ß-hemolytic Streptococcus, Staphylococcus spp., Escherichia coli, Proteus spp., Corynebacterium spp., and Klebsiella pneumoniae were the bacteria most often found. In uterine samples, only four samples from END showed bacterial grow. C-reactive protein frequency was higher in END (6/23, 23%) vs NE (0/16, 0%; Van der Waerden P-value = 0,0302). Our results support the hypothesis that END is a frequent finding in uterine biopsy and could be associated with subfertility and infertility in the bitch. A low degree of agreement was observed between the diagnostic results from the uterine biopsy and endometrial cytology. Bacteriology would not be recommended as a diagnostic tool because no bacteria highly associated with uterine diseases were isolated from bitches with END. Finally, the usefulness of C-reactive protein concentration as a marker for END in bitches could not be conclusively demonstrated.

Vaginal isolation of beta-haemolytic Streptococcus from bitches with and without neonatal deaths in the litters.

The aim of the study was to identify beta-haemolytic streptococci in the vagina of bitches who had delivered healthy litters and bitches who had delivered litters in which neonatal deaths occurred. Fifty-one bitches divided into two groups were used. Group 1 (G1) included 28 bitches that had delivered healthy litters and group 2 (G2) included 23 bitches that had delivered puppies who died in the neonatal period. Two vaginal samples were taken, one in proestrus and the other at the end of gestation (EG). Beta-haemolytic Streptococcus (BS) was isolated from 16 bitches (57%) in G1 and from 21 bitches (91%) in G2. The bacteriological cultures, serological tests (Streptex® ) and PCR assay allowed identification of Streptococcus canis and Streptococcus dysgalactiae in G1 and G2. Ultramicroscopic studies allowed the observation of M Protein and capsules in strains of S. dysgalactiae and S. canis in G1 and G2. The S. canis strains isolated from G2 showed thicker capsules than S. canis strains isolated from G1 (234 ± 24.2 vs 151.23 ± 28.93 nm; p < .001.). No differences were observed in capsule thickness between strains of S. dysgalactiae isolated from G1 and G2 (210 ± 13.54 vs 211.66 ± 19.67 nm; p > .70). All strains of beta-haemolytic Streptococcus isolated were penicillin sensitive. Penicillin was administered from EG to 5 days post-partum in 10 G2 females with isolation of BS (G2A). Saline solution was administered in eleven G2 females with isolation of BS (G2B). Ninety per cent of the puppies survived in G2A and 25% survived in G2B. Our results suggest BS is involved in canine neonatal deaths.

Prostaglandin synthesis enzymes' gene transcription in bitches with endometritis.

Endometritis is a major cause of infertility in many domestic species. However, until now the pathogenesis of the endometritis in the bitch is unclear. The aim of this study was to evaluate the gene transcription pattern of prostaglandin (PG) synthesis enzymes (cyclooxygenase [COX2], PTGES-1 and PGFS) in the endometrium of bitches with or without endometritis. Thirty mixed breed bitches in dioestrus, aged between 1 and 5 years, and weighing between 10 and 30 kg were used. After ovariohysterectomy (OVX), uterine biopsy samples were collected from the middle part of both horns. Then, endometrial epithelium was collected using the cytobrush method and mRNA analysis was performed by real-time RT-PCR. Data were analysed with Kruskal-Wallis anova using the sas® software. Uterine condition was identified by endometrial biopsies (normal endometria [n = 11; NE], acute endometritis [n = 10; AE] and chronic endometritis [n = 9; CE]). The COX2, PTGES-1 and PGFS/AKR1C3 mRNA expression in bitches with and without endometritis was similar. Except for PGFS/AKR1C3, gene transcription of COX2 and PTGES-1 was significantly increased in AE compared with CE. In addition, COX2 gene transcription was significantly increased in AE compared with NE. In contrast, no differences were found for COX2, PTGES-1 and PGFS/AKR1C3 mRNA expression in the samples of NE compared with CE.

Progesterone and ultrasonographic changes during aglepristone or cloprosternol treatment in queens at 21 to 22 or 35 to 38 days of pregnancy.

Progesterone (P4) is a requirement for pregnancy development. Previous reports observed a maximal value of serum P4 concentration on 21 days after the first mating after which it slowly declines throughout the rest of pregnancy. Ultrasound examination should be performed to ensure that pregnancy interruption is complete. Limited information is available on the ultrasonic appearance of conceptuses during pregnancy termination in cats The objective was to study serum P4 concentration and ultrasonographic changes during aglepristone (ALI) or cloprostenol (CLO) treatment and to evaluate the fertility after treatment. Two experiments (EXP) were carried out to accomplish this aim. Sixty queens, 12- to 36-month-old, were used. On Days 21 to 22 of pregnancy (EXP I) or 35 to 38 of pregnancy (EXP II), queens were divided into three groups (G). Queens in G1 received ALI (10 mg/kg, sc; EXP I, n = 10; EXP II, n = 10) for 2 consecutive days. Queens in G2 received CLO (5 µg/kg, sc; EXP I, n = 10; EXP II = 10) for 3 consecutive days. Queens in G3 received 1 mL of saline solution (PLA, sc; EXP I, n = 10; EXP II = 10). Blood samples were taken before treatment (Day 0) and every day during 10 days after the treatment to measure serum P4 concentrations. Likewise, after treatment, queens were monitored daily by ultrasonography for 10 days and weekly until the end of gestation to obtain gestational sacs measurements (GS), fetal measurements, and fetal biophysical profile. Data were analyzed by ANOVA. Serum P4 concentrations were significantly different on Day 6 (EXP I) and on Day 1 (EXP II) in ALI and CLO groups compared with PLA group (P < 0.05 and P < 0.01; respectively). The ultrasonographic monitoring during treatment allowed assessing changes in the GS and fetal measurements, embryo-fetal viability, and risk of pregnancy loss. In conclusion, the results from this study reported changes in serum P4 concentration and in ultrasonography measurements during pregnancy interruption with ALI or CLO treatment. Also it was observed that ALI and CLO are safe drugs and can preserve posttreatment queen fertility. Therefore, the results obtained in our work will be applied in feline reproduction practice.

Prolactin, Androstenedione and IGF1 Serum Concentrations During Induced Follicular Growth by eCG Administration in the Bitch.

The oestrus cycle in the domestic bitch, a monoestrous species, differs considerably from that of other veterinary domestic animals species. In the bitch the combined use of eCG and hCG is effective to induce oestrus predictably and safely (Stornelli et al., Theriogenology, 78, 2012 and 1056). Although several studies were done to describe the hormonal changes during the canine oestrus cycle, to our knowledge none was done to describe the hormonal changes during induced follicular growth after the administration of eCG. The aim of this work was to study prolactin (PRL), insulin-like growth factor (IGF1) and androstenedione (ANDR) serum concentrations during follicular growth induced by a single dose of eCG administered to late anoestrous bitches. PRL and ANDR concentrations were lower before than after eCG TRT (before eCG vs pro-oestrus, oestrus and dioestrus; 4.3 ± 1.8 ng/ml vs 6.5 ± 1.6 ng/ml, p < 0.05; 0.08 ± 0.2 ng/ml vs 0.42 ± 0.16 ng/ml, p < 0.05). Conversely, IGF1 concentrations were similar before and after eCG TRT (286.0 ng/ml ±32.2, p > 0.53). Additionally, PRL concentrations were similar before oestrus compared to during oestrus and dioestrus (6.9 ± 1.7 ng/ml, p > 0.19). Furthermore, IGF1 concentrations were higher before and during oestrus compared to first day of dioestrus (286.1 ± 29.8vs 200.4 ± 29.2 ng/ml, p < 0.01). On the contrary, ANDR concentrations were lower before and during oestrus compared to first day of diestrum (0.35 ± 0.17 ng/ml and 0.38 ± 0.15 vs 0.68 ± 0.17 ng/ml, p < 0.05). These results show that treatment with a single injection of 50 IU/kg of eCG in late anoestrous bitches successfully induced changes in follicular growth which were paralleled with changes in PRL, IGF1 and ANDR serum concentration similar to those occurring during a normally occurring oestrous cycle. In addition, our results suggest that IGF1 in the bitch could play an important role in ovarian folliculogenesis.

Ultrasonographic and progesterone changes during Days 21 to 63 of pregnancy in queens.

Ultrasonography has been used to diagnose and monitor pregnancy. However, in the queen, most of ultrasonographic and endocrinological studies have been performed using small number of observations during limited periods of pregnancy. The aim of this study was to derive equations to predict the gestation age and parturition time using ultrasonographic embryo fetus measurements and serum progesterone (P4) concentration measurements. Mixed-breed queens (n = 16), aged between 24 and 36 months and weighing between 2 and 4 kg, were daily monitored by ultrasonography since 21 days after the first mating to parturition. Gestational sac (GS) was measured from longitudinal (length [LEN], anterior-posterior [ATP]) and transverse images (width [WID]), GS volume was calculated by the prolate ellipse formula, and GS diameter was calculated by orthogonal measurements. Fetal measurements included crown-rump length (CRL), head diameter (HD), and body diameter (BD). Gestational sac, fetal measurements, and serum P4 concentration were recorded and analyzed by ANOVA. Correlation and linear regression analyses were performed and equations were derived to estimate predicted values and 95% confidence interval for GS parameters and P4 concentrations from 21 to 63 days after the first mating and to estimate predicted values and 95% confidence interval for fetal parameters from Day 35 to 63 of gestation. The average concentrations of serum P4 concentration from Day 22 to 47 of gestation remained between 32.27 ± 4.25 and 16.25 ± 2.45 ng/mL. After that, a gradual decline occurs reaching a concentration of 2.99 ± 1.29 ng/mL 1 day before parturition. A positive and significant correlation between the ultrasonographic measurements (LEN, ATP, WID, GS volume and diameter, uterine wall thickness, CRL, HD, and BD) with number of days after the first mating was observed (P < 0.001). We observed a positive and significant correlation between GS measurements (LEN, ATP, and WID) and between fetal measurements (CRL, HD, and BD) and a negative and significant correlation between serum P4 concentration with GS (LEN, ATP, and WID), uterine wall thickness, and fetal (CRL, HD, and BD) measurements. In addition, there was a positive and significant correlation between serum P4 concentrations with days after the first mating to parturition. In conclusion, the equations derived from this study will be useful for pregnancy monitoring and for estimating pregnancy age in queens from Day 21 until parturition for animals with similar weight and age.

Effect of melatonin implants on spermatogenesis in the domestic cat (Felis silvestris catus).

The aim of this study was to assess the efficacy of subcutaneous melatonin implants to temporarily and reversibly suppress spermatogenesis in male cats. Tomcats (n = 8) were housed in a conditioned room with alternating long and short 2-month photoperiod cycles to maintain sperm production and quality. Animals were randomly assigned to one of the two treatments. Four animals received a subcutaneous melatonin implant (MEL, 18 mg; Syntex, Argentina), whereas the other four received a subcutaneous placebo implant (PLA, 0 mg; Syntex). Semen samples were collected by electroejaculation every 14 days for 252 days. Sperm parameters were evaluated in all ejaculates, and data were analyzed by ANOVA. Melatonin-implanted cats significantly decreased their sperm quality in all the parameters studied compared with the control group (MEL vs. PLA; least squares means ± SEM; motility, 71.3 ± 3.4 vs. 82.1 ± 3.6; velocity, 3.4 ± 0.1 vs. 4.6 ± 0.1; total sperm count, 2.6 ± 2.2 vs. 19.4 ± 3.3; acrosome integrity, 48.7 ± 5.6 vs. 62.8 ± 5.6; plasma membrane integrity, 52.2 ± 4.7 vs. 72.9 ± 5.5; normal sperm morphology, 45.8 ± 3.3 vs. 63.7 ± 3.4; P < 0.05). Conversely, volume and serum testosterone concentrations were similar in both groups (volume, 0.15 ± 0.02; serum testosterone concentrations, 1.1 ± 0.1; CV 18.9%; P > 0.05). At 91 ± 7 days after implant insertion, sperm motility decreased 38.5%, velocity 26.5%, total sperm count 82%, acrosome integrity 22%, plasma membrane integrity 30%, and normal sperm morphology decreased 32% of preimplant values. This effect was present until 120 ± 15 days after implant insertion. After that, seminal parameters started to increase and reached preimplant values at about 140 ± 7 days after implant insertion. Nevertheless, treated animals conserved the capacity to produce semen during the treatment period. In conclusion, a single subcutaneous melatonin implant effectively and reversibly reduced sperm production and quality in male domestic cats for approximately 120 ± 15 days without clinically detectable adverse effects.

Pharmacokinetics of eCG and induction of fertile estrus in bitches using eCG followed by hCG.

The aim was to design a protocol combining eCG followed by hCG for estrus induction in the bitch. In Experiment 1, three ovariohysterectomized bitches received 10 000 IU of eCG iv, and 15 days later 10 000 IU of eCG im. Blood samples were taken up to 144 h after each injection to measure eCG concentrations. In Experiment 2, 25 healthy, intact late anestrous bitches were assigned to one of five doses of eCG (5, 10, 15, 20, 44, or 50 IU/kg eCG im; [TRT5-TRT50]). Sexual behavior (SB), clinical signs of estrus (CSE) and vaginal cytology (VC) samples were obtained and scored before eCG administration and every other day until onset of estrus, or for 14 days. In Experiment 3, intact late anestrous bitches were assigned to a treatment group (TRT; n = 16) and received eCG (50 IU/kg im) followed by hCG (500 IU im) 7 days later; or to a placebo group (PLA; n = 8) where they received 1 mL saline solution im. All bitches that were induced in estrus were mated or AI with fresh semen. In Experiment 1, maximum observed concentration (C(max)) eCG were similar between im and iv routes (6.1 ± 0.9 vs. 8.6 ± 0.5 IU/mL, P > 0.08), whereas time for maximum observed concentration (T(max.)) was longer for im compared to iv routes (17.5 ± 0.5 vs. 11.6 ± 0.3 h, P < 0.01). The area under the curve (AUC) was similar for im and iv routes (P > 0.48), and eCG was detectable in serum for at least 144 h for both routes. In Experiment 2, 3 days or 3 to 5 days after treatment, all bitches in TRT50 had higher scores compared to TRT5-44 animals (P < 0.01). In TRT50, the mean interval from treatment to estrus was 4.0 ± 0.4 days. In Experiment 3, the mean interval from treatment to estrus was shorter in the TRT group compared to the PLA group (4.1 ± 3.3 vs. 68.5 ± 4.4 days, P < 0.01). The previous interestrus interval was similar for TRT and PLA groups (199.6 ± 7.2 vs. 197.5 ± 10.2 days), but the new interestrus interval was shorter for the TRT compared to the PLA group (164.0 ± 7.2 vs. 212.2 ± 10.2 days; treatment by interval interaction, P < 0.007). Serum P(4) concentrations increased on the first day of cytologic diestrus after treatment in bitches in TRT (0.7 ± 0.3 vs. 22.8 ± 4.2 ng/mL; P < 0.01); but did not change in PLA (P > 0.84). Ninety-four percent of animals were bred (15/16; AI, n = 7; natural mating, n = 8), and 80% (12/15) became pregnant. None of the bitches had any side effects from the eCG and hCG therapy. We concluded that 50 IU/kg of eCG combined 7 days later with 500 IU of hCG was effective to induce normal and fertile estrus in bitches at 164 days post estrus, with an 80% pregnancy rate, with no side effects, and with a reduction of 48 days of the interestrus interval.

Efficacy of cloprostenol or aglepristone at 21-22 and 35-38 days of gestation for pregnancy termination in queens.

The objective of this study was to evaluate the efficacy of cloprostenol (CLO) or aglepristone (ALI) for pregnancy termination in queens at 21-22 and 35-38 days of gestation. Two experiments (EXP) were carried out to accomplish this aim. Thirty-seven 12- to 14-month-old mixed breed queens were used in a randomized design. At oestrus, queens were housed for mating with a tom, and pregnancy was confirmed by transabdominal ultrasonographic examination (US). On days 21-22 of pregnancy (EXP1) or 35-38 of pregnancy (EXP2), queens were divided into three groups (G). Queens in G1 received ALI (10 mg/kg, sc; EXP1, n = 6; EXP2, n = 6) on two consecutive days. Queens in G2 received CLO (5 µg/kg, sc; EXP1, n = 6; EXP2 = 7) on three consecutive days. Queens in G3 received 1 ml of saline solution (PLA, sc; EXP1, n = 6; EXP2 = 6). After treatment, females were monitored daily by US during for 10 days and weekly until the end of gestation. In EXP1, pregnancy was terminated in (6/6, 100%), (0/6, 0%) and (0/6, 0%), for the ALI, CLO and PLA groups, respectively (p < 0.001). In EXP2, pregnancy was terminated in (6/6, 100%), (1/7, 14%) and (0/6, 0%) for the ALI, CLO and PLA groups, respectively (p < 0.001). In both EXP, after CLO administration, animals vomited and were depressed for 30 min; but no side effects were observed in the animals in the ALI group. In conclusion, the results from this study indicate that three injections of CLO are not effective, but two injections of ALI are effective to induce abortion in queens at 21-22 or 35-38 days of pregnancy.

Effect of natural photoperiod on epididymal sperm quality and testosterone serum concentration in domestic cat (Felis silvestris catus).

The aim of this study was to assess epididymal sperm characteristics and serum testosterone concentration in cats under natural photoperiod. The hypothesis was that natural photoperiod induces seasonal changes in spermatozoal quality and serum testosterone concentration. Mixed breed tomcats (n = 43) that underwent bilateral orchiectomy at a municipal public pet shelter were used in the study. Epididymides were divided into two groups according to time of castration. In Group I, toms were castrated during increasing light (IL; [winter and spring; n = 24]), and group II, during decreasing light (DL; [summer and fall; n = 19]). Only mature toms castrated in the two lasts weeks of each season were included in this study. Sperm samples were obtained by cutting the cauda epididymis in Tris solution and tested for motility (MOT,% motile), velocity (VEL, 0-5), total sperm cells (TS, 10(6) ), acrosome integrity (ACR,% intact; FITC-PSA), plasma membrane integrity (MI,%intact; CFDA-PI) and sperm morphology (SM,% normal). Before orchiectomy, blood samples were taken to measure serum concentrations of testosterone (T2) by a solid-phase RIA. Data were analysed with the mixed procedure of SAS. Toms castrated during IL had higher sperm plasma membrane integrity and better sperm morphology compared to toms castrated during DL (69.0 ± 2.7 vs 60.6 ± 2.1, p < 0.01; 45.9 ± 2.5 vs 35.9 ± 3.4; p < 0.02; respectively) and tended to have higher sperm motility and total number of sperm cells compared to toms castrated during DL (56.3 ± 2.8 vs 47.3 ± 3.7, p < 0.06; 13.8 ± 1.4 vs 10.0 ± 1.8, p < 0.09). However, velocity, acrosome integrity and serum testosterone concentrations were similar between both groups (3.5 ± 0.1 vs 3.4 ± 0.1, p > 0.6; 45.8 ± 3.3 vs 44.0 ± 4.0, p > 0.72; 0.76 ± 0.15 vs 0.59 ± 0.19, p > 0.51; respectively). In conclusion, natural photoperiod induces seasonal changes in sperm quality with a moderate variation in serum testosterone concentrations.

Effect of refractoriness to long photoperiod on sperm production and quality in tomcats.

The aim of this study was to assess whether refractoriness to long photoperiod (LP) could be reversed by subjecting tomcats to a period of short days. Our hypothesis was that photoperiod changes can avoid refractoriness and restore sperm quality and production to that before refractoriness. Tomcats (n = 6) were housed in a conditioned room with LP (12L: 12D) for 45 days of acclimation and then maintained under LP for 18 month. Then, tomcats were changed to a period of decreasing light at a rate of 8 min/day for 1 month. Tomcats stayed for 1 month with short photoperiod (SP; 8L: 16D) and then were switched back to a period of increasing light at a rate of 8 min/day for 1 month. The experiment was completed after tomcats remained in LP for 2 months. Toms were anaesthetized and semen samples were collected by electroejaculation every 2 weeks. Sperm parameters were evaluated in all ejaculates, and data were analysed by anova. Motility, velocity, volume, sperm concentration, total sperm count, viability, acrosome integrity, plasma membrane integrity and sperm morphology were higher during LP compared with a refractory LP (p < 0.01). Likewise, velocity, viability, acrosome integrity, plasma membrane integrity and sperm morphology were higher in a LP compared with a SP (p < 0.05). On the other hand, motility, volume, concentration and total sperm count were similar between LP and SP (p > 0.20).Whereas motility, velocity, viability, acrosome integrity and plasma membrane integrity were similar in a refractory LP compared with SP (p > 0.05), volume, sperm concentration, total sperm count and sperm morphology were lower in a refractory LP compared with SP (p < 0.05). In conclusion, refractoriness and reduced sperm production and quality induced by a prolonged LP of 18 month can be restored after placing tomcats to a SP.

Effect of storage media and storage time on histological and ultrastructural changes in cat epididymal cells.

The aim of this study was to assess the histological and ultrastructural changes in cat epididymides (n = 22) stored at 4 °C in two different media [saline solution (SAL) or tris-egg yolk (TEY)]. Our hypothesis was that epididymides stored in TEY would have delayed epithelial cell autolysis. Four epididymides were fixed and processed immediately, and the remaining 18 epididymides were stored at 4 °C in SAL or TEY for 24, 48 or 72 h. In histological sections, the nuclear features and stereocilia morphology were scored from 0 to 3. Ultrastructurally, nuclear chromatin and stereocilia morphology were scored from 0 to 3. In addition, using transmission electron microscopy nuclear number, nuclear area, mitochondrial number and mitochondrial area were recorded. In the histological study, parameters changed with time and media (p < 0.01). A significant effect of time was observed (p < 0.01), and the morphological changes were greatest when the storage time increased. Morphological changes were higher in SAL compared with TEY (p < 0.01). In the ultrastructural study, nuclear chromatin and stereocilia morphology decreased with time and media as in the histological study (p < 0.01). In addition, nuclear number and nuclear area changed with time (p < 0.004; p < 0.001) but not with media. Conversely, mitochondrial number and mitochondrial area did not change with media or time (p > 0.05). In conclusion, these results show that TEY preserved epididymal epithelial cells better than SAL; this finding could help improve sperm quality of stored epididymides.

Seasonal changes in testicular cell morphology in domestic male cats (Felis catus).

The aim of this study was to asses the variation in the morphology of the seminal epithelium in relation to natural photoperiod in male cats. Tom cats (n = 240) were castrated every other week throughout the year. Each testis was fixed in Bouin's solution and cut into sections. The percentage of tubules with round spermatids (RS), elongated spermatids (ES), tailed spermatids (TS), mature spermatids (MS) and the number of Sertoli cells (SC) and Leydig cells (LC) were recorded in each sample. Testicles from males during short days (SHD) had a higher percentage of tubules with RS and ES compared to testicles from males during long days (LHD, 31.3 +/- 0.6 vs 2.1 +/- 0.6%, p < 0.001; 30.9 +/- 0.7 vs 11.0 +/- 0.7%, p < 0.001). Conversely, testicles from males during SHD had a lower percentage of tubules with TS and MS compared to testicles from males during LHD (24.5 +/- 0.8 vs 29.7 +/- 0.8%, p < 0.01; 13.1 +/- 1.2 vs 57.0 +/- 1.2%, p < 0.01). Furthermore, testicles from males during SHD had a higher number of SC and lower number of LC compared to testicles from males during LHD (11.4 +/- 0.1 vs 8.0 +/- 0.1%, p < 0.01; 19.2 +/- 1.0 vs 38.0 +/- 1.0%, p < 0.01). In conclusion, there are seasonal changes in testis cell morphology in the tom which may be related to seasonal sperm production.

Suppression of estrus in cats with melatonin implants.

The objective of this study was to assess the efficacy of a subcutaneous melatonin implant to suppress estrus in queens (felis catus). The hypothesis was that this implant would temporarily and reversibly suppress estrus in queens without producing any clinically detectable side effects. Fourteen adult queens were maintained in cages under artificial illumination (14h light:10h dark) for 45 d and then randomly assigned to one of two treatments. At interestrus, queens received a single subcutaneous melatonin implant (18mg; Melovine [CEVA Sante Animal, Libourne, France]; MEL: n=9), or a single subcutaneous placebo implant without melatonin (0mg; PLA; n=5). At the next estrus, all queens received a second MEL (n=9) or PLA (n=5) implant. Blood samples were taken when queens displayed estrous signs and during interestrus to measure estradiol (E(2)) and progesterone (P(4)), respectively, by radioimmunoassay. There were no significant differences in duration of the interestrus interval in PLA cats, regardless of whether the implants were placed during interestrus or estrus (6.0+/-9.7 d vs. 6.0+/-9.7 d, respectively; least square means [LSM]+/-SEM). However, when MEL implants were placed during interestrus, the duration of interestrus was approximately twice as long as that occurring when MEL implants were placed during estrus (113.3+/-6.1 d vs. 61.1+/-6.8 d, respectively; P<0.01). Serum E(2) and P(4) concentrations were similar in queens with PLA and MEL implants and in queens that received implants in estrus and interestrus. In conclusion, a subcutaneous MEL implant effectively and reversibly suppressed estrus in queens for approximately 2 to 4 mo with no clinically detectable side effects.