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.

Uterine blood flow evaluation in bitches suffering from cystic endometrial hyperplasia (CEH) and CEH-pyometra complex.

Doppler ultrasound is a useful diagnosis tool to evaluate uterine blood flow in different canine reproductive states. The aim of this study was to describe and compare uterine blood flow in bitches suffering from cystic endometrial hyperplasia (CEH) and CEH-pyometra complex (CEH-P). Ninety diestrous bitches were clinically, hematologically, and ultrasonographically classified into four groups: (1) clinical signs, leukocytosis, CEH, and uterine luminal contents (CEH-P, n = 31); (2) asymptomatic bitches with CEH and uterine contents (CEH-C, n = 15); (3) asymptomatic bitches with CEH without uterine contents (CEH, n = 16); and (4) normal diestrous bitches (ND, n = 28). The widest cross-sectional diameter and uterine wall thickness (W) of uterine horns were measured using two-dimensional ultrasound. Peak systolic velocity and end diastolic velocity of uterine arteries were measured by Doppler ultrasound in all the bitches. Peak systolic velocity and end diastolic velocity were higher in CEH-P than in CEH-C, CEH, and ND (P < 0.01); although both parameters did not show differences among the latter three groups (P > 0.1). Conversely, resistance index (RI) reported lower values in CEH-P than that in the other three groups (P < 0.01), being ND higher (P < 0.01) than both CEH-C and CEH which did not differ between themselves (P > 0.1). When all the bitches were considered, correlation between RI and cross-sectional diameter was r = -0.69 (P < 0.01) and between RI and uterine wall thickness was r = -0.02 (P > 0.1). It is concluded that the uterine artery blood flow velocity of bitches suffering from pyometra was higher, not only from normal bitches, but also from females with endometrial hyperplasia. Furthermore, endometrial hyperplasia, accompanied or not by luminal contents, had a higher blood flow velocity than normal uterus. Hemodynamic parameters appear as useful markers to differentiate uterine pathologic conditions.

Simultaneous pyometra and viable puppies' gestation in a bitch.

Here we describe a case of pyometra coexisting with gestation in a 4.5 year-old miniature short-haired Dachshund. The dog exhibited depression, vaginal discharge, polydipsia and dehydration. Ultrasound examination revealed the presence of low to moderate anechoic fluid collection in the left uterine horn. Blood analysis revealed mild neutrophilia with a left shift. Based on these findings a presumptive diagnosis of pyometra was made and the bitch was treated using amoxicillin-clavulanate with dopaminergic agonist (cabergoline). A second ultrasound scan revealed the presence of two gestational vesicles in the right uterine horn that were successfully carried to term. Unusually, while pyometra persisted in the left uterine horn, two viable puppies were delivered by caesarean section from the right uterine horn.

Doppler ultrasonographic assessment of uterine arteries during normal canine puerperium.

The aim of this study was to describe Doppler ultrasonographic changes of uterine arteries during normal canine puerperium. Eight healthy, pure-bred bitches, were ultrasonographically assessed during the postpartum period on Days -3, 3, 10, 17, 24, 38, 52 and 80 (Day 0 defined as the day of parturition). Total horn diameters (TD) and endometrium thickness (E) were evaluated. Color Doppler was used to localize uterine arteries at both sides of the body and pulsed-wave Doppler was performed to obtain the waveforms. Peak systolic velocity (PSV) and end diastolic velocity (EDV) were measured. Resistance index [(PSV-EDV)/PSV] was automatically calculated. Values of TD, E, PSV, EDV and RI were analyzed by repeated measures ANOVA followed by LSD test (SPSS 18.0; SPSS, Chicago, IL, USA). A correlation analysis was also carried out between RI and TD. A progressive decrease of TD (P<0.01) and E (P<0.01) was found in the course of the study. A gradual diminution of PSV (P<0.01) and EDV (P<0.01) and an increase of RI (P<0.01) were also found throughout the study period. The resistance index negatively correlated with TD (r=-0.46; P<0.01) and E (r=-0.44; P<0.01) while the ultrasonographic and vascular changes in this period are concurrent with regenerative changes in the glandular and epithelial structures of the uterus. It is concluded that uterine artery RI progressively increased during normal canine puerperium, associated to the two-dimensional ultrasonographic regression of the organ.

Long-term-release GnRH agonists postpone puberty in domestic cats.

The aim of this study was to assess the efficacy and safety of deslorelin acetate implants on domestic queen puberty postponement. Thirty, 114.4 ± 12.7 days old, 1.5 ± 0.1 kg prepubertal crossbred female cats were included in this study. The animals were kept under a positive photoperiod and randomly assigned to deslorelin acetate 4.7 mg SC implants (n = 15) or to a non-treated control group (n = 15). The queens were followed up daily and weighed weekly until puberty. Vaginal cytology was also carried out three times a week. Puberty was diagnosed by the presence of the typical oestrous behaviour and vaginal cytology findings. At puberty, ovariectomy was performed and the gonads grossly described. Age (281.2 ± 21.6 vs 177.8 ± 10.8; p < 0.01) but not weight (2.6 ± 0.1 vs 2.5 ± 0.1; p > 0.1) at puberty differed between the deslorelin and control groups, respectively. One deslorelin-treated female showed an oestrous response and another showed clinical signs of pyometra after the implants. Deslorelin-treated ovaries appeared small, while control gonads were normal. It was concluded that long-term-release deslorelin, administered at approximately 50% adult body weight, postponed feline puberty without altering growing rate.

The GnRH antagonist acyline prevented ovulation, but did not affect ovarian follicular development or gestational corpora lutea in the domestic cat.

Two experiments were conducted to investigate the effects of the GnRH antagonist acyline (330 microg/kg, given sc) on ovarian follicular development and ovulation, as well as on pregnancy maintenance in domestic cats. In the first experiment, seven queens in proestrus (total of 24 proestrus periods), were randomly assigned to treatment with either acyline (ACY; n=17) or a placebo (PLC; n=7). All queens were mated with a fertile tomcat. In the ACY and PLC groups, cessation of estrus occurred (mean+/-SEM) 7.0+/-1.3 and 7.0+/-1.7 d after treatment (P>0.1), ovulation occurred in 2 of 17 and all seven estrus periods (P<0.05), and pregnancy rates were 1 of 16 and 7 of 7 (P<0.05), respectively. In the ACY and PLC groups, intervals from treatment to the onset of the ensuing proestrus were 18.4+/-1.7 and 120+/-17.2 d. In the second experiment, 14 pregnant queens were randomly allocated, according to their mating date, to treatment with acyline in early pregnancy (from 20 to 25 d, n=3), mid pregnancy (from 26 to 45 d; n=4), late pregnancy (> 45 d; n=3), or injection of a placebo in early (n=1), mid (n=2), or late pregnancy (n=1). Ultrasonographic assessments of the uterus were done every second day for 2 wk post treatment, and serum progesterone (P(4)) concentrations were determined before treatment, and at 7 and 14 d after treatment. No pregnancies were prematurely terminated and post-treatment P(4) concentrations did not differ among treatment groups (P>0.1). In conclusion, in the domestic cat, GnRH withdrawal by acyline prevented ovulation when given in early follicular phase (proestrus), but did not significantly affect luteal function during pregnancy.

Comparison of two doses of the GnRH antagonist, acyline, for pregnancy termination in bitches.

Gonadotropin-releasing hormone (GnRH) antagonists are particularly useful when a rapid inhibitory effect on the gonadal axis is required. The aim of this study was to test the efficacy and clinical safety of a low and high dose of the third generation GnRH antagonist, acyline, on pregnancy termination in female dogs. The effect of the antagonist on the progesterone (P(4)) serum concentration was also described. Twenty-one mid-pregnant bitches were randomly assigned to a single subcutaneous (SC) dose of a placebo (PLACE; n = 7), a low (ACY-L; 110 microg/kg; n = 6) or high (ACY-H; 330 microg/kg; n = 8) dose of acyline. The animals were followed up for 15 days. All ACY treated but no placebo-treated animals terminated their pregnancy by abortion (p < 0.01). The ACY-L and ACY-H groups interrupted their pregnancy 7 +/- 1.9 and 6.4 +/- 1.3 days after treatment, respectively (p = 0.7). A significant interaction between treatment and day was found (p < 0.01) for P(4) serum concentrations when PLACE was compared with both ACY groups. No difference was found for this hormone between both ACY groups (p > 0.05) where P(4) diminished throughout the study. The decreasing rate varied among animals and was closely related to the time of abortion when P(4) reached basal concentrations. In PLACE animals, gestation progressed normally and P(4) did not change throughout the study (p > 0.05). None of the bitches presented side effects. It was concluded that acyline safely terminated mid-pregnancy by permanently decreasing P(4) serum concentrations.

An experimental model to study resistance index and systolic/diastolic ratio of uterine arteries in adverse canine pregnancy outcome.

The aim of this study was to describe the changes in the resistance index (RI) and systolic/diastolic ratio (S/D) of the uterine arteries during mid-pregnancy abortion induction in the dog. Sixteen 30-35 day pregnant bitches were randomly assigned to either a pharmacological protocol to interrupt gestation (n = 8) or were used as untreated control group (n = 8). Doppler assessments of uterine arteries blood flow were carried out before the initiation of the protocol and then every other day up to abortion (treated group) or parturition (control group). All treated bitches aborted 6 +/- 1.2 days after initiation of the treatment (while none of the non-treated bitches aborted). Pre-treatment RI and S/D did not differ between groups (p > 0.2) while average post-treatment indexes were (mean +/- SD): 0.62 +/- 0.1 vs 0.53 +/- 0.1 (p < 0.01) and 2.96 +/- 0.9 vs 2.23 +/- 0.3 (p = 0.01), for the treated and non-treated group respectively. Correlations between days to abortion and RI or S/D were 0.75 (p < 0.01) and 0.79 (p < 0.01) and, -0.78 (p < 0.01) and -0.73 (p < 0.01) for the treated and non-treated groups respectively. In the treated group, correlations between serum progesterone (P(4)) concentrations and RI and S/D were -0.76 (p < 0.01) and -0.59 (p < 0.01) respectively. It is concluded that, during induction of abortion, RI and S/D of uterine arteries progressively increased while P(4) decreased.

Endocrine effects of the GnRH antagonist, acyline, in domestic dogs.

Gonadotrophin-releasing hormone (GnRH) antagonists may have a future role in the control of canine reproductive function. In this study, the effects of a single dose of the potent GnRH antagonist, acyline, on serum concentrations of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T) were evaluated in male dogs. Blood samples were drawn before (Day -1) and after (30, 60, and 90 min, 3, 6, 9, 12, and 24h, and 3, 6, 9, 14, 22, and 29 d) treatment with acyline (330 microg/kg, sc); serum concentrations of FSH, LH, and T varied throughout the study period (P<0.01, <0.05, and <0.01, respectively). Gonadotrophins decreased below pretreatment concentrations 60 min after injection, whereas T took 90 min to decrease below baseline (P>0.05). Follicle-stimulating hormone, LH and T decreased until Day 9, when they reached their nadir at 2.0 +/-1.1 ng/mL (P<0.01), 1.2+/-0.2 ng/mL (P>0.05), and 0.5+/-0.2 ng/mL (P<0.05), respectively. Both gonadotrophins and T began increasing on Day 14 after treatment, although FSH and T serum concentrations still remained below baseline on that day (P>0.05). Follicle-stimulating hormone and T rebounded above baseline on Day 29, whereas LH reached concentrations were similar to baseline at this time (P>0.05). No local or systemic side effects were detected in any dog following acyline treatment. In conclusion, a single acyline treatment safely and reversibly decreased serum gonadotrophin and T concentrations in dogs for 9 d.

Interruption of the canine estrous cycle with a low and a high dose of the GnRH antagonist, acyline.

To test the efficacy and clinical safety of a low and high dose of the GnRH antagonist, acyline, on estrous cycle interruption and anovulation in female dogs, 20 proestrous (<3d) bitches were randomly assigned to one of the following pharmacological protocols (given sc): acyline 110 microg/kg (ACY-L; n=6); acyline 330 microg/kg (ACY-H; n=8); or placebo (PLACE, n=6). The animals were monitored (clinical and vaginal cytology examinations) daily for 60d. Blood samples for serum progesterone serum concentrations were collected 14d after treatment to determine if ovulation had occurred. Appearance of side effects and days to the onset of the first spontaneous estrous cycle after treatment were also recorded. In both ACY groups, but not the PLACE group, estrous cycles were interrupted after treatment (P<0.05). The interval from treatment to estrus interruption in ACY-L and ACY-H groups was 3.0+/-0.6 and 3.2+/-0.2d, respectively (LSM+/-SEM; P>0.05). In the PLACE bitches, physical, behavioral and cytological proestrus slowly progressed to estrus and diestrus. Ovulation was absent in all ACY, but not in PLACE bitches (P<0.05). None of the females manifested side effects related to the treatments (P>0.05). Spontaneous return to a normal estrous cycle during the study period occurred in all ACY (ACY-L 19.5+/-2.7d vs ACY-H 24.8+/-2.0d; P>0.05), but in none of the PLACE bitches (P<0.05). In conclusion, acyline efficiently, safely and reversibly interrupted an early phase of the estrous cycle in bitches by preventing ovulation.

Effect of the GnRH antagonist, acyline, on canine testicular characteristics.

The primary objective was to assess the effects and clinical safety of a single high-dose of the third generation GnRH antagonist, acyline, on testicular characteristics in male dogs. Seven dogs were followed up weekly for six, 2-week periods (-2, -1, 1, 2, 3 and 4). At the end of the second period, they were given acyline (330 microg/kg sc). Responses to treatment varied among individual animals. Testicular consistency and scrotal diameter were slightly diminished (P>0.05) in Periods 1, 2, and 3. Libido and erection decreased during Periods 1 and 2 (P<0.05). Second and third fractions of the ejaculate volume, sperm count and motility varied throughout periods (P<0.01); there was a clear impairment of these parameters (< or =0.2 mL, < or =0.6 mL, < or =0.5 million/mL and < or =30%, respectively) around the second week of Period 1, followed by slow improvement (to the end of the study). Semen volumes and motility diminished during Period 1 (P<0.05). Sperm count decreased during Periods 1, 2, and 3, relative to Periods -2 and -1 (22.7+/-11.7, 62.8+/-19.9, and 51.0+/-25.4 versus 235.7+/-63.3 and 315.5+/-27.3, respectively; P<0.05; (L.S.M.+/-S.E.M.). Morphologically abnormal sperm increased during Periods 2 and 3 (up to 64.9+/-2.6%; P<0.05). Throughout the study, no dog had hematological, biochemical, local, or systemic side effects. In conclusion, a single high-dose acyline treatment severely decreased semen quality with no adverse effects.

Combination dopamine agonist and prostaglandin agonist treatment of cystic endometrial hyperplasia-pyometra complex in the bitch.

Cystic endometrial hyperplasia-pyometra (CEH-P) complex is a progesterone-dependent disease that requires medical treatment in bitches intended for breeding. To test the efficacy and safety of a combined protocol and to assess the effect of age, stage of cycle, previous steroid hormone administration and parity on treatment, 29 bitches diagnosed with CEH-P complex were treated daily with cabergoline 5 microg/kg PO and cloprostenol 1 microg/kg SC for 7-14 days, along with supportive antibiotic and hydration therapies. Before treatment, and on Days 3, 7 and 14, all bitches were evaluated clinically and uterine horn diameter measured during trans-abdominal ultrasonography. Twenty-four of 29 bitches were cured by either Day 7 or 14. Nine bitches had mild digestive side effects. Clinical signs related to pyometra began to improve markedly as early as Day 2 of treatment. Uterine diameters decreased (P < 0.05) by Day 3 of treatment, and continued to gradually decrease, reaching normal size by Day 14. Relapses occurred in 6 of 29 cases. Pregnancy was achieved in one of the two young bitches bred after treatment. No significant relationships were found between success rate and age, stage of the estrous cycle, previous hormone administration or parity. Although no variables affecting treatment results could be identified, this combination of compounds was found to be an efficient and safe for treatment of CEH-P.

Short-term progestin treatments prevent estrous induction by a GnRH agonist implant in anestrous bitches.

The objective of this study was to test the efficacy and safety of a short-term progestin treatment administered at two different times to prevent estrous induction in response to the administration of an implant releasing the GnRH agonist, deslorelin acetate (DA), in anestrous bitches. Interestrous intervals (IEI) observed prior to and post DA were compared. Forty-two anestrous bitches, with previous IEI history, were randomly allocated to one of the following treatments: PL: placebo sc (n = 12); MA: megestrol acetate 2mg/kg po for 8 days (n = 4); DA: 10mg sc (n = 8); MA&DA-1: MA beginning the day before DA (n = 8); and MA&DA-4: MA beginning 4 days before DA (n = 10). The dose of MA was identical for each treatment. All bitches were examined daily for 1 month and then every 3 months until the next spontaneous post-treatment estrous cycle. Post-GnRH estrous response occurred in 0, 0, 100, 50, and 10% of the PL, MA, DA, MA&DA-1, MA&DA-4, groups, respectively (<0.01). There was an interaction between the treatment and period for the duration of the IEI (< 0.01). Changes in IEI were different among treatments (p<0.01); the three DA-treated groups (147.5% +/- 10.3, 161.3% +/- 14.1, 148.6% +/- 19.2) differed from both the MA (12.9% +/- 17.6) and PL (8.1% +/- 7.8), but not among themselves. It is concluded that an 8 days megestrol protocol and DA on Day 4 was better than DA on Day 1 to prevent estrous response in anestrous bitches and that both protocols significantly increased the IEI.

Decrease of body temperature after aglepristone treatment in bitches.

Body temperature responses and the timing of abortions were evaluated in pregnant bitches with the anti-progestin aglepristone. Fifteen purebred and crossbred, 25-45 days pregnant, were included in this study and seven untreated bitches at the same stage of pregnancy served as controls. Treated bitches were administered two applications of aglepristone (10 mg/kg SC) 24 h apart for pregnancy termination. Pregnancy termination was confirmed by ultrasonographic assessment. Body temperature was rectally measured three times a day for 6 days beginning 24 h before treatment or pregnancy diagnosis in the treated and control bitches, respectively. Additionally, serum progesterone concentrations were assessed at time points during the study in the treated bitches. Pregnancy was terminated in 14 treated bitches in a mean+/-S.E.M. of 4.3+/-0.7 days after treatment. Control bitches remained pregnant. In the treated bitches, but not in the controls, body temperature significantly decreased 24 h after the beginning of the treatments (P < 0.01) and then gradually returned to pre-treatment values. Correlation between the day of mean minimum body temperature and the day of pregnancy termination was low (0.07; > 0.05). Progesterone did not show significant change throughout the study. Body temperature does not seem to be a suitable variable to clinically monitor the aborting effect of aglepristone. Decrease of body temperature after aglepristone treatment could represent further evidence of its hypothalamic effects.

Effect of tamoxifen citrate on reproductive parameters of male dogs.

Tamoxifen is a synthetic, nonsteroidal Type I antiestrogenic compound that competitively blocks estrogen receptors with a mixed antagonist-agonist effect. The manifestation of these different actions depends on each species, organ, tissue and cell type considered. Very little is known about the effect of antiestrogens in dogs. The objectives of this study were to determine the effects of tamoxifen citrate on some testis, prostate, hormone, and semen parameters in seven Beagle dogs with uncomplicated spontaneous benign prostatic hyperplasia. Two dogs were normospermic, four were oligozoospermic, and one was azoospermic. The dogs were allocated to a control pre-treatment period, followed by a treatment period, and five post-treatment periods (the duration of each period was 4 weeks). During the treatment period, 2.5mg tamoxifen citrate was given p.o. daily for 28 days to all the dogs. Maximum scrotal width, testicular consistency, libido semen parameters, prostatic volume, serum testosterone concentrations, and side effects were assessed. Tamoxifen negatively affected testis size and libido (P<0.01), and decreased prostatic volume (P<0.01) and testosterone concentrations during treatment. Semen quality deteriorated to nadir values (P<0.01) approximately one spermatic cycle after treatment and returned to pre-treatment values on the second cycle after treatment in all the dogs, except one young oligoazoospermic dog, in which the sperm count was higher ( P<0.01 ) at that time. No side effects were observed and fertility was conserved at the end of the study. Tamoxifen acted more like an agonist than antagonist on the gonadal axis and, therefore, upon both the prostate and testis. Therefore, tamoxifen may have therapeutic applications in dogs.

Coat colour changes associated with cabergoline administration in bitches.

Cabergoline or bromocriptine were administered orally to 60 bitches at doses of 5 microg/kg and 15 microg/kg daily, respectively, for two to 45 days for the treatment of pseudopregnancy or for oestrus induction. Seven of the dogs which received cabergoline for more than 14 days developed coat colour changes from the second week of administration to the next coat shedding. Of these, fawn-coloured bitches developed a yellowish coat colour while Argentine boar hounds became black spotted, mainly on their extremities. In previous untreated oestrous periods, these bitches had shown no coat colour changes. It is concluded that a colour shift in certain haircoats of particular breeds could be mediated through the inhibition of the secretion of melanocyte-stimulating hormone by the administration of the dopaminergic agonist cabergoline for more than two weeks. Transient coat colour changes should be considered a possible side effect when planning long-term treatment with dopaminergic agonists in dogs.

Secretory patterns of prolactin in dogs: circannual and ultradian rhythms.

The objectives of the present study were to characterize in dogs circannual and ultradian prolactin (PRL) secretory patterns and also to compare gender differences in the ultradian period of study in the Southern hemisphere. Blood samples were collected at 15-min intervals for 2.5 h from seven male and seven female dogs and a single monthly sampling, over a 1-year time span, from six male dogs for the ultradian and circannual studies, respectively. Plasma PRL was measured by a homologous enzyme immunometric assay. The ultradian study evidenced PRL elevations suggesting pulsatile secretion in both genders. Significantly higher mean smoothed baseline (ng / ml [7.02 +/- 1.2 vs 1.23 +/- 1.0, p < 0.01]) and AUC (ng/ml * 2.5 h [25.2 +/- 3.8 vs 4.4 +/- 3.8, p < 0.01]) were found in females when compared with males. In the circannual study, plasma PRL concentrations did not statistically differ among the months of the year. When grouped together the 3 months with a longer daylight had significantly higher PRL concentrations than the 3 months with the shortest (2.31 +/- 0.37 vs 0.96 +/- 0.37, p < 0.01). The correlation between length of daylight and PRL concentrations was 0.24, p < 0.05. It is concluded that PRL does have a circannual rhythmicity and that there are ultradian gender-related differences in the period under study in these groups of dogs. This study also demonstrates plasma PRL elevations suggesting pulsatile secretion in male dogs.

Concentraciones séricas de hormona de crecimiento en perras con tumores mamarios espontáneos antes y después de la mastectomía / Growth hormone serum concentrations in bitches with spontaneous mammary tumors before and after mastectomy

La producción no pituitaria y autónoma de hormona del crecimiento (GH) en la grándula mamaria ha sido reportada en perros. Se determinó el impacto de la mastectomía de glándulas mamarias tumorales sobre las concentraciones séricas de GH, en casos clínicos de tumores mamarios espontáneos de dieciocho perras enteras, a las que se les realizó mastectomía de todas las glándulas tumorales. Tres perras sanas fueron mantenidas solo bajo protocolo anestésico por un período similar al del procedimiento quirúrgico. Se tomaron muestras sanguíneas por venopunción periférica para determinar GH sérica, antes (día -1), 2 y 11 horas y 7 y 14 días después de la mastectomía o de la anestesia. Se realizó el estudio histopatológico de las glándulas mamarias tumorales extirpadas en la cirugía. . La GH sérica fue determinada por un radioinmunoensayo homólogo de fase líquida. La media ñ SEM (ng/ml) del grupo tratado antes y después de la cirugía fue de 17.3ñ 2.8; 8.5ñ1.5; 6.3ñ1.1 y 6.1ñ1.5 para el día -1, 2 horas, 7 y 14 días respectivamente. Los mismos valores para el grupo control fueron de 4.2 ñ1.0; 5.5 ñ 1.3 y 5.2 ñ 1.5 para el día -1, 2 y 11 horas luego de la anestesia. Después de la cirugía, la GH sérica descendió (media ñ SEM) -22.6 por ciento ñ 4.9 a las 2, -31,8 por ciento ñ 5,1 al día 7, y -29,7 por ciento ñ 9 al día 15, mientras que en el grupo control se incrementó en un 31.1 por ciento ñ 08 y 26.3 por ciento ñ 9 a las 2 y 11 horas, respectivamente luego de la anestesia. La histopatología de las mamas tumorales analizadas reveló carcinoma tubular y papilar, adenocarcinoma, carcinosarcoma y carcinoma complejo. Se concluyó que en perras la GH ectópica es también producida por la glándula mamaria con tumores espontáneos malignos (AU)

Effects of vincristine treatment on semen quality in a dog with a transmissible venereal tumour.

The effect of vincristine treatment on semen parameters in a male boxer with a genital transmissible venereal tumour are described. The dog was treated with vincristine intravenously at 0.5 to 0.7 mg/m2 body surface area per week for six weeks until complete regression of the tumour occurred. Semen samples were collected before each application and then at weeks 10, 12, 17, 21 and 23 after the start of therapy. There were no alterations in libido or in testicular size and consistency either during or after treatment. Total sperm count decreased to abnormally low values during weeks 4 and 5, and then began to increase up to pretreatment values. No significant alterations in the other semen parameters were found during the study period.