Practical use of hormones in small animal reproduction / Uso clínico de hormônios na repodução de pequenos animais

The abortifacient efficacy of prostaglandin F2alpha products (PGF) involves induction of luteolysis,stimulation of uterine contraction and cervical dilation. PGF will induce luteolysis and depress progesterone (P4)concentrations to nearly non-detectable levels very easily after day 25 or 30 following just a 4-5 day course oftreatment. PGF can be used also earlier in pregnancy provided that the onset of cytological diestrus is timedprecisely and treatment course is longer than 5 days. With late abortion, the treatment must be continued untilverification of efficacy by ultrasound as partial abortion of litters can occur. Other uses of PGF includeshortening of diestrus in bitches, emptying the uterine content and improving semen quality in dogs. Antiprolactinagents include dopamine agonists (bromocriptine or cabergoline), and serotonin antagonists(metergoline). Anti-prolactin drugs can be used to control pseudopregnancy, induce abortion and the resumptionof estrus. Antiemetic (metoclopramide and domperidone) and antipsychotic drugs (chlorpromazine andsulpiride) have prolactin release properties which are widely documented in human medicine; their clinicalefficacy in the treatment of agalactia or hypogalactia is anecdotally reported also in bitches and queens.Aglepristone saturates P4 receptors causing abortion when administered at the dose of 10 mg/kg twice 24 hoursapart. The early administration of aglepristone at 0 to 25 days after mating is approximately 99% effective inprevention of pregnancy; however, care should be taken when using it without having assayed serum P4 or afterday 35 of pregnancy. Aglepristone can be used for several other purposes among which induction of parturitionand treatment of feline mammary hypertrophy. The clinical use of other hormonal drugs such as estrogens andsympatho-mimetics for conditions such as urinary incontinence and retrograde ejaculation is briefly discussed.(AU)

Early-age neutering in dogs and cats: advantages and disadvantages / Castração precoce em cães e gatos: vantagens e desvantagens

Prepubertal gonadectomy is defined as the surgical sterilization of immature male and female animalsaging from 6-to-14 weeks, and it is a less invasive, less traumatic surgery when performed prior to puberty thanin adult animals. In dogs, growth plate closure is delayed when surgery is performed prior to puberty, but thedelay is significantly longer when neutering is done at 7 weeks as compared to 7 months. External genitalia donot develop fully: penile and preputial immaturity and decreased radiodensity of the os penis are frequentlyobserved. Vulvar development is also often insufficient in bitches gonadectomised at 7 weeks. Heat productionis 28% lower in neutered compared to intact cats. A decrease in urethral diameter has been observed in neuteredfemale but not male cats. Effects of prepuberal gonadectomy on behaviour vary depending on species and sex. Ingeneral, excitability and degree of activity are increased in males and females gonadectomised at 7 weeks or 7months, and when surgery is done at 7 weeks animals are found to be more excitable if compared to thosegonadectomised at 7 months. Incidence of urinary incontinence in the canine population may increasesignificantly when gonadectomy is done prior to 3 months of age. The most important anesthetic and surgicalconsiderations concern fasting, the use of a warm environment, the use of short-acting inducing drugs, of volatileanesthesia. Prepubertal neutering is probably an acceptable technique for dogs and cats, although it carries some(minor) risks which should be explained in details whenever using it for client-owned animals.(AU)

Practical use of hormones in small animal reproduction / Uso clínico de hormônios na repodução de pequenos animais

The abortifacient efficacy of prostaglandin F2alpha products (PGF) involves induction of luteolysis,stimulation of uterine contraction and cervical dilation. PGF will induce luteolysis and depress progesterone (P4)concentrations to nearly non-detectable levels very easily after day 25 or 30 following just a 4-5 day course oftreatment. PGF can be used also earlier in pregnancy provided that the onset of cytological diestrus is timedprecisely and treatment course is longer than 5 days. With late abortion, the treatment must be continued untilverification of efficacy by ultrasound as partial abortion of litters can occur. Other uses of PGF includeshortening of diestrus in bitches, emptying the uterine content and improving semen quality in dogs. Antiprolactinagents include dopamine agonists (bromocriptine or cabergoline), and serotonin antagonists(metergoline). Anti-prolactin drugs can be used to control pseudopregnancy, induce abortion and the resumptionof estrus. Antiemetic (metoclopramide and domperidone) and antipsychotic drugs (chlorpromazine andsulpiride) have prolactin release properties which are widely documented in human medicine; their clinicalefficacy in the treatment of agalactia or hypogalactia is anecdotally reported also in bitches and queens.Aglepristone saturates P4 receptors causing abortion when administered at the dose of 10 mg/kg twice 24 hoursapart. The early administration of aglepristone at 0 to 25 days after mating is approximately 99% effective inprevention of pregnancy; however, care should be taken when using it without having assayed serum P4 or afterday 35 of pregnancy. Aglepristone can be used for several other purposes among which induction of parturitionand treatment of feline mammary hypertrophy. The clinical use of other hormonal drugs such as estrogens andsympatho-mimetics for conditions such as urinary incontinence and retrograde ejaculation is briefly discussed.

Early-age neutering in dogs and cats: advantages and disadvantages / Castração precoce em cães e gatos: vantagens e desvantagens

Prepubertal gonadectomy is defined as the surgical sterilization of immature male and female animalsaging from 6-to-14 weeks, and it is a less invasive, less traumatic surgery when performed prior to puberty thanin adult animals. In dogs, growth plate closure is delayed when surgery is performed prior to puberty, but thedelay is significantly longer when neutering is done at 7 weeks as compared to 7 months. External genitalia donot develop fully: penile and preputial immaturity and decreased radiodensity of the os penis are frequentlyobserved. Vulvar development is also often insufficient in bitches gonadectomised at 7 weeks. Heat productionis 28% lower in neutered compared to intact cats. A decrease in urethral diameter has been observed in neuteredfemale but not male cats. Effects of prepuberal gonadectomy on behaviour vary depending on species and sex. Ingeneral, excitability and degree of activity are increased in males and females gonadectomised at 7 weeks or 7months, and when surgery is done at 7 weeks animals are found to be more excitable if compared to thosegonadectomised at 7 months. Incidence of urinary incontinence in the canine population may increasesignificantly when gonadectomy is done prior to 3 months of age. The most important anesthetic and surgicalconsiderations concern fasting, the use of a warm environment, the use of short-acting inducing drugs, of volatileanesthesia. Prepubertal neutering is probably an acceptable technique for dogs and cats, although it carries some(minor) risks which should be explained in details whenever using it for client-owned animals.

Ocorrência de incontinência urinária em cadelas castradas no Hospital Veterinário da universidade Anhmebi-Morumbi, São Paulo, Brasil / Occurrence of urinary incontinence in spayed bitches at the Veterinary Hospital of the Anhembi-Morumbi University, São Paulo, Brazil

Incontinência urinária (IU) pode ocorrer após castração de cadelas, quando há diminuição nos níveis circulantes de hormônios esteroides e aumento nos de gonadotrofinas, além de alteração funcional no esfíncter uretral. Para determi- nar a ocorrência da IU em cadelas castradas no Hospital Veterinário da Universidade Anhembi-Morumbi, os prontuá- rios de cadelas esterilizadas no período 2002-2009 foram analisados de agosto de 2010 a março de 2011. Foi feito conta- to telefônico com os proprietários para investigar um possível desenvolvimento de IU após a castração. Nesse período, foram contatados osproprietários de 227 cadelas. Destas, 73 (32,2%) vieram a óbito sem sintoma de IU pós-castração, 146 (64,3%) não apresentaram IU e oito (3,5%) desenvolveram IU no período de 3,8 ± 1,6 anos após castração.(AU)

Urinary incontinence (UI) can occur in bitches after spaying due to a functional alteration in the urethral sphincter. which may be caused by a number of different causes among which a decrease in the blood levels of steroidal hormones or an increase in gonadotropin in order to determine the occurrence of UI in spayed bitches at the Veterinary Hospital, University Anhembi-Morumbi, the medical records of spayed bitches in the period 2002-2009 were examined from August 2010 to March 2011. The owners of 227 bitches were contacted by telephone to search for development of UI after spaying. Of these, 73 (32.2%) died with no symptom of UI, 146 (64.3%) did not develop UI, and eight (3.5%) de- veloped UI in the period of 3.8 ± 1.6 years after castration.(AU)