Intro to small animal reproduction

• Oestrus control common in small animal species - Progestogen

  Temporary prevention.

  Single dose injected in anoestrus or proestrus.

  Long term prevention: additional closes given at 3 then 4 then every 5 months.

  This can cause signs of oestrus before the down regulation.
• Oestrus control common in small animal species - GnRH Superagonist


  Temporary infertility in sexuality immature female dogs (licensed).

  Temporary infertility in sexually mature female dogs (not licensed but good data).

  Implant placed and can be repeated every 6-12 months dependant on bodyweight and size of the implant.
• Overview of the cycle in the Bitch

  Mon-oestrus (interval 7 months)

  Spontaneous ovulator.

  Obligatory long luteal phase similar to pregnancy.

  Non-seasonal anoestrus.
• Schematic representation of the non-pregnant oestrus cycle of the bitch

  Long period of time when progesterone is dominant, in the dog we have 3 or 4 months when nothing is happening.

  Progesterone levels in pregnancy and non-pregnancy similar.

  
• Schematic representation of pregnancy vs non-pregnancy in the bitch

  Very obvious pre-ovulatory rise in progesterone, this can be measured to guess breeding times. Progesterone falls massively before parturition, but will slowly return to basal values in the non-pregnant animals.

  
• Prolactin secretion during pregnancy and non-pregnancy of the bitch

  Prolactin is responsible for supporting the progesterone production of the CL, so prolactin is luteotrophic.

  Also there to support lactation, the initiation and maintenance, can also cause behavioural changes.

  
• Overview of the cycle in the Queen

  Seasonal (long day breeder = doesn’t cycle over winter).

  Polyoestrus

  Induced ovulatory (no luteal phase unless ovulation), no ovulation, no luteal phase, so no progesterone.

  Cyclicality differs if ovulates or doesn’t ovulate.
• Cyclicity of the queen

  Queen is a typical induced ovulator:

  • New follicular wave develops a few weeks later.
  • Average interval is 16 to 21 days.

  When in between oestrus, described as inter-oestrus (as there is no luteal phase). So follicle waves with no ovulation, therefore no luteal phase.
• How to induce ovulation in queens

  LH concentrations from mating must exceed a threshold to induce ovulation. There can be a significant difference between queens in magnitude of the LH surge, and there is a difference depending on the day of the cycle (greatest response is mod-oestrus).

  
• optimising breeding in the dog - measure hormone changes

  Progesterone levels in the blood. Repeated sampling for progesterone starting on Day 7 and looking for an increase.
• optimising breeding in the dog - indirect assessment of hormones

  Vaginal cytology looking mating from 80% a nuclear cells (vaginal wall changes when in oestrus or anoestrus).

  Vaginoscopy looking for mating from angulated phase.

  Behavioural looking for mating from 4 days after onset standing in oestrus (but not reliable).

  Vulval swelling looking for mating from onset of distinct softening (but not reliable).
• To optimise breeding timing in cats

  Ensure breeding occurs on the correct day (day 3).

  Ensure that multiple breedings are allowed within a short period of time.

  Possibly could consider inducing ovulation using hCG or short acting GnRH (this requires the queen to be to be in oestrus so often these are given at the time of mating or immediately after mating).
• Developing a diagnostic plan for those presented with vulval discharge.

  A breeding soundness exam.

  Investigating of infertility or disease.

  Diagnosis/ evaluation of pregnancy.

  Investigation of dystocia

  Investigation of post-partum disease.

  Also use clinical history to rule things out, for example if is a prepubertal bitch then is not going to be dystocia or Pyometra (which requires progesterone).
• Examination of the reproductive tract of the bitch

  Clinical history

  Previous breeding records

  Venereal pathogen screening

  General clinical examination.

  Specific reproductive examination.
• Clinical history questions for reproductive problems

  Previous cycles (normal/abnormal)

  Normal mating

  Ovulation confirmed

  Previous pregnancy confirmed

  Pregnancy to term

  Reproductive tract discharge

  Behavioural manifestations.
• Bitch venereal pathogen screening - bacteriology

  The vestibbule and vagina have a normal commensal flora which changes daily

  • Many bacteria present: Staphs, Streps, E.coli
  • Often there is a mixed flora
  • Pseudomonas is not commonly isolated
  • Brucella canis is a venereal pathogen in the UK (can cause abortion, stillbirth, fading pups and is ZOONOTIC but witch a low chance of transmission to man).

  The uterus is normally bacteriologically sterile

  • Vaginal bacteria may enter the uterus at oestrus.
• Bitch interpretation of Vaginal swabs


  Most swabs are taken from the vestibule.

  Swabs should be expected to contain commensal bacteria.

  The only known bacterial venereal pathogen is Brucella canis.

  Routine screening of the clinically normal bitch is pointless (may change if Brucella becomes more prevalent). However a lot of stud dog owners insist on a negative swab pre-mating, this can cause a problem as will likely grow commensals.

  Routine antibiotic use is not appropriate.
• Bitch venereal pathogen screening - virology

  Canine herpes virus

  • A known venereal pathogen causing vesicular lesions in the genital tract of dogs and bitches.
  • Appears to be increasingly common but no studies on prevalence in UK.
  • In bitches it may cause resorption, abortion, stillbirths; depending upon when infection occurs.
  • Infection can be venereally or via the respiratory tract.
  • Some viral recrudescence occurs with many herpes virus.
  • A vaccine is available for bitches and is given twice during pregnancy to protect that litter.
• Queen venereal pathogen screening - bacteriology

  The vestibule and vagina have a normal commensal flora which changes daily.

  • Many bacteria are present: staphs, Streps, E.coli.
  • Often there is a mixed flora.
  • Bacteria are commonly isolated from stillborn kittens and are likely opportunistic commensals.

  The uterus is normally bacteriologically sterile:

  • Vaginal bacteria may enter the uterus at oestrus.
• Queen venereal pathogen screening - virology

  Feline Leukaemia Virus (FeLV)

  • Implicated in infertility, resorption and abortion.
  • The most common cause of infectious infertility.
  • Screening of queens prior to breeding is important.

  Other viruses that cause pregnancy loss associated with infection during pregnancy - but are not venereal pathogens:

  • Feline herpes virus
  • Feline panleukopenia virus.
• Vaginal cytology

  Assessment of the stage of the cycle.

  Establishment of normality;

  • Collection by aspiration
  • Collection by swab
  • Use of haemotology stains - look for large a nuclear cells.

  Elevated plasma oestrogen causes epithelial proliferation

  Epithelium changes from cuboidal to stratified squamous.

  Surface cells are collected and relative number reflects the degree of epithelial proliferation.
• Uterine ultrasound

  The uterus is positioned dorsal to the bladder:

  • Tubular in sagittal plane
  • Circular in transverse plane.

  Appearance varies according to stage of the oestrus cycle.
• Common uterine pathology

  Cystic endometrial hyperplasia, mucometra, pyometra complex.
• Diagnosis of pregnancy

  As early as day 20 after ovulation bitch

  • But can normally scan undertaken 28 days from mating as day of ovulation not always known.

  As early as day 18 after ovulation in queen:

  • But normally scan undertaken 28 days from mating.
• Ultrasound examination of the ovaries - normal cyclicity


  Situated in the dorsal abdomen caudal to the kidneys.

  Appearance varies according to stage of the oestrus cycle.

  Can be difficult to detect as bursa often contains much fat.

  Ovulation difficult to determine as CLs have fluid cavities.
• Ultrasound examination of the ovaries - abnormal ovaries

  Abnormalities are rare.

  Commonest abnormality where imaging used to investigate would probably be ovarian neoplasia.
• Radiography of the reproductive tract

  Usually conducted to determine pregnancy or fetal number/ fetal death.

  Otherwise less commonly used to examine the reproductive tract as been replaced by ultrasound.

  Plain radiographs and contrast studies.
• Radiology for pregnancy diagnosis and detection - overview

  Mineralisation. of the skeleton at day 45

  Documentation of fetal number by counting skulls.

  Can see the size of the foetus compared to the dam.

  Detection of fetal death occurs several days after death:

  • Loss of normal posture
  • Overlapping of skull bones.
  • Accumulation of gas in fets/ uterus.
• Radiology for pregnancy diagnosis and detection - plain radiography

  Normal ovaries and uterus are not normally visible in plain radiographs.

  Detection of enlargement may be possible in some cases; usually this is a soft tissue opacity mass causing displacement of other structures where location is suspicious of the reproductive tract.
• Endocrine testing for pregnancy

  Progesterone rises before and throughout ovulation.

  Progesterone declines prior to parturition.

  hCG stimulation test:

  • Confirmation of functioning (presence) of the ovary.

  GnRH stimulation test:

  • Confirmation of functioning (presence) of the ovary and pituitary.
• What is the most common cause of infertility in the bitch?

  Mating at an incorrect time
• What is the most common cause of infertility in the queen?

  Mating insufficient number of times on the correct day to induce ovulation.