Introduction

• Diagnosis:
  • Females: for bitches of small breeds, onset of puberty begins between 6-10 months of age; whereas it may not begin until 24 months of age in bithces of large breeds.
  • Males: first ejaculation with viable sperm by 7-10 months of age but some dogs may not reach it until 12 months of age.

Pathogenesis

Etiology

• Poor body condition.
• Disorders of sexual development in males and females (cases of sex reversal) leading to delayed puberty and primary anestrus Disorders of sexual development.
  Evidence of cyclicity does not rule out the presence of genetic, chcromosomal abnormalities.

Predisposing factors

• Poor nutrition.
• Lack of contact with sexually mature animal; social effect demonstrated in several domestic species but not completely elucidated in the dog.

Pathophysiology

• Poor nutrition → failure to attain critical bodyweight (60% adult bodyweight) → delayed hypothalamic-pituitary-gonadal axis maturation.
• Chromosomal abnormalities - unknown.

Timecourse

• Most never reproduce successfully; irregular cyclces, short interestrus intervals.

• Litter size and sperm output may be suppressed for the life.

Epidemiology

• Stray dogs associated with poor nutrition; tropical regions.

Diagnosis

Treatment

Outcomes