Camelid Breeding Cycle - Anatomy & Physiology

Male

Puberty

• Puberty in the male is generally defined as the time when he is capable of successfully mating a female and getting her pregnant.
• 3 - 5 years of age.
• Sexual activity can continue until 20 years of age
  • Can vary with breed, genetics, nutrition and climatic changes.

Seasonality

• Changes in sexual behaviour, morphology and function of the genital organs, as well as changes in endocrinological profiles.
• Very variable but generally coincides with the period of low humidity, low temperature, and increased rainfall.

Anatomical Evidence for Seasonality

• Increase in size and activity of the testis and accessory glands during the coolest months of the year.
• Increased spermatogenic and secretory activity during the rutting season.
• Increased secretory activity of the poll glands giving the characteristic smell of the rutting male.

Endocrinological Evidence for Seasonality

• Increased secretion of androgen, especially testosterone.
  • May be due to increased synthesis and release of testosterone either by an increased sensitivity of Leydig cells to LH, or an enhanced secretion of LH from the pituitary gland or both.

Pituitary and circulating Follicle Stimulating Hormone (FSH) levels are significantly affected by season.

• • The highest concentrations are reached during winter and tends to drop reaching a minimum in summer before increasing again in Autumn.
  • Highest frequency and amplitude of LH pulses during the cooler months (December - January).
• Serum prolactin levels are high during the non-breeding season and decrease significantly in the rutting season.

Female

Cyclicity

• Induced ovulator
  • A few individuals will ovulate in absence of mating.
• Follicular waves occur, where a follicle will gradually mature to a point when it could be ovulated should mating occur. It will then regress if no mating takes place.
• Folicular waves generally occur every 10-12 days, but there is variation between individual animals.
• As follicles mature, they produce Oestrogen, which is responsible for receptivity behaviour.
• Once ovulation has occured,luteinization occurs with the formation of a corpus luteum.
• Corpus luteum produces progesterone.
• Progesterone inhibits further follicular development and triggers rejection behaviour.
• If there is no pregnancy, luteolysis occurs and the corpus luteum is broken down. This allows a new follicle to develop.
• The overlapping nature of follicular waves and the fact that the female is receptive even if the follicle is not mature enough to ovulate makes it difficult to determine from behaviour when the optimum time for mating is.

Ovulation

• Triggered as a result of hormones released by the act of copulation.
• Occurs 24-48 hours after mating.
• Will only occur if the follicle is sufficiently mature, yet not so mature that it has lost the ability to ovulate.
• Sperm ejaculated into the uterine horns are protected inside a gelatinous plug until fertilization.
  • The plug gradually liquifies.