Parturition Pharmacological Manipulation - Anatomy & Physiology

BACK TO REPRODUCTIVE SYSTEM BACK TO PARTURITION

Why Control Timing of Parturition?

Herds

• Improves supervision to ensure the farmer can be around at the time of parturition.
• Reduces the incidence of parturition at night/weekends which is socially undesirable.
• Aids cross fostering between litters.
• Tightens the calving interval in cattle.

Individuals

• Maternal emergrncy such as abnormal foetal position, bone fracture of the pelvis etc.
• Foetal abnormality, or an oversized foetus.

Disadvantages of Parturition Induction

• Timing may not be absolutely perfect, there is considerable variation in the timing of drug action and effect.
• Premature delivery of small, immature offspring.
• Increased incidence of retained placenta.
• Pharmacological induction can only be used commercially in cattle and pigs. Induction in other species is used only to overcome birth associated problems.

Requirements for Parturition Induction

  Prostaglandin F2α: Cervical dilation
  Prostaglandin F2α and Oxytocin: Uterine contractions
  Oxytocin: delivery of the Placenta

• Oxytocin and Prostaglandin F2α both signal by the Gαq -> IP3 + DAG pathway to raise intracellular calcium , so are able to effect each other in the Fergusson reflex.

Drugs Influencing Uterine Activity

Myometrial Innervation and Manipulation

Induction of Parturition