Introduction
The manipulation of normal cyclic activity ensures optimum production or is convenient for the herdsmen or owner. In the case of seasonal breeders, it allows them to breed out of season, or to advance the onset of cyclic activity. There are also advantages in ensuring all animals in a group come into oestrus at the same time for ease of management.
There are two methods of oestrus synchronisation. One is physiological manipulation of the oestrous cycle, and the other pharmacological manipulation of the cycle. Various factors must be considered before deciding which method to use. These factors will be specific to the type of production unit and species, also the stage of the natural oestrous cycle in the animal/herd involved.
Factors Influencing Reproduction
Physiological
Light
Nutrition
Other Methods
Pharmacalogical
Preparations which Stimulate Release of Anterior Pituitary Hormones
Preparations which Supplement or Replace Pituitary Gonadotrophins
Oestrogens
Progestogens
Manipulation of the Oestrous Cycle in Various Species
Sheep
Factors to Consider Before Deciding which Method to Use
Physiological: The Ram Effect
Pharmacological: Progestagens
Intravaginal Sponges
Pharmacological: Prostaglandins
Pharmacological: Melatonin
Cow
Controlling Oestrous
Pharmacological: Prostaglandins
Pharmacological: Progestagens
Mare
Reasons to Control the Oestrous Cycle
Control in the Transition Period
Control in the Breeding Period
Inducing Ovulation
Sow
Pharmacological: Progestagens
Pharmacological: Gonadotrophins
Bitch
Pharmacological: Progesterone
Pharmacological: Synthetic Progestagens
Proligestone (PRG)
Pharmacological: Testosterone
Queen
Pharmacological: hCG
Pharmacological: Androgens
Pharmacological: Synthetic Progesterone
