Ag in the News: Foaling and Breeding
Foal's Gold: The Quest for a January 1st Birthday
For many horse breeders, January 1st holds a special significance: it's the coveted birthday for their foals. This seemingly arbitrary date carries weight in the horse world, offering several advantages for breeders and their young charges.
Market Value
In the competitive world of horse sales, age plays a crucial role. Yearlings born closer to the 1st of January have a developmental edge, typically being larger and more mature by the time of major yearling sales and other events. This can translate to a higher market value, a significant factor for breeders and investors.
Seasonal Advantage
Foals born in early January benefit from the onset of spring in the Northern Hemisphere.
They have access to fresh pasture, abundant sunlight, and warmer weather, all of which contribute to optimal growth and development.
Management Convenience
Another benefit to estrus synchronization is a concentrated foaling season, with most births occurring around the same time. This simplifies tasks like labor, feed, and veterinary care for breeders.
Synchronizing Estrous Cycles
January births, however, do not happen naturally. Mares are seasonally polyestrous, meaning they naturally cycle and breed during particular seasons. For horses, this is the longer daylight hours of spring, summer, and early fall. In winter, many mares enter a period of anestrus, where their reproductive activity shuts down. To achieve January foals, breeders must manipulate the mare's reproductive cycle to induce early breeding. Several techniques are used to synchronize estrus in mares.
Artificial Lighting
Exposing mares to extended light (14 to 16 hours per day) starting 8 to 10 weeks before the desired breeding time can stimulate the onset of their cycle. This process mimics the longer days of spring and encourages the mare's natural hormone production.
Prostaglandins (PGs)
Prostaglandins cause the regression of the corpus luteum, the structure in the ovary that produces progesterone. This drop in progesterone triggers the mare to come back into heat within a few days. PGs are effective in mares that are already cycling but not in those in deep anestrus.
Progestins
Progestins, like altrenogest, mimic the action of progesterone. They can be used to suppress estrus and then, upon withdrawal, allow the mare to come into heat. This method is used often in combination with PGs for tighter synchronization.
Combination Protocols
Often, a combination of techniques is used for optimal results. For example, mares may be put under lights and then given progestins followed by PGs to induce a synchronized estrus.
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