It’s important to be able to detect estrus in your does to determine when breeding is viable and also to predict birthing schedules. We do not have a buck at our farm so it is important for us to be able to recognize when the doe is coming into heat to introduce a buck at the appropriate time or to be able to manipulate the heat cycle if we were to take our does to an outside breeder.
Goats are generally seasonal breeders. Meaning, they begin to come into heat or estrus in the fall and stop cycling in February. Some goats are considered “equatorial” and can cycle year round. The seasonality is caused by the animal’s’ ability to detect shortening daylight. The shorter days increase the release of Gonadotropin releasing hormone (GnRH), which causes the start of the estrous cycle.
Goats typically have an estrous cycle every 21 days which lasts for 12 to 36 hours.
Signs of Estrus are:
- Loud vocalizations and bleating
- Tail wagging
- Slightly red and swollen vulva
- Increased urination
- Decreased appetite
Teaser bucks (and buck rags) can be used to detect when a doe is in heat and the appropriate time to introduce the buck to the does. The does may exhibit interest in the teaser buck or the buck rag. The teaser buck may attempt to mount the does once the doe is in heat. Teaser bucks have been surgically altered to prevent them from reproducing but maintain the hormones and drive to detect estrus.
The estrous cycle can be artificially manipulated to allow for breeding year round through methods such as:
- Use of artificial lighting
Lighting can be adjusted to imitate shortening days to stimulate the release of GnRH. To induce a heat cycle, goats must be exposed to 16 hours of lighting at 70 lumens during the fall or spring. Remove the artificial lighting and resume natural lighting. The doe should cycle 4-6 weeks after the removal of the lighting. Generally, the buck should be exposed to the same lighting schedule. Even though bucks are fertile year round, they also experience seasonal levels of libido.
2. Controlled internal drug release (CIDR)
CIDRs are placed intravaginally and deliver progestogen (progesterone-like hormone) which prevents ovulation until the breeder is ready to have the animal bred. This helps to control when kidding will occur to coincide with show circuits, ethnic holidays, kidding schedules, etc. CIDRs can be purchased through most farm supply stores or even on Amazon Click to View .
Please feel free to share your best practices with us! We’re always interested in hearing what others have learned and what works best for you!