Controlled Reproduction for
Off Season Milk Production

For many years the processing side of Ontario's dairy goat industry has been indicating to the production side, that good quality milk is needed in consistent volumes throughout the year. Although many improvements have been made to milk quality, not enough has been done to even out milk volumes produced through the year. There is still a large flood of milk in the spring and summer months oversupplying the market, followed by insufficient volumes produced to meet market demands in the fall and winter months.

Goats in Ontario are seasonal breeders, naturally starting their estrus cycles as the day length diminishes in the fall. In order to get more does pregnant in the 'off' season, the doe needs to be fooled into showing heat when she would not normally.

Options to bring does into heat out of season include: hormones, light manipulation, introduction of a breeding buck, and combinations thereof. One of the more common, albeit least successful methods, is to simply introduce a breeding buck to the does. Many producers report that some of the does will conceive. However, in the off season it is rare to have a large number bred and pregnant using this method. In fact, it is quite common to have a zero result.

One option that is very inexpensive is to manipulate the length of the daylight period for the does. This requires sufficient light for a minimum of 15 hours per day for a minimum of 21 days. The length of light period is then gradually and steadily decreased by one to two hours per week until eight to10 hours of light per day is achieved. It is very important that the breeding bucks intended for use are exposed to the same light regime such that they are equally prepared for the upcoming breeding period.

Another option involves using hormones to jump-start the estrus cycle. Vaginal sponges treated with Progesterone (P4) can be very effective when used on their own, or with additional hormone injections. The sponges are inserted into the vagina for approximately nine to11 days and upon removal the doe will show signs of estrus in three to seven days, at which time she will accept the buck. In addition to the sponges, PMSG (Pregnant Mare Serum Gonadotropin) can be injected just before sponge removal to induce a more refined period of estrus (and ovulation). Feeding Melangesterol Acetate (MGA) for a period of time mimics a similar effect that the sponges have and can be used to induce estrus. Injections of Prostaglandins (PGF) such as Estrumate or Lutalyse can also be used.

Any of the aforementioned products should only be used in conjunction with veterinary consultation, as not all products are suitable for all animals. It is important to recognize that although these hormone preparations are safe they are considered 'off-label' and must be used with veterinary approval.

A combination of the above options may be the most effective means for maximizing pregnancies in the off-season and evening out milk production. Many producers report having good success with sponging five to 10 per cent of the does, while at the same time using light manipulation to stimulate both the does and breeding bucks. From personal experience, sponging the does and some light manipulation has worked well with up to 90 per cent success rate achieved on our farm.

Although these methods may not work perfectly all of the time, they have been used successfully by many producers to level out their production peaks and lows and achieve more even milk production year round.