Artificial Insemination and Embryo Transfer Develop Elite Herds

By Catherine Riley

To develop an elite herd of small ruminates, artificial insemination and embryo transfer offer the most economical way to infuse superior genetics into the herd or flock.   While not inexpensive these two reproductive avenues allow the producer to select from numerous sires that can be matched to the needs of the herd, rather that using a one size fits all philosophy of one buck or ram for the entire group.

When considering AI or ET, the producer has to think well in advance of breeding dates, this decision is not one that can be made in just a few weeks.

As with any breeding program, the number one prerequisite for success is the health of the herd,  All females must be in good flesh and parasite free.  Free choice mineral is necessary particularly in areas of mineral deficiency like Kentucky. There are several on the market that are specifically formulated for reproductive health.

Selection of the sire, is dependent on your herd, you need to balance budget, quality and availability.  If the most budget friendly option doesn’t improve your herd then you waste money and time. After selection is made you will then need to decide whether to ultilize fresh or frozen semen.  There are pros and cons to both,  Talk with you reproductive service and with breeders who have successful ET and AI programs to determine what will be the best for you. Select reputable breeders and storage facilities who have reliable shipping available.

Programming your females- Both AI and ET require a hormone protocol for the females. Protocols vary depending on the reproductive service you have selected, time of year and type of semen you are planning on using.

AI is a simpler procedure but does require insertion of a progesterone infused controlled internal drug release or Cidr into the vagina of the female, for either a short or full cycle or 7-21 days.  Progesterone is the pregnancy hormone and the doe’s endocrine system thinks she’s pregnant.  Prior to the procedure the Cidr is pulled and a shot of a synthetic hormone is given and the female should respond by coming into heat within 48 hrs.

ET is more complex with a rigid hormone shot protocol.  The protocol will vary from service to service.  Of course the rationale around a flush is a superior doe can produce more than two offspring.

Beginning 17 - 21 days prior to breeding  both donors and receipts or the surrogate mothers receive Cidrs.  

Seven days prior to breeding the donors begin five days of shots of a synthetic follicle stimulating hormone or FSH.  These shots are given twelve hours apart. These shots cause the super ovulation.  The Cidr is pulled prior to breedingwith timing dependent of time of breeding and type of semen being used. The use of a teaser buck is helpful in bringing the does into estrus and releasing those all important oocytes.

The donors can be bred naturally, with frozen semen or fresh.

Just like the donors the receipiants need to be in prime health, parasite free and good body condidtion. The recips are programmed similarly to the donor but without the super ovulation.  Again a teaser buck helps bring these does into estrus.

Six days after breeding the embryos which are at the blastocyst stage are flushed from the doe’s reproductive tract and implanted into recip females.

There are several things that can keep work against a successful flush.  Donors not coming into estrus is frustrating, but just happens. It appears that the ovulation is weather dependent. If the barometer drops from a rain storm three days after breeding, the doe will regress or literally pull the unreleased ova back into the ovary.

At the 6th day after breeding the embryos are removed via laparoscopic flush or transcervicial flush. Embryos are graded and only those that are fertile and viable are used to implant in the recip females. Some embryos may be considered degenerative or degens and some unfertilized or UFO’s.

What can a producer expect as far as number of embryos  AI and flush in small ruminants is not an exact science.  But as one producer noted anything over 3 is a success.  Some does may ovulate numbers as large as 25 and others in the single digits. Embryo production is dependent on a genetic lines, overall health of the donor, increasing nutrition levels and the environment.

Conception rate is also not a given.  It does appear that some recepts are “sticky”- regularly hold embryos and give birth.

One of the downsides of flushing is travel to a facility or partnering up with another breeder to organize a flush and bring a service to the farm.

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Catherine Riley with Eclipse Livestock is in the process of building a small ruminant reproduction center on her farm in Henry County.  Catherine received funds from the KADC as well as local county’s and currently has a usable facility but shortly a finished facility with area specific rooms which are cleaned and sanitized between flush days will be available.  Catherine has dates set for her own herd and invites others to use those dates for a sheep and goat AI and/or ET.  She will help groups use the facility at dates of their own choosing. Consultations are recommended prior to scheduling, to review sire and semen selection, medication and protocol needs. Feel free to contact Catherine at cmrile4@gmail.com