Insemination of sheep may be vaginal, cervical (posterior or transcervical), or intrauterine.

Vaginal insemination deposits fresh diluted semen into the anterior of the vagina without an attempt to locate the cervix.  It is the simplest and easiest method but requires a larger dose of semen and the success rates are usually less than other methods.
 

Posterior cervical insemination uses a pipette to transverse the vagina and deposit fresh diluted semen at the cervical opening.   It is a technique that is relatively easy to perform, but is limited to fresh semen (diluted or undiluted) since conception rates are generally lower with frozen semen.  It is the most common method used in sheep.
 

Trancervical insemination is performed by inserting a thin pipette through the cervix and depositing the sperm directly into the uterus. Because of the anatomic complexity of the ewe’s cervix, it is more difficult to perform than posterior cervical AI.  This method requires a special pipette but allows the use of either fresh or frozen semen at fairly high success rates.
 

Intrauterine insemination is often referred to as laparoscopic artificial insemination (LAI) and is accomplished by depositing semen directly into the uterus through an abdominal incision. Conception rates are typically very high.  Because LAI is an invasive procedure, it requires  the  expertise  of  a  trained  veterinarian  which  makes  it  cost-prohibitive  and  less  available  for producers.