Recent interest has been directed toward deep intrau-terine deposition of extended semen and a possible role this technique can have in allowing a decreased total sperm number and dose volume to be inseminated into sows. Rath et al. demonstrated no differences in pregnancy rate, farrowing rate and litter size when gilts were surgically inseminated into the tip of the uterine horn with either 1 X 10~9, 2 X 10~8, 2 X 10~7, or 1 X 10~7 sperm/animal in 0.5 ml extended volume. In addition, no differenceswere found in fertility among sows surgically inseminated into the uterine horns with 2 X 10~9, 2 X 10~8, and 2 X 10~7 sperm versus sows inseminated intracervically with 1 X 10~9 or 3 X 10~9 sperm (1). A Spanish research group has reported a 100% pregnancy rate (n=5) by using a flexible fiberscope to traverse though the cervix and deposit 2 X 10~8 sperm/ dose in 5 ml of volume. These results provide encouragement at the possibility of deep intrauterine insemination expanding boar power, however, surgical and fiberscopic inseminations are not practical in today's production systems. In an effort to apply deep intrauterine deposition of extended semen on a more economical and commercially viable basis, inexpensive transcervical catheters have been recently developed. In general, these transcervical catheters consist of a conventional-type disposable AI catheter, with an inner catheter that can extend past the tip of the conventional AI catheter, through the cervix, and into the uterine lumen. Extended semen traverses through this inner catheter, allowing for its deposition within the uterine lumen. Preliminary field reports using a commercially available, disposable transcervical catheter have provided support that as little as 1.0 billion sperm/80 mLdose could be inseminated into sows without an appreciable loss in fertility (3). When taken collectively, the results appear promising that transcervical artificial insemination (transAI) may be a viable assisted reproductive technique. To further define the field capabilities of transAI, two studies were performed to determine if the variables of insemination technique (conventional versus transAI) and total sperm number/dose had an effect on 30-day conception rate, farrowing rate, total born and live born.
展开▼
