Page 451 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

426 CHAPTER 2

VetBooks.ir lection, extension, preservation, monitoring and • There is a huge variation between and within
The technique and technology of semen col-
stallions in the ability of their semen to
transport are covered in Chapter 2.2, The male
in the longevity of the chilled semen
reproductive tract (p. 526). withstand freezing and thawing techniques and
The advantages of AI are:
The cost of some AI programmes may mean that a
• An increased conception rate in some stallions full BSE is indicated to avoid insemination in a mare
and mares with fresh or chilled semen. that does not have a uterus capable of facilitating
• Mares can be bred by stallions that would conception and pregnancy. It is recommended that
otherwise be geographically inaccessible. all mares and stallions have appropriate pre- breeding
• Mares and foals are not subject to transport stress. tests performed (equine viral arteritis [EVA], CEM,
• Mares can remain in training. equine infectious anaemia). A cervical/ endometrial
• Mare owners save on transport costs. swab and smear taken in oestrus are also recom-
• Reduced contamination of mares and less risk of mended to identify any endometritis or uterine
disease transmission. inflammation. Suggested protocols for insemination
• Increased flexibility in timing of mating, thus of mares with different inseminates are listed below.
maximising the use of a stallion during and There is considerable variation among clinicians in
beyond his reproductive years. their approach to this, particularly when using fro-
• Control/prevention of venereal diseases. zen semen, and the information should be viewed in
• Frozen semen additional benefits include: semen this light (Fig. 2.24).
can be kept indefinitely; mare can be bred at any
time, including when the stallion is unavailable; Fresh or chilled semen
worldwide availability of semen; single shipping • Ultrasound scan the mare until she is in oestrus
of semen per season. with a >35 mm follicle, uterine oedema and a
• Reduced risk of injury to mare and stallion as relaxed cervix. The aim is to inseminate the
there is no physical contact. mare prior to ovulation and for ovulation to
• The stallion is not ‘overworked’, as one ejaculate occur within 24 hours of insemination. The use
can be split between numerous mares depending of hCG or deslorelin is routine.
on the semen concentration.

The disadvantages of AI are: 2.24

• Veterinary input and expenses are greater,
especially when using frozen semen.
• Communication between veterinarian, mare
owner and stallion owner is essential.
• Repeat inseminations lead to increased semen
collection and shipping costs.
• Conception rates using frozen semen may be less
than that with fresh semen or natural covering.
With good management, conception rates are
>75% for fresh semen and >60% for both cooled
and frozen semen.
• International quarantine requirements for
collection and import restrictions.
• High semen processing costs and specialised
equipment and laboratory facilities required, Fig. 2.24 Hysteroscopic artificial insemination of a
especially for the production of frozen semen. mare. (Photo courtesy Tracey Chenier)