Using Cooled or Frozen Semen in Equine AI Programs

According to the American Association of Equine Practitioners (AAEP), using advanced technologies such as cooled or frozen semen, embryo transfer, and gamete inter fallopian tube transfer (GIFT) has given horse breeders a wide range of choices and freedoms when deciding which stallion to use with a particular mare.  These technologies are not new, but have been slower to be adopted and used in the equine industry due to a lower tolerance of equine semen to the processes of cooling or freezing and thawing than some other species.  However, using a form of artificial insemination certainly opens to door to a lot more options than using the tried and true traditional method of shipping mares all over the country for boarding and exposure to a certain stallion.  It also extends the season for a stallion, which can be interrupted due to other obligations such as shows or races.

Cooled semen is semen that has been collected, had an extender added, and was cooled to a temperature of 4-6 degrees Celsius (39 – 43 degrees F).  This semen can be kept for up to 72 hours and still be viable for use with a mare.  During that 72 hours, the semen is usually shipped using a special container that keeps the temperature constant.  Using cooled semen will result in a higher pregnancy rate than when using frozen semen – IF all the protocols are followed to the letter.  Taking short cuts in the procedure results in a lower success rate and fewer foals.  The AAEP has a list of considerations that need to be addressed before attempting to use the cooled semen process.

The advantages of using the cooled semen process include:

·      The location of the stallion is not really critical.

·      Avoids the cost, stress, and danger of shipment for the mare and foal.

·      Avoids the risk of exposure to contagious diseases at the boarding and breeding facilities.

·      Increases the ability to select a stallion with the desired pedigree and/or performance records.

Disadvantages are:

             ·      Some stallions having acceptable fertility using fresh semen will not maintain that level of fertility when their semen is cooled and shipped.

             ·      More sperm is necessary for good pregnancy rates when compared to using fresh semen for AI.

             ·      Good mare management is crucial for an acceptable pregnancy rate.
       ·      Costs of equipment, supplies, semen, semen transport, and veterinary costs can offset any savings.

Generally, pregnancy rates for a given stallion run 5 to 10 percent lower using cooled, shipped semen rather than fresh semen.  The range of fertility results runs from 0% to 70%.  This wide variation points out the necessity of good management and quality control in the process of using cooled, shipped semen for breeding mares.

The advantages and disadvantages of using frozen semen are similar to those associated with using cooled semen for breeding.  One additional advantage is that once frozen, the sperm can remain viable for a long time, so the timing of breeding can be more flexible.  

Some disadvantages (other than getting access to liquid nitrogen) of using frozen semen include an even lower conception rate (though success rates of around 60% have been reported) and the discrepancy/distinction between using a dose of semen for a breeding session versus using a straw of semen.  Depending on how the semen is processed and frozen, a single straw will likely not contain enough viable semen.  A dose can be up to eight straws, again depending on how they were processed.  Consider the costs associated with the dose required for best results rather than just the cost of a straw of semen.  

Horse owners considering one of these forms of AI should visit with their veterinarian to ensure that the necessary arrangements and details can be satisfied.   There is also more information available through AAEP.

Breeding Horse Hygiene

 When it comes to breeding, clean horses are very important. In particular, the hygiene of your stallion can “make or break” the success of your breeding program. I will cover the basics of female and male hygiene as it pertains to breeding.

Female:

            A major cause of failure to breed in female horses is persistent post-breeding endometriosis (PPBM). This inflammation is caused by the deposition of semen, bacteria and debris into the horse; in normal cases, this is reduced and/or gone by 48 hours after natural cover. In other situations, the female remains inflamed and problems arise (embryonic death, failure to conceive, etc). Minimizing contamination is important…utilizing proper hygiene can help with the prevention of PPBM. Bandaging the mare’s tail, and cleaning the vulva and perineal area with sterile water contribute to proper hygiene. Some studs will clip the top of the tail which may be more hygienic than simply bandaging the tail.

http://www.youtube.com/watch?v=srZhtfLFVFg

Male:

            The most important upkeep of your stallion for breeding purposes, other than making sure he is physically able to mount and ejaculate, is the cleaning of his sheath. In fact, whether the horse is a gelding or a stallion, the sheath should be cleaned periodically. A dirty sheath can lead to infection and urinary problems. Prior to breeding, the penis should be rinsed with clean water (no soap), including the urethral diverticulum. The external genitalia should be cleaned with a bucket, and that bucket cleaned between stallions in a stud, to prevent transfer of possible diseases.

http://www.thehorse.com/videos/30323/sheath-cleaning-for-male-horses-how-to

It's important to have clean, healthy animals before breeding. This can help ensure diseases are not spread between animals or herds, and increases your chances of a health foal!

             

            

Feeding Your Horse

I'm sure this article has already been linked to this site numerous times but it is an excellent read for horse owners.  I  encourage everyone to look at their pastures strive to increase the yield of the forage to reduce the need for additional, often very costly, hay.  Remember that you are not only a horse owner but you are a hay farmer as well!

Look at the growth seasons of the grasses (Page 8) if you are thinking about changing the forage species that you currently have.  Winter over-seeding is also an option to help you gain forage supply year round.

http://content.ces.ncsu.edu/managing-pastures-to-feed-your-horse.pdf

Preparing for Fly Season

By: Lee Townsend, Extension Entomologist

University of Kentucky College of Agriculture

House flies and stable flies are common pests around horse barns, stables, and corrals.  Persistent house flies are very annoying and potential carriers of human and animal pathogens.  Stable flies give painful bites making activities unpleasant for humans and making horses nervous and difficult to manage.

House flies visit most any moist material from manure and decaying organic matter to garbage to blot up a liquid meal with their sponging mouthparts.  They can carry a range of pathogens for such things as intestinal disorders and eye infections on their restless journeys.  Females may deposit batches of eggs as they feed on a variety of moist, fermenting organic matter, manure, rotting hay, feed silage, or garbage.  The cycle from egg to adult takes from 7 to 14 days, depending on environmental conditions.  Mature larvae will crawl to drier sites to pupate and emerge as adults.

The stable fly resembles a house fly but has a distinct piercing mouthpart that projects from the front of its head.  Males and females are blood feeders, usually attacking the flanks or below the knee causing horses to stamp or kick themselves.  The fly is on the animal for only a few minutes; after feeding it moves to walls, fences, or other surfaces to digest its meal.  Stable fly maggots develop in decaying organic matter.  A fermenting mixture of straw, spilled feed, or hay, and urine or water is ideal.  Horse manure is usually too dry but becomes suitable if moistened. Females lay several batches of 40 to 80 eggs. Development from egg to adult takes 21 to 25 days during the summer.

House flies and stable flies need breeding material, moisture, and warmth to develop.  A successful fly control program must rely on timely elimination of breeding sites and moisture control.  Insecticides can help to provide some temporary reduction of house fly and stable fly populations but cannot be the basis of effective fly management.

Elimination of breeding site is the key to a successful fly control program.  Barns and corrals should be cleaned once a week to break fly life cycles.  Removed manure and other fly breeding materials should be spread thinly over an appropriate area or composted, if practical.

Maintain good drainage to eliminate wet manure, spilled feed, and hay or straw.  Check for and correct wet areas around animal waterers.  Dry manure and accumulated organic matter are not good breeding sites.

Mechanical Control

·      Screening is an excellent way to keep flies out of feed and tack rooms and box stalls

·      Fans that direct a downward and outward air flow will keep flies from entering barns.

·      Fly traps and sticky paper will capture flies.  They may be most useful as a means of documenting fly numbers over time.  A significant increase in catch from one week to the next can be a warning to check on sanitation and to increase fly control measures.

·      Several commercial firms offer a fly parasite (predator) release program that can be used to supplement fly control.

Insecticides as Supplements to Fly Control

Insecticides are used to kill adult flies after a problem has developed.  While they can help to reduce fly numbers, they do not address their source – moist breeding materials.  There are many alternatives for fly control but they should be viewed as a temporary solution until the root cause of the problem can be corrected.  Large numbers of flies mean lots of breeding sites and a situation that cannot be corrected by insecticides alone.

Residual insecticides are applied to walls, ceilings, and rafters of barns and sheds where flies rest.  General observations and accumulations of fly specks (waste drops) will help to identify these spots.  Be sure to protect water and feed when making applications.  In order to minimize control failures due to insecticide resistance, do not apply the same insecticide or insecticide within he same chemical class repeatedly throughout an entire season.

Class	Brand Name	Precautions and Remarks
Cyromazine	Neporex	Spray or dry application to stall bedding or muck pile
	Solitude IGR	In feed to control fly larvae in manure
Spinosad	Elector	Spray to runoff: 1 gallon per 500 to 1,000 square feet.  Horses may be present when applied.  Do not use more than once each week.  Do not make more than 5 consecutive applications

CAUTION:  ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR SAFE USE OF ANY PESTICIDE!

Homemade Horse Fly Spray Recipe:

·      2 cups White Vinegar

·      1 tablespoon Eucalyptus Oil

·      1 cup Water

·       

Directions: Mix the ingredients together well in a spray bottle - always shake well before every use – and spray the horse

Results: Effective protection for about 45 minutes to 1 hour.