artificial insemination. The stallion

Introduction
For successful fertilization, the stallion used is just as important as the mare. Since a stallion can produce many more descendants in his lifetime than a mare, people have been applying the principles of selection to stallions for centuries. This has lead to the blooming sector known as stud management. Until recently, this activity was regulated in the Netherlands by the Horse Breeding Act of 1939 in whichonly stallions approved by the studbooks could be used for breeding. This legislation, however, has been replaced by European regulations. These days, all stallions satisfying minimum veterinary standards may be used for servicing. The studbooks may provide direction in regard to breeding and arc required to register horses. In practice, however, it appears that stallions being used for breeding are usually approved by studbooks, and the number of mares being served by stallions not approved by studbooks is very modest.

It turns out that only a few stallions available for breeding arc actually being used to serve the many mares being bred. Naturally, this can lead to problems, In the Netherlands, the vast majority of male animals are not used for reproductive purposes and are castrated.

Anatomy
The stallion's reproduction system consists of:

The testicles (testes)
The epididymus
The seminal vesicles
The seminal ducts
The prostate
The bulbo-urethral glands
The urethra
The penis

The testicles (testes)
Sperm cells are produced in the testicles. The number produced daily is more or less constant. In horses, the testicles arc located in the scrotum which is located outside of the abdominal cavity.

The epididymus
This is where the sperm cells arc stored and where they mature as they travel through the epididymus. Since the s maturation process lasts several weeks, diseases and fevers can harm the quality of the semen ejaculated at a much later date.

The seminal ducts
The seminal ducts are accompanied by blood vessels to form the spermatic cord which runs from the abdominal cavity through the inguinal canal to the testicles am and epididymus.

The accessory sex glands
The accessory sex glands add a number of I mucous-like substances to the sperm cells. In terms of equine health, they seldom cause any problems. The seminal vesicles, however, can sometimes become infected and cause blood and/or puss to be ejaculated with the semen

Hormone regulation of the male animal
Stallions display no clear hormone cycle and can also be used for breeding during the winter. The development of the stallion's sex organs and the development of sperm, however, are also controlled by hormones. In the male animal the hypophys is also produces the same sexual hormones as it does in the female animal FSH. Follicle stimulating hormone. Among male animals, this stimulates semen production.

LH. Luteinizing hormone.
This hormone stimulates certain cells in the testicles to produce male sex hormones (including testosterone).

Testosterone.
This is produced by the cells in the testicles and stimulates sperm development as well as typical male behavior and the development of secondary sexual characteristics (e.g., thickened neck and heavy muscling). Testosterone slows the production of FSH and LH so that a certain hormonal balance develop

Pharmaceutical agents.
Unfortunately, semen production in the stallion can be increased only minimally by the administration of hormones, What's more, a stallion that produces semen of poor quality cannot be helped by the use of drugs. Although testosterone like substances (anabolic steroids) are often used for such purposes as increasing performance among sporting horses due to their ability to save protein and encourage muscle development, they lessen semen quality.

The quality and quantity of semen
For a reasonable chance of pregnancy after covering (or insemination), a certain quantity of sperm cells exhibiting reasonable quality arc needed. Semen is assessed according to these criteria:

Volume (number of ml.)
Concentration (expressed in millions of sperms per ml)
Motility (expressed as the percentage of progressive mobile spermatozoa)
Morphology (expressed as the percentage of normally shaped cells among live spermatozoa)

Volume
Volume can vary widely. For the average 'Warmblood' volume fluctuates between 30 and 150 cc. The quantity of mucous (that contains very few sperm cells) can also vary significantly among stallions. Volume is measured in a glass beaker or similar device. Volume is greater during the spring and summer.

Concentration
The concentration can also vary widely. Usually, the higher the volume of semen, the lower the concentration. This is measured with a sperm counting chamber Linder a microscope.

Motility
To assess motility, the semen is viewed immediately after collection. This is done at body temperature under a microscope equipped with a heated platform. To be ejaculate is first diluted and then the percentage of moving sperm cells are estimated. This requires a certain amount of experience. The ca minimum requirement that most studbooks will accept to approve a stallion for stud service is 50% moving cells.

Morphology
Morphology involves the exterior shape of the spermatozoa. A normally shaped sperm cell consists of a head, a neck and a tail. All ejaculates contain a certain number of sperm cells exhibiting abnormal appearances such as those with no tail, a recurved tail, a double tail, etc., which are assumed to be less fertile or infertile. The percentages of these abnornialities can be increased by disease, fever, toxic substances, long-term rest from servicing, etc. Morphology is expressed in terms of a percentage of normally developed sperm cells among the living sperm cells and is assessed by viewing hundreds of spermatozoa. The minimum requirement that most studbooks will accept to approve a stallion for stud service is 50% of normally developed sperm cells among all the living sperm cells.

Total number of moving sperm cells (TNM)
Once these calculations have been made, they can be compiled into one number. This is the TNM or total number of normally developed, moving sperm cells as expressed in millions of spermatozoa. This is the total number of sperm cells that are deemed able to fertilize an ovum.

Formula
TNM is the volume x concentration x % of motile cells x ('/,, normally developed cells among living cells. Most studbooks require that for a stallion to be approved for breeding, it should be able to produce an average TNM of 2000 million as measured by two services separated by a one-hour rest period. In recent years, however, many studbooks have decreased their demands in this regard. (Note editors: At the FPS, this is 600 million for 3-year-old stallions and '1000 million for 4-year-old stallions.) In regard to transported semen, 600 million TNM is considered sufficient for an artificial insemination, while 300 million TNM is considered sufficient for AT when the stallion and mare are located at the same breeding facility.

Semen production
A stallion produces a more or less constant quantity of spermatozoa every day. These sperm cells undergo a maturation process in the epididymus where they are being stored. When the stallion is used more often for servicing, he does not start to produce more sperm cells! By using the stallion several times in one day for servicing, his semen will contain steadily fewer sperm cells throughout that day. When a stallion serves several mares in one day, the first one will receive many sperm cells, but the last one far too few. For a stallion in great demand, Al can offer a solution by dividing his daily production (one collection a day) among the mares to be bred by him. This procedure, however, is not unlimited and does not even approach what can be done with bulls in which one collection of semen can yield 1000 insemination doses. In comparison, the semen from one ejaculation from the average stallion can produce only 3 to 8 insemination doses for transport of cooled semen to be used in Al (calculated at 600 million TNM). What this means is that a popular stallion can still have trouble meeting the needs of inseminating several mares in one day during the height of the breeding season. It is also important for the mare that she be inseminated as few times as possible (preferably only once per cycle). Overly frequent inseminating can damage the uterus and increases the risk of uterine infection since the uterus must process semen more often.

Servin methods / insemination

Natural service
In the Netherlands, natural service still accounts for a great deal of the total number of services especially among harness horses and ponies. In 'hand service', the stallion is allowed to mount the prepared mare in heat with both horses being restrained by handlers. (Actually, therefore, this is not very 'natural'). Only among a few breeds (Island and Shetland ponies) is it still fairly common to have a stallion running among a herd of mares. During service, the head of the stallion's penis swells up considerably. Even fifteen minutes after service, the first sperm cells may be entering the fallopian tubes where fertilization can take place. At the moment of ejaculation, a pulsating movement can be felt at the base of the penis. Another good sign of ejaculation is 'flagging'. Almost every stallion jerks his tail at the moment of ejaculation. It is not unusual for a stallion being used for natural service to visit many clients in the immediate vicinity, or even far away (traveling stud service).

General information
The application of Al has had much success as a method for cattle, but it was first applied with horses in Russia to build up the number of horses after the revolution and to avoid Dourine, a sexually transmitted disease.

The advantages of Al are:

Breeding more mares per stallion
Semen can be transported over long distances (export)
Avoids infections transmitted by natural service

Technique
The stallion mounts a special mare (known as a 'jump mare') for this purpose or is trained to mount an artificial mare dummy or 'phantom mare' in which the semen is collected in an artificial vagina. The semen is processed and mixed with a diluting fluid (extender) that gives the sperm cells a certain amount of protection from harmful influences and contains nutrients. Finally, the semen is cooled to 5 degrees Celsius and divided into doses. Cooled semen is viable for two days. The mare is inseminated by inserting a pipette into her uterus and then injecting the semen.

Types of AI

AT performed on location
In this case, the stallion and mare are accommodated at the same breeding facility. Semen is collected, processed and injected into the mare within a relatively short period of time. This is convenient when the stallion has a heavy schedule because only half of the amount of semen has to be used (300 million TNM) in comparison with the amount used if the semen is transported. Using cooled transported semen for AT Here, the semen is collected at one breeding facility (a semen collection facility) and then delivered to another breeding farm where the mare will be inseminated (insemination facility). The dose here should be 600 million TNM. It is transported by means of special courier services or through the mail.

Door-to-door AI
Semen is collected at the semen collection facility and the inseminator (usually the stud manager himself inseminates the mare at her owner's location.

AI using frozen semen
It is possible to freeze a stud's semen. This is usually done with semen from very heavily booked stallions during the out of-season period or with high-achieving stallions, or to collect semen for use far away. It is also used, however, for rare breeds, legendary stallions, or to store a supply of semen before selling a stallion, etc. Freezing semen requires a considerable monetary investment and know-how. The average life span of frozen semen (once thawed) is shorter than that of fresh semen. It is thus important that the mare's ovulation has been estimated very accurately before insemination takes place. This requires veterinary assistance. The dose of semen being used for insemination should display a score of 300 million TNM once it is thawed.

What can be expected of the stallionmanager or insemination facility?

It can be expected that the stallion manager or insemination facility will do everything they can to make sure that your mare becomes pregnant. The service season usually runs from March to about August- September. During this period, optimum provision of services should be expected.

Natural service
Traveling stud service: Teasing and covering on request.
In general, the stallion manager offers teasing service to occur 3, 4 and 6 weeks after service.

Insemination facility
The insemination facility should take care of teasing and usually provides a veterinary who will attempt to determine the time of ovulation for effective covering. The insemination facility makes sure that the right semen arrives on site on time. It may be expected in any event that the semen will be examined before insemination takes place. Teasing and checking for pregnancy usually takes place in consultation with the insemination facility and a veterinary.

Door-to-door AI
The inseminator- stallion manager comes to inseminate your mare upon request. Services such as teasing or veterinary services are not automatically included.

Using frozen semen for AI
See insemination facility. The frozen semen is available on site and can be used at the best possible time for a successful insemination.

Certification
A certified facility In the Netherlands, there are various agencies Bond van Hengstenhouders (stallion managers' association), K.I. commission (AI committee)] that have attempted to develop a quality control system for Al and stud farms. Approved, certified facilities then have to satisfy certain norms in regard to hygiene, quality, administration, farm management, etc. These facilities are checked regularly for conformance. They are not, however, checked for semen quality!!!

EU facility
This is a facility that is allowed to export semen. Only health requirements are controlled, this being conducted by the State Inspection Service for Cattle and Meat. This involves no quality requirements for the semen! The FPS. will be drawing up more detailed guidelines in this regard in the near future. These will be published in Phryso.


		Introduction Hormone regulation of the male animal Pharmaceutical agents The quality and quantity of semen Servin methods / insemination Types of AI What can be expected of the stallionmanager or insemination facility?
	Introduction For successful fertilization, the stallion used is just as important as the mare. Since a stallion can produce many more descendants in his lifetime than a mare, people have been applying the principles of selection to stallions for centuries. This has lead to the blooming sector known as stud management. Until recently, this activity was regulated in the Netherlands by the Horse Breeding Act of 1939 in whichonly stallions approved by the studbooks could be used for breeding. This legislation, however, has been replaced by European regulations. These days, all stallions satisfying minimum veterinary standards may be used for servicing. The studbooks may provide direction in regard to breeding and arc required to register horses. In practice, however, it appears that stallions being used for breeding are usually approved by studbooks, and the number of mares being served by stallions not approved by studbooks is very modest. It turns out that only a few stallions available for breeding arc actually being used to serve the many mares being bred. Naturally, this can lead to problems, In the Netherlands, the vast majority of male animals are not used for reproductive purposes and are castrated. Anatomy The stallion's reproduction system consists of: The testicles (testes) The epididymus The seminal vesicles The seminal ducts The prostate The bulbo-urethral glands The urethra The penis The testicles (testes) Sperm cells are produced in the testicles. The number produced daily is more or less constant. In horses, the testicles arc located in the scrotum which is located outside of the abdominal cavity. The epididymus This is where the sperm cells arc stored and where they mature as they travel through the epididymus. Since the s maturation process lasts several weeks, diseases and fevers can harm the quality of the semen ejaculated at a much later date. The seminal ducts The seminal ducts are accompanied by blood vessels to form the spermatic cord which runs from the abdominal cavity through the inguinal canal to the testicles am and epididymus. The accessory sex glands The accessory sex glands add a number of I mucous-like substances to the sperm cells. In terms of equine health, they seldom cause any problems. The seminal vesicles, however, can sometimes become infected and cause blood and/or puss to be ejaculated with the semen Hormone regulation of the male animal Stallions display no clear hormone cycle and can also be used for breeding during the winter. The development of the stallion's sex organs and the development of sperm, however, are also controlled by hormones. In the male animal the hypophys is also produces the same sexual hormones as it does in the female animal FSH. Follicle stimulating hormone. Among male animals, this stimulates semen production. LH. Luteinizing hormone. This hormone stimulates certain cells in the testicles to produce male sex hormones (including testosterone). Testosterone. This is produced by the cells in the testicles and stimulates sperm development as well as typical male behavior and the development of secondary sexual characteristics (e.g., thickened neck and heavy muscling). Testosterone slows the production of FSH and LH so that a certain hormonal balance develop Pharmaceutical agents. Unfortunately, semen production in the stallion can be increased only minimally by the administration of hormones, What's more, a stallion that produces semen of poor quality cannot be helped by the use of drugs. Although testosterone like substances (anabolic steroids) are often used for such purposes as increasing performance among sporting horses due to their ability to save protein and encourage muscle development, they lessen semen quality. The quality and quantity of semen For a reasonable chance of pregnancy after covering (or insemination), a certain quantity of sperm cells exhibiting reasonable quality arc needed. Semen is assessed according to these criteria: Volume (number of ml.) Concentration (expressed in millions of sperms per ml) Motility (expressed as the percentage of progressive mobile spermatozoa) Morphology (expressed as the percentage of normally shaped cells among live spermatozoa) Volume Volume can vary widely. For the average 'Warmblood' volume fluctuates between 30 and 150 cc. The quantity of mucous (that contains very few sperm cells) can also vary significantly among stallions. Volume is measured in a glass beaker or similar device. Volume is greater during the spring and summer. Concentration The concentration can also vary widely. Usually, the higher the volume of semen, the lower the concentration. This is measured with a sperm counting chamber Linder a microscope. Motility To assess motility, the semen is viewed immediately after collection. This is done at body temperature under a microscope equipped with a heated platform. To be ejaculate is first diluted and then the percentage of moving sperm cells are estimated. This requires a certain amount of experience. The ca minimum requirement that most studbooks will accept to approve a stallion for stud service is 50% moving cells. Morphology Morphology involves the exterior shape of the spermatozoa. A normally shaped sperm cell consists of a head, a neck and a tail. All ejaculates contain a certain number of sperm cells exhibiting abnormal appearances such as those with no tail, a recurved tail, a double tail, etc., which are assumed to be less fertile or infertile. The percentages of these abnornialities can be increased by disease, fever, toxic substances, long-term rest from servicing, etc. Morphology is expressed in terms of a percentage of normally developed sperm cells among the living sperm cells and is assessed by viewing hundreds of spermatozoa. The minimum requirement that most studbooks will accept to approve a stallion for stud service is 50% of normally developed sperm cells among all the living sperm cells. Total number of moving sperm cells (TNM) Once these calculations have been made, they can be compiled into one number. This is the TNM or total number of normally developed, moving sperm cells as expressed in millions of spermatozoa. This is the total number of sperm cells that are deemed able to fertilize an ovum. Formula TNM is the volume x concentration x % of motile cells x ('/,, normally developed cells among living cells. Most studbooks require that for a stallion to be approved for breeding, it should be able to produce an average TNM of 2000 million as measured by two services separated by a one-hour rest period. In recent years, however, many studbooks have decreased their demands in this regard. (Note editors: At the FPS, this is 600 million for 3-year-old stallions and '1000 million for 4-year-old stallions.) In regard to transported semen, 600 million TNM is considered sufficient for an artificial insemination, while 300 million TNM is considered sufficient for AT when the stallion and mare are located at the same breeding facility. Semen production A stallion produces a more or less constant quantity of spermatozoa every day. These sperm cells undergo a maturation process in the epididymus where they are being stored. When the stallion is used more often for servicing, he does not start to produce more sperm cells! By using the stallion several times in one day for servicing, his semen will contain steadily fewer sperm cells throughout that day. When a stallion serves several mares in one day, the first one will receive many sperm cells, but the last one far too few. For a stallion in great demand, Al can offer a solution by dividing his daily production (one collection a day) among the mares to be bred by him. This procedure, however, is not unlimited and does not even approach what can be done with bulls in which one collection of semen can yield 1000 insemination doses. In comparison, the semen from one ejaculation from the average stallion can produce only 3 to 8 insemination doses for transport of cooled semen to be used in Al (calculated at 600 million TNM). What this means is that a popular stallion can still have trouble meeting the needs of inseminating several mares in one day during the height of the breeding season. It is also important for the mare that she be inseminated as few times as possible (preferably only once per cycle). Overly frequent inseminating can damage the uterus and increases the risk of uterine infection since the uterus must process semen more often. Servin methods / insemination Natural service In the Netherlands, natural service still accounts for a great deal of the total number of services especially among harness horses and ponies. In 'hand service', the stallion is allowed to mount the prepared mare in heat with both horses being restrained by handlers. (Actually, therefore, this is not very 'natural'). Only among a few breeds (Island and Shetland ponies) is it still fairly common to have a stallion running among a herd of mares. During service, the head of the stallion's penis swells up considerably. Even fifteen minutes after service, the first sperm cells may be entering the fallopian tubes where fertilization can take place. At the moment of ejaculation, a pulsating movement can be felt at the base of the penis. Another good sign of ejaculation is 'flagging'. Almost every stallion jerks his tail at the moment of ejaculation. It is not unusual for a stallion being used for natural service to visit many clients in the immediate vicinity, or even far away (traveling stud service). General information The application of Al has had much success as a method for cattle, but it was first applied with horses in Russia to build up the number of horses after the revolution and to avoid Dourine, a sexually transmitted disease. The advantages of Al are: Breeding more mares per stallion Semen can be transported over long distances (export) Avoids infections transmitted by natural service Technique The stallion mounts a special mare (known as a 'jump mare') for this purpose or is trained to mount an artificial mare dummy or 'phantom mare' in which the semen is collected in an artificial vagina. The semen is processed and mixed with a diluting fluid (extender) that gives the sperm cells a certain amount of protection from harmful influences and contains nutrients. Finally, the semen is cooled to 5 degrees Celsius and divided into doses. Cooled semen is viable for two days. The mare is inseminated by inserting a pipette into her uterus and then injecting the semen. Types of AI AT performed on location In this case, the stallion and mare are accommodated at the same breeding facility. Semen is collected, processed and injected into the mare within a relatively short period of time. This is convenient when the stallion has a heavy schedule because only half of the amount of semen has to be used (300 million TNM) in comparison with the amount used if the semen is transported. Using cooled transported semen for AT Here, the semen is collected at one breeding facility (a semen collection facility) and then delivered to another breeding farm where the mare will be inseminated (insemination facility). The dose here should be 600 million TNM. It is transported by means of special courier services or through the mail. Door-to-door AI Semen is collected at the semen collection facility and the inseminator (usually the stud manager himself inseminates the mare at her owner's location. AI using frozen semen It is possible to freeze a stud's semen. This is usually done with semen from very heavily booked stallions during the out of-season period or with high-achieving stallions, or to collect semen for use far away. It is also used, however, for rare breeds, legendary stallions, or to store a supply of semen before selling a stallion, etc. Freezing semen requires a considerable monetary investment and know-how. The average life span of frozen semen (once thawed) is shorter than that of fresh semen. It is thus important that the mare's ovulation has been estimated very accurately before insemination takes place. This requires veterinary assistance. The dose of semen being used for insemination should display a score of 300 million TNM once it is thawed. What can be expected of the stallionmanager or insemination facility? It can be expected that the stallion manager or insemination facility will do everything they can to make sure that your mare becomes pregnant. The service season usually runs from March to about August- September. During this period, optimum provision of services should be expected. Natural service Traveling stud service: Teasing and covering on request. In general, the stallion manager offers teasing service to occur 3, 4 and 6 weeks after service. Insemination facility The insemination facility should take care of teasing and usually provides a veterinary who will attempt to determine the time of ovulation for effective covering. The insemination facility makes sure that the right semen arrives on site on time. It may be expected in any event that the semen will be examined before insemination takes place. Teasing and checking for pregnancy usually takes place in consultation with the insemination facility and a veterinary. Door-to-door AI The inseminator- stallion manager comes to inseminate your mare upon request. Services such as teasing or veterinary services are not automatically included. Using frozen semen for AI See insemination facility. The frozen semen is available on site and can be used at the best possible time for a successful insemination. Certification A certified facility In the Netherlands, there are various agencies Bond van Hengstenhouders (stallion managers' association), K.I. commission (AI committee)] that have attempted to develop a quality control system for Al and stud farms. Approved, certified facilities then have to satisfy certain norms in regard to hygiene, quality, administration, farm management, etc. These facilities are checked regularly for conformance. They are not, however, checked for semen quality!!! EU facility This is a facility that is allowed to export semen. Only health requirements are controlled, this being conducted by the State Inspection Service for Cattle and Meat. This involves no quality requirements for the semen! The FPS. will be drawing up more detailed guidelines in this regard in the near future. These will be published in Phryso. Page up