Artificial insemination (AI) is the deliberate introduction of semen into a female's vagina or oviduct for the purpose of achieving a pregnancy through fertilisation by means other than ejaculation. It is the medical alternative to sexual intercourse, or natural insemination.
Artificial insemination is a fertility treatment for humans, and is a common practice in the breeding of dairy cattle and pigs. Artificial insemination may employ assisted reproductive technology, donated sperm, and/or animal husbandry techniques.
Artificial insemination is a means of attaining pregnancy not involving sexual intercourse. A couple having trouble getting pregnant can benefit from the exact timing and placement of the sperm. It can overcome instances where a woman's immune system can reject her partner's sperm as invading molecules. In the case of an impotent male, donor sperm may be used. It is also a means for a woman to conceive when two women wish to parent a child, or a single woman does not have a male partner, when she does not want a male partner, or when a male partner's physical limitation impedes his ability to impregnate her by sexual intercourse. Women who have issues with the cervix such as cervical scarring, cervical blockage from endometriosis, or thick cervical mucus may also benefit from artificial insemination since the sperm must pass through the cervix to result in fertilization.
A woman needing artificial insemination to achieve pregnancy can obtain a sperm sample from her male partner or sperm from sperm donation may be used if, for example, the woman's partner produces too few motile sperm, or if he carries a genetic disorder, or if the woman has no male partner. Sperm is usually obtained through masturbation or the use of an electrical stimulator, although a special condom, known as a collection condom, may be used to collect the semen during intercourse.
Sperm provided by a sperm bank will always be produced by a donor attending at the sperm bank's premises in order to ascertain the donor's identity on every occasion. The donor masturbates to provide an ejaculate in a small container. The contents of the container are usually extended with chemicals in order to provide a number of vials for insemination. The sperm is frozen and quarantined for a period of usually six months and the donor re-tested prior to the sperm being used for artificial insemination.
A sperm donor is usually advised not to ejaculate for two to three days before providing the sample, to increase the sperm count.
A woman's menstrual cycle is closely observed, by tracking basal body temperature and changes in vaginal mucus, or using ovulation kits, ultrasounds or blood tests.
When using intrauterine insemination (IUI), the sperm must have been “washed” in a laboratory and concentrated in Hams F10 media without L-glutamine, warmed to 37C. The process of “washing” the sperm increases the chances of fertilization and removes any mucus and non-motile sperm in the semen. Pre and post concentration of motile sperm is counted.
Sperm from a sperm bank will be frozen and quarantined for a particular period and the donor will be tested before and after production of the sample to ensure that he does not carry a transmissible disease. Sperm samples donated in this way are commonly produced through masturbation by the sperm donor at the sperm bank. A chemical known as a cryoprotectant is added to the sperm to aid the freezing and thawing process. Further chemicals may be added which separate the most active sperm in the sample as well as extending or diluting the sample so that vials for a number of inseminations are produced. For fresh shipping, a semen extender is used.
If sperm is provided by a private donor, either directly or through a sperm agency, it is usually supplied fresh, not frozen, and it will not be quarantined. Donor sperm provided in this way may be given directly to the recipient woman or her partner, or it may be transported in specially insulated containers. Some donors have their own freezing apparatus to freeze and store their sperm. Private donor sperm is usually produced through masturbation, but some donors use a collection condom to obtain the sperm when having sexual intercourse with their own partners.
When an ovum is released, semen provided by the woman's male partner, or by a sperm donor, is introduced into the woman's vagina or uterus. The semen may be fresh or it may be frozen semen which has been thawed. Where donor sperm is supplied by a sperm bank, it will always be quarantined and frozen and will need to be thawed before use.
For vaginal artificial insemination, semen is usually placed in the vagina using a needleless syringe. A longer tube, called a tom cat, may be attached to the end of the syringe to facilitate deposit of the semen deeper into the vagina. The woman is generally advised to lie still for a half hour or so after the insemination to prevent seepage and to allow fertilization to take place.
A more efficient method of artificial insemination is to insert semen directly into the woman's uterus. Where this method is employed it is important that only 'washed' semen be used and this is inserted into the uterus by means of a catheter. Sperm banks and fertility clinics usually offer 'washed' semen for this purpose, but if partner sperm is used it must also be 'washed' by a medical practitioner to eliminate the risk of cramping.
Semen is occasionally inserted twice within a 'treatment cycle'. A double intrauterine insemination has been theorized to increase pregnancy rates by decreasing the risk of missing the fertile window during ovulation. However, a randomized trial of insemination after ovarian hyperstimulation found no difference in live birth rate between single and double intrauterine insemination.
An alternative method to the use of a needleless syringe or a catheter involves the placing of partner or donor sperm in the woman's vagina using a specially designed cervical cap, a conception device or conception cap. This holds the semen in place near to the entrance to the cervix for a period of time, usually for several hours, to allow fertilization to take place. Using this method, a woman may go about her usual activities while the cervical cap holds the semen in the vagina. One advantage with the conception device is that fresh, non-liquified semen may be used.
If the procedure is successful, the woman will conceive and carry to term a baby. The baby will be the woman's biological child, and the biological child of the man whose sperm was used to inseminate her, whether he is the woman's partner or a donor. A pregnancy resulting from artificial insemination will be no different from a pregnancy achieved by sexual intercourse. However, there may be a slight increased likelihood of multiple births if drugs are used by the woman for a 'stimulated' cycle.
Either sperm provided by the woman's husband or partner (artificial insemination by husband) or sperm provided by a known or anonymous sperm donor (artificial insemination by donor) can be used.
Intracervical insemination (ICI) is the easiest way to inseminate. This involves the deposit of raw fresh or frozen semen (which has been thawed) and which has been provided by the woman's partner or by a sperm donor into the cervix usually by injecting it with a needleless syringe. Where fresh semen is used this must be allowed to liquefy before inserting it into the syringe, or alternatively, the syringe may be back-loaded. After the syringe has been filled with semen, it should be raised slightly and any air bubbles removed by gently pressing the plunger forward before inserting the syringe into the vagina.
The syringe should be inserted carefully so that the tip is as close to the entrance to the cervix as possible. The woman should be comfortable at all times. A vaginal speculum may be used to hold open the vagina so that the cervix may be observed and the syringe inserted more accurately through the open speculum. The plunger is then pushed forward and the semen in the syringe is emptied into the vagina. The syringe (and speculum if used) may be left in place for several minutes and the woman is advised to lie still for half-an-hour or so to assist fertilization.
A conception cap, which is a form of conception device may be inserted into the vagina following insemination and may be left in place for several hours in order to hold the semen close to the entrance to the cervix.
The process of intracervical insemination closely replicates the way in which fresh semen is directly deposited on to the neck of the cervix by the penis during vaginal intercourse. When the male ejaculates, sperm deposited this way will quickly swim into the cervix and toward the fallopian tubes where an ovum recently released by the ovary(s) hopefully awaits fertilization. It is the simplest method of artificial insemination and "unwashed" or raw semen is normally used. It is probably therefore, the most popular method. It is commonly used home, self-insemination and practitioner insemination procedures, and for inseminations where semen is provided by private donors.
Other methods may be used to insert semen into the vagina notably involving different uses of a conception cap. This may, for example, be inserted filled with sperm which does not have to be liquefied. The male may therefore ejaculate straight into the cap. Alternatively, a specially designed conception cap with a tube attached may be inserted empty into the vagina after which liquefied semen is poured into the tube. These methods are designed to ensure that donor or partner semen is deposited as close as possible to the cervix and that it is kept in place there to assist fertilization.
Timing is critical as the window and opportunity for fertilization, is little more than 12 hours from the release of the ovum. For each woman who goes through this process be it AI (artificial insemination) or NI (natural insemination); to increase chances for success, an understanding of her rhythm or natural cycle is very important. Home ovulation tests are now available. Doing and understanding Basal Temperature Tests over several cycles; there is a slight dip and quick rise at the time of ovulation. She should note the color and texture of her vaginal mucous discharge. At the time of ovulation the protective cervical plug is released giving the vaginal discharge a stringy texture with an egg white color. A woman may also be able check the softness of the nose of her cervix by inserting two fingers. It should be considerably softer and more pliable than normal.
Advanced technical (medical) procedures may be used to increase the chances of conception.
When performed at home without the presence of a professional this procedure is sometimes referred to as intravaginal insemination or IVI.
Washed sperm, spermatozoa that have been removed from most other components of the seminal fluids, can be injected directly into a woman's uterus in a process called intrauterine insemination (IUI). If the semen is not washed it may elicit uterine cramping, expelling the semen and causing pain, due to content of prostaglandins. (Prostaglandins are also the compounds responsible for causing the myometrium to contract and expel the menses from the uterus, during menstruation.) The woman should rest on the table for 15 minutes after an IUI to optimize the pregnancy rate.
Unlike intracervical insemination, intrauterine insemination must normally be performed by a medical practitioner.
To have optimal chances with IUI, the female should be under 30 years of age, and the man should have a TMS of more than 5 million per ml. In practice, donor sperm will satisfy these criteria. A promising cycle is one that offers two follicles measuring more than 16 mm, and estrogen of more than 500 pg/mL on the day of hCG administration. A short period of ejaculatory abstinence before intrauterine insemination is associated with higher pregnancy rates. However, GnRH agonist administration at the time of implantation does not improve pregnancy outcome in intrauterine insemination cycles according to a randomized controlled trial.
It can be used in conjunction with ovarian hyperstimulation. Still, advanced maternal age causes decreased success rates; Women aged 38–39 years appear to have reasonable success during the first two cycles of ovarian hyperstimulation and IUI. However, for women aged ≥40 years, there appears to be no benefit after a single cycle of COH/IUI. It is therefore recommended to consider in vitro fertilization after one failed COH/IUI cycle for women aged ≥40 years.
Intrauterine tuboperitoneal insemination (IUTPI) is insemination where both the uterus and fallopian tubes are filled with insemination fluid. The cervix is clamped to prevent leakage to the vagina, best achieved with the specially designed Double Nut Bivalve (DNB) speculum. The sperm is mixed to create a volume of 10 ml, sufficient enough to fill the uterine cavity, pass through the interstitial part of the tubes and the ampulla, finally reaching the peritoneal cavity and the Pouch of Douglas where it would be mixed with the peritoneal and follicular fluid. IUTPI can be useful in unexplained infertility, mild or moderate male infertility, and mild or moderate endometriosis. In non-tubal sub fertility, fallopian tube sperm perfusion may be the preferred technique over intrauterine insemination.
IUI can furthermore be combined with intratubal insemination (ITI), into the Fallopian tube although this procedure is no longer generally regarded as having any beneficial effect compared with IUI. ITI however, should not be confused with gamete intrafallopian transfer, where both eggs and sperm are mixed outside the woman's body and then immediately inserted into the Fallopian tube where fertilization takes place.
Success rates, or pregnancy rates for artificial insemination may be very misleading, since many factors including the age and health of the recipient have to be included to give a meaningful answer, e.g. definition of success and calculation of the total population. For couples with unexplained infertility, unstimulated IUI is no more effective than natural means of conception.
As seen on the graph, the pregnancy rate also depends on the total sperm count, or, more specifically, the total motile sperm count (TMSC), used in a cycle. It increases with increasing TMSC, but only up to a certain count, when other factors become limiting to success. The summed pregnancy rate of two cycles using a TMSC of 5 million (may be a TSC of ~10 million on graph) in each cycle is substantially higher than one single cycle using a TMSC of 10 million. However, although more cost-efficient, using a lower TMSC also increases the average time taken before getting pregnant. Women whose age is becoming a major factor in fertility may not want to spend that extra time.
How many samples (ejaculates) that are required give rise to a child varies substantially from person to person, as well as from clinic to clinic.
However, the following equations generalize the main factors involved:
The pregnancy rate increases with increasing number of motile sperm used, but only up to a certain degree, when other factors become limiting instead.
With these numbers, one sample would on average help giving rise to 0.1–0.6 children, that is, it actually takes on average 2–5 samples to make a child.
For intrauterine insemination (IUI), a centrifugation fraction (fc) may be added to the equation:
On the other hand, only 5 million motile sperm may be needed per cycle with IUI (nr=5 million)
Thus, only 1–3 samples may be needed for a child if used for IUI.
• In 1300’s, Fredrick Exuctiat first inseminated his mare with the stolen semen from an outstanding stallion. But no result was found. Although the commercial use of artificial insemination is recent (1937), the sequence of events leading to today’s industry traces back to the 17th century.
It was in 1677 that Leeuwenhoek saw spermatozoa through the newly discovered microscope AND he concluded that semen must contain motile things. and
in 1780 when an Italian physiologist Spallanzani in Italy discovered that a dog could be impregnated with the cellular portion of semen. He also observed that the spermatozoa could be inactivated by cooling and reactivated later . Spallanzani” carried out it in his own bitch, and he got three puppies after 62 days. • In late 19 th century studies were made on the physiology of male reproductive system.
In 1897 – Walter Haep, first time discovered that one ejaculate can be divided and served for multiple female animals. He worked on dogs and horses.
About 1900, Professor Ivanov was hired by the Russian throne to develop AI for horses. He was an ambitious man and by 1933 he had developed methods for collecting semen and inseminating horses, cattle, sheep and swine. Most of these early inseminations were with sheep and horses. • In 1914 – G. Amntae developed artificial vagina for semen collection – for dogs and later on for other animals (bulls, stallions). • In 1931 – Russia took A.I. at mass scale and several thousand cows were bred via A.I. A Dane by the name of Sorenson, who had studied in Russia, returned to Denmark and established the first AI cooperative in 1933. First association of A.I. (A.I. Association) was established in Denmark in 1936.
E.J. Perry, an extension dairyman from New Jersey, was in Denmark at this time. He returned in 1937 and hired a Dane by the name of Larson to help establish the first AI cooperative in the United States. he developed rectovaginal technique for A.I. for large animals. • In 1930’s – extenders / semen dilutors were developed. Research with cattle AI had been in progress in the U.S. and by 1939 seven AI cooperatives had developed. The number of AI organizations increased rapidly, as did the number of cows inseminated, the number of breedings obtained from each male, and the conception rate. As competition between organizations developed and costs increased, the small cooperatives consolidated, resulting in the large cooperatives and companies that exist today. • In early 1940’s – electro-ejaculators were developed.
In 1940’s – role of glycerol was described as cryoprotectant for semen. In 1964 – first time semen was frozen in straws before this semen was kept in ampule.
In Pakistan AI was started at College of Animal Husbandry, Lahore in 1954. Government of Punjab started 10 AI Centres at Changa Manga, Shiekhupura, Sialkot, Ghakhar, Nathuwal, Chakwal, Rawalpindi, Mianwali, Sargodha and Jhang using fresh semen. Use of frozen semen in AI was started in late sixties. Since then AI has spread to all other provinces and currently about 10-15 percent of breed able cows and buffaloes are serviced through AI. Currently, there are 189 A.I. Centresand 7 Semen-Production Units in the country. Semen of buffaloes (both Nili-Ravia and Kundi) and cattle (Sahiwal and Red Sindhi) is produced locally at four Semen-Production Centres. In addition to these, semen from Holstein-Friesian and Jersey cattle is produced locally, as well as imported from other countries.
Artificial insemination (AI) is the manual placement of semen in the reproductive tract of the female by a method other than natural mating. It is one of a group of technologies commonly known as “assisted reproduction technologies” (ART), whereby offspring are generated by facilitating the meeting of gametes (spermatozoa and oocytes). ART may also involve the transfer of the products of conception to a female, for instance if fertilization has taken place in vitro or in another female. Other techniques encompassed by ART include the following: in vitro fertilization (IVF) where fertilization takes place outside the body; intracytoplasmic sperm injection (ICSI) where a single spermatozoon is caught and injected into an oocyte; embryo transfer (ET) where embryos that have been derived either in vivo orin vitro are transferred to a recipient female to establish a pregnancy; gamete intrafallopian transfer (GIFT) where spermatozoa are injected into the oviduct to be close to the site of fertilization in vivo; and cryopreservation, where spermatozoa or embryos, or occasionally oocytes, are cryopreserved in liquid nitrogen for use at a later stage. AI has been used in the majority of domestic species, including bees, and also in human beings. It is the most commonly used ART in livestock, revolutionising the animal breeding industry during the 20thcentury. In contrast to medical use, where intra-uterine insemination (IUI) is used only occasionally in human fertility treatment, AI is by far the most common method of breeding intensively kept domestic livestock, such as dairy cattle (approximately 80% in Europe and North America), pigs (more than 90% in Europe and North America) and turkeys (almost 100% in intensive production). AI is increasing in horses, beef cattle and sheep, and has been reported in other domestic species such as dogs, goats, deer and buffalo. It has also been used occasionally in conservation breeding of rare or endangered species, for example, primates, elephants and wild felids. The other ARTs in animals are generally confined to specialist applications or for research purposes, since the cost would be prohibitive for normal livestock breeding. In contrast, IUI is used less often in human fertility treatments than IVF or ICSI. Future trends in AI It is highly probable that the use of AI in livestock will continue to increase. AI not only facilitates more effective and efficient livestock production, but can also be coupled to other developing biotechnologies, such as cryopreservation, selection of robust spermatozoa by single layer centrifugation, and sperm sex selection. apart from some specialist sheep or goat units focussing on milk production for cheese and intensive meat production, farming of these species tends to be confined to marginal land that is unsuitable for crop production or grazing for dairy cattle. There has been limited selection for production traits. However, there is a resurgence of interest in them now in developed countries because of growing awareness that small ruminants could represent better utilization of scare resources than larger ones, such as cattle, while producing less methane and effluent. In many developing countries, sheep and goats are better suited to the climate than cattle, and it is culturally acceptable to eat their meat and milk products. Thus it is likely that there will be an upsurge in the use of AI in sheep and goats in the future, with an emphasis on improving production traits by the introduction of superior genes. However, it is essential that any A.I. scheme aimed at large scale improvement of the national herd must be supported by improved animal husbandry and animal health, otherwise the pregnancies resulting from AI will not go to term, and the offspring will either not survive or will fail to thrive. Many of the advanced ART are of little help in areas where basic husbandry skills are inadequate. AI revolutionized animal breeding in the 20th century, particularly in combination with sperm cryopreservation. The AI industry has developed dramatically in most domestic species in the last few decades and its use is now widespread in intensive animal production. The development of other associated technologies, such as sperm selection and sex selection, are predicted to create powerful tools for the future, both for domestic livestock breeding and for the purposes of conservation. AI will continue to play a role in fertility treatment for human patients, although it may be superseded by IVF or ICSI. It has been suggested that AI (in animals) is entering a new era where it will be used for the efficient application of current and new sperm technologies (Roca, 2006). Exciting possibilities are offered by emerging techniques, such as Single Layer Centrifugation, for improving sperm quality in AI doses as well as for increasing sperm survival during cryopreservation.
the reason for low rate of AI is the lack of availability of good quality livestock semen The success of AI depends upon many factors, the important being reproductive health of the animal, time of insemination, quality of semen and expertise of the technician. The selection of bull for use in AI is of prime importance as it transmits genetic characteristics to a large number of animals. To ensure the quality of bull for use in AI, elaborate systems of bull selection have been evolved and followed in the world. • Requires well-trained operations and special equipment. • Requires more time than natural services. • Necessitates the knowledge of the structure and function of reproduction on the part of operator. • Improper cleaning of instruments and in sanitary conditions may lead to lower fertility. • If the bull is not properly tested, the spreading of genital diseases will be increased
The major limitations are due to lack of trained personnel to provide proper service. Poor breeding efficiency may occur in herds when owners do not watch their animals closely for estrus and the inseminator does not breed them at the proper time. The inseminator may be, if not careful, a means of spreading infections from one herd to another. Herd owners should avoid intensive use of a limited number of sires, which may increase inbreeding in the herd. Increased inbreeding is usually associated with low fertility and decrease in vigor and overall productivity.
there is only a 60 to 70% conception rate for AI than with using a fertile herd bull - still have to use a bull as "clean-up" to cover the females that were missed or didn't catch - if you don't want to use a clean-up male you may have to breed those that didn't catch a second or third time before they concieve. - have to have adequate knowledge of heat periods of female stock and know what to look for to see if any stock are in heat and then judge the time to AI them (for cows, when a female is observed to have heat behaviour, the rule of thumb is to AI 12 hours later) - cost for keeping semen straws frozen in a container of nitrous oxide (dry ice), having storage to keep AI equipment, handling facilities for breeding, etc. - may be added stress involved when females have to be restrained - AI isn't a job that can be learned by trail and error, it has to be taught first by a trained professional (an AI technician) before it can be carried out in the field. - you can't be afraid to get dirty because it involves sticking your whole arm up a cow's anus - semen has to be stored properly otherwise it will become no longer viable; improper handling will also render it inviable. Detection inaccuracies Estrous
With proper detection of estrus can help operators Artificial Insemination in determining the appropriate time in doing artificial insemination. Different ways to determine estrous cow that is silent when ridden by another cow, female animals genitals swollen, tender and red, or in terms that are widely known, especially among farmers in Java, Indonesia with terms 3A, the female animals genitals looked Abang (red) , Abuh (swelling) and Anget (temperature rise). Usually slightly decreased appetite.
INCENTIVES FOR FARMERS It would thus be reasonable to assume that a basic precondition for the successful introduction or extension of A.I. services in developing countries would be the provision of economic incentives to farmers to breed improved animals. STAFFING AN A.I.SERVICE The execution of an A.I. breeding service requires specialized staff at various levels. The importance of well-trained inseminators is sometimes overlooked. The success of an A.I. scheme is dependent on its reliability and on its technical results, which are to a large extent governed by the link that the service has with the farmers, namely, the inseminators. Inseminators must therefore be well trained and must undertake their job as a full-time responsibility. Sometimes A.I. is performed by an animal health assistant as part of his duties; experience with this kind of dual-purpose technician has demonstrated the unreliability of the resulting service. The best way of producing efficient inseminators is to select young men or women with agricultural backgrounds at the time they leave school, and give them a course in general animal husbandry followed by a specialized course in A.I. techniques. During the first months of practical work, supervision should be exercised by a senior inseminator and the work should be carried out by the trainees on a full-time basis. It should be borne in mind that some people will never become good inseminators because they do not have the necessary practical talent, and therefore in the training of inseminators provision should be made for drop-outs. ORGANIZATION OF FIELD SERVICES In addition to reliability and good technical results, the successful extension of an A.I. breeding service is dependent on its ready availability to farmers. The pattern developed in industrialized countries, where a central office receives orders by telephone for insemination and inseminators move from one farm to another by car, is usually not applicable in developing countries. Different systems have been evolved to resolve local difficulties. In Asia, extensive use is made of A.I. subcentres, to which farmers bring their cows in heat. This system works well in densely populated areas, and has the advantage of enabling groups of farmers to be brought together for demonstrations of milking techniques, feeding and care of newborn calves, and so on, by other extension personnel. Audiovisual aids have been found to be extremely valuable in these demonstrations. The drawback of this system, however, is that it does not bring the technical staff into direct contact with the problems of the farms. HEAT DETECTION Heat detection has been reported to be one of the major management problems in developing countries in connexion with A.I. (Dassanayake et al., 1961; Settergren, 1969). Zebu cattle show less intensive symptoms of heat and remain in oestrus for a shorter period than temperate breeds (Anderson, 1944). Also, high environmental temperature has a direct effect on the reproductive functions of both temperate and tropical cattle. Gangwar et al. (1965) found a higher incidence of clinical anoestrus among Holstein heifers under hot controlled climatic conditions; the oestrous cycle was prolonged but duration and intensity of oestrus were decreased. Other experiments in the United States (Bond and McDowell, 1972) have also indicated that severe heat stress will cause true anoestrus, but that beef heifers can become acclimatized and reestablish their oestrous cycles Certainly, problems in recording oestrus depend to a great extent on the interaction between the accuracy of the procedures for heat detection and the intensity of oestrus symptoms shown by the animals. Increased frequency of oestrus observation increases the number of heat periods detected. Most reports suggest that the detection of oestrus is markedly facilitated by the use of teaser bulls. But this method has certain limitations. If vasectomized bulls are used the risk of spreading venereal disease is present, and the method should therefore be precluded from areas where vibriosis and trichomoniasis are known to exist. The use of bulls with surgically deviated penes is safer. but such bulls perform their task for only a limited period and must then be replaced. RECORDING An efficient information system is a necessary component of an A.I. breeding service. First, the actual conception rates per bull, per inseminator and per area would need to be recorded. Complete information on the number and performance of inseminated animals in various areas is also essential. It has been frequently observed that while the detailed primary data on A.I. may be well recorded, they are seldom processed and made use of in the future planning and implementation of the service. There is a real danger that the primary collection of data can be made so ambitious that the processing becomes too difficult. It is therefore important to limit records to those which are really necessary, and to establish a system for the regular processing of up-to-date information from the operations SUPPLY OF SEMEN . The locally produced livestock semen is affordable for the farmers but is of extremely marginal quality. Furthermore imported livestock semen in Pakistan is of good quality but is prohibitively expensive and beyond the reach of the small holding dairy farmers of Pakistan. In view of this 90 – 95% of the farmers use natural breeding methods which produces offspring with traits either similar to the low milk producing mother or at times inferior milk yields.
The long-term preservation of semen by deep-freezing allows considerable flexibility in arrangements for the supply of semen. In the initial phase of an A.I. programme, the semen can often be imported and domestic semen production postponed to a later phase. Another important implication of the use of frozen semen is that the semen production unit can be geographically independent of the actual A.I. field work. Freezing also permits a more efficient use of the semen; 10 000 to 20 000 doses can be utilized per A.I. bull per year, whereas if the semen is used in liquid form the actual number of doses used is reduced to around 5 000. Whether semen should be produced domestically or imported should be determined in the context of both the breeding programme and the costs involved. Thus, where the breeding policy dictates that exotic blood should be maintained at somewhere between 50 and 75 percent in the breeding animals it may be necessary to produce semen from domestic crossbred bulls, and this would call for the establishment of a national semen production unit at the time when the F1 and/or the first backcross generations are ready for insemination. Similarly, when the number of semen doses is of the order of hundreds of thousands per year, it may be economically justified to produce the semen locally even if the bulls have to be imported. There may also be instances where domestic production may have to be supplemented by the importation of semen from, say, progeny-tested bulls. COSTS The costs of an A.I. breeding service vary widely among countries, and depend mainly on cattle density and the number of cows served. In the initial stages, with a small number of animals being inseminated, the cost per cow is high. The graph (opposite) shows the approximate relation between the variable costs per inseminated cow and the total number of animals served. The costs are expressed in litres of milk at producer prices, and are derived from planning documents for comprehensive A.I. services in Tanzania and Pakistan, prepared in collaboration with the governments of these countries, and from actual costs in Kenya. In industrialized countries A.I. costs per cow vary between the equivalent of 40 and 75 litres of milk, depending on cattle density, the intensity of selection of sires, the costs of progeny testing and other evaluation activities. The major expenses of an A.I. breeding service are represented by the wages of the personnel, which in many instances amount to over 80 percent of the total variable costs. The foreign currency cost in developing countries is relatively small, compared with the alternative costs of acquiring a corresponding number of genetically improved cows, or bulls for natural service. However, in the initial stages of an A.I. scheme, as it would not be possible for the farmer to pay a fee corresponding to the full cost of the service, a government subsidy is usually provided.
Pioneering AI begun in Russia in 1899 by Ivanoff. In 1935 Suffolk sheep diluted semen was sent from Cambridge by plane to Krakoiv Poland, in and international research joint (Prawochenki from Poland, Milovanoff from URSS, Hammond from Cambridge, Walton from Scotland, and Thomasset from Uruguay). Artificial insemination is used in many non-human animals, including sheep, horses, cattle, pigs, dogs, pedigree animals generally, zoo animals, turkeys and even honeybees. It may be used for many reasons, including to allow a male to inseminate a much larger number of females, to allow use of genetic material from males separated by distance or time, to overcome physical breeding difficulties, to control the paternity of offspring, to synchronise births, to avoid injury incurred during natural mating, and to avoid the need to keep a male at all (such as for small numbers of females or in species whose fertile males may be difficult to manage).
Semen is collected, extended, then cooled or frozen. It can be used on site or shipped to the female's location. If frozen, the small plastic tube holding the semen is referred to as a straw. To allow the sperm to remain viable during the time before and after it is frozen, the semen is mixed with a solution containing glycerol or other cryoprotectants. An extender is a solution that allows the semen from a donor to impregnate more females by making insemination possible with fewer sperm. Antibiotics, such as streptomycin, are sometimes added to the sperm to control some bacterial venereal diseases. Before the actual insemination, estrus may be induced through the use of progestogen and another hormone (usually PMSG or Prostaglandin F2α).
Artificial insemination of farm animals is very common in today's agriculture industry in the developed world, especially for breeding dairy cattle. (75% of all inseminations[clarification needed]) Swine are also bred using this method (up to 85% of all inseminations). It provides an economical means for a livestock breeder to improve their herds utilizing males having very desirable traits.
Although common with cattle and swine, AI is not as widely practised in the breeding of horses. A small number of equine associations in North America accept only horses that have been conceived by "natural cover" or "natural service" – the actual physical mating of a mare to a stallion – the Jockey Club being the most notable of these, as no AI is allowed in Thoroughbred breeding. Other registries such as the AQHA and warmblood registries allow registration of foals created through AI, and the process is widely used allowing the breeding of mares to stallions not resident at the same facility – or even in the same country – through the use of transported frozen or cooled semen.
Modern Artificial Insemination was pioneered by Dr. John O. Almquist of the Pennsylvania State University. His improvement of breeding efficiency by the use of antibiotics (first proven with penicillin in 1946) to control bacterial growth, decreasing embrionic mortality and increase fertiilty, and various new techniques for processing, freezing and thawing of frozen semen significantly enhanced the practical utilization of AI in the livestock industry, and earned him the  1981 Wolf Foundation Prize in Agriculture. Many techniques developed by him have since been applied to other species, including that of the human male.
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