Choice of breeding technique

12.06.2018

The breeding techniques vary in complexity, mainly depending on whether the stallion is present during the act of breeding itself. The choice of technique will depend on the availability of semen from the selected stallion, its expected per cycle pregnancy rate, the stud book rules and the cost of the technique, which is highly variable and must remain in proportion to the economic value of the future foal. 

Definition of the various techniques

The various breeding methods are authorized subject to compliance with the applicable regulations (decree 24/01/2008 for artificial insemination in France for example) and with the studbook rules.

• Pasture breeding: mares and stallions mate in total freedom, generally in the pasture without direct human intervention. The horses are hence turned out in a herd with no selection of individual mating pairs.
• Hand breeding: mating between a mare, which usually restrained, and a chosen stallion, which is held by a stud farmer.
• Artificial insemination with fresh semen: The semen is collected from the stallion on a breeding mount with the aid of an artificial vagina. It is then filtered, diluted and packaged in doses (syringes) containing at least 200 million sperm and 10 to 20 ml in total. These doses can be used immediately after collection – this is referred to as immediate artificial insemination (here abbreviated IAI) – or kept at 4°C for a few hours and up to 48 hours. This is referred to as AI with chilled semen (here abbreviated AIC), either on the premises (AICP) or following transport (AICT). In the case of AIC, antibiotics must be added to the extender in order to prevent certain bacteria from multiplying.
• Artificial insemination with frozen semen (AIF): The diluted semen from the stallion is frozen in liquid nitrogen (-196°C) with an extender containing a cryoprotectant. The semen is frozen in 0.5 ml straws at a recommended concentration of 100 million sperm per ml.
• Embryo transfer (ET): this consists in transferring an embryo recovered from the uterus of a donor mare, the genetic mother of the foal, to the uterus of a recipient mare who will carry it to term.

Factors governing the choice of breeding technique

Pregnancy rate

Per cycle pregnancy rate is a good basis for evaluating the various breeding methods:

The per cycle pregnancy rate is the percentage chance of a mare being pregnant following coverage at the end of her heat phase. It is calculated using the following formula: Per cycle pregnancy rate = Number of cycles resulting in a pregnancy / (total number of cycles bred) x100

Availability of the stallion’s semen

Thanks to the diverse range of available breeding techniques, the mare no longer needs to be systematically moved to the location of the stallion, unless this is required under the stud book rules (PS (thoroughbred), AQPS (other than thoroughbred) and TF (French Trotter) in particular). For most other breeds, AI can be carried out using semen that is either chilled following transport or frozen when the pregnancy rates of the stallion and the mare allow, to avoid moving the mare over excessively long distances. This nevertheless has an impact on the cost of the technique.

Cost of the breeding techniques

These costs are on top of the price paid for the semen itself, which depends on the stallion’s genetic value (origins, performance, etc.) – and this is itself extremely variable.

The table below compares the cost of the various breeding techniques through to birth of a foal (excluding genetics)

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Points to note

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The breeding technique used depends on the availability of the chosen stallion’s semen or the ability of the mare to carry a pregnancy to term.

The chances of obtaining a foal vary from one breeding technique to another.

These breeding techniques vary extremely widely in cost; the costs incurred must always be in proportion to the estimated value of the future foal.

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