Artificial breeding

This principle is central to the Deer Progeny Test (DPT) programme, where genetic merit of sires are ranked across farms and years by use of AI alongside natural mating. This involves developing sire linkages, in which common sires are used across farms in the same year, and subsequent years, allowing the calculation of across-farm Breeding Values (BVs).

This use of AI is not limited to stud farms; commercial breeders can also acquire top genetics. Used as an alternative option to buying high BV stags – especially within closed herds where there is concern about the introduction of disease through outside animal purchases. Semen has a very low risk of disease introduction.

AI is not something to be embarked upon lightly and involves considerable planning, the use of skilled people, and a time investment. If done well AI is a very successful genetic tool. Success rates of 70-80% pregnancy are commonly achieved with a single-time insemination. This is considerably better than what is achieved in other livestock industries.

See below in the more resources section for links to pages that will take you through the various considerations and actions for a successful AI programme. Attention to detail is important to a rewarding programme.

Semen selection will invariably be based on the perceived or actual genetic merit of the stag(s). In many cases BVs will be available through DEERSelect, making the choices easier. However, for many stags for which semen is commercially available, there are no across-farm BVs for traits of interest (particularly antler traits) and judgement of genetic merit will largely be based on the reputation of the stud breeder and the fit of the available animals with your own breeding objectives.

• The principal reason for using AI is to acquire the best stag genetics for your particular production system. The choices you make for semen purchase will ultimately influence the genetic performance of the whole herd.
• In many respects it may seem that hind selection for AI programmes is secondary to stag selection. However, the hinds carry half of the genetics in any AI programme. Where possible select those hinds with proven track records for production (particularly reproductive success). Also, hinds that display poor temperament often perform poorly in AI programmes particularly if they become highly stressed during handling. Ideally, hinds chosen for AI are the best in the herd for the production traits of interest, and are temperamentally suited to the frequent handling required for AI.
• Another consideration of hind selection is to ensure that they are in good body condition at the time of synchronisation and AI. This may require some preferential treatment and feeding prior to these events; particularly if it has been a hard summer. Early pre-rut weaning of their calves is preferable to allow for an early dry-off. This will help in gaining condition for AI.

Key factors to consider when discussing the option of beginning an AI programme

• Because of the frequent animal handling required for AI programmes, it almost goes without saying that the handling facilities need to be in top order and capable of easily accommodating the mob sizes required for each AI session.
• Hygiene is of utmost importance, so the facilities need to be capable of frequent and thorough cleaning e.g. of floors, table and crush.  It is preferable to have a separate clean room particularly for the semen thawing process.
• A pneumatic, hydraulic or manual crush is generally required for CIDR device insertion (oestrous synchronisation) and insemination. Crushes need to be maintained in good working order…crush failure presents a risk to operators and to the hinds themselves. They must secure the hind tightly but without risk of injury to hinds held in them for up to several minutes at a time. Also, inseminators are at risk of receiving severe kicks from the hinds back feet. A padded kicker board up to 300 mm high should be installed at the rear of the crush.

As AI programmes require a minimum of three separate hind yardings over a period of two weeks, it is important that risk of animal injury in minimised (i.e. ensure sharp projections that may injure hinds are identified and removed). The procedures used for AI are reasonably invasive (e.g. CIDR device insertion and removal, trans-cervical insemination) and farmers sometimes note a deterioration in hind behaviour in the yards with each successive yarding. This can be avoided by minimising hind stress during yarding. Attention to detail is important.

Why synchronise?

Hinds are fertile for a very short period (12 hours) every 18-21 days, when they show oestrus (heat) and ovulate. The insemination of hinds needs to be aligned as closely as possible to the precise timing of oestrus and ovulation. Unfortunately, there is insufficient natural synchrony between hinds to be able to inseminate at a natural oestrus (heat). Besides, oestrus detection is very difficult in deer. This means we are obliged to artificially synchronise oestrus and ovulation in hinds for successful AI programmes. Such synchronisation programmes are generally performed by vets.

When should synchronisation be done?

The seasonal timing of the synchronisation/insemination programme is a very important consideration. The primary concern is to ensure that the procedures are conducted within the natural timing of breeding (i.e. CIDR device removal occurs close to the time when most or all hinds would have naturally shown oestrus). There is a temptation to conduct the programme earlier in the season on the belief that the synchronisation procedure will advance the seasonal timing of oestrus and ovulation. This is simply not the case! In some cases we have seen catastrophic failure of AI programmes because synchronisation was conducted too early in the season and hinds failed to ovulate following CIDR device removal.

The window of opportunity for AI programmes (i.e. planned insemination dates) are from late March/early April to late April. Early-mid March inseminations run a high risk of failure.

What materials will the vet supply?

Research during the 80s looked at various ways to synchronise hinds but only one method ultimately proved highly successful. The “intravaginal progesterone type-G CIDR (‘Controlled Internal Drug Releasing’) device”. This device is supported by the injection of eCG (equine chorionic gonadotrophin) in red deer and wapiti-cross hinds. Two type-G CIDR devices are inserted intravaginally for 12 days early in the breeding season and between 150 and 250 units of eCG are injected intramuscularly at device removal. Hinds will come into oestrus about 36-48 hours later and ovulate about 12 hours after the onset of oestrus. AI is timed to occur 54-58 hours after CIDR device removal.

What is the procedure?

The procedure for synchronising hinds is as follows:

1. Two CIDR devices are tied together (by their strings) and inserted into the anterior chamber of the vagina via an applicator device liberally coated in lubricant (an alternative method is to insert a single CIDR device initially and replace it with a new device 8 days later, but this requires an additional hind yarding and does not seem to improve success rates).
2. The devices are removed 12 days later, at which time each hind is given an i.m. injection of eCG (generally in the neck). The timing of CIDR device removal during the day is dependent on the planned timing of insemination for batches of 40-60 hinds. This will necessitate in some cases the removal of CIDR devices during the hours of darkness for batches of hinds.
3. Hinds are inseminated 54-58 hours later

More resources

Fennessy, P.F., Fisher, M.W., Webster, J.R., Mackintosh, C.G., Suttie, J.M., Pearse, A.J.T., Corson, I.D. (1986) Manipulation of reproduction in Red Deer NZVA Deer Branch Conf. Proceedings No.3 / 103-120

Insemination

Remember, timing is everything! Planning and strict attention to detail is the key to a successful AI programme. AI in red deer and wapiti crossbreds involves transcervical inter-uterine insemination, and requires rectal manipulation of the reproductive tract. This procedure is conducted by highly trained AI technicians. Follow the instructions of the AI contractor to the letter.

Due to the rather short AI season, it is very important to arrange for insemination services well in advance of requirements. Generally, inseminators will supply the synchronisation scheduling and organise dispatch and transport of frozen or fresh semen in time for the AI. However, in some cases the farmers themselves may need to co-ordinate semen dispatch from AI centres.

 It is normal practice to run the inseminated hinds with ‘back-up’ stags from about 10 days after AI. This ensures that hinds that fail to conceive to AI have a chance of getting pregnant for the year.  However, this can mask the success of the AI programme unless hinds are ultrasound scanned early in pregnancy to assess foetal age or DNA is used to assess paternity of calves born.

Pregnancy scanning

Pregnancy scanning of AI success is a straight forward procedure, but requires appropriate timing in order to distinguish AI conceptions from those of the ‘back-up’ stags.

The ideal time of scanning is 45-50 days after AI. Foetuses of this age are very easily visualised and distinguished (see attached ultrasonogram of a Day 45 red deer foetus). By contrast, hinds conceiving to ‘back-up’ stags will have a pregnancy at least 10 days younger but most likely to be 18-21 days younger (length of an oestrous cycle).

An ultrasonogram of a Day 45 red deer foetus

Semen is collected from stags by electro-ejaculation, a procedure that is conducted by professional Artificial Breeding (AB) companies and veterinarians. In some cases it requires the use of sedatives and anaesthetics.

Generally, the farmer’s only involvement is to yard the stags at a scheduled time, and leave the rest to the professionals. Needless-to-say, good facilities are a must for the safety of everybody concerned.

Semen processing is again at the hands of the professionals and is a reasonably complex process. Collection of an ejaculate from a stag does not necessarily mean that good, usable semen will be obtained. AB companies will assess the semen quality once it is processed and judge whether it is suitable for AI based on a set of quality standards.

It is not uncommon for stags to provide poor quality ejaculates early in the breeding season (remember stags are infertile over spring and early summer) generally semen quality will improve approaching the rut and even well after the rut.

Most stag semen is frozen (‘cryopreserved’) and then thawed immediately before insemination. However, some AB companies can offer fresh semen collected within days of the insemination programme. Whilst frozen semen can be successfully preserved for many years, In terms of conception rates to AI, usually ‘fresh is best’. However, many batches of frozen semen have very high AI success.

Other reasons to collect semen

• to check the stag's fertility
• as a back-up option if the stag dies prematurely as an insurance policy
• post-mortem semen collection

Occasionally valuable stags die during or after the rut. With quick action, it is often possible to remove the testes, store them in a cool box and send them to an AB company for epididymal sperm extraction. The testes need to be processed within 6-8 hours of death. Talk to your nearest AB company to discuss this option should the need arise.