Step-by-step practical guide to using AI in your spring-calving beef herd

Artificial insemination is a significant tool for beef producers looking to boost genetic gain and performance, yet the practicalities of how to do it often put farmers off.

However, the development of synchronisation programmes means it is possible to minimise time needed for heat detection and maximise conception rates. Even those not using these programmes can still make AI work for them by thinking about how they do things on farm.

How should I use AI?

The first thing to ask yourself is what you are trying to achieve. One of the main benefits of AI is the ability to access high-genetic merit sires to drive herd improvements.

How AI is used will vary from farm to farm depending on breeding goals, but could be used on individuals or groups of animals.

For example, you could use one AI bull for producing calves with superior carcass traits and one to improve maternal traits in replacements.

The key is to use EBVs to select bulls that will produce progeny to fit requirements and complement the females to which they are born.

Farm set-up

Before doing anything, farmers should assess their system to see what needs to be done to implement AI on farm, advises Eblex senior beef and sheep scientist Mary Vickers.

“Speak to your vet and approach AI companies to discuss what they need and how your farm could fit in their round,” she says.

Dr Vickers advises looking at the following:

• Handling facilities – good facilities are crucial. Cattle need to be moved calmly as any stress will affect conception rates.
• Groupings – can you keep cattle due for service close to the handling system?
• Cow health – animals should be healthy, on a rising plane of nutrition and in good body condition, otherwise conception rates will suffer and AI could become costly
• Records – do you have good records of cow health and fertility so you can serve appropriate animals?
• Labour – do you have time to observe and record heats? This affects which programme you use.

©Cogent

What AI options are available?

Observing heats

If done well, AI based on visual observations of heat is the best way to maximise conception rates as you can time insemination more accurately. However, time required to observe can make it unpractical.

Ideally cattle should be observed twice a day for 20 minutes in the morning and evening. Animals should be inseminated 12 hours after they are first seen standing to be mounted.

Using aids such as Kamars or automated heat detection systems can help detection.

Synchronisation

Synchronised breeding strategies use hormones to bring cows into heat in a set period. This strategy can help:

• Facilitate block serving and a compact calving period
• Reduce time and labour needed for constant heat detection
• Improve the timing of AI.

Many beef farmers will synchronise heifers to get them to calve at the start of the calving season.

Producers will still need to determine a heat detection strategy for serving animals returning to heat after any synchronisation programme has finished, unless a sweeper bull is being used.

Vet Keith Cutler of the Endell Veterinary Group says details of synchronisation programmes can vary and must be designed in discussion with a vet.

“However, all synchronisation protocols are variations of two themes and stem around the use of two hormones; prostaglandin and progesterone,” he explains.

In a cow’s natural cycle, a structure called the corpus luteum is produced after ovulation which secretes progesterone. Progesterone prevents another egg from being produced or a cow from coming into heat.

Prostaglandin is naturally produced near the end of a cow’s cycle if she is not pregnant to cause the corpus luteum to regress. As a result progesterone levels decline, resulting in a hormonal response causing the cow to start cycling again and come into oestrus.

All synchronisation programmes are designed to adjust this cycle:

• Prostaglandin-based programmes generally give two doses of prostaglandin (PG) 11 days apart. PG causes the corpus luteum to regress and the animal to come into heat. Fixed-time AI (FTAI) then takes place at set times, once or twice after the last PG injection (see example).
• Progesterone-based programmes are based on using a progesterone-releasing device (either a PRID or CIDR) which is inserted into the vagina. This device acts like a corpus luteum. By pulling it out after eight days it induces a hormonal response resulting in all animals coming bulling. FTAI then takes place once or twice at set times after the removal of the device.

This system may be combined with a PG injection the day before the device is pulled out.

This helps any animals that are naturally cycling to get rid of their natural corpus luteum.

A vet may decide to modify the above programmes to include other hormones to improve results. This will add extra costs to the system.

Mr Cutler says there’s also the potential to do a partial PG programme that still requires some heat observation.

“This can involve injecting all animals with PG and watching for signs of bulling three to four days afterwards and serving animals in heat. Anything not served could then receive a second PG injection and FTAI,” he explains.

“Whatever the programme, it’s crucial to stick to the correct timings. If your plan says inject at 9am on a set day, you’ve got to do it then or you’ll compromise results.”

DIY or technician?

DIY AI is an option, but consider the need for training, investment in equipment and the skills needed. Cogent estimates initial set-up costs for DIY AI at about £1,475 in the first year for training, equipment and AI tank maintenance. It will then be about £210/year.

The cost on a daily call basis for a technician to serve an individual cow could be about £8.50 a cow (prices vary by company).

If a batch is synchronised, this price is likely to be lower, but there will be additional vet costs.

Pros and cons of different AI methods

Example synchronisation programmes