Artificial Insemination (AI) in the Suckler Herd
29 January 2026While more commonly used in the dairy industry and pedigree beef cattle, artificial insemination (AI) still has a place in commercial suckler herds because of the increased costs of replacement females and bulls, greater focus on calving intervals, and strong desire to improve financial and environmental efficiency within the beef industry.
Conception rates achieved through AI using conventional semen can be 60 – 70% and therefore on par with natural service. However, the time commitment associated with heat detection and handling can be a deterrent for implementing AI within suckler herds, nevertheless, practical solutions exist and the benefits can far outweigh the barriers.
In short
- AI in the suckler herd provides access to improved genetics and subsequently fertility, survival and growth leading to financial and environmental benefits.
- A combination of physical observation and technology can improve heat detection and success rates.
- Careful planning is required to implement AI in the suckler herd, and you should work with your vet to design a protocol to suit your herd.
Benefits for the suckler herd
A Livestock Health Scotland study found that using AI instead of natural service resulted in 7% less barren cows, 34% more cows calving within the first 3 weeks, 8% less assisted calvings, 6% lower mortality, 14% higher weaning percentage, and calves being 25 kg heavier at weaning, to produce a return on investment of over £120 per cow. These findings are likely due to having access to bulls with superior genetics or good EBVs and tightening of the calving period to aid management. The Borders Monitor Farm successfully used AI in their suckler herd to pull later calving cows forward by two to six weeks.
Other benefits of AI for the sucker herd include negating the need for keeping a bull with the associated costs, risk of introducing disease to the herd, and safety of farm staff and the public.
Sexed semen
Sexed semen is now available which provides over 90% accuracy of gender. This can be particularly useful for herds seeking to breed their own replacements without keeping a separate bull. However, conception rates from sexed semen can be 90% of that of conventional, it is more expensive and, in some cases, straws can take longer to thaw.
Research has shown that greenhouse gas emissions produced within a 100-cow suckler herd could be reduced by 14 tonnes annually and 3 tonnes more beef output produced by changing the proportion of male to female calves from 50:50 to 80% males, 20% females using sexed semen. This is due to selection of sires with superior growth EBVs and the greater feed conversion efficiency of male animals.
Things to consider before starting AI in the suckler herd
- Are your cows/heifers in the correct body condition score (BCS)?
- Cows should be BCS 2.5 – 3. https://www.fas.scot/article/body-condition-scoring-suckler-cows/
- Are they receiving the correct nutrition and mineral supplementation?
- Thin cows and those receiving inadequate nutrition are more likely to have prolonged anoestrus (lack of expression of oestrus).
- Avoid changing the diet too much in the weeks preceding, during, and after AI.
- Are the cows/heifers cycling?
- Cows naturally are anoestrus for 50 – 60 days. Suckling calves can supress the onset of oestrus. Restricting suckling by calves for short periods twice daily for 3 weeks from 30 days post calving can shorten this anoestrus period in most cows.
- Cows should have calves at least 40 days before starting AI programme.
- Perform a pre-breeding check 45-60 days post calving to check the reproductive tract. In heifers this will identify any poorly developed animals and in cows this will identify any infections.
- Blood samples can be taken to measure progesterone levels if uncertainty of cycling still exists after pre-breeding checks.
- What is the health status of your herd? Are your treatments and vaccinations up to date?
- All treatments and vaccinations should be done well in advance (at least 4 weeks) before AI.
- What handling facilities do you have?
- Depending on the protocol used, females will have to be handled several times. A well-maintained crush and race or self-locking head yolks are essential.
- Who will perform the AI?
- AI can be performed by trained vets, technicians or DIY.
- Those performing AI need to observe high standards of semen handling, thawing and insemination technique to ensure good results.
- Training courses are available for undertaking DIY insemination. Funding may be available through the Next Generation Practical Training Fund for those eligible.
- You should time your attendance at an AI training/refresher course to be as close to when you will be AI cows as possible. Refresher training may be advisable if you are not regularly performing AI in cattle or some time has elapsed since initial training.
Heat detection
Poor heat detection leading to semen being deposited early (meaning sperm is no longer capable of fertilising the egg) or too late (the egg is no longer viable), is one of the most common cause of cows and heifers failing to conceive from AI. Consequently, heat detection is critical to the success of AI, but this can also be the most off-putting element of considering AI in the suckler herd.
Heat detection (see box 1 for signs to look for) should be performed two or three times per day for 20 to 30 minutes per session. Early morning and evening are key times for heat detection especially when females are at rest and feeding times or when moving to new paddocks are times to avoid. Performing this indoors is much easier than when cattle are out at pasture.
| Box 1. Signs of heat in cows | |
|---|---|
| Primary signs | Standing to be mounted – research has shown <50% may do this |
| Secondary signs | Attempting to mount others Head mounting Sniffing/licking others Restless behaviour Bellowing Chin resting Scuff marks on tails/flanks Small increase in body temperature Bulling string – a clear mucous discharge from the vulval. If this also contains blood it indicates heat occurred 48 hours previous Poor milk let down (less obvious in beef cattle) |
Adapted from DHPPS
The combination of larger herd sizes and reduced labour on farms can make visual observation of heat detection challenging for many farms. Various aids and technology to aid heat detection are now available on the market and can be used to overcome some of the time and labour constraints. Information gathered from heat detection can be logged in livestock management software to select groups of animals for further heat detection or AI, then monitor reproductive efficiency through metrics such as the interval between calving and return to normal oestrus, heat detection efficiency when AI is used, and conception rates per service.
Table 1. Advantages and disadvantages of heat detection aids. Adapted from NADIS
| Heat Detection Aid | Advantages | Disadvantages |
|---|---|---|
| Tail paint/chalk applied to tail head and rubbed off when mounted | Cheap | Experience required to identify rubs from mounting |
| Easy to apply | Regular (weekly) reapplication needed. | |
| Heat mount detectors applied to spring above pelvis and change colour by pressure or rubbing. | Relatively cheap (approx. £1.50/cow) | Knocks can activate detector |
| e.g. Kamar®, Estrotect™, Heat Seeker® | Less skill than tail paint | Can be lost |
| Teaser bulls to mark cows in heat with chin-ball marker or can combine with an activity collar worn by bull e.g. Moocall HEAT Collar & Ear tags | Accurate | Cost of bull maintenance |
| Sensitive | Safety | |
| Can stimulate oestrus activity in cows | Disease risk | |
| Natural method | ||
| Activity monitors attached to cow via neck or leg collar, ear tag or rumen bolus. Activity increases 400% when cows are in heat. | Accurate | Expensive (£100 per cow) |
| E.g. SmaXtec, Tru-Test Active Ear Tags or Collar Tags; Track a Cow; SenseHub™; CowManger® | Sensitive | Requires compatible computer system/app |
| Heattime®, MooMonitor+ | Automatic recording 24 hours a day | Staff training required |
| Can also detect illness/lameness | ||
| Milk progesterone | Accurate | Less suitable for suckler herds. |
| Sensitive | Need to collect milk | |
| Cheap | Needs excellent record keeping | |
| Synchronisation | Avoids need for heat detection. | Needs excellent record keeping |
| Increased submission rates | Lower conception rates than AI to observed heat | |
| Cost of vet visit to administer treatments. | ||
| Use of hormones. |
A Swedish study showed combining visual oestrus detection for 20 minutes three times daily at 6 am, 2pm and 10 pm and automatic activity-based oestrus detection systems (Heattime®) could correctly identify 96% of cows in oestrus and 90% of cows not in oestrus, which was of greater accuracy than visual observations alone.
AI protocols
There are several AI protocols available, and these can vary for cycling or non-cycling animals and between heifers and cows. Progesterone implants e.g. PRID®, CIDR® and prostaglandin injections form the basis of most common AI protocols to induce oestrus. Some protocols also include pregnant mare serum gonadotrophin (PMSG/eCG) to improve follicular development. Synchronisation of oestrus to allow fixed time AI can be achieved by the addition of GnRH to protocols. The use of fixed time AI allows animals to be served whether bulling or not, which can be beneficial for repeat breeders that may have short or silent heats.
An example synchronisation protocol is:
| Day 0 | Day 7 | +56 hours |
|---|---|---|
| Insert progesterone device & inject GnRH | Remove progesterone device & inject prostaglandin | Inject GnRH & Fixed time AI |
SRUC’s Easter Howgate operates a triple synchronisation programme which is detailed in this webinar and factsheet.
You should speak to your farm vet for advice on selecting a protocol.
Timing is crucial
Oestrus (the period of maximal sexual activity) in cows can range from 2 – 30 hours, with an average of 8 hours in dairy cattle. Generally, ovulation occurs 24 to 32 hours after the start of standing heat, but there can be variation between cows and heifers. The best conception rates are seen in mid-oestrus to two to three hours after oestrus ends. Therefore, for the greatest success rates AI needs to be performed at least 6 hours before ovulation or within 12 hours of being seen standing to mount to ensure sperm reaches the female reproductive tract when the egg is fertile. This forms the basis of the AM/PM rule i.e. cows showing heat in the morning have AI performed in the evening and vice versa.
In fixed time AI protocols, AI is administered at a fixed time and can negate the need for heat detection. As a result, conception rates can be lower using this method due to variation in oestrus and ovulation timing. Some protocols use two semen straws 12 – 24 hours apart to counteract this effect.
Following AI, cows and heifers should be monitored for repeats 19 – 23 days later. Any females not holding to the first service and have the synchronisation programme repeated or go to natural service using a sweeper bull.
Costs
AI costs can vary depending on synchronisation protocol, cost of semen straws, and who is undertaking AI (technician or DIY), but may not be dissimilar to the cost of retaining a bull, especially for smaller herds or those breeding their own replacements. For those undertaking DIY AI additional costs associated with purchasing the semen tank, regular liquid nitrogen top-ups, rods, sheaths, gloves and an electric thawer or flask will be necessary.
An often-hidden cost in AI protocols is that of time. Having to gather cattle three or more times can be time consuming, but the elements of the protocols e.g. inserting/removing progesterone devices and injecting hormones may only take 20 – 30 minutes for 10 animals depending on handling facilities. Performing AI should not be rushed to ensure appropriate placement of the semen within the reproductive tract and increasing stress levels in cows and heifers.
Laura Henderson, SAC Consulting
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