Using AI over natural service can bring a lot to the table in terms of being able to match the bull to the cow and focus on improving specific traits in calves, along with having the ability to target maternal breeding more clearly.
There are a number of factors which will influence conception rate to AI in suckler herds. Heat detection is one of the more crucial ones, and poor detection rates can have a significant effect on conception and in-calf rates.
The first step in heat detection should be accurate data recording. Calving dates should be noted and available in the shed. From this, farmers can predict when cows should be coming in heat. Insemination dates should also be recorded to allow farmers to watch for repeats.
Where a tight calving herd (10 to 12 weeks) is being bred, approximately 75% to 80% of cows should be submitted for breeding in the first three weeks.
1 Timing of observations
Where cows are housed on slats, signs of oestrus may be reduced significantly.
In addition, the ground surface in pens can have a significant effect on the expression of oestrus. Where cows are housed on slats, or where underfoot conditions are slippy, less expression of oestrus will be seen.
Research has shown that the length of time a cow will be in standing heat on slats is approximately 8.6 hours, compared with 14.7 hours when at grass.
Where cows are on slats with rubber attached, the length of time in standing heat can rise to 12.2 hours, while cows housed on straw bedding can show a standing heat for up to 14.2 hours.
The average number of mounts exhibited on slats are 20 to 28 times fewer than at grass. For farmers operating AI where cows are housed, observation is critical to identifying cows in heat.
The best times for observing cows are at 7am, when approximately 40% of cows will show heat, and 9pm when 30% of cows will exhibit heat. At 5pm, approximately 18% would be observed in heat.
2 Vasectomised bull
One of the most common and most effective methods of heat detection in spring AI suckler herds is the teaser bull. If you are considering using a teaser bull for heat detection, then now is the time to source the bull and have him vasectomised as soon as possible.
A young vasectomised bull may be ideal for heifers. Where more than three cows are coming into heat on a daily basis, the effectiveness of a teaser bull may be reduced. However, he is still your best bet.
If sourced off-farm, he should be vaccinated in accordance with the vaccination programme on the farm.
The vasectomy should be carried out 60 days prior to him being introduced to the herd.
It is also advisable to place a chin ball harness on the vasectomised bull well in advance of the start of the season so that he is accustomed to it.
3 Heat detection aids
Tail paint can be effective to identify cows in heat, as can scratch cards. Where tail paint is being used, it should be applied in a strip 8cm to 10cm wide to a clipped tail head. Paint attached to a thick matt of hair will not be removed.
Other detectors such as scratch pads rely on a change of colour once a cow has been mounted. This may be effective if used in conjunction with frequent observations.
When cows are out at grass, it may be more difficult to identify scratch pad colour changes without regular handling.
4 Time of insemination
Best conception rates have been recorded when AI is carried out 12 to 18 hours after the start of the standing heat. Most farmers doing AI will go by the AM/PM system, where cows that are in heat in the morning will be inseminated in the evening.
Where sexed semen is being used, some farmers will wait 24 hours after the first sign of standing heat before insemination. Where cows are housed during the breeding season, the change in diet and energy intake can have an effect. It is critical to watch for repeats approximately three weeks after housing.
5 Manage nutrition pre-breeding
Rapid reductions in the body condition score (BCS) of a cow should be avoided between calving and breeding. A spring-calving suckler cow should calve down in a BCS of 2.5.
Between calving and breeding, BCS should not reduce by more than 0.5 units. Where a spring-calving cow is due to go to grass within a month of calving and is in adequate BCS, average-quality silage will suffice. However, supplementation may be required if silage quality is below 65DMD, or where cows remain housed on silage for longer than a month prior to breeding. It is advisable to supplement first-calved cows with 1kg to 2kg of concentrates per day until they go back in calf.
6 Get cows cycling
Ideally, a cow should calve every 365 days. As the gestation length is 288 days; that leaves just 77 days to get the cow back in calf.
To keep the calving period tight, you must ensure that the anoestrus period, or period during which the cow is not cycling, is kept to a minimum. This period can vary from 30 days to 180 days, depending on cow condition, nutrition etc. Some farmers will opt to scan cows prior to breeding, particularly those who experienced a hard calving, to check if the cow is cycling.
Those that are not can be brought in heat through an injection of progesterone – this will have to be done under veterinary supervision.In addition, cows that had hard calvings or retained placenta may need infections treated.This is commonly done in a washout procedure – the earlier the intervention once an infection is detected the better.
7 Facilities
Regardless of whether cows are being served to AI indoors or outdoors, good handling facilities are crucial. Most suckler farmers avoid AI due to its high demand on labour.
For farmers new to AI, or considering the option, ensure that there is a handling yard near the fields they are turned out to. The crush for use should be safe and secure.
It is often worthwhile to bring in at least one more cow with the cow that is in heat to help keep her settled.
Once in the pen, ensure they are separated to avoid excess mounting and potential injuries.
If serving cows to AI on your own, ensure that the cow is adequately restrained in a head lock before entering the crush behind the cow.
Ensuring a viable return from suckler cows is not a guaranteed outcome with the top-performing suckler herds able to make a profit from suckler cow enterprises before subsidies.
These top performing herds will have a number of performance indicators in common such as consistently producing 0.95 calves/cow/year, achieve heavier weights at weaning which will both be driven by cows with high fertility which can have a calf every 365 days.
If autumn calving cows do not get back in calf and are let slip around to the spring herd you are not saving money, but you are reducing the overall fertility of your herd.
No system can afford to carry passengers over the winter period given the cost of inputs.
In short
Use records such as calving date to identify cows which should be coming in heat.Note all cows served and watch for repeats.Observe cows at 7am, 5pm and 9pm for best results when identifying cows in heat.A vasectomised bull and chin ball is very effective for heat detection.Aids such as scratch cards and tail paint also play a role. Target inseminations 12-18 hours after a standing heat.Consider a pre-breeding scan to identify non-cycling cows.Ensure handling pen and crush are safe and fit for use before the start of the season.
Using AI over natural service can bring a lot to the table in terms of being able to match the bull to the cow and focus on improving specific traits in calves, along with having the ability to target maternal breeding more clearly.
There are a number of factors which will influence conception rate to AI in suckler herds. Heat detection is one of the more crucial ones, and poor detection rates can have a significant effect on conception and in-calf rates.
The first step in heat detection should be accurate data recording. Calving dates should be noted and available in the shed. From this, farmers can predict when cows should be coming in heat. Insemination dates should also be recorded to allow farmers to watch for repeats.
Where a tight calving herd (10 to 12 weeks) is being bred, approximately 75% to 80% of cows should be submitted for breeding in the first three weeks.
1 Timing of observations
Where cows are housed on slats, signs of oestrus may be reduced significantly.
In addition, the ground surface in pens can have a significant effect on the expression of oestrus. Where cows are housed on slats, or where underfoot conditions are slippy, less expression of oestrus will be seen.
Research has shown that the length of time a cow will be in standing heat on slats is approximately 8.6 hours, compared with 14.7 hours when at grass.
Where cows are on slats with rubber attached, the length of time in standing heat can rise to 12.2 hours, while cows housed on straw bedding can show a standing heat for up to 14.2 hours.
The average number of mounts exhibited on slats are 20 to 28 times fewer than at grass. For farmers operating AI where cows are housed, observation is critical to identifying cows in heat.
The best times for observing cows are at 7am, when approximately 40% of cows will show heat, and 9pm when 30% of cows will exhibit heat. At 5pm, approximately 18% would be observed in heat.
2 Vasectomised bull
One of the most common and most effective methods of heat detection in spring AI suckler herds is the teaser bull. If you are considering using a teaser bull for heat detection, then now is the time to source the bull and have him vasectomised as soon as possible.
A young vasectomised bull may be ideal for heifers. Where more than three cows are coming into heat on a daily basis, the effectiveness of a teaser bull may be reduced. However, he is still your best bet.
If sourced off-farm, he should be vaccinated in accordance with the vaccination programme on the farm.
The vasectomy should be carried out 60 days prior to him being introduced to the herd.
It is also advisable to place a chin ball harness on the vasectomised bull well in advance of the start of the season so that he is accustomed to it.
3 Heat detection aids
Tail paint can be effective to identify cows in heat, as can scratch cards. Where tail paint is being used, it should be applied in a strip 8cm to 10cm wide to a clipped tail head. Paint attached to a thick matt of hair will not be removed.
Other detectors such as scratch pads rely on a change of colour once a cow has been mounted. This may be effective if used in conjunction with frequent observations.
When cows are out at grass, it may be more difficult to identify scratch pad colour changes without regular handling.
4 Time of insemination
Best conception rates have been recorded when AI is carried out 12 to 18 hours after the start of the standing heat. Most farmers doing AI will go by the AM/PM system, where cows that are in heat in the morning will be inseminated in the evening.
Where sexed semen is being used, some farmers will wait 24 hours after the first sign of standing heat before insemination. Where cows are housed during the breeding season, the change in diet and energy intake can have an effect. It is critical to watch for repeats approximately three weeks after housing.
5 Manage nutrition pre-breeding
Rapid reductions in the body condition score (BCS) of a cow should be avoided between calving and breeding. A spring-calving suckler cow should calve down in a BCS of 2.5.
Between calving and breeding, BCS should not reduce by more than 0.5 units. Where a spring-calving cow is due to go to grass within a month of calving and is in adequate BCS, average-quality silage will suffice. However, supplementation may be required if silage quality is below 65DMD, or where cows remain housed on silage for longer than a month prior to breeding. It is advisable to supplement first-calved cows with 1kg to 2kg of concentrates per day until they go back in calf.
6 Get cows cycling
Ideally, a cow should calve every 365 days. As the gestation length is 288 days; that leaves just 77 days to get the cow back in calf.
To keep the calving period tight, you must ensure that the anoestrus period, or period during which the cow is not cycling, is kept to a minimum. This period can vary from 30 days to 180 days, depending on cow condition, nutrition etc. Some farmers will opt to scan cows prior to breeding, particularly those who experienced a hard calving, to check if the cow is cycling.
Those that are not can be brought in heat through an injection of progesterone – this will have to be done under veterinary supervision.In addition, cows that had hard calvings or retained placenta may need infections treated.This is commonly done in a washout procedure – the earlier the intervention once an infection is detected the better.
7 Facilities
Regardless of whether cows are being served to AI indoors or outdoors, good handling facilities are crucial. Most suckler farmers avoid AI due to its high demand on labour.
For farmers new to AI, or considering the option, ensure that there is a handling yard near the fields they are turned out to. The crush for use should be safe and secure.
It is often worthwhile to bring in at least one more cow with the cow that is in heat to help keep her settled.
Once in the pen, ensure they are separated to avoid excess mounting and potential injuries.
If serving cows to AI on your own, ensure that the cow is adequately restrained in a head lock before entering the crush behind the cow.
Ensuring a viable return from suckler cows is not a guaranteed outcome with the top-performing suckler herds able to make a profit from suckler cow enterprises before subsidies.
These top performing herds will have a number of performance indicators in common such as consistently producing 0.95 calves/cow/year, achieve heavier weights at weaning which will both be driven by cows with high fertility which can have a calf every 365 days.
If autumn calving cows do not get back in calf and are let slip around to the spring herd you are not saving money, but you are reducing the overall fertility of your herd.
No system can afford to carry passengers over the winter period given the cost of inputs.
In short
Use records such as calving date to identify cows which should be coming in heat.Note all cows served and watch for repeats.Observe cows at 7am, 5pm and 9pm for best results when identifying cows in heat.A vasectomised bull and chin ball is very effective for heat detection.Aids such as scratch cards and tail paint also play a role. Target inseminations 12-18 hours after a standing heat.Consider a pre-breeding scan to identify non-cycling cows.Ensure handling pen and crush are safe and fit for use before the start of the season. 
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