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 have the ability to target maternal breeding more clearly.
There are a number of factors which will influence conception to AI in suckler herds. Heat detection is one of the 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 is being bred, approximately 75-80% of cows should be submitted for breeding in the first three weeks.
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.
Teagasc research has shown that the length of time a cow will be in standing heat on slats is approximately 8.6 hours, compared to 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 in-calf cows will show heat, and 9pm when 30% of cows will exhibit heat. At 5pm, approximately 18% would be observed in heat.
Vasectomised bull
One of the most common and most effective methods of heat detection in spring AI suckler herds herds is the teaser bull. If you are considering using a teaser bull for heat detection, then it is well time to be sourcing the bull and having him vasectomised as soon as possible.
A young vasectomised bull may be ideal for heifers. Where more than three or more cows are coming in heat on a daily basis, the effectiveness of a teaser bull may be reduced. After arrival on the farm, he should be vaccinated in accordance with the vaccination programme. The vasectomy should be carried out 60 days prior to him being introduced to the herd. It is also advised to place the chin ball harness on the vasectomised bull well in advance of the start of the season so that he is accustomed to it.
Heat detection aids
Tail paint can be effective in identifying cows in heat, as can scratch cards. Where tail paint is being used, it should be applied in a strip 8-10cm 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.
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 3 weeks after housing.
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, 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 1-2kg concentrates per day until they go back in calf.
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.
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 demands on labour. For farmers new to AI, or considering the option, ensure that there is a handling yard near the fields they are to 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 and 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.
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 with a chin ball can be 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.Read more
Focus on winter AI and BDGP
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 have the ability to target maternal breeding more clearly.
There are a number of factors which will influence conception to AI in suckler herds. Heat detection is one of the 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 is being bred, approximately 75-80% of cows should be submitted for breeding in the first three weeks.
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.
Teagasc research has shown that the length of time a cow will be in standing heat on slats is approximately 8.6 hours, compared to 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 in-calf cows will show heat, and 9pm when 30% of cows will exhibit heat. At 5pm, approximately 18% would be observed in heat.
Vasectomised bull
One of the most common and most effective methods of heat detection in spring AI suckler herds herds is the teaser bull. If you are considering using a teaser bull for heat detection, then it is well time to be sourcing the bull and having him vasectomised as soon as possible.
A young vasectomised bull may be ideal for heifers. Where more than three or more cows are coming in heat on a daily basis, the effectiveness of a teaser bull may be reduced. After arrival on the farm, he should be vaccinated in accordance with the vaccination programme. The vasectomy should be carried out 60 days prior to him being introduced to the herd. It is also advised to place the chin ball harness on the vasectomised bull well in advance of the start of the season so that he is accustomed to it.
Heat detection aids
Tail paint can be effective in identifying cows in heat, as can scratch cards. Where tail paint is being used, it should be applied in a strip 8-10cm 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.
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 3 weeks after housing.
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, 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 1-2kg concentrates per day until they go back in calf.
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.
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 demands on labour. For farmers new to AI, or considering the option, ensure that there is a handling yard near the fields they are to 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 and 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.
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 with a chin ball can be 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.Read more
Focus on winter AI and BDGP
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