Preparing for mating
One date that often creeps up unnoticed is when to apply tail paint to record pre-mating heats.
To get maximum value from observing these heats, the herd should be painted 32 days prior to planned start of mating (PSM). Early identification of non-cyclers provides you with:
- an indication of likely submission rate (SR) during the first round of mating
- the opportunity to treat non-cyclers early to improve SR
Evidence shows treating non-cyclers early provides the best economic outcome by increasing the 6-week in-calf rate, which is essential to improving your calving pattern. By contrast, waiting to the end of the first round to treat non-cyclers does not improve calving pattern so next season the herd is no better off.
The target non-cycling rate at PSM is <15%. Rates typically encountered are closer to 25-30%. Reducing that rate requires improvements in:
- body condition score (BCS) at calving 5.0-5.5
- limiting weight loss after calving to less than 1 BCS
- heat detection
- calf and heifer management
The indications are that up to 45% of non-cyclers will cycle during the first round if left untreated, but these are not the cows that are limiting improvement to your calving pattern, the remaining 55%+ are.
If large numbers are involved and you are concerned about costs, you can prioritise cows for treatment by selecting younger animals, those of higher genetic merit and those without baggage such as chronic lameness, poor udder conformation and a history of mastitis.
Heat detection
Heat detection is probably taken for granted, yet indications are that it is not being done as well as it could be. This contributes to lower SR and poorer conception.
A cow is highly likely to be in heat if:
- She is standing to be mounted by other cows
- Tail paint is removed or
- Heat mount detector is triggered
If a cow is showing two or more of these signs, she is possibly in heat:
- Attempts to mount other cows
- Tail paint is rubbed but not removed
- Restless or bellowing
- Poor milk letdown
- Mucous around the vulva
- Mud marks on the flanks
- Heat mount detector lost
The decision whether to mate can be made as follows:
- Record a ‘?' whenever a cow is inseminated to an uncertain heat
- Look up any previous inseminations for that cow
- Inseminate if the cow has not been inseminated since calving
- Inseminate if previous insemination more than 20 days ago
- Inseminate if previous insemination was marked with ‘?' and was less than 20 days ago
If more than 10% of inseminations are on cows with weak signs, re-evaluate your heat detection methods.
Relying solely on observation of heat detection aids such as tail paint and heat mount detectors in the shed increases the risk of missed heats. A combination of heat detection aids and paddock observations is best. Paddock observation does not have to be time-consuming. Cows show strongest signs after grazing, so the best observation time is 2 hours after the morning milking and again early afternoon.
A final consideration is to make heat detection the responsibility of experienced staff members and to provide them with the time and resources to do this well.
Totally Vets can provide you with a mating plan that includes the important dates such as pre-mating tail painting, metrichecking, trace element tests, examination of non-cyclers and other refinements as required. Knowing these in advance takes the pressure off and avoids important dates being missed. Contact Totally Vets now to organise your repro calendar.
