Heat Detection Strategy

InCalf research shows it is likely that heat detection errors are limiting reproductive performance in around one-quarter of seasonal calving herds.

Two mistakes that are commonly made by many farmers when detecting heat are missing heats and inventing heats.

It sounds unusual to invent heats, but it’s easy enough to record the wrong cow ID or mistake when a cow is on heat.

As most farms will only carry out heat detection once a year, and there’s often new team members on board, it is worth revisiting your heat detection strategy each season to ensure your team is ready to go by upskilling and refreshing their skills.

The best heat detection programmes start with careful planning, good observation and the effective use of detection aids. Being able to distinguish and interpret cow behaviour and other signs is critical. So is good record keeping and training  those responsible for heat detection.

Forming a heat detection strategy

Step 1 - Review the heat detection skills available on your farm

Are they up to scratch? Does everyone involved know exactly what to look for when detecting cows on heat?

Step 2 - Determine which aids you will use.

Remember, farmers with the best heat detection results use a combination of observation and heat detection aids. No one method is perfect. Be prepared to test several combinations of options to identify the one most suitable to your herd. Tail paint is the most commonly used heat detection aid.

Step 3 - Decide how best to record cows on heat and train staff to do this.

Make sure all cows are tagged and that numbers can be clearly identified for accurate drafting.

Outline all the processes surrounding heat detection and mating on farm and break it down into easy to follow steps. This will be helpful for new staff now and into the future.

Finally, keep an eye on the detail. Schedule regular times to monitor the success of the programme. This information is critical to spot trends early. A successful heat detection programme relies on monitoring and fine-tuning all through the mating period.

Recording heats before mating begins

The period before mating begins offers an opportunity to practise heat detection skills, check for cows not detected on heat, and anticipate when cows may next come on heat. Farm team training should be organised at this time. The most experienced person can help less experienced team members interpret signs of heat.

Train team members by making a paddock visit at the recommended time for a 'look-and-learn' session. Next day, let team members do the detecting with you just checking. Monitor  heat detection efficiency is being maintained by checking tailheads during milking and comparing daily heat records.

Planning pre-mating heat detection:

• Determine what date to tail paint cows (35 days before mating start date) and what colour to use.
• Check tail painted cows for rubbed tail paint at least twice weekly until MSD.
• At these checks:
  • ensure all cows have an unbroken strip of paint throughout the monitoring period and
  • repaint rubbed cows with a different colour paint (e.g. red).
• Determine when you will change colours (to easily identify late calvers).
• Determine who is responsible for monitoring which cow has cycled and what needs to be done with the information. Will it be recorded anywhere? Using mobile apps and some automated systems make electronic data entry of herd mating events quick and easy.
• Confirm when you will make a decision regarding any non-cycling treatment, and talk to your veterinarian.

The level of pre-mating heat activity is an early indicator of how fertile the herd is approaching AB.

If the herd is meeting pre-mating cycling rate targets, then it is on track to achieve a 90 percent 3-week submission rate without non-cycling treatments.

You should also expect a good conception rate as 85 percent of cows will be first inseminated on their second or third heat post-calving if the pre-mating cycling rate is on target.

Meet with the AI technician

Before mating starts, meet with your technician and the farm team to confirm timing, plan who will meet the technician on the day, and what the process will be with drafted cows before and after they are inseminated.

Identify whose responsibility it is to re-apply tail paint and heat detection aids and when they should do so. This should occur no sooner than the following milking, but ideally the next day.

Assessing heat detection using submission rate

Submission rates are a useful tool in assessing your current management of heat detection. Submission rates can be low for two reasons:

• Your cows are showing heat normally but you are not detecting them.
• You have lots of ‘non-cyclers’ in your herd that are not showing heat normally.

Submission rates below trigger levels suggest action is required. Start by reviewing heat detection practices. Then look at other areas such as body condition, lameness, or other health issues.

To assess heat detection efficiency, it is best to look at the 3-week submission rate of cows likely to be cycling normally.

Early-calved mature cows have every reason to be cycling normally, and should be detected and submitted to AB in the first three weeks.