Unlike castration, this means the bull can still produce high levels of testosterone whilst remaining excellent at detecting heat activity in cows and heifers.

The biggest advantage of the presence of the bull in the field during breeding season means wasting less time observing cows on such a regular basis for heat activity.

Bulls increase the intensity of oestrus in cows and reduce the reliance on veterinarian intervention through use of hormonal synchronisation methods such as progesterone.

If using AI, teasers are an extremely useful and accurate means of heat detection and where staffing levels are low for daily observation checks, they make this busy time of the year a lot more manageable.

What is the recommended ratio of bulls to females?

As a very good rule of thumb in block calving herds is that you should run one bull to every 50 cows. However, where your calving spread may be split between the spring and autumn or your calving all year round, then a ratio of one bull to every 100 cows is acceptable.

If bulls are placed with too many females, they can easily become overworked which will affect your overall breeding performance.

It is a good idea to have spare bulls that you can swap in and out, so if a bull becomes tired, he can be rested for a few days.

What breeds of bull work best as teasers?

Moocall finds that Aberdeen Angus X or Friesian X bulls are hardier than most other breeds, particularly when it comes to heat detection. They both have a relatively small frame and also have a good libido.

However, often the dairy bred bulls can become aggressive at a younger age so it is good practice to just keep them for one or two breeding seasons or move them on if they show any signs of having temperament issues.

When should you put the teaser(s) in with the batch of females?

It is a good idea to run the teaser with the cows or heifers in advance of when you want to start breeding to give him a chance to get used to running with the cows and familiarise himself with the routine of milking or herding. Ideally, he should be introduced three weeks before breeding to identify cows that are cycling and more importantly those that are not.

Alternatively, some herds will only start using teaser bulls after the first weeks or six weeks of breeding, heats tend to be easier to detect early in the season when there are large volumes of cows cycling and a lot of activity.

Teasers are particularly useful when a large percentage of the cows are in-calf and activity slows down making it more difficult to identify cows in heat.

Can I use a specific teaser bull for more than one season?

Teaser bulls can be kept for more than one breeding season. Older bulls can become more difficult to handle and are quite likely to show signs of aggression posing a risk on health and safety.

Also, aged bulls in some cases can show signs of laziness or have reduced libido making them less adaptable at detecting heats and aiding the farmer.

Looking ahead to the 2021 breeding season, what should my targets look like?

For pasture-based spring-calving systems, the target three-week submission rate is 90%. This means having 90% of cows detected in heat and submitted for service during the first three weeks of breeding. The second main target is to have a six-week calving rate of 90%, or having 90% of all cows calved during the first six weeks of calving.

This can only be achieved by having a high submission rate as well as conception rates to service (ie timely use of AI).

Irish national target calving interval according to Teagasc: one calf per cow every 365 days

Why should Moocall HEAT be your go-to detection aid?

For AI, a vasectomised bull fitted with a Moocall HEAT collar is proven to increase submission rates and reduce the number of missed heats, while saving on the time spent visually observing cows for signs of heat.

Moocall HEAT sends a message to the farmer once the bull detects a cow in standing heat giving an optimum time to serve the cow. If using a stock bull you can be rest assured, as the collar will not only detect when heats are present but also that your bull has served the cow. This provides you with accurate calving due dates for the Spring but also identifies any non-cycling or problematic cows within the first few weeks of breeding. As well as being one of the most affordable heat detection technologies on the market, Moocall also stands over being able to achieve a 96.5% submission rate within the first three weeks of breeding. The system also provides the farmer with complete control and tracking of their breeding performance through the Moocall Breedmanager App.

For a FREE breeding consultation please contact the Moocall team on (01) 969 6038 or visit the website here: www.moocall.com/heat/