Implementing controlled mating into an extensively managed northern beef herd

MAKING the decision to transition to controlled mating on an extensively-managed northern Australian property can be challenging.

In this article, beef reproduction experts and FutureBeef contributors Mick Sullivan, Tim Emery and Roxanne Morgan provide key considerations and planning options to help make the shift less complicated.

In summary, here’s what’s needed for a successful controlled mating program:

Ease of mustering to remove bulls from cows.
A secure bull paddock/s.
Yard facilities to handle larger mobs of weaners.
Additional staff may be required at particular times of the year with condensed branding and weaning rounds.
Timeliness of management activities and sticking to the timeline/plan.
A good data recording system (not necessarily electronic).
Vaccination program, particularly for vibriosis and leptospirosis.
Conduct an annual bull breeding soundness evaluation (BBSE) (including morphology).
Recording wet and dry lactation status and preferably pregnancy test/foetal age.
Management of cow body condition – through stocking rates, weaning and supplementation.

The following property scenario is used as an example to help simplify some of the management decisions made. This property and information may not be relevant to each application, but FutureBeef have many experienced extension staff that can help with local circumstances.

Example property details:

Reasonably large-scale property in Central Queensland with multiple large paddocks that are extensively grazed
Green date in mid-January
First weaning muster April to June
Second weaning muster August to September
Wanting to change from continuous mating to controlled without impacting heavily on production.

Set out below is a three-year plan for transition to controlled mating:

Year-One: Setting up the herd

August-September (Second round muster)

Remove bulls – Removing bulls now prevents calves being born next dry season (June–September) minimising time cows are lactating on poor quality feed. Ensure bulls have a secure paddock, not bordering with cows and have access to good quality feed.

Wean calves early – During this time wean as many calves as possible. Determine what the lowest calf liveweight you can manage and focus on weaning calves off cows in lower condition (less than body condition score 3). Resources to help you manage weaning early.

Vaccinate cows – While you have cows in the yards, you can vaccinate cows for diseases that are relevant in your area e.g. botulism, clostridial diseases, leptospirosis and pestivirus (screen mobs first). Keep in mind first-time vaccinations need a booster in 4–6 weeks.

Sort cows by lactation status – Segregating your breeders by lactation status (wet or dry) will help with the different management requirements of each group. Accurate records are crucial during this time. At this point managers can also pregnancy test and foetal age. By foetal ageing, a predicted calving pattern can be determined which can be very useful for planning your future management program. Segregating into calving groups may be useful to plan nutritional management and branding, weaning and bull removal in the following year.

Book a vet for bull checks – To ensure the health and fertility of your bulls book an ACV (Australian Cattle Veterinarians) accredited vet to perform a Bull Breeding Soundness Evaluation on your bulls, ideally 2–3 months before mating (to give you time to buy new bulls or re-test if needed).

Vaccinate all bulls for vibriosis (they will require 2 doses a minimum of 4 weeks apart with the second being at least 2 weeks before joining with the cows), 3-day sickness, botulism and clostridial diseases. Ensure your bulls have also been cleared for pestivirus (testing can be done through ear notch, hair or blood samples).

Supplement cows if needed – Supplement cows when back in the paddock if needed and dependent on season (weaning may be sufficient) to get them back up to body condition score 3 before mating. To help determine the level and type of supplementation required, diet quality of pastures can be determined through faecal testing.

Find out your ‘Green Date’ – Typically, the ‘green date’ is considered the date by when there is a specified chance of receiving over 50 mm of rain over 3 days (after 1 September). This is where there is a better than average chance for sufficient rain to support pasture growth. Producers can calculate their own Green Date here, and reach out to local extension officers if assistance is needed.

The Green Date for each area helps determine when to best support wet cow nutrition. It is also important to consider how long you want your calving window to be. This will be a personal and business decision depending on:

The country’s production capacity
when calves will be sold – all at once or staggered
the level of selection pressure the manager wants to place on females
business input levels and labour efficiency
appetite for risk.

In order to best support wet cow nutrition, peak lactation demand begins six weeks after calving. To line up this demand with pasture quality we consider the green date and adjust as follows: Bulls go into mating one month after green date so the first calves are born six weeks before green date in the following year.

Use this breeding table to plan when to put bulls out.

Year Two: Applying the program

Mid-February: Bulls out for mating. Put bulls back in with cows and heifers a month after the calculated Green Date (so bulls would go out in mid-February for this example property). Depending on individual situation, managers may adjust the timing based upon staff availability or weather and accessibility.

April-May: Undertake a forage budget. Conducting a forage budget at the end of the growing/wet season will help estimate how many animals can be carried through the dry season. Forward plan management options can then be considered if feed ends up short e.g. agistment or sale.

April-June: First round weaning. Wean as many calves as possible. Following the same principles as year one, cows in the lightest condition need to be weaned to support re-conception.

August-September: Second round weaning. Muster the herd for second-round weaning, Remove bulls and vaccinate and pregnancy test cows. As a minimum remove cows not detectably pregnant (Note: if pregnancy testing is performed at the time of bull removal, pregnancies less than six weeks may not be detected).

Managers may want to segregate the breeders based upon foetal age also.

Repeat bull checks and cow supplementation: Same as year one

Testing bulls at this time each year will create consistency in the management calendar and give plenty of time before joining to purchase replacement sires.

Year-Three and beyond: Refining the system

Repeat steps from year two.

Over time, herd managers implementing controlled mating can expect:

More calves in first-round weaning.
Better cow condition – Less need for dry season supplements.
Fewer second-round weaners.

Some advanced options to consider:

Shorten joining period to tighten calving pattern (e.g., 3 months).
Sell late-calving cows as surplus.
Pregnancy test 6–8 weeks after bulls are removed.

Source: FutureBeef