Replacing rams

Replacing rams regularly will keep your ram flock young, and physically and reproductively healthy. It will also maximise your rate of genetic gain.

When bringing in replacement rams, be mindful of the health of both the new animals and your existing ram flock.

Order ahead

It's important to plan ahead when timing your replacement rams' arrival. Mustering, yarding, transporting and shearing are stressful situations that affect fertility.

Any fertility problems associated with delivery should be relatively short lived, but it can take up to 8 weeks before viable sperm is produced.

To allow for this, you should plan delivery no later than 8 weeks before the intended date of joining.

Rams that are not locally bred, and from a better environment, are much more likely to be affected by a change of location. They can take 6 months or more to adapt to their new surroundings and grazing conditions.

You should think well ahead when purchasing rams from an environment that is not as harsh as the new environment where they will be expected to perform.

Check before purchasing

Before you buy any replacement rams, you should examine them carefully for physical faults.

Check your newly purchased replacement rams before they are loaded for transport home and ensure they are delivered according to Queensland's livestock movement requirements.

Inspect on arrival

On arrival, give your replacement rams a thorough physical examination to check for any injuries that may have happened since purchase, perhaps in transit. Let your ram supplier know immediately if any animals have physical problems. This is especially important if rams have testicular abnormalities.

By informing the stud supplier straight away you can claim for replacement animals or reimbursement. If you detect illness or injuries after the rams have been joined (mated) or had contact with older rams, it will be too late to claim.

The rams may have been injured or have contracted an infection from one of your animals after arriving on your property. The disease ovine brucellosis can be transmitted with palpable lesions evident in as little as 4 weeks.

Quarantine new rams

Replacement rams may introduce pests and diseases on to your property. To protect your farm and minimise the risk to your stock, purchase your replacement rams from a known and reliable disease-free source.

To reduce risks from new animals you should always:

  • purchase new stock from a known and reliable source
  • request the history of livestock and obtain supporting paperwork, such as animal health statements
  • ensure movement requirements are met
  • quarantine new sheep on arrival.

Check for parasites

On arrival, check your replacement rams for parasites like worms and lice so that these parasites are not introduced to your property.

Replacement rams carrying more than 3 months wool should be:

  • shorn when they arrive
  • inspected for lice and treated if infested
  • poll-jetted—i.e. spraying (jetting) the top of the ram's head (poll) with insecticide to prevent flystrike
  • placed in a well-shaded paddock.


Your replacement rams should have been drenched before leaving the stud.

On arrival, check your rams for worms using a worm egg count and treat if appropriate with an effective quarantine drench. This will ensure that they are not bringing drench-resistant worms with them.

After treatment, hold the rams for at least 2–3 days in a quarantine area before releasing them into the ram paddock.


If your replacement rams are infested with lice, use LiceBoss to identify, treat and prevent lice infestations.

Some treatments take weeks to kill lice, so make sure you refer to the product information and isolate the rams for the specified time. It is important to treat lice infestations as the itching, rubbing and biting can damage skin and pre-dispose animals to flystrike.

The irritation and discomfort can also cause:

  • reduced libido
  • loss of body condition
  • reduced testicular weight (and therefore sperm production).


If blowflies are active, newly arrived rams should be shorn or given a thorough jetting on the poll, shoulders, backline, breech and pizzle with a minimum residue chemical such as FlyBoss.

Flystruck rams are less interested in serving ewes than healthy rams, and even small blowfly strikes will reduce ram fertility for about 8 weeks after the problem is fixed.

Badly struck rams should be culled so that they don't pass their susceptibility to flystrike on to their progeny.

Vaccinate new rams

On arrival, your replacement rams should begin an immunisation program with a 6-in-1 vaccine. They will require 2 injections, 4 weeks apart, followed by an annual booster.

This will provide lifetime protection against:

  • tetanus
  • blackleg
  • malignant oedema (blood poisoning)
  • black disease
  • pulpy kidney.

It will protect against cheesy gland (caseous lymphadenitis), which is also known as shearer's boils, yolk boils or CLA.

Consider supplementary feeding

Depending on seasonal conditions, your replacement rams may require some form of supplementation to ensure peak condition at joining (mating).

Rams may need time to adapt to a change in diet. If rams are moving from good-quality feed onto dry pastures, you may need to provide supplementary feed for a short period of time (6–8 weeks) after arrival.

This helps:

  • minimise stress
  • minimise fertility problems associated with poor nutrition
  • prevent digestive upsets
  • prevent unacceptable condition loss from rapid change in diet quality.

If there is good paddock feed available, you may not need to supplementary feed your replacement rams. Another way to help replacement rams adjust is to offer the rams slowly decreasing amounts of medium-quality grassy hay.