Best practice for managing newly purchased sheep

A lot of stock – whether it is rams, breeding females or store lambs – will move directly between farms or indirectly through marts over the coming weeks. With this movement of stock, Teagasc Sheep Specialist, Ciaran Lynch reminds us of the importance of having proper biosecurity measures in place.

Whether it’s the purchase of stock, or the return of animals from the marketplace or shows, animals entering or returning to a flock come with the inherent risk or bringing unwanted health problems with them. It’s important to be aware of the risks and have a plan in place to minimise their impact on your own sheep system. 

Take care when buying. Where possible, limit the number of flocks stock are sourced from. Always aim to source new stock from a healthy flock. Where possible, particularly in the case of breeding stock, enquire what vaccination programme is being used, or if there are any health issues with the flocks.

Avoid buying problems may seem obvious but it’s something that can be easily overlooked, particularly where larger numbers of animals are being purchased. When buying, carry out a thorough check for any signs of disease or ill health; do not buy sheep that are lame or with any other visible issues.

Lameness

New arrivals should be footbathed on arrival on the farm in a 10% zinc or copper sulphate solution, ensuring adequate stand-in time. This will treat scald and mild forms of footrot. It may also make it easier to identify more serious forms of lameness, particularly footrot and contagious ovine digital dermatitis (CODD). Isolate any lame sheep and consult with your vet for the most appropriate antibiotic treatment of any clinical lameness. Do not mix lame sheep with their counterparts until they are fully cured

Internal parasites

New sheep entering flocks run the risk of bringing resistant stomach worms with them. This is one of the ways anthelminthic resistance has spread from farm to farm. Therefore, it’s important that there is a proper quarantine procedure to deal with these upon arrival to clear out any worm burden they may be carrying.

In order to prevent this, we need to quarantine dose these sheep. This is one of the few times where it is recommended to dose adult sheep. Given the wide spread anthelminthic resistance that’s present on farms, this should include the use of one of the two new anthelminthic groups Group 4-AD (Monapantel), sold under the trade name of Zolvix. This is a prescription only medicine (POM), so you will need to contact your local veterinary practitioner to order this.

Quarantine Drench:

• Dose with 4-AD (Zolvix) + a second wormer either - the choice of the second wormer can be one from either the 3-ML (clear group - macrocyclic lactone) or alternatively 2-LV (yellow group - levamisole). These doses need to be given sequentially and not mixed.
• House for 48 hours - a minimum of 24 hours but ideally 48 hours - to prevent any resistant worms that may be in the digestive tract passing out on to your pasture
• Turnout to dirty pasture (i.e. ground under continual/regular sheep grazing) to pick up the worm population on your own farm.

In the below video, Dr Orla Keane explains the process or quarantine treatment in more detail:

Fluke is another consideration and should be assessed based on time of year and prevalence of liver fluke infection on the farm of origin. Where treating, use a product that has an active ingredient that is effective against immature fluke (e.g. closantel or rafoxainide based).

External Parasites

If there is any signs of external parasites observed during the quarantine period, the first option is to plunge dip the entire group. Where facilities are not available, there are a number of mobile operators providing this service. Ensure the dipping process is carried out correctly, i.e. the correct product is used at the correct rate with each animal having at least 60 seconds contact time in the solution.  An Organophosphate based dipping product should not be used within 14 days of using a levamisole based drench.

In the situation where only small numbers of sheep are coming onto the farm, rams for example, dipping may not be practical. In this case, an injectable macrocyclic lactone where the correct protocol is followed may be used to cover external parasites and can double up as part of the quarantine drench for stomach worms already outlined.

Vaccination

Newly-purchased sheep should be enrolled on the vaccination programme that is in place on the farm e.g. primary and booster course of Clostridial/Pasteurella vaccines. In the case of breeding females, vaccination against Enzootic and Toxoplasmosis abortion should be considered.

Keeping new arrivals separate

This is perhaps one of the most basic steps that can be implemented on a farm, keep all sheep coming onto a farm isolated and managed separately from the existing flock for a minimum of 28 days in order to monitor for clinical signs of disease. This will give the opportunity to help limit the spread of an infectious disease to other groups of other sheep.

Even with the best laid plans, some diseases won’t be easy to identify at purchase or quarantine thereafter (e.g. iceberg diseases). Therefore, it’s necessary to be proactive and investigate issues to identify the causes with your vet.

It’s also worth remembering it’s not only new sheep that can bring disease challenges on to your farm. It is recommended to provide disinfection facilities for all farm visitors. Additionally, sharing of livestock trailers or other sheep equipment between farms should be avoided unless they are thoroughly disinfected after use.

Consult with your vet and have a plan in place on your farm to quarantine new additions to your flock to ensure their health, welfare and performance of sheep on your farm.  

Also read: A guide on the Genotyped Ram Task