Advice on buying replacement ewes for breeding

Most sheep farmers scrutinise rams before purchase, but how many pay the same attention to ewe replacements?

They should – not only do they make up half of a flock’s genetics, but they are also the future of that flock, says independent sheep consultant Nerys Wright.

Nerys believes most farmers are good at assessing physical characteristics, but warns that traits that are not always visible can wreak havoc in the flock if they have failed to do their homework.

Here, she gives advice on buying flock replacements and sets out the most important questions to ask.

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Review physical characteristics

There is a higher chance of mastitis occurring in the first two years, so it is important to check udders if ewes have been bred before.

Locomotion, teeth and body condition are also important, and the following should be checked:

• Do ewes walk well?
• Do they have under/overshot jaws?
• Are there any signs of lameness?
• Are they uniform in size?
• Have they been scratching? This could be a sign of scab.

Shearlings that have lambed as ewe lambs should have their udders checked for lumps – ewe lambs will not have developed any mammary tissue, so it is fruitless checking their udders.

Questions to ask the seller

Data are not often readily available to buyers, but that does not mean questions should not be asked. “There’s a chicken and egg situation with data collection,” says Nerys.

“Breeders don’t think they [will] get any more money for their stock, but as buyers, if you don’t ask these questions, there is never going to be a premium.”

Questions will be farm-specific and should depend on the goals for the flock: “If you want to increase prolificacy, you can ask if ewes are from twins or singles, for example.”

Some good general areas to sound out include:

• The ewe replacements’ eight-week weights and weaning weights.
• Their sires – and if they have estimated breeding values (EBVs), find out more.
• If buying ewe lambs, ask the seller about their threshold for breeding weights. That will indicate if this aligns with the buyer’s goals and if the lambs are up to par.
• To understand this, it is essential for the farmer to know their average mature ewe weight. Ewe lambs should be 60% of mature weight at tupping, and shearlings must be more than 80%. For example, if the mature ewe weight is 75kg, ewe lambs and shearlings should weigh 45kg and 60kg, respectively.

Quarantine

Given the value of ewes this year, it is more important than ever to adhere to good quarantine protocols. Bought-in sheep should be quarantined for a minimum of three to four weeks.

“Ideally, they should be kept separate until they have lambed, but this is not always practical,” Nerys advises. “Although, if you are lambing ewe lambs, most of these will be kept separate.

“The reason for three to four weeks is that when you get them home, you need to treat them and make sure that treatment has worked and give time for any disease to surface.”

Endemic diseases can be notoriously difficult to eradicate, so onus should be placed on doing everything possible to prevent them entering the flock in the first place.

“We buy car insurance, even though we don’t expect to crash, and that’s what we need to do when we buy animals, by quarantining them properly,” she adds.

Diseases and infections to consider include:

• Worms Always assume sheep will bring in resistant worms. As “gold standard”, treat with group 4 (orange) and group 5 (purple) wormers to reduce the chances of resistant worms surviving treatment. Yard sheep for 24-48 hours and turn out to dirty pasture (ground that other sheep have grazed that year) to ensure any resistant worms that survive are diluted by susceptible worms already present on the farm. For more information, see the Scops website.
• Fluke Find out if ewes are from a high-risk area for fluke by observing the Nadis parasite forecast. Ask the seller if the ewes have been treated and if their flock has resistance to triclabendazole. Blood tests carried out on ewe lambs will determine if they have been exposed to fluke in their first season. However, the test is less helpful on shearlings because it only indicates exposure to fluke in their lifetime, rather than how recently. Faecal egg counts can also be taken, but these can only detect egg-laying adults. Always use reduction tests three weeks post-treatment to check this has worked.
• Scab Ask questions to determine if sheep are coming from a low- or high-risk area for scab. Unless clinical signs are observed, wait two weeks and then blood-test sheep using the Elisa sheep scab test, which will highlight exposure. This prevents unnecessary treatment.
• Lameness and orf Ask the seller if they give routine vaccinations for foot-rot and orf to gauge risk. It is good practice to run incoming animals through a foot-bath to prevent transmission of foot-rot. Stress can trigger contagious ovine digital dermatitis, so observe ewes for signs of infection (ulcerated area at the coronary band). Contact the farm vet if an outbreak is suspected.
• Clostridial vaccinations Find out which clostridial vaccines ewes have been given and how many doses. Be careful if ewes have been given a different vaccine to the home flock. For example, if bought-in ewes have been given Bravoxin, and the flock they are joining has been vaccinated with Heptavac, they should still be given two doses of Heptavac to ensure they are fully protected.
• Abortion vaccines Ask the seller if they have toxoplasmosis or enzootic abortion in their flock. Ewe lambs pick up enzootic abortion at birth from their mother. Vaccination will suppress the infection, but they can still abort during their first lambing. Ewes that have contracted toxoplasmosis are immune, but susceptible replacements must still be vaccinated. While not cheap, both vaccines are relatively cost-effective given the significant losses that can be incurred in an outbreak. Vaccines must be given at least six weeks prior to tupping, but can be given sooner than this.
• Endemic diseases Ask the breeder if they screen cull ewes for iceberg diseases. These have been on farm the longest and will be a good place to start hunting for disease. It is also worth finding out if the flock is testing under a flock health accreditation scheme. Funding under the Animal Health and Welfare Pathway should increase testing for endemic diseases and make this information more freely available in the future.

Finally, Nerys says it is important breeders are given good and bad feedback about how their ewes perform.

“Telling the seller how they [the ewes] suit the farm, or feeding back any issues that arise, can be valuable information.”