Culling for the Future of the Flock

A whirlwind of a year with more changes coming

It’s been a while. This year, 2023, has been one change after another. Unfortunately, that meant I had to focus on other priorities than this blog. At this point, I can not even promise when I will have a predictable posting schedule. I have so many ideas and topics to discuss but there’s only one of me. A significant amount of time this year has been spent on flock improvement. I’ve already discussed some of our ram purchases and genetic investments. Tonight’s topic will be a much more difficult one, culling.

Culling is necessary to improve your flock if you want to continue to either stabilize or improve. It essentially means removing sheep from your flock and either sending them for slaughter or selling them to another producer. Usually culling is for removing unproductive animals but it can also be when the farm changes directions, ie switches breeds. That would still be a cull for the farm but those ewes might still be fit enough to meet the needs of another farm. Every farm has its criteria, or at least they should. I do have some important notes to highlight before getting deeper into this topic. These are specifics for our farm that impact our decision-making process.

• Our preferred breeds are hard to purchase in larger quantities (packages of more than 50 ewes) and genetic diversity is more limited than in some more common and popular breeds.

• We do breed out-of-season and use synchronization programs for that. We have our own on-farm ultrasound machine for scanning ewes.

• As of 2023, our entire flock is enrolled in the Maedi-Visna program. This post will not focus on the details of that decision, but it greatly impacted our cull decisions. There is a noticeable performance difference between a positive and negative status ewe.

• All of our sheep have individual RFID tags and have been tracked using that tag since birth. Every sheep has some kind of record.

Timing & Records

For our farm, culling is an ongoing process. This is only possible partly because we have decent records and can track our ewes through their RFID ear tags. Since we farm in Quebec, each sheep has two ear tags and while losing one happens, it’s rare and to date, we’ve never had a sheep lose both tags. This provides us with the means to look up a ewe’s performance and keep notes. We do use BioTrack Plus but the majority of our notes are still in a good old-fashioned notebook.

We typically cull at three or four stages:

1. After lambing, any ewe that is not raising lambs or didn’t lamb is likely leaving the farm.

2. After weaning, there is an inspection about two weeks later to check how the ewes are drying off and look for damaged udders or any other physical concerns that would prevent us from re-breeding.

3. After ultrasound scanning for open ewes, any open ewe gets checked against her records.

4. Ongoing assessment of replacement ewe lambs.

   

   Some recently selected cull ewes.

Criteria for Culling

Each farm is going to vary a bit on how they do their culling but it can usually be divided into segments or areas of management.

Fertility

A ewe that does not conceive or a ram that is not covering ewes is not productive and will not pay the bills. This means fertility matters a great deal. There are numerous approaches on how and when to select for this but for us, it looks something like this:

• Any ewe that does not catch in the natural breeding season is culled. They are given a 30-day exposure window and if they fail to conceive in that, they are gone.

• Replacement ewe lambs are given a 35-day exposure and depending on their age, may be exposed a second time before that culling decision is made. An 8-month-old ewe lamb might get a second opportunity while a 12-month-old ewe lamb is not.

• Any ewe bred out-of-season in the summer months but fails to catch gets one chance in the fall. They do receive a note for being open and we typically do not retain ewe lambs from these ewes.

We find open ewes either through ultrasound scanning or during lambing if they lost the lambs at some point. Ewes are scanned usually 50-65 days after breeding at which point we make decisions. Only a small percentage are missed in the scanning process and these are usually found closer to lambing.

Fertility can also be the number of lambs an ewe produces. This trait is not one we regularly visit outside of factors surrounding productivity. Our goal is 1.8-2.2 lambs per ewe and unless we forget to flush a group, usually that is attainable. Most of our ewes are not producing only singles each lambing.

Lamb Performance

A big part of our annual culling is based on lamb performance. This a fairly new for us, we’ve been working on this criteria since about 2020 when we decided our ewes needed to meet a standard higher than just “weaned a lamb.” Currently, this criteria looks like:

• The ewe had to raise at a minimum twins without assistance. If she had triplets or quads, we only remove one or two lambs at most for bottle feeding. We don’t like bottle lambs so ewes that consistently need help are removed from the flock.

• The lambs had to reach target weights in 50 days. These targets are based on historical averages for our flock and are adjusted for how many lambs the ewe raised. If the ewe raised twins, these had to be fairly close in their weights, any large differences between lambs are always investigated. Any ewe who fails to raise lambs to a weight at or above the target is automatically culled, there are no exceptions.

This has made a huge difference. While we were culling a larger number of ewes, the number of lambs making it to market increased in 2021 and we were getting similar performance from fewer ewes. We are now also looking at continued performance after weaning.

Replacements

In the past, we were not picky about which ewe lambs we kept as long as they looked nice and grew well. This allowed us to expand from 85 ewes to over 250 in less than 3 years as raising our own is more affordable than buying. Potential ewe lambs are tagged with an identifying mark at birth. This means her mother met basic criteria like a shedding coat, good milk production and had an unassisted lambing.

Once weaned, the ewe lambs are assessed several times. First, they are assessed for their own performance and average daily gain. Any ewe lamb that is tagged to keep and meets the weight targets is then assessed for conformation. We look at the legs, teeth and her overall build. If they pass that inspection, which is usually around 70 lbs, they are moved to another pen to grow out. We walk through the pen and weigh the lambs again a couple of times to be sure they are growing as we want them to.

Health Status

The overall health of our ewes is important. A healthy ewe will do better overall. We regularly inspect for issues like udder damage, loss of teeth and leg issues. Any ewe that has a prepubic tendon rupture is culled, we do not risk rebreeding these. Body condition scores also play a role, if a ewe is struggling to hold a good BSC and not responding to treatment, we may opt to cull her.

The sheep now also have to have a negative status for MV. Any ewe that comes back positive after a blood test is culled on the next available shipping date or removed from the main barn immediately if she can not safely be shipped yet (very late gestation ewes or nursing ewes).

Other Reasons

Outside of the aforementioned reasons, there are other reasons sheep may be culled or the selection criteria tightened. These can include:

• Lack of feed - in a drought situation downsizing might be necessary

• Milk production for dairy - if you have dairy sheep you might have additional performance criteria you are monitoring

• Difficulties during lambing - various producers have different approaches to this but if you want an easy-to-manage flock, removing ewes that need help might be on your list

• Management issues - if that one sheep is always escaping, it’s definitely leaving the farm at some point

Marketing

Marketing culled sheep can be done in a variety of ways. If the reason for the cull is not performance or health-related, they might get sold to another producer. In this case, they are probably going to be listed for sale to find a buyer. At the moment, there are a number of these sales listed as lack of feed and rising costs are impacting producers in the industry.

Some do a big seasonal cull and can then arrange for buyers to purchase the entire group directly from the farm. This is an option for those who graze or have larger flocks where you can make a package for a buyer. There are markets for culled older sheep specifically.

For smaller producers like us, culls get shipped usually with market lambs. We might hold onto them for a few weeks to make a larger shipment but generally, they’re sold in smaller groups through auction sales. This is part of why you should not build a flock with sheep out of a sales barn, they’re usually there for a reason.

A Year of Culling

We’re going to end 2023 with fewer sheep than we started with. It’s better than we had hoped for when we enrolled in the MV program. As with any cull, the goal is to improve the quality and health of our flock. There is already a significant difference in the flock this fall compared to last year. That’s a sign that it was the right decision. Culling sheep is never easy but it is a very necessary part of management.

That will be all for tonight! I hope to have a few more posts before the end of the year, however, I cannot promise that they will happen due to some personal life things happening. I’m always happy to talk sheep and numbers so please do reach out with questions!