Seven Reasons To Cull Ewes (and Does)

Seven Good Reasons to Cull Ewes (and Does) By Jane Fyksen, Crops Editor, Agriview Most sheep producers have a few ewes that are “just on the payroll” and not really contributing to the operation’s profitability. With increasing production costs, producers really need to evaluate each and every ewe and decide whether she’s really productive. Marginal ewes –and rams—should not be maintained in the flock, says Roger High with Ohio State University’s Sheep Program. He offers a few guidelines for culling sheep. “Open ewes are the greatest contributor to low weaning percentages and are costly in terms of feed, labor and management,” he says of starting your cull list with open ewes (and then move on to those that lost lambs due to excessive lambing difficulty, as well as those that prolapsed). He maintains that a ewe that doesn’t breed one time will lose a significant amount of her lifetime production potential. It will take returns from two to three productive ewes just to pay for maintaining one open ewe. Health issues are another reason to cull. They can be a large drain in terms of labor. Sheep limping from foot rot and foot scald perform poorly and should definitely be culled. Mastitis is another health issue that suggests culling. Resulting low milk production can increase labor and cost due to having to raise orphan lambs. Also check eyes for cloudiness or other issues that may cause vision problems, High mentions. A third reason for culling a ewe is udder quality and/or soundness. “Non-functional ewes are those that have lost all or part of their udder’s function. These ewes create management difficulty because they generally cannot produce enough milk to maintain the nutritional needs of their lambs, thereby creating a need to orphan or bottle feed the lambs so they can survive until weaning,” notes High. Structurally unsound ewes, those with few teeth left and hard keeping, emaciates ewes are also candidates for culling, as their nutritional needs are higher than average, “and there is no reason to continue producing these types of genetics as possible replacements,” he stresses. A fourth reason for culling is late lambing. Look at lambing distribution during the lambing season and identify ewes that lamb during the third, fourth or later cycles. Generally, ewe and ram lambs born in the earlier lamb groups will be the most productive sheep in the flock, says High, noting, though, that “producer should keep in mind whose fault it was that the ewe bred in a later heat cycle.” Reasons not the fault of thee ewe include: Inadequate nutrition prior to breeding season (i.e. flushing) or ram infertility. “In general, the primary reason that a ewe flock does not breed early is due to ram infertility, and the primary reason that a single ewe does not breed early is due to ewe infertility at an inappropriate time of the year,” he remarks. Rams generally have lower fertility early in the breeding season (July, August and early September) and higher fertility later in the breeding season (late September, October and November). A ewe may be cycling normally in the early breeding season, but due to ram infertility, she may not become pregnant. Heat-stressed rams and infertile rams will generally need 60 days to become fertile enough to impregnate the females. If the entire ewe flock is not settling in the first two heat cycles (34 days), then a ram infertility problem should be suspected, and another ram should be placed with the ewes if you want a lamb crop during that production year, says High. A fifth potential reason for culling is a ewe’s age. “You should not automatically cull a ewe that is six years of age, but you should consider if she can effectively make it through another year,” he points out. “Ewes need to be culled while they still have a cull value, because dead ewes have no value.”“If she can effectively produce another set of lambs without requiring more of your time and attention, then she can be maintained in the flock,” he says. A sixth reason to cull is for genetic progress. Based on flock records, get rid of ewes that are most likely to produce poor quality lambs with lower-than-average weaning weights. Take into account ewe age, multiple births and so on. A two-year-olds adjustment for twins is different than a six-year-olds adjustment for twins. It may be detrimental to the flock to only select and keep females based on actual data rather than using genetic adjustment data, High cautions. Culling for poor disposition – a seventh reason – is often overlooked. However, doing so can prevent a lot of stress down the road. Ewes that are difficult to maintain in a grazing situation (i.e. run through temporary fence or get under gates) shouldn’t get kept. Ewes that step on and lay on lambs in the lambing pens because of a poor and/or flighty disposition are also candidates for culling. “In some part-time operations, ewe disposition is a very important criterion…due to lack of time for dealing with mis-mothering, injured and poor-doing lambs,” says High. He emphasizes that culling is a better tool for eliminating dysfunctional and/or non-profitable ewes than for building genetic improvement. “The vast majority of the genetic capability of the ewe comes from the rams that you have used in the past,” he reports. While some recommend replacing 15 percent of the ewe flock annually, High says the decision to cull ewes changes from one year to the next, depending on feed supply and costs, the need for cash flow, current lamb prices and the flock’s production cycle. Though not a big money-maker, cull ewes can still be included as income on the balance sheet; shepherds should watch markets and sell culls when the price is up. “Generally, the thinner ewes will have a higher value per pound of body weight, and may even create more total dollars than those ewes that are fat,” adds High. Producers might want to clip the ears on a ewe they’ve decided to cull so she’s easily identifiable; the notched ears will also serve as a mental roadblock to prevent them from going soft later on and deciding to keep her after all.