Producers should evaluate sheep at key times throughout the year such as prior to breeding season, late pregnancy and at weaning. Evaluate body condition at these key times not only for profitability, but also for the health and welfare of the animals.
Body condition is typically evaluated using a scale from 1 to 5 for sheep. The scale allows you to assess the amount of fat covering on the animal. A score of 1 means the animal is extremely thin while a score of 5 means that the animal is extremely fat. Ideally, ewes should have an average body condition score of 3 to 4 at lambing. A score of 3 means that the spinous bones are smoothly covered with fat but can still be felt with some pressure. The loin eye muscle should be full and should be covered with some fat. Females that are thin at breeding are likely to produce fewer lambs than ewes in good body condition. In addition, ewes that are thin at lambing are like to produce smaller and less vigorous lambs. Females that are too fat are more like to have birthing difficulty and may also have problems with pregnancy toxemia. Very thin ewes are more prone to pregnancy toxemia also if they are not receiving adequate nutrition.
As sheep producers, we often take advantage of spring's high quality pastures to get animals to gain weight to increase body condition score. We also take advantage of the high quality nutrition in pasture grasses for milk production. This increased milk production benefits young animals nursing their mother or can benefit ewes that will be rebred shortly after weaning. It can take as long as four to six weeks to make any major changes in an animal's body condition score, so it is important to evaluate body condition throughout the year.
Let's take a look at an example of how this works in a flock. If the average body condition score of a ewe flock is less than the recommended 3 to 4 body condition score, then the producer should evaluate the feed quality as well as feed quantity. If only a few ewes are too thin, then the producer may want to evaluate those ewes individually. The producer can then answer some questions. Is there some problem other than feed quality or quantity that causes these ewes to carry less condition? Should these ewes be culled or do I need to separate them from the main flock and feed them differently?" In some cases, a young ewe may be thin because she has done a great job raising her lamb or lambs. In this case, the producer may want to see how that ewe performs the next time she lambs and then re-evaluate her at weaning time. Or, are these ewes thin because they are more susceptible to internal parasites?
We can expect ewes to lose weight while nursing lambs, but they should regain this lost weight quickly once the lambs are weaned. The body condition of the ewe in this photo is very acceptable for a ewe that recently weaned lambs.
For those ewes that are too fat, the producer may want to ask why? If the entire flock is overweight, the producer may need to take a look at the feeding program. Feed makes up a major portion of the cost to keep a ewe and therefore warrants some consideration. Most producers balance rations to meet the nutritional requirements of animals. If producers have only a few ewes that are overweight, they may want to look at the lambs that the ewe weaned. Instead of producing milk for the lambs, did the ewe take the nutrients she consumed and convert them into body fat? If last year's lambs weighed less than the average, the producer should consider the option of culling the ewe. If last year's lambs weighed more than the average, then the producer should be thankful to own a ewe that is very efficient and is an "easy keeper."
Whatever the situation, producers should evaluate body condition throughout the year. Body condition can earn producers money if the ewes are in the proper condition, breed quickly, and produce healthy, vigorous twins that are moderate in birth weight. Time lost in breeding will translate into later born lambs that weigh less at weaning time as well as lambs that reach market weights for harvest later in the year.