To best express their genetic potential, sheep must be in optimal body condition. Both overly fat sheep and sheep that are too thin are not as productive as they can potentially be. Body condition scoring (BCS) enables you to identify the animals that fall outside of a preferred range. You can use this information to evaluate feeding strategies and to identify animals that are not doing well in your management system. This article will cover the use of BCS as a management tool. Links to information on how to perform BCS can be found in the reference section at the end of this article.
BCS is evaluated by feeling the loin area of an animal and allocating a score based on how much tissue covers the bones of the vertebrae. The fatter the animal, the more tissue sits between your fingers and the bones. BCS uses set criteria to assign a number that represents the animal’s body condition ensuring standard and consistent scores. The criteria range from 1 (emaciated) to 5 (obese) in ½ score increments. You do not need special equipment or training to perform BCS. It can be performed easily in a chute, but with tame animals you can even sneak it in while they are busy eating.
Ewes
Ewe body condition plays an important role in fertility and the vigor of their offspring. Ewes in BCS 2.5 to 4 are best able to express their genetic potential for reproduction and milk production. BCS can be used to make culling decisions and allocate your feed appropriately, which can make a big difference in your bottom line, as seen in a farm survey done in New Zealand.
“In the 2009-10 B+LNZ Farm Survey1, the bottom-line difference between the top 20% farmers and the average was $185 per hectare (2.47 acres). High sheep performance is a key driver of these top 20% businesses. A common trait among top performers is that they continuously monitor the tail end ewes in their flock and regularly BCS their ewes. They also use a split flock approach and targeted feeding, based on ewe BCS.”
There are many benefits of using BCS rather than weight or visual comparison of ewes.
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It is hard to fairly compare ewes with different frame sizes based on weight. A small-framed obese ewe might weigh the same as a large-framed thin ewe, making it difficult to establish an acceptable weight range for optimal production.
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The degree of gut fill can significantly affect weight from one day to the next and therefore affect the perception of her body condition.
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Comparing pregnant ewes is difficult because of differences in the number of lambs they are carrying.
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It is hard to visually evaluate sheep in full winter coats or while they are shedding.
Most of your ewes should fall in the optimal range of 2.5 to 4. If more than 20% are too skinny or too fat on multiple scoring occasions, you may want to reconsider your stocking rate, feeding program, or genetics. BCS on ewes should be done prior to these various production stages: before breeding, mid- pregnancy, at lambing, mid-lactation, and at weaning. If you are doing accelerated lambing, you will need to keep your ewes in good body condition throughout all production stages, as you need them to breed back shortly after weaning. If you lamb once a year, you can afford a lower BCS at weaning, as your ewes have more time to regain condition before breeding.
Pre-Breeding
(3-4 weeks prior)
Having offspring is a “luxury item” for animals, physiologically speaking. Very thin or obese ewes have irregular cycles and can stop cycling altogether if severe, leading to open ewes or ewes only getting pregnant late in the breeding season. Using an adequate number of fertile rams, you should be able to get >90% of your adult ewe flock pregnant in the first 17 days of the breeding season, as long as ewes are in good body condition and breeding in the fall. Checking BCS on ewes 3-4 weeks before breeding allows time to adjust nutrition levels and correct undesirable BCS scores.
Flushing is the practice of increasing the level of nutrition for ewes for 3-4 weeks before the start of the breeding season and continuing into the first month of pregnancy. It can give a boost of 10-20% in your lamb crop. It is less effective in ewes that are already in good body condition. If feed is limited, and you can run separate flocks, target those ewes under a 3 BCS to achieve the greatest effect from flushing. Remember to continue into the first month of pregnancy, as ewes can suffer early embryonic death (EED) if they are losing weight in early pregnancy.
BCS 1-1.5 Ewe
Do not breed this ewe. She is unlikely to carry a pregnancy to term and if she does, she is likely to lose lambs, or produce lambs that do not grow well. This ewe will probably not breed early. She will have a higher chance of getting pregnancy toxemia, will have trouble producing enough milk for her lambs, and will end up in even worse body condition after weaning. Breeding this ewe is an animal welfare concern and not good business. You can cull her now and get something rather than keeping a ewe that is likely to cause extra work or die further into the production cycle. Remember, this ewe had 4-5 months to recover after weaning last year’s lambs. If she could not regain weight while on maintenance, it is unlikely she will gain weight while pregnant or lactating.
A ewe this thin pre-breeding needs further evaluation. Why do you have a ewe that is this thin, and what do you do with her?
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Are all of your ewes this thin or is this the only one? If they are all thin, you need to seriously evaluate your management and nutrition program.
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Was she sick, healthy now, but lost a lot of weight? Do her a favor and let her skip this year, regain condition, and breed her next year.
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Did she raise a great set of triplets, or twins if she is a yearling? Are all the ewes with similar production in this condition? If so, look at your management and either select for less prolific genetics or improve their feed. Do you have other ewes that can do the same thing and not end up skin and bones? If so, this ewe is not doing well in your management system and may be a candidate to cull.
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Does she have parasites? Adult ewes that are not pregnant or nursing should not be affected by worms bad enough to be this thin, unless they have poor genetics for parasite resistance or additional health issues. She should be culled.
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Have you checked her teeth? If she has no teeth it is time to cull. If she is a sentimental favorite, don’t breed her. Instead, keep her as a mother figure for the bottle lambs and feed her individually.
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No obvious reason? Be careful. These ewes could have contagious diseases like Johnes or OPP. It is in your best interest to get her off the farm ASAP. If you have multiple ewes like this, a visit with your veterinarian is in order to determine what is going on.
BCS 2-2.5 Ewe
You can successfully breed ewes in 2 BCS if you are going to flush them so they are at 2.5 BCS at the start of breeding and if you can continue to provide improved nutrition. Check teeth in ewes at 2 BCS. If the teeth are ok, consider deworming her. If you do not get the ewe up to at least 2.5 at breeding, and she becomes pregnant with triplets, it will be a hard road ahead. Flushing works best in ewes under 3 BCS, so if feed is limited, target the ewes that will receive the most benefit.
BCS 3-4 Ewe
These girls are great. If you have extra feed, you can flush them, but you will probably not get a big boost in lambing percentages. These girls should breed quickly and have uneventful pregnancies.
BCS 4.5-5 Ewe
Do not flush them as it might have the opposite effect. They do not need to get fatter. These ewes are less prolific and have a greater chance of being open or producing a single. Look at the production history on these ewes. If they consistently produce singles or wean small lambs, consider culling. If the ewe is fat because she lost a lamb, or lambs, this year, proceed with breeding her. Pregnancy and lactation should slim her down so that she becomes a productive member of society again.
Mid-Pregnancy
(8-10 weeks prior to lambing)
Most of a lamb’s growth occurs during the last 4-6 weeks of gestation and it is VERY hard to put weight on a ewe at that time. Checking BCS gives you a chance to intervene soon enough if you have ewes that lost weight between breeding and mid pregnancy.
BCS 1-2 Ewe
You should not have any this thin if all ewes were at least 2.5 BCS at breeding and your nutritional program has been adequate. Have other ewes lost body condition? Is she sick, lame, being bullied? Feed her separately from the other ewes so she does not have to compete. Feed her very well and deworm her. She is at high risk of ketosis, especially if she is carrying triplets or quads. Keep a close eye on her. Her colostrum quality will be substandard, and she might not have a lot of milk so be prepared to supplement her lambs.
BCS 2.5 – 4 Ewe
These ewes should be healthy and most of your ewes should be in this range.
BCS 4.5 – 5 Ewe
This ewe is too fat. Hopefully she is carrying multiples and will slim down after lambing. Because of internal fat and growing lambs, these ewes do not have a lot of room, so they cannot eat large amounts at a time. This will put them at risk for pregnancy toxemia. Providing constant access to food will allow them to eat frequent small meals. Even short periods of fasting can put these ewes into pregnancy toxemia. When fat ewes get pregnancy toxemia, they are much more likely to die than ewes that are too thin. They are also more likely to have trouble lambing, especially if only having a large single lamb.
Lambing
Lactation is the period of highest nutritional requirements in a ewe’s production cycle. Very thin ewes do not produce a quality colostrum. They will also not produce as much milk as they are genetically capable of and their lambs will not be able to express their genetic potential for growth. This BCS check is to see if you should pull lambs or offer supplemental bottle feeding.
BCS 1-1.5 Ewe
You should not have any, but it can happen in ewes with big triplets or quads. Supplement her lambs with colostrum, pull some (or all) of the lambs and/or bottle feed or graft them. If she has milk, frequently weigh the lambs that you leave on her to make sure they are gaining weight. Feed her aggressively with high quality feed (hay and/or pellets), deworm her, and re-check her BCS in a week or two. If she keeps losing weight, then pull all her lambs. It is a good idea to train these lambs to bottles early in case you need to pull them later. This ewe is going to be more work than a ewe with a better BCS. Is this ewe too prolific for your management system? If this is a trait that you want, you need to adjust your feeding program to support these ewes so they can maintain their body condition and realize their full genetic potential.
BCS 2 Ewe
Starting lactation at this BCS is a concern if you do not provide supplemental feed to your ewes and creep feed to your lambs. This ewe should be able to raise her lambs, but she will most likely lose more weight as lactation progresses. Consider deworming her to address any effects from parasites. You might have to wean her lambs earlier than others in the flock.
BCS 2.5-4 Ewe
These girls should be healthy. They will probably lose some weight during lactation but should have good quality colostrum and an adequate milk supply.
BCS 4.5-5 Ewe
This ewe is too fat but that should not be a problem at this stage. If she only has a single, do not supplement her; she needs a diet. If she is raising multiples, hopefully she will slim down while lactating.
Mid-Lactation (30 to 60 days after lambing)
By mid-lactation, most ewes will be in lower BCS than they were at lambing, which is normal if it is not an excessive difference. Stop supplementing any ewes that lost their lamb(s) and consider earlier weaning for ewes in BCS less than 2. Any very thin ewes (<2 BCS) should be dewormed.
Weaning
(60 to 120 days after lambing)
Weaning is a good time to evaluate your ewes. But be careful to not select for good body condition by itself. Less productive ewes will be in better body condition because they were not expending energy on lactation. Ewes that produce well and can maintain >2 BCS are efficient and well adapted to your management system.
BCS 1-1.5
What did she wean? If this ewe was in good condition at lambing, this is extreme weight loss, even if she raised triplets. If you have multiple ewes in this situation you need to look at your ewe nutrition and consider creep feeding the lambs which would further reduce nutritional demands on the ewes. She will need good nutrition during the dry period to have a chance of being in good enough body condition to breed in the fall. If she only weaned a single or two small lambs, she might not be well adapted to your management system or she may have underlying health issues. Consider culling.
BCS 2-4
Great! Ewes that wean a nice set of twins or triplets and still maintain good body condition, are keepers. This gives you many more options for feeding your ewes during the dry period.
BCS 5
Fat ewes that did not produce nice lambs are fat because they are not good producers. If they lost one or more lambs, consider the circumstances behind their losses. In general, these are not good ewes to keep.
Lambs
If you breed your ewe lambs to lamb at 1 year of age, BCS is a really good way to evaluate which ewe lambs are likely to breed. Ewe lambs need to put on some fat to start puberty. Thin large-framed ewe lambs will go through puberty later than smaller framed ewe lambs in better body condition. Do not feed ewe lambs excessively as they can accumulate excess fat in their udders. This will negatively affect their milk production.
Ewe lambs who have twins at 1 year of age will often lose a lot of body condition as they are still growing while first gestating, and later lactating to grow those lambs. They do need higher quality feed to prevent severe weight loss and to ensure that they gain back their body condition for the next season’s breeding. It is a good practice to feed your ewe lambs separately from the adults during gestation to make sure they are not bullied by the big girls.
You can also use BCS to evaluate if your meat lambs are finished for slaughter, especially the producers that do direct marketing with set slaughter dates. They can use BCS to select the lambs that have adequate carcass fat covering at the right times to produce the best product for their customers.
Ram lambs that are used for breeding often lose a lot of condition during the breeding season. Be sure to evaluate their body condition and increase feed after breeding to bring them back to good body condition, especially if going into a cold winter.
Rams
Rams in adequate body condition produce better quality sperm than rams that are underweight. Rams that are too fat are not able to regulate their testicle temperature as well as thinner rams. This can lead to poor quality sperm, especially if you breed in warmer temperatures. Flushing can also have a positive effect on the quality of a ram’s sperm.
Summary
BCS is a great way to evaluate how “efficient” individual animals are on your farm. This trait can be used as an aid in selection but should never be used without evaluating a ewe’s production. If you have EBVs on your ewes, compare BCS on animals with similar NLB and MWWT EBVs and keep the ones in better condition. They are better adapted to your farm. If you do not have EBVs on your ewes, compare the ewes with singles to each other, the ewes with twins with each other, and the ewes with triplets to each other. Be sure that they have raised nice lambs as well. It is easier for ewes to maintain body weight if they do not produce a lot of milk.
Ewes need good nutrition to make milk. Dairy farmers can see differences in milk production with daily changes in feed quality. If you would like to increase prolificacy and milk production in your flock, remember they will need better nutrition. With that being said, by selecting ewes with the better BCS out of ewes with similar production you will end up with lower maintenance sheep.
References
Beef and Lamb NZ – Ewe Body Condition scoring handbook
https://www.ablamb.ca/images/documents/resources/health/Ewe-body-condition-scoring-handbook.pdf
Videos on how to perform BCS
https://www.youtube.com/watch?v=1F5V-GcG1Qk
https://www.youtube.com/watch?v=gCu04ueCKOo&feature=youtu.be
Videos on FAMACHA
“Why and how to do FAMACHA Scoring” – https://youtu.be/I5rcuvVG56Q
“FAMACHA in a Nutshell” – https://youtu.be/RL3SBR1qIX0
Factsheet on Periparturient Egg Rise (PPER)
By EAPK Communications Committee
Isabel Richards, Kathy Bielek, Roxanne Newton
