by Verl Thomas & Rodney Kott Animal & Range Science Dept., Montana State University

 

"Regular condition scoring and action on the results will
ensure healthier ewes and pounds of lamb and wool marketed per year."

 

The use of both body weight and condition scores can help producers make important feed management decisions. Are my breeding animals too fat or thin for breeding? Have ewes maintained proper body condition during the wintering period?

Condition scoring is a system of describing or classifying breeding animals by differences in relative body fatness. Simplicity is the beauty of condition scoring because it allows sheep producers to have ewes in the right condition for maximum profitability. The scoring is based on feeling by hand the degree of muscling and fat deposition over and around the vertebrae in the loin region (last rib to the hip bone). The loin vertebrae has, in addition to the central spinal column, a vertical portion of the bone termed the Spinous process (back-bone) and a short horizontal portion termed the Transverse process (Figure 1).

Body condition scores range from 0 to 5, with 0 being a dead ewe and a 5, a big fat ewe (see Figures 2, 3 and 4). Usually, 90% of the ewes fall within the 2, 3 or 4 range.

Ewes should be standing in a level area and be relaxed when being condition scored. Your fingers, held together, and thumb are used to determine sharpness of the spine behind the last rib and in front of the hip bone, and the sharpness of the transverse process. In addition, it may be helpful to determine the extent of fat covering over the foreribs because in many cases the handler may feel sharpness over the spine (condition score 2), but will find considerable fat over the ribs (condition score 3) then one must arrive at some average for the condition score. If a producer is unsure as to whether a ewe is a 2 or 3, a condition score of 2.5 should be used.

Important nutritional periods during the annual management program of the ewe include: 1) flushing and breeding; 2) last 4 weeks of gestation; 3) lactation and 4) the dry period. Ewes should be condition scored prior to flushing. Fat ewes (condition scores 4 to 5) cannot be economically flushed. Fat ewes tend to have a lower ovulation rate (eggs produced), while ewes in moderate condition (3 to 4) respond to the flushing process. New Zealand research indicates that a score of 3.5 will produce an optimum ovulation rate. It is also important that ewes be kept at 3.5 for at least 30 days following breeding. Failure to keep a ewe in good condition after breeding could result in the loss of eggs.

As much as 80% of the total fetal growth occurs during the last 4 to 6 weeks of gestation. If the ewe is excessively thin (1 to 2), lambing problems, small lamb birth weights and low milk production are likely to occur. A recent study I conducted at Montana State University found that ewes with a lambing rate of 2.5 and a body condition score four weeks prior to lambing of 3.5, produced heavier lambs and more total lamb weight than ewes that had a body condition score of 2.5. The relationship between birth weight and survivability is high. Therefore, producers must feed so that ewes entering the last 4 to 6 weeks of gestation will be provided with optimum nutrition to insure normal fetal growth and development.

During the dry period when a ewe is not producing milk, an attempt should be made to keep her body condition score between 2.5 to 3.5. Ewes tend to become excessively fat on little feed during this period. This tends to be more of a problem in farm flick operations than range operations.

Table 1 gives suggested rations for different body condition scores.

Body condition scoring is easy to learn and use. Occasional discrepancies in categorizing ewe condition scores can be handled by assessing a half score to the nearest score (2 .5). In general, young developing breeding animals, i.e., ewe lambs up to two years old, will show less individual variation than older ewes. It may be impractical for large sheep producers to condition score all ewes; however, if a producer condition scored approximately 10-20% of the flock, this would be adequate to get an estimate of the condition of his entire flock. Regular condition scoring and action on the results will ensure healthier ewes and pounds of lamb and wool marketed per year.

Table 1. Suggested rations for different condition scores and functions1

Physiological

Function

Condition Scores

0 to 2

2.5 to 3.5

4

5

Flushing

Breeding

1. Excellent pasture + 2 to 1 lb grain

2. Free-choice good hay+ 1 to 1-1/2 lb

1. Excellent pasture

2. Free choice good hay + 2 to 1 lb grain

1. Good pasture

2. Free choice hay

Same as 4
Early to mid-

gestation

1. Same as breeding

2. 3 to 4 lb wheat or barley straw2+ 1 to 1-1/2 lb grain

1. Fair to good pasture

2. Winter range + 1/3 lb 16% protein supplement

3. 3 to 4 lb good hay

4. 3 to 4 lb wheat or barley straw + 3/4 to 1 lb grain

1. Winter range

2. 3 to 3-1/2 lb good hay + exercise3

3. 3 to 4 lb wheat or barley straw + 2 lb grain

1. Winter range

2. 3 lb hay + exercise

3. 3 to 4 lb wheat or barley straw + 1/4 to 2 lb grain

Late

Gestation

1. Free-choice good hay + 1 to 1-1/2 lb grain 1. 3 to 4 lb good hay + 2 to 3/4 lb grain 1. 3 to 4 lb good hay + 2 lb grain + exercise Same as 4
Lactation 1. Free-choice good hay + 1 lb grain for singles + 2 lb grain for twins 1. 4 to 5 lb good hay + 1 lb grain for singles + 2 lb grain for twins 1. 4 to 5 lb good hay for singles or 4 to 5 lb good hay + 1 lb grain for twins Same as 4
Assumes a lambing rate of 100-140% and ewes weighing 130-150 lbs.
Straw should be fed free-choice in bunks or self-feeders. Straw should be supplemented with calcium, phosphates and vitamin A in addition to grain. Grain should contain 16-18% crude protein which means some protein supplement must be added as grain.
Daily exercise is vital for ewes during early and late gestation regardless of condition score. Over conditioned ewes (4-5) need more.

 

 

View Text-only Version Text-only Updated: 11/23/2005
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