Great Lakes Dairy Sheep Symposium - the Department of Animal ...

Body condition score
Body condition score (BCS) was one of the first nutritional indicators used for sheep. It
can be used to define the optimal state of animal's reserves at various stages of the productive
cycle. This application of BCS on lactating ewes has been already covered by INRA (1989) and
Cannas (2004), among others, who reported reference values for the various stages of the
production cycle. The information derived from BCS measurements and from its variations in the
first stages of lactation can be matched with the nutritional information given by milk fat
concentration, as previously discussed.
Another use of BCS in diet balancing of grazing sheep is related to the estimation of the
energy costs of fattening or of the amount of energy available for milk production in animals that
are in negative energy balance. In fact, if predicted changes in BCS, based on diet energy excess
or deficiency estimated by diet balancing, match those observed over a certain period of time, it is
likely that the inputs regarding pasture intake were correct. To use this approach it is necessary
to know the relationship between BCS and body weight (BW), which varies depending on the
mature size of the breed and of the population considered within each breed. Since this
relationship has been studied only for some sheep breeds and populations, Cannas and Boe
(2003) developed a model to predict it in ewes of any breed or population. They suggested that
the prediction of BW for mature ewes of any sheep breed or population at any BCS (scale 0-5)
could be done as long as the mature weight of that breed or population at BCS equal to 2.5
(BW@BCS 2.5) is known:
[10] BW (kg) = (0.594 + 0.163 *BCS) * BW@BCS 2.5.
Rearranging equation [10], it is possible to estimate the BW@BCS2.5 when current BCS
and BW are known:
[11] BW@BCS 2.5 = current BW /(0.594 + 0.163 * BCS).
This equation can be easily applied to identify the BW@BCS 2.5 for a certain breed or
population, in case this value is not available for them, by measuring BW and BCS of a group of
sheep (possibly more than 10) belonging to the breed or population of interest. Once BW@BCS
2.5 is predicted, equation [10] can be used for all flocks of that breed or population.
This model was further expanded by Cannas et al. (2004) to estimate body energy
variations associated with BCS variation.
Faeces as a nutritional indicator
Faeces are currently used as a nutritional indicator in dairy cows (e.g. Bertoni et al.,
1999). Since they are one of the final products of the digestion process, their analysis can give a
lot of information on the type of diet eaten and on its utilisation. Cannas (2004) proposed a
tentative classification of faeces based on their characteristics. However, the same author stated
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