- Tunisia, like many other countries in the world, suffers
from a shortage of feedstuffs and an overall nutrition problem
is facing the livestock industry. Large quantities of feeds
are imported to meet the animals' needs in energy and protein.
At the same time, considerable quantities of crop residues and
agro-industrial wastes suitable for use as feed for the
animals are lost or underutilized. Grape pomace, which is the
refuse left from the production of grape juice and wine,
constitutes one of the most important crop residues, second
only in volume to straw.
The purpose of this study was to assess the suitability
of this by-product in dried and wet forms as supplementary
feed for sheep and to determine its influence, when incorporated in the diet at a level of 20%, on the weight gain
and voluntary feed intake of sheep.
To conduct this feeding trial, 108 female lambs of an
average age of 10 months including representatives of three
available sheep breeds (Coopworth, Polypay and Suffolk and
crosses of these), and weighing an average of about 41.5 Kg,
were used over a period of 30 days. The trial was laid out in
a completely randomized block design with more than one
observation per block. The blocking criterion was the breed
(six different breed types). Three animals from each breed
were randomly selected according to their weights (heavy,
medium or light) and randomly assigned to the three
treatments: Control diet of barley grain, chopped grass hay
and soybean meal mixed with salts and minerals; Treatment 1 of
20% wet grape pomace replacing the same amount of barley
grain; and Treatment 2 of 20% dried grape pomace replacing the
same amount of barley grain. Substitutions were made on a
Since there were six breeds and 108 lambs in total, there
were 18 lambs per group and two groups per treatment, totaling
6 groups housed in 6 adjacent pens. Daily dry matter intakes
did not differ significantly among treatments. The values
obtained were 1.475, 1.495, and 1.495 Kg respectively for the
control, treatment 1, and treatment 2. There were, however, significant differences in daily live weight gains between
treatments. The values obtained were 166, 198, and 219 g
respectively for the control, treatment 1, and treatment 2.
These results indicate a satisfactory animal performance
in terms of live weight gain and feed intake. Both forms of
grape pomace (wet and dried) were readily accepted by sheep.
These results were in agreement with the findings of other
grape pomace feeding trials cited in the literature review.