Effects of underfeeding and refeeding on offals weight in the Barbary ewes

The influence of long-term (161 days) underfeeding and refeeding (154 days) on the weight of offal components, and digestive content, was studied in 26 adult Barbary ewes. Effects on the protein and mineral content of offals were also measured. Animals were split in three groups: one was fed hay at maintenance level (M), another also received vetch-oat hay to cover 0.2 of maintenance energy requirements (L), and the third one was fed at 0.2 of maintenance requirements during 161 days, then refed at 1.3 times of energy requirements with a diet of hay and barley grain (LH) during 154 days. Underfed animals body weight (BW) at slaughter was 31kg. Animals of groups M and LH were slaughtered at similar BW (50kg). Underfeeding reduced empty BW by 38% and the weight of most metabolically active organs: skin (40%), blood (31%), rumen (34%) and liver (19%), but not others (small intestine). Total offals weight was reduced by 27%. Overfeeding of previously underfed animals (LH) induced a significant increase in liver weight in comparison to M group (18%), owing to a higher nutrient supply. The amount of protein in offals and their fat-free weight were decreased by underfeeding, whereas the amount of minerals was significantly modified only in components rich in bone. These results showed that splanchnic organ mass decreases with underfeeding which leads to energy requirements decrease and contributes towards resistance of Barbary ewes to harsh food conditions.