Tropicultura (Jan 2000)
Incorporation de tourteau de soja et/ou de tourteau de colza dans le concentré à base d'orge sur les performances de croissance des agneaux des races D'man et Queue Fine de l'Ouest
Abstract
Addition of Soyabean Meal and/or Rapeseed Meal in Barley-Based Concentrate for Fattening Sheep ofD'Man and Queue Fine de l'Ouest Breeds. The influence of incorporating a nitrogen source in barley based concentrates was determined using respectively 38 and 32 lambs of the Queue Fine de l'Ouest and D'man breeds in two separate trials. In both trials, animals were fed hay made of oat and vetch mixture. In the first trial, carried out on a private holding, a treatment of 450 g dry matter DM day of a barley concentrate (BC) was compared with 450 g DM day of a protein concentrate (PC) containing 27, 7 % soya meal. The addition of soya meal significantly improved (P <0, 05) the average daily growth of Queue Fine de l'Ouest lambs being 188 and 139 g/day in the BC and PC groups respectively. Live-weight difference between animals in the two groups increased with the trial duration reaching 3, 9 kg/animal at the end of the fattening period. In the second trial, carried out on station, raising the crude protein content of the concentrate from 10, 2 to 15, 8 % (fresh matter basis) did not improve hay voluntary intake (59 g DM/kg W 0, 75 in average) and growth performances of lambs in the D'man breed. These two parameters were not affected when soya meal was partially (50 %) or totally replaced by rapeseed meal. The results clearly show that nitrogen restricts growth of growing Queue Fine de l'Ouest lambs fed hay as a basal diet. This does not seem to be the case for D'man lambs and suggestions, which require further investigations, are part forward to explain the lack of response in this breed. The trials emphasize the opportunitiy to replace soya meal as a nitrogen source by rapeseed meal which is becoming increasingly available in the north of Tunisia.
