THE EFFECT OF LEVEL OF NON-DEGRADABLE PROTEIN IN DIET ON FATTENING PARAMETERS AND DIGESTIBILITY OF NUTRIENTS IN LAMBS

Results of the study of the effect of the level of non-degradable protein in diet on fattening performance and digestibility of nutrients in weaned lambs are presented in the paper. Objective of the study was to establish the optimal level of non-degradable protein in diets for weaned and intensively fattened lambs. Experiment was conducted on 60 lambs of F1 generation: Pirot Pramenka x Wurttemberg x Ile de France, weaned at the age of 60 days and divided into three groups. The effect of use of three concentrated mixtures which differed in the share of protein non-degradable at the level of rumen: 43% (I), 51% (II) and 58% (III). Average daily gain of lambs fed types of mixtures I:II:III was 0.169: 0.205 : 0.227 kg, respectively. Dry matter conversion (kg/kg of gain) on analogue treatments was: 4.54 : 3.71: 3.30, respectively, of energy (MJ NEM/kg) : 33.77: 29.37 : 26.25, and of total proteins (g/kg): 732 : 596 : 549. Level of intake of proteins was not influenced by the treatment considering that the digestibility coefficients recorded were: 52.58% : 51.30% : 55.12%. With the increase of the share of non-degradable protein in concentrate mixtures, the tendency of increase of the digestibility of fat was present: 76.13 : 77.98 : 87.17%, as well as of decrease of the intake of fibre: 67.40 : 45.87: 22.39% and NFE: 83.87 : 76.05 : 82.96%. Values of the dressing percentage of warm carcass with giblets according to nutrition types I:II:III were: 58.70 : 58.02 : 57.42%, respectively.