COMPARISON OF MECHANICALLY SPRAYING UREA IN SOLUTION IN THE FIELD OR MANUALLY SPRAYING THE SHEAVES FOR TREATING WHEAT-STRAW - EFFECTS ON DIGESTIBILITY AND GROWTH OF LAMBS

Treating straw with a lu ca solution can increase its nitrogen level f rom 3.3 to 7.1% when the treatment method used is mechanical spraying in the field (PTUA) and from 3.3 to 10.8% when the sheaves are manuall y sprayed (PTUB). The increase in the amounts ingested was 34% for the PTUA straw and 39% for the PTUB straw in adult sheep. In growing lamb s, the increase was only 18.2% and 19.8% for the PTUA and PTUB straws, respectively. The difference between the quantities ingested by the a dult and the growing animals can he explained by the fact that the lam bs were fed a different amount of complement. The two spraying techniq ues used improved the digestibility of the treated straw by the same p roportion with respect to untreated straw (PNT). The increase in growt h attained by the lambs was slightly greater with the PTUA straw(112 g /day) as compared to the PTUB straw (103 g/day) or PNT straw (104 g/da y). However, both PTUA and PTUB diets involved the same amount of comp lement, whereas the PNT diet involved more. Therefore, the PTUA and PT UB diets were 8-12% cheaper per kg of growth. ((C) Elsevier/Inra).