WHEAT SILAGE - EFFECT OF CULTIVAR AND STAGE OF MATURITY ON YIELD AND DEGRADABILITY IN-SITU

Dry matter (DM) yields and degradability in situ of two wheat cultivar s--an early-maturing, Bet Hashita (BH), and a late-maturing, Ariel (A) , harvested and ensiled at four maturity stages, shooting, flowering, milk, and dough--were evaluated. The wheat was ensiled in minisilos fo r 90 days. The DM yields (t ha(-1)) of A tended to be higher than thos e of BH at all maturity stages. Average neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of both cultivars were lowest at the shooting stage and highest at flowering stage. Average NDF and ADF contents of A silages were higher than those of BH: 631 vs 582 g k g(-1) DM and 378 vs 338 g kg(-1) DM (P < 0.05), respectively. In situ DM degradability of BH was higher than that of A at all stages of matu rity P < 0.05). (average 27.1 vs 20.1%; P < 0.05), and it decreased si gnificantly with maturity. In situ NDF degradability during 24 h of in cubation decreased with maturity in both cultivars (P < 0.05) and was higher for BH than for A at the milk stage. Total degradable NDF yield s tended to increase with maturity and to be higher in cultivar A. The refore, A, harvested at a later ripening stage, is preferable to BH as a roughage crop for dairy cattle.