Methods of conservation of ryegrass and short-term feeding preferences

摘要

Does the method of conservation of forage, known to affect voluntary intake, also affect short-term preferences ? A regrowth of ryegrass was harvested partly as silage with and without the addition of formic acid (EAF and ESC respectively), partly as hay (F), and 200 kg of fresh forage (FV) was frozen. Preferences between the four forages were studied with the six pairs (FV-EAF, FV-ESC, FV-F, EAF-ESC, EAF-F, ESC-F) tested according to a 6 X 6 Latin square design with 6 sheep. For each pair, 400 g DM of each type of forage, cut to the same length, was offered at 9 a.m. in a choice test, repeated on four consecutive days. The first half-hour intake of F, ESC, EAF and FV was 100~a 201~b, 241~c and 270~c g DM (P<0.01) respectively and the second half-hour intake was 184~a 90~b, 83~b, 83~b g DM (P<0.01) respectively. The preference for fresh forage or silage compared to hay during the first half-hour is consistent with the lower digestibility and voluntary intake of hay. A preference for wet forages cannot be excluded since the animals were fed orchard grass hay on non-experimental meals. The preference for EAF compared to ESC is consistent with the quality of conservation (slightly lower NH_3 and VFA contents in EAF).