科研之友
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摘要
Pasture bloat is a major deterrent to the grazing of alfalfa (Medicago sativa L.) pastures by ruminants, despite the high growth rates that are obtainable. Sainfoin (Onobrychis viciifolia Scop.), a condensed tannin-containing legume, is known to reduce alfalfa pasture bloat in mixed stands. Experiments were conducted in 2010 to 2012 at Lethbridge, AB, using two sainfoin/cultivar AC Blue J alfalfa mixed pastures originally seeded as 50: 50 mixes in 2008 and rotationally grazed by steers (Bos taurus). New sainfoin population cultivar LRC-3519 specifically selected for improved performance under a multi-cut system, persisted better (29% of total herbage dry matter [DM]) compared to cultivar Nova (5%) after two cycles of rotational grazing in each year. Bloat incidence and severity in steers were reduced (P %26lt; 0.001) by 98% in LRC-3519 mixed stands compared to Nova mixtures when Angus steers grazed sainfoin/alfalfa mixed pastures under conditions for maximizing bloat occurrence. In a separate crop preference study during 2011-2012, eight steers were randomly paired and assigned to four alfalfa and sainfoin strip pastures to determine DM utilization and time spent grazing the two forages. Steers spent more time (55%) in alfalfa strips compared to sainfoin and grazed more (P %26lt; 0.05) alfalfa (2048 kg DM) than sainfoin (1164 kg DM). In spite of higher preference for alfalfa, a high proportion of new sainfoin in mixed alfalfa stands reduced risk of bloat substantially in cattle grazing mixed alfalfa/sainfoin pasture.
- 出版日期2014-8
