Alfalfa Pasture Bloat Can Be Eliminated by Intermixing with Newly‐Developed Sainfoin Population

Abstract

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 < 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 < 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.

Condensed Tannins in Sainfoin: Composition, Concentration, and Effects on Nutritive and Feeding Value of Sainfoin Forage

“…In another 3-yr study to compare incidence of bloat, ruminal fermentation, and feed intake of steers grazing alfalfa and mixed alfalfasainfoin pastures showed that inclusion of 35% sainfoin in mixed alfalfa-sainfoin pastures reduced but did not eliminate bloat (Wang et al, 2006). In a 3-yr grazing study, Sottie et al (2014) observed that bloat incidence increased from 5 to 43 and from 1 to 48 when the percentage of sainfoin was reduced from 29 to 7% and from 28 to 5% in sainfoin-alfalfa mixture, respectively. The CT content in forage mixtures used in these studies all exceeded 1.0 mg kg -1 DM.…”

“…Like all other tannin‐containing plants, CTs are synthesized by a chloroplast‐derived organelle, the tannosome, and stored in vacuoles within the plant cell. In sainfoin there is an even distribution of tannin cells throughout the plant, a characteristic that differs from other tannin‐containing fodder legumes (Skadhauge et al, 1997). It has been shown that the compositions of sainfoin CTs vary with species, accessions, and growth stage and are composed of procyanidins (catechin + epicatechin; PC) and prodelphinidins (gallocatin + epigallocatechin; PD) (Koupai‐Abyazani et al, 1993a, 1993b; Leeds et al, 1995).…”

“…Several new sainfoin populations have been developed and compared with the old population (Nova) under different growing conditions for their persistence and competitiveness with alfalfa in the alfalfa-sainfoin mixture pastures and for their efficacies in reducing alfalfa pasture bloat Sottie et al, 2014). These new populations produced better DM yields than Nova in pure stands under rain-fed and irrigated conditions (such as in Lethbridge, AB, Canada) but not under extremely dry and variable conditions (such as in Swift Current, SK, Canada) during three production years.…”

“…high-performance grazing alfalfa pasture have been developed, and strategy to utilize sainfoin CT to prevent alfalfa pasture bloat by incorporating sainfoin into alfalfa pasture has been demonstrated to be effective Sottie et al, 2014;Wang et al, 2006). This review attempts to capture the latest research in characterizing the impact of polyphenolics on the feeding and nutritive value of sainfoin with an emphasis on CT. On the basis of the HCl-butanol assay, as described by Terrill et al (1992), CT in plant material can be described by three fractions: extractable, protein-bound, and fiber-bound CT.…”

Assessment of sainfoin (Onobrychis viciifolia Scop.) germplasm for agro‐morphological traits and nutritive value

“…Sainfoin can be grown as a monoculture or in mixtures with perennial grasses or alfalfa (Frame et al., ; Goplen et al., ; Hayot‐Carbonero, Mueller‐Harvey, Brown, & Smith, ). When sainfoin is grown in a mixture with alfalfa, it has been shown to reduce bloat incidence in beef cattle relative to the grazing of pure alfalfa (Malisch et al., ; Sottie et al., ).…”