The Relationship of Rumen Cations and Soluble Protein With Predisposition of Cattle to Alfalfa Bloat

Abstract

Rumen-fistulated cattle were fed fresh alfalfa herbage daily during two growing seasons. Samples of rumen fluid were collected daily prior to feeding and the frothiness of the rumen fluid was assessed. Concentrations of soluble protein nitrogen in the rumen fluid were higher in animals that subsequently bloated than in those that did not (P < 0.01). There was no relation between soluble protein nitrogen and the occurrence of foam in the rumen prior to feeding. The concentrations of Na and K in the rumen fluid were negatively correlated. Bloat was associated with a low concentration of Na and a high concentration of K (P < 0.01). Concentrations of Ca and Mg were lower than those of the two monovalent ions but were also positively associated with bloat (P < 0.01). The high concentration of chlorophyll associated with a predisposition to bloat may be the result of a colloidal aggregation of chloroplast particles stabilized by cations. Key words: Pasture bloat, alfalfa, chlorophyll, ions, cattle

Rapid screening of feed supplements for the prevention of legume bloat

“…Sci. 72: 613-617 (Sept. 1992) Recent bloat research (Hall et al 1988; Majak and Hall 1990) The ability of the sequential test to detect treatment differences was initially demonstrated with the the data from an experiment comparing the effects of feeding animals either once or twice a day (Majak and Hall 1990 (Wetherill 1966 (Hall et al 1988;Majak and Hall 1990 (Table I ) . In a previous study the prefeeding concentration of sodium in rumen fluid was lower in cattle that subsequently bloated than in those that did not (Hall et al 1988 …”

The effects of poloxalene on ingestion by cattle grazing Lucerne†

“…Experimental conditions were favourable for the development of legume bloat (Hall et al,, 1988). The immature stage at which the lucerne was grazed (Table 1), the extremely high quality of the ingesta (Table 3) and the environmental conditions during the grazing meal (Table 5) are conditions normally associated with bloat.…”

“…Cattle are able to resume grazing high quality lucerne at maximum rates 3 h later but on lower quality herbage the rate of intake is not fully restored until much later (Dougherty et al, 1989a). It is possible that the formation of a stable foam from the rapid disruption of mesophyll cells of bloat-prone herbage (Hall et al, 1988) activates mechanoreceptors of the reticulo-rumen wall that induce satiety and halt grazing activities. Presumably grazing may resume when the foam disintegrates and if satiety is alleviated.…”

Bloat in cattle grazing alfalfa cultivars selected for a low initial rate of digestion: A review

“…Grazing bouts are shorter, rumination times are reduced and ruminal movements increase in frequency (Hancock 1954). Production losses are primarily a result of a reduced feed intake (Johns 1954;Reid and Johns 1957;Alder et al 1967;Hall et al 1988). In cases of sub-acute frothy bloat on legume pasture, the rumen has normal motility and low to moderate pressure but may be fully charged with a stable, amorphous foam containing elevated chlorophyll levels, cation imbalances and an increased capacity to produce gas (Cole and Boda 1960;Reid 1960;Howarth et al 1977Howarth et al , 1978bMajak et al 1980Majak et al , 1985Majak et al , 1986aLedgard et al 1990;Majak and Hall 1990).…”

“…In cases of sub-acute frothy bloat on legume pasture, the rumen has normal motility and low to moderate pressure but may be fully charged with a stable, amorphous foam containing elevated chlorophyll levels, cation imbalances and an increased capacity to produce gas (Cole and Boda 1960;Reid 1960;Howarth et al 1977Howarth et al , 1978bMajak et al 1980Majak et al , 1985Majak et al , 1986aLedgard et al 1990;Majak and Hall 1990). The danger for animals with sub-acute frothy bloat is that they are predisposed to the onset of an acute bloat (Majak et al 1983;Hall et al 1988). …”