Walter Majak

Effect of sainfoin on in vitro digestion of fresh alfalfa and bloat in steers

The effects of sainfoin (Onobrychis viciifolia) on digestion of alfalfa (Medicago sativa) were investigated in vitro and in vivo. Fresh alfalfa and sainfoin were incubated in an artificial rumen (Rusitec) in ratios of 100:0, 75:25, 50:50, 25:75 and 0:100 (as-fed). Disappearances of dry matter and N from sainfoin were 77 and 65% of those from alfalfa, respectively. Protease and endoglucanase activities, NH3-N and methane production declined (P   0.05), but cells incorporated more 15NH3N as sainfoin in the diet increased. Chopped leaves (100:0, 95:5 and 90:10 alfalfa:sainfoin) were incubated for 48 h with diluted ruminal fluid containing 0 or 50 mg polyethylene glycol, which binds tannins. Gas and volatile fatty acid productions were similar (P > 0.05) across treatments, but including 10% sainfoin (without polyethylene glycol) reduced (P < 0.05) NH3 concentrations between 8 and 24 h. Sainfoin tannins reduced degradation...

Enhancing pasture productivity with alfalfa: A review

Alfalfa has been recognized for its superior yield and quality in seeded pastures. However, when grazing immature alfalfa there is a risk of animal losses due to frothy bloat in some ruminant livestock. Inclusion of at least 50% grass in the pasture mixture is commonly recommended to reduce the risk of bloat. Two decades of plant breeding have resulted in the release of AC Grazeland, an alfalfa cultivar that reduces the incidence of bloat. Other bloat control agents such as pluronic detergents and ionophores can also be of value. Development of grazing-tolerant alfalfa varieties is solving some of the problems associated with lack of persistence of alfalfa in mixed stands; however, they are not bloat-safe. Animal productivity commonly increases when alfalfa is included in pasture mixtures. Improvements in cattle rate of gain are observed when alfalfa contributes as little as 35% to the sward. Grazing management is the principal method for controlling pasture yield and quality as well as animal performance...

A review of the development of a bloat-reduced alfalfa cultivar

The studies that led to the development of a bloat-reduced alfalfa began in 1970. Initial work focused on the causes of bloat, the characteristics of bloat-safe and bloat-causing legumes and the development of screening methodologies. The characteristics that were examined as causal factors of bloat in legume species included soluble proteins, saponins, absence of condensed tannins, and rapid breakdown of cells in the rumen. The factor or combination of factors responsible for causing bloat in animals grazing legumes have not been clearly identified; however, of the above, rapid cell breakdown was considered to be the most promising line of research to pursue in selecting a bloat-safe legume. A 4-h nylon-bag rumen digestion technique was developed, which was used to assess the initial rate of digestion (IRD) of fresh leaf material in large numbers of alfalfa genotypes. Using this technique on a population of four alfalfa cultivars, four cycles of recurrent selection for low initial rate of digestion (LIRD...

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

and Cheng, K.-J. 2000. Bloat in cattle grazing alfalfa cultivars selected for a low initial rate of digestion: A review. Can. J. Plant. Sci. 80: 493‐502. The occurrence of frothy bloat limits the practice of alfalfa grazing in spite of the availability of strains bred specifically for pasture. Bloat is a chronic condition, endemic to cattle. Prophylactics and management techniques are ava ilable to reduce its incidence but they are expensive, difficult to administer, conflict with traditional grazing management regi mens and do not eliminate bloat in all circumstances. A program to breed and evaluate a bloat-reduced strain of alfalfa was initiate d in 1980 to overcome some of these limitations. A review of the results of grazing and feeding trials using alfalfas with low initi al rates of digestion (LIRD) shows that this new strain reduces the incidence and severity of frothy bloat on pasture. Their effec tiveness in controlling bloat was related to feeding or grazing management practices, the maturity of the plants and the season of use. Graziers may reduce the risk of occasional livestock losses from bloat by using LIRD cultivars, like AC Grazeland, or managing species/cultivar mixtures in ways that reduce the initial rate of digestion. Other bloat preventive strategies, including coseeding with bloat-free legumes and using bloat-controlling prophylactics in combination with a LIRD alfalfa, are being investigated.

Flavonoids of Equisetum species

Abstract A survey of Equisetum species found in British Columbia showed that they all contained flavonoid di- and tri-glycosides especially those of kaempferol and, to a lesser extent, those of quercetin. Three other minor flavonoids were identified as gossypitrin, herbacitrin and apigenin-4′-glucoside.

Three nitropropanoyl esters of glucose from Indigofera linnaei

Three 3-nitropropanoyl esters of d-glucose were isolated from Indigofera linnaei, the known 1,2,6-tri-O-3-nitropropanoyl-β-d-glucopyranose (karakin) and 2,3,4,6-tetra-O-3-nitropropanoyl-α-d-glucopyranose, and the apparently previously undescribed 3,4,6-tri-O-3-nitropropanoyl-α-d-glucopyranose. The use of countercurrent chromatography for the isolation of these compounds is described, as well as the spectroscopic evidence which led to their structural elucidation.

Nitropropanylglucopyranoses in Coronilla varia

Abstract The isolation and characterization of 6-(3-nitropropanyl)- d -glucopyranose from Coronilla varia is described and the concentration of the compound is determined by quantitative microisolation. Di- and tri-nitropropanylgluco-pyranoses are detected in C. varia and three Astragalus spp.

Content of zygacine in Zygadenus venenosus at different stages of growth

Abstract A TLC-scanning procedure was developed for the quantitative determination of zygacine in death camas. The alkaloid levels increased during the pod stage of development when the veratryl and angelyl esters of zygadenine were also detected at high concentrations.

Diterpenoid and norditerpenoid alkaloids fromDelphinium nuttallianum

Abstract A further 14 alkaloids, seven known and seven new (three diterpenoid and four norditerpenoids) were isolated as minor constituents ofDelphinum nuttallianum. The spectroscopic evidence which resulted in the structures of the new alkaloids is described, as is the revision of the structure previously proposed for nuttallianine.

Palatability of Douglas fir foliage to mule deer in relation to chemical and spatial factors.

Highlight: Relative preference of Douglasfir needles from eight environmental conditions was determined in a feeding trial with penned tame deer of mixed age and sex. Relative preference (percent fresh weight ingested) varied between 0 and 74%, with significant differences between open (16%) and gully (970) sites, between old (20%) and young (4%) trees, and between tops (16%) and bottoms (8%) of trees. Shading was found to be responsible for some diflerence in palatability, unshaded being preferred (22%) over shaded needles (4%). Relative preference was found to be correlated with moisture content (r = -0.57). Relative preference was also found to be correlated with chlorogenic acid (r = 0.41), a naturally occurring phenolic ester which was quantifted by fluorometric scanning after being observed in a thin layer chromatography (TLC) screening experiment. Crude protein was not significantly correlated with preference.