The degradation of Rhinanthus minor (yelow rattle) in vitro

Contributed to: Proceedings of the British Society of animal Science ( York, Reino Unido, Apr 4-6, 2005).Rhinanthus minor is a facultative hemiparasitic plant of the Scrophulariaceae family native to the British Isles. It is typically found in meadows associated with a high floristic diversity, but it can also be found in pasture, where it is susceptible to heavy grazing. Containing the iridoid glycoside rhinanthin (C29H52O20), R. minor is strongly suspected of being poisonous, but it is not clear how harmful this is to livestock (Long 1924). Through parasitism, particularly of the grasses, R. minor is also associated with a loss of grazing. Consequently, the presence of R. minor in a sward is often viewed negatively. However, through reductions in productivity of grasses, R. minor may have a role in the restoration of species-rich grasslands. As a result, the probability of cattle consuming R. minor might be expected to increase. This paper aims to evaluate the degradation of R. minor and discusses the implications of R. minor inclusion in the diet.Peer reviewe

Non-additivity of feedstuffs examined in vitro and the influence of incubation medium pH.

Contributed to: Proceedings of the British Society of Animal Science 2001, p.133. (York, Reino Unido, April 9-11, 2001)Non-additivity occurs when the nutritive value of a mixture of feedstuffs differs from that of the sum of its components. It is most commonly observed when one dietary constituent influences, either positively or negatively, the apparent digestibility of another under conditions where components such as nitrogen and sulphur are non-limiting. In general negative effects occur due to the depression of rumen pH or substrate competition, while positive effects have been identified when readily fermentable fibre sources such as sugar beet pulp have been included in rations containing poorly fermented forages such as cereal straw. With the increasing use of in vitro systems, not just to examine feed degradation characteristics but to derive parameters such as microbial protein yield, the following study was conducted to determine whether such interactions could be identified in vitro.Peer reviewe

The effect of cultivar on the rate and extent of combining pea straw degradability examined in vitro using the Reading Pressure Technique

9 pages, 10 tables.-- Available online 13 Feb. 2002.The definitive version is available at: http://www.blackwell-synergy.comAlthough about 225 000 t dry matter (DNA) pea straw is produced annually in the UK, no recent data exist with respect to its nutritive value when offered to ruminants. This study, to examine field pea crop waste (straw) from 12 commercial cultivars of combining peas, was therefore undertaken when material grown as part of a European field pea network trial at Reading in 1998 was made available. The straw was subjected to chemical analysis and examined in vitro using the Reading Pressure Technique to generate gas production profiles and to determine built rate and extent of DM arid organic matter degradation. Ash and crude protein (CP) concentrations (69 and 65 g kg(-1) DM) were generally lower than published values for legume straws but higher, especially CP, than cereal straws. Neutral-detergent fibre concentrations were slightly lower, and metabolizable energy (ME) values, derived from degradable organic matter assessed in vitro (iOMD), higher than cereal straws, ranging from 6.0 to 8.1 MJ ME kg(-1) DM. Both cumulative gas production and rate of gas release varied significantly between cultivars, as did degradation with 96-h iOMD values ranging from 468 to 602 g kg(-1). By combining these with the quantity of material harvested, ME yields for the different cultivars were found to range from 15 to 27 GJ ME ha(-1). Considerable, and general highly significant, variation was found between the cultivars examined, which may be used to rank straws with respect to their nutritive value. The cultivars Baccara and Solara followed by Athos and Vital were readily ranked higher than the other cultivars in terms of in vitro fermentation parameters and ME yields. These data suggest that pea straw, although often incorporated into the soil in post-harvest operations, show, excellent potential as a ruminant forage feedstuff.Peer reviewe