|Turner, Kenneth - Ken|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/14/2010
Publication Date: 5/17/2010
Citation: Cassida, K.A., Foster, J.G., Turner, K.E. 2010. Forage characteristics affecting meat goat preferences for forage chicory cultivars. Agronomy Journal. 102:1109-1117. Interpretive Summary: Some chemical compounds in forage chicory may help sheep and goats tolerate gastrointestinal worms, but their bitter taste reduces palatability of forage. Improved soil phosphorus fertility may reduce bitterness to acceptable levels. We evaluated palatability to goats of three cultivars of forage chicory grown under varied phosphorus fertility levels. Palatability of chicory was good, but preferences of goats were only partly explained by differences in bitter compounds, indicating that other characteristics, which need to be identified, also affect preferences for this forage. This work is useful because it increases understanding of why animals sometimes refuse to eat chicory. The work will benefit small ruminant producers interested in using chicory to reduce dependence on commercial dewormers.
Technical Abstract: Concentration of bitter sesquiterpene lactones (SL), lactucin, lactucopicrin, and 8-deoxylactucin, has been associated with low soil phosphorus fertility and reduced livestock preference for forage chicory (Cichorium intybus L.). We evaluated the effect of cultivar and available soil P (ASP) on meat goat (Capra hircus L.) preferences for ‘Grasslands Puna (Puna)’ ‘Forage Feast,’ and ‘INIA le Lacerta (Lacerta)’chicory grown under varying P fertility. Soil Bray-P was used to designate ASP as low (LP, mean 8.6 mg kg-1), medium (MP, 21.7 mg kg-1), and high (HP, 40.1 mg kg-1) for the preference test. In September, clipped fresh forage was offered to confined Boer-cross goat kids using a replicated 3x3 Latin square design with an extra period. Preferences were measured using dry matter intake for cultivar effects and multidimensional scaling (MDS) for ASP effects. Across cultivars, soil Bray-P was positively related to leaf P and Mg concentrations. Soil Bray-P did not affect lactucopicrin or 8-deoxylactucin, and was positively associated with lactucin, in contrast to the hypothesis. Goats exhibited no preferences among cultivars despite up to fourfold differences in individual SL. Within cultivars, goats preferred Puna with less lactucin and total SL, Lacerta with less lactucopicrin and leaf Mg, and Forage Feast with more cell wall. Goats were able to detect relatively small differences in SL within cultivars, but this had little practical effect on intake of the forage because they ate it even when bitter. Therefore, P fertilization for fall-grown chicory is unlikely to improve forage intake in goats.