Effect of season on tedera (Bituminaria bituminosa) intake by goats

The voluntary intake of three varieties of Bituminaria bituminosa (crassiuscula, albormaginata and bituminosa), commonly called psoralea or tedera, collected in summer and winter was assessed using adult male goats. Dry matter (DM) content of varieties ranged from 221 to 281 g per kg fresh varieties, and chemical composition (per kg DM) of varieties ranged from 866 to 915 g organic matter, 150 to 202 g crude protein and 411 to 532 g neutral detergent fibre. In vitro OM digestible content ranged from 514 to 564 g/kg DM and it did not differ among varieties or season. When goats could choose among forages, including alfalfa hay, they consumed 0.71–0.88 of the offered tedera varieties and only a third of the offered alfalfa hay in the winter study. However, in summer, goats consumed all the offered alfalfa hay and only about a third of each offered tedera varieties, probably because of the secondary compounds in the fruits and seeds. Moreover, when preference for tedera hay or alfalfa hay was compared, daily intake of goats was composed by 0.67 tedera hay and 0.33 alfalfa hay. This research showed a goat preference for tedera (in fresh or as hay) than for alfalfa hay, except for fresh tedera collected in summer. However, haymaking overcomes this problem.