Growth performance of lambs fed mixed diets containing halophyte ingredients

The growth rates of lambs fed on diets containing halophyte components were assessed in two trials of 84days duration each, from weaning to slaughter weight. Three halophyte forages, Atriplex barclayana, Suaeda esteroa and Salicornia bigelovii straw, were compared with Cynodon dactylon hay at 30% of the diet. Halophyte forages were much higher in mineral content than Cynodon hay (24–34% vs. 5%). The trials also compared Salicornia seed meal with cottonseed meal at 10% inclusion. All diets were high in concentrate (70%) and contained 12.5–15% protein. Dry matter intake was higher for lambs fed diets containing halophyte forages than for lambs fed on the grass control diet. Because of the increased intake, halophyte-fed lambs were able to gain at the same rate as the control lambs, but, as expected, feed efficiency was lower and water intake was higher. Carcass merit of all lambs was excellent and was not affected by the inclusion of halophyte forages in the diet. In one trial an additional control treatment was included in which Cynodon hay was supplemented with NaCl to attempt to isolate the effect of excess salt on feed intake and growth. However, the simulated halophyte diet (Cynodon + NaCl) supported lower weight gains and intake rates than the control or natural halophyte diets, showing that the form in which salts are present in halophyte forages is important to their acceptability to animals. It is concluded that halophytes could become important feed resources at moderate inclusion levels wherever production of these plants can be justified agronomically.