Comparison of feeding value of a treated sea plant, Posidonia australis, with lucerne, pasture and wheat

An experiment was carried out to compare the effect of feeding posidonia australis as a non-conventional feedstuff with cereal straw for sheep maintenance; and to compare seagrass/chicken litter with lucerne hay and pasture for sheep production on a scale such as would be applicable to lot-feeding of sheep in the area of suthern Australia in case of short term feed scarcity. To approach this target a Randomized Completely Block Design with six treatments was applied on sixty adult merino. The six experimental diets were: (A) 75% treated seagrass+25% lucerne; (B) 75% treated wheat straw+25% lucerne; (C) 75% treated wheat straw+25% chicken litter (seagrass bed+chicken manure from a 7-week broiler raising period); (D) 50% treated wheat straw+50% treated seagrass; (E) 100% treated straw; (F) Green pasture, mixture of legume and graminea. To treat seagrass and straw a solution containing 8% fertilizer grade urea, 15% sugarcane molasses and 1% calcium-diphosphate was mixed with either seagrass or straw (1 Kg/Kg DM). The mixture was stored under anaerobic conditions for 3 weeks. The total experimental period of 109 days was used to measure the effect of experimental rations on the voluntary intake, body weight gain, fat score, feed efficiency and wool growth rate of sheep. There were different DMI of diets A, B and C during the experiment but these differences were not significant.  Similar results were obtained for diets D and E as well. Among sheep of groups A, B and C total body gain of the sheep in group A was significantly less than that of the other two groups. The body weight gain of sheep grazed on pasture was significantly less than that of the sheep groups B and C, more than for the sheep in groups D and E (P<0.05) and equal that of the to sheep group A. In general there were few statistical differences, except that sheep on diet A showed consistently lowest values for greasy and clean fleece weight, staple growth rate, length: diameter ratio and staple strength. There was not a significant difference in clean fleece growth rate between sheep grazed on pasture and sheep in diet groups B, C, D and E, but this value was higher than for sheep in group A. It can be suggested that seagrass litter can be used proportionally in a mixed diet to provide enough nutrients and energy for sheep production in time of drought or feed scarcity. Meanwhile the cheaper diets D (seagrass containing) or E (straw only) could be used with equal efficiency in a lot-feeding system.

Keywords:

Sea plants , Posidonia australis , Lucern , Pasture , Feeding value , Sheep