An evaluation of fababean (<i>Vicia faba</i>) and lupin (<i>Lupinus albus</i>) stubble and seed for sheep

Abstract

The experiment was carried out to compare fababean with lupin crop residues for summer grazing by young Merino wethers. The crude protein (CP) and dry matter (DM) degradability as well as chemical composition of fababean and lupin seed and stalks were also determined. Sheep which utilized both crop residues gained in live mass (P ≤ 0.01) over the first 35 days of grazing, after which average live mass of sheep on both crop residues started to decline. No significant differences in the average live masses of sheep between treatments were observed, although sheep which grazed fababean crop residues tended (P ≤ 0.07) to have higher live masses than sheep which grazed lupin crop residues at the fourth week after the start of the trials. That observation can probably be attributed to a higher amount of seed remaining on the land after harvesting the crops (384 vs. 204 kg/ha). The CP (22.3%), in vitro digestibility of organic matter (89.1%) and crude fibre (8.8%) content of fababean seed were lower than the corresponding values found for sweet lupins (35.5, 91.1, and 10.1% respectively). Fababean as well as lupin seed was highly degradable in the rumen, and at an outflow rate of 0.05/h, lupin seed had an undegradable protein (UDP) content of 3.1% and fababeans a UDP content of 1.6%. The DM of lupin stalks were degraded to a larger extent in the rumen than fababean stalks (55.8% vs. 46.1%).

Die eksperiment is uitgevoer om fababoon- en soetlupien-oesreste as somerweiding vir jong Merinohamels te vergelyk. Die droë materiaal (DM)- en ruproteïen (RP)-degradeelbaarheid sowel as die chemiese samestelling van fababoon- en lupiensaad en stoppel is bepaal. Skape op beide stoppellande het toegeneem in liggaamsmassa (P ≤ 0.01) oor die eerste 35 dae van beweiding, waarna skape op beide weidings se gemiddelde liggaamsmassa afgeneem het. Die gemiddelde liggaamsmassa van die hamels het nie betekenisvol tussen behandelings verskil nie, hoewel die gemiddelde liggaamsmassa van hamels wat fababoonoesreste bewei het, geneig het (P ≤ 0.07) om hoër te wees gedurende die vierde week van beweiding. Hierdie verskil in liggaamsmassa kan moontlik toegeskryf word aan die hoeveelheid saad wat ná oes op die land agtergebly het (384 teenoor 204 kg/ha). Die RP-inhoud (22.2%), in vitro-verteerbaarheid van organiese materiaal (89.1%) en ruveselinhoud (8.8%) van fababoonsaad was laer as die onderskeie waardes vir soetlupiene (35.5, 91.1 en 10.1%). Die fababoonsaad sowel as lupiensaad is hoog degradeerbaar in die rumen. Lupiensaad het 'n nie-degradeerbare proteïen (NDP)-inhoud van 3.1% en fababoon 'n NDP-inhoud van 1.6% by 'n uitvloeitempo van 0.05/h. Die DM van lupienstoppel (55.8%) word tot 'n groter mate as DM van fababoonstoppel (46.1%) in die rumen gedegradeer.

Keywords: Crop residues, degradability, fababean, in situ, lupin, sheep, summer grazing, supplementary feed.