Mereu, Alessandro (2009) Palatability of concentrates fed to sheep. Doctoral Thesis.
Palatability of concentrates is important to avoid feed refusal and production losses in ruminants. Thus, the palatability of 14 feeds (soybean meal 44 and 49; soybean hulls; corn grains; canola meal; wheat grains; beet pulps; dehydrated alfalfa; sunflower meal; oat grains; pea grains; wheat brans; corn middlings; corn gluten meal) was measured in 6 min daily tests on 14 female lambs and 14 dry multiparous ewes. The palatability of the feeds fed to the lambs varied from high to low values in a continuum, suggesting that sensorial perceptions were more important than previous feeding experiences or post-ingestive effects. In contrast the ewes clearly preferred 4 feeds (beet pulps and wheat, pea, and corn grains) over the others, which are common ingredients in concentrate mixes but are rarely used as single ingredients. In two subsequent trials the possibility of enhancing the palatability of canola meal and oat grains, which had low palatability in the previous trial, was tested by adding to them synthetic flavours. The results showed that some flavours improved the capacity of the animals to eat the feeds tested. This was more evident in the ewes than in the lambs. Eventually, the volatile organic compounds of the feeds were measured by gas chromatography olfactometry and related to feed palatability. Sulphur volatile compounds seemed to influence negatively feed palatability in both lambs and ewes, while terpenes seemed to negatively affect the palatability of oat grains.
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