Differences in digestive ability of more-selective and less-selective sheep ( Ovis aries L.) : A dissertation submitted in partial fulfilment of the requirements for the Degree of Bachelor of Agricultural Science

This study aimed to determine if differences in digestive ability between more and less selective sheep exists. 24 sheep were ranked on their selective ability and divided into two groups, 12 more-selective (mean 9.92% stem consumed in diet) and 12 less-selective (mean 11.8% stem consumed in diet). Ewe hoggets were offered two feed types, one where selective behaviour could be expressed (hay chaff offered ad lib) and one where no selection could take place (lucerne pellets offered at maintenance). Sheep were offered each feed type for two weeks, with total faecal and feed residue collection in the second week. The trial ran for 5 weeks from the 16th June to the 21st July 2009. There was a significant difference in apparent digestibility between the more and less selective sheep on the hay chaff diet. More-selective ewes had 2.8, 3.1, 7.0, 3.9 and 2.9% units higher apparent DM, OM, CP, NDF and ADF digestibility respectively. There was no difference in apparent DM, OM, CP, NDF or ADF digestibility between the two groups on the lucerne pellet diet. On the hay chaff diet there was no significant difference in daily ad lib intake (g/kg of body weight) between the more (15.9 g/kg BW) and less-selective (16.4 g/kg BW) ewe hoggets, but the more-selective hoggets had a lower (P