Effect of dry matter content and feeding level on intake and organic matter digestibility of perennial ryegrass offered to sheep

摘要

The objective of this experiment was to evaluate the effect of grass dry matter (DM) content on OMD at two feeding levels in wether sheep. A Latin square experimental design, with four periods and four treatments, was used. There were four sheep per treatment per period (n=16), with the four treatments arranged in a 2x2 factorial; wilted or fresh grass offered it ad libitum or maintenance feeding level. Each 12-d period consisted of a 6-d adaptation phase and a 6-d measurement phase (MP). Fresh and wilted grasses were fed to the sheep daily at 4 pm. The DM content of the wilted and fresh grass was 27.8% and 18.6%, respectively. Ad libitum fed sheep were offered 110% of the previous day's DMI. Maintenance fed sheep were fed 40 g grass DM kg"1 metabolic BW. Sheep were housed in stalls to allow for individual feeding and total faecal collection. During each MP, a sample of the grass fed to, and faeces voided by, each sheep was collected daily. The daily grass and faeces samples were dried and bulked to give one sample per treatment and per sheep per period. Wilted grass (819 g kg'1) had greater OMD than fresh grass (807gkg1;P<0.01) and maintenance level feeding (825 gkg'1) resulted in greater OMD than ad libitum (806 gkg"1; /><0.001). When fed ad libitum, wilted grass (1.50 kg DM day"1) resulted in greater DMI than fresh grass (1.40 kg DM day"1; /,<0.05) but fresh grass had greater fresh weight intake (7.5 kg day"1) than wilted grass (5.5 kg day"1, P<0.001). These results indicate that increasing perennial ryegrass DM content results in increased OMD and increased DMI in sheep fed indoors, and the results are not interacted upon by the feeding level employed.