Abstract

The objective of this study was to investigate the effects of feeding frequency and level of intake on rumen fermentation parameters of sheep fed chicory or perennial ryegrass. Fresh, vegetative chicory or perennial ryegrass were fed twice daily at 0900 h and 1630 h in the first period, and hourly in the second period to eight rumen-fistulated wethers at 1.3 and 2.2 times their maintenance metabolisable energy requirements. Rumen fluid pH, ammonia and volatile fatty acid (VFA) concentrations at 0900, 1000, 1100, 1200, 1300 and 1500 h were determined. When fed hourly (P < 0.05), but not twice-daily, forage type and feeding level significantly affected rumen pH. Differences in total VFA concentrations between forages and feeding levels were influenced by feeding frequency. Ammonia concentrations were always lower in sheep fed chicory than ryegrass (P = 0.001). Differences in rumen pH, ammonia and total VFA concentrations attributed to either forage species, level of intake or their interactions and were more likely to be detected when sheep were fed hourly, compared to twice-daily, as a result of the reduction in diurnal variation of these parameters. Manipulation of feeding frequency and/or feed intake can modulate the responses of ruminal metabolism to fresh forage diets.

XZ, Sun, D Pacheco, SO Hoskin, and DW Luo

Proceedings of the New Zealand Society of Animal Production, Volume 72, Christchurch, 111-116, 2012