Effect of the last diet on the selective feeding behavior of heifers

The present study examined and discussed the way the basal diet (BD) during the preliminary phase and the last diet (LD) before the food selection test affected the selective feeding behavior of heifers. For the BD and LD, oat hay and concentrate were used. Three different levels of roughage content (low, medium and high) were prepared by changing the mix ratios of oat hay and concentrate. Low and high roughage diets were used for the BD, and all three of the roughage levels were used for the LD. A mixture of orchard grass and white clover (MIX), and Japanese pampas grass leaf (JP) were used as testing foods. In the preliminary phase, all heifers were fed the BD three times per day. In the test phase, heifers were fed the LD for the first meal (06.00-12.00 hours), and food selection under different BD and LD was examined during the second meal (13.00-16.00 hours) of the day. The effects of the BD were significant for MIX dry matter intake (DMI), JP DMI and the rate of MIX DMI for total DMI. Under the high roughage BD condition, heifers ingested more MIX than under the low roughage BD condition. The effect of the LD was significant on JP DMI, whereas the rate of MIX DMI for total DMI was not significant. Selective feeding behavior was strongly affected by the BD and slightly by the LD.