New research published in the January Journal of Dairy Science takes a look at how exposure to grain or hay at an early age impacts feeding behavior post-weaning.
University of Guelph researchers randomly assigned eight Holstein bull calves at birth to a feed exposure treatment of concentrate or grass/alfalfa hay. At weaning, calves were given a mixed ration. Interestingly, they sorted for familiar feed; that is, calves previously exposed to concentrate sorted for short particles that were primarily concentrate. Calves previously exposed to hay tended to sort for long particles that were solely hay. After four weeks of exposure to the mixed ration, sorting was similar between treatments, with calves in both treatment groups sorting for short and against long particles and consuming a diet with a similar concentration of nutrients and energy.
Researchers concluded that feed familiarity affected initial diet selection post weaning, but may not have a lasting effect, with all calves developing similar feed-sorting patterns.