Abstract #M45

# M45
Effects of different feed type exposure in early life on performance, rumen fermentation and feed preference of dairy calves.
Ya Jing Wang*1, Jianxin Xiao1, Shengli Li1, Zhijun Cao1, Gibson Maswayi Alugongo1, 1China Agricultural University, Beijing, P. R. China.

The aim of the study was to evaluate the effects of early feed exposure (EFE) in dairy calves to different feedstuffs on feed preference once fed a free-choice diet and a TMR later in life. Thirty female calves were randomly assigned to one of the 3 EFE treatments including CON (only concentrate), HAY (only hay) and COH groups (both concentrate and hay) from d 2 to 56. All calves were offered both concentrate and hay in different bucket from d 57 to 70 to allow them free choice between the 2 feedstuffs. Calves were then fed TMR from d 71 to 196. Feed intake was recorded daily from d 2 to 70 to determine the feed preference before and after weaning. Upon transition to a TMR, feed sorting was calculated from d 190 to 196 as the actual intake of each fraction expressed as a percentage of predicted intake by using a particle separator. BW, ADG, glucose, total protein (TP), ruminal pH and VFA concentrations were analyzed throughout the experiment. Early feed exposure did not significantly affect the feed intake, BW, ADG, blood glucose and structural growth before and after weaning, but did affect feed preference and rumen fermentation. After transition to a free-choice diet, HAY calves consumed more hay (550.2 g/d) on the first day after transition than CON (177.4 g/d, P < 0.01) and COH (396.4 g/d, P < 0.01), but this effect lasted for only a day. Provision of both concentrate and hay early in life resulted in greater intake of hay and higher ratio of hay to total solid (35.6%) than provision of either concentrate (17.7%, P = 0.03) or hay (16.5%, P = 0.02), giving rise to a higher rumen pH (CON:5.59, HAY:5.44 and COH:5.84, P = 0.01) and numerically lower total VFA (147.5 mmol/L, 163.7 mmol/L and 135.8 mmol/L, P = 0.09) and blood glucose (3.78 mmol/L, 3.85 mmol/L and 3.62 mmol/L, P = 0.59) at d 70. Upon transition to a TMR, a similar sorting pattern was exhibited, sorting against the long particle (CON: 97.1%, HAY: 97.7% and COH: 99.3%, P = 0.12) and for the fine particle fraction (104.3%, 104.2% and 103.9%, P = 0.15). Therefore, our results suggested that EFE could influence choice of feed immediately after weaning, but did not have a long-lasting effect on feed preference in calves.

Key Words: dairy calf, feed preference, early experience