Effect of different levels of neutral detergent fibre levels of starter diets on performance, ruminal fermentation, and structural growth of Holstein calves

Chunyan Ren¹Yanliang Bi²Yan Tu²Yanli Guo¹Rui Bing¹Jiqing Wang^1*Qi Yu Diao²

• ¹Gansu Agricultural University, Lanzhou, China
• ²Feed Research Institute, Chinese Academy of Agricultural Sciences, Beijing, Beijing Municipality, China

We evaluated the effect of starter diets with 4 levels (12.85%,19.91%, 26.99%, and 34.04% of dry matter) of neutral detergent fiber (NDF) on the growth, ruminal fermentation, and structural growth of Holstein calves. Sixty Holstein calves [42.3 ± 1.1 kg, body weight (BW)] aged 1-3 days were randomly assigned to 4 treatments:Starter diet with dry matter basis without hay forage, 12.85%NDF; with 14% forage, 19.91% NDF; with 28% forage, 26.99% NDF; with 42% forage, 34.04% NDF. Hay forage (alfalfa hay and oat grass) was pelleted together with the concentrate to provide calves, which had ad libitum access to water and starter feed throughout the experiment. Following weaning at 70 days, calves continued on their respective diets until trial termination at 112 days of age. The average daily gain (ADG) was dietary NDF levels at both 70 and 112 days of age. Total volatile fatty acids (TVFA) concentrations increased linearly with increasing dietary NDF levels. Elevating dietary NDF levels showed a linear reduction in final body weight (BW) and weaning BW. Calf body length exhibited a linear decrease with increasing NDF levels, with the 12.85% and 19.91% NDF diets yielding greater values at 112 days of age. Blood BHBA concentration was linearly elevated by higher dietary NDF levels at 70 days of age. Under the experimental conditions, dietary NDF level of 12.85% or 19.91% enhanced average daily gain (ADG), BW and structural growth parameters. These findings suggest that dietary NDF content below 26.99% constitutes the optimal range for Holstein calves aged 1-3 months.