Growth performance of dairy heifers limit-fed distillers dried grains with ad libitum forage

Abstract Text: Most previous research on feeding distillers dried grains with solubles (DDGS) to dairy heifers has been conducted using a set forage to concentrate ratio in total mixed rations. Our objective was to determine the growth performance and DMI of heifers when fed DDGS or a corn and soy products concentrate mix with ad libitum grass hay. Our hypothesis was that heifers fed DDGS would have improved G:F because of slightly greater dietary fat, but growth performance would be maintained. A 16-wk randomized complete block design study was conducted using 24 heifers (18 Holstein and 6 Brown Swiss; 219 ± 2 d of age; 230 ± 4 kg BW). Heifers were blocked based on age and breed. Treatments were: 1) a control corn and soy products concentrate mix (CON) and 2) DDGS based concentrate mix (DG). Both concentrate mixes were fed at 0.8% of BW (DM basis) and grass hay was fed ad libitum. Heifers were individually fed respective concentrate mixes at 0800 h and hay was offered at 0900 h using a Calan gate feeding system. Orts were recorded daily prior to feeding. Frame sizes, BW, and BCS were measured at 4 h post feeding on 2 consecutive d during wk 0 and then every 2 wk thereafter throughout the feeding period. Data were analyzed using the MIXED procedures of SAS 9.4 with means compared using Tukey’s test. Significance was declared at P < 0.05 and tendencies were declared at 0.05 ≤ P < 0.10. There were no significant interactions of treatment by wk. Heifer DMI (6.18 and 6.31 kg/d; SEM = 0.276 for the CON and DG, respectively), BW (269.8 and 266.9 kg; SEM = 9.86), and ADG (0.99 and 0.96 kg/d; SEM = 0.050) were similar (P > 0.05) between treatments. The G:F (0.168 and 0.156 kg/kg; SEM = 0.0099) was also similar (P = 0.38) between treatments. There were no differences (P > 0.05) in hip height (123.3 and 122.8 cm; SEM = 0.38), heart girth (140.6 and 139.9 cm; SEM = 0.40), or hip width (36.6 and 36.2 cm; SEM = 0.71) between treatments. Body condition scores (3.10 and 3.11; SEM = 0.026) were similar (P = 0.68) between treatments. Feeding heifers DDGS at 0.8% of BW with ad libitum forage maintained frame growth, ADG, DMI, and G:F compared to the CON concentrate mix.

Keywords:

distillers grains, dairy heifer,  growth performance