Abstract #T426

# T426
Evaluation of camelina meal as a feedstuff for growing dairy heifers.
Rhea D. Lawrence*1, Jill L. Anderson1, 1Dairy Science Department, South Dakota State University, Brookings, SD.

Our objective was to evaluate growth performance of dairy heifers fed camelina meal (CM) compared with linseed meal (LN) or reduced-fat distillers dried grains with solubles (DG). A 12-wk randomized complete block design study was conducted using 33 Holstein and 9 Brown Swiss heifers (144.8 ± 22 d of age; body weight (BW) 171.8 ± 24.3 kg) with 3 treatments. Treatments were 10% of the diet as CM, LN, or DG (DM basis). Concentrate mixes also included corn and soybean meal, at slightly different inclusion rates to make diets isocaloric and isonitrogenous. All diets contained 60% grass hay and 40% concentrate mix. Diets were limit-fed to 2.65% of BW (DM basis) using a Calan gate feeding system. Frame sizes, BW, and body condition scores (BCS) were measured on 2 d during wk 0, 2, 4, 6, 8, 10, and 12. Data were analyzed using MIXED procedures with repeated measures and ADG was found using REGRESSION procedures of SAS 9.4. Heifer DMI was similar between CM and LN, but greater (P = 0.03) for DG (4.83, 4.82, and 5.03 kg/d; SEM = 0.17 for CM, LN, and DG, respectively). Body weights (199.5, 210.9, and 205.1 kg; SEM = 2.86) were found to be less (P < 0.01) for heifers fed CM and greatest for LN, which could be due to unequal initial BW. Treatments had similar (P > 0.05) ADG (0.67, 0.75, 0.71 kg/d; SE = 0.15). Gain to feed was similar for CM and DG, but greater (P < 0.05) for LN (0.14, 0.17, 0.15 kg/d; SEM = 0.006). Hip height (116.3, 115.8, and 115.4 cm; SEM = 0.67), withers height (112.3, 112.3, and 112.4 cm; SEM = 0.47), and heart girth (128.6, 128.3, and 128.9 cm; SEM = 0.81) were similar (P > 0.05) among treatments. Hip width (31.7, 31.3, and 31.4 cm; SEM = 0.27) and body length (105.2, 102.0, and 103.3 cm; SEM = 0.77) were greater (P < 0.05) for CM compared with LN and DG. Body condition score (3.16, 3.10, and 3.17; SEM = 0.02) was greater (P < 0.01) for CM and DG compared with LN. Feeding CM maintained frame growth and ADG but decreased gain to feed compared with DG and LN. The decreased feed efficiency may be related to glucosinolates in the CM. Further research should be conducted before implementing CM as a primary protein source for growing heifers.

Key Words: camelina meal, dairy heifer