Evaluation of 2 sugarcane molasses feeding strategies on measures of growth and reproductive performance of replacement beef heifers

Abstract

ABSTRACT Our objectives were to compare the effects of 2 sugarcane molasses feeding strategies on growth (Exp. 1 and 2), reproductive performance (Exp. 1), and forage intake (Exp. 2) of replacement beef heifers. In Exp. 1 and 2, treatments consisted of cottonseed meal manually mixed with molasses in a slurry form (SLU), or cottonseed meal and molasses provided in separate bunks (SEP). In Exp. 1, 48 Brangus-crossbred heifers (BW = 236 ± 4 kg; age = 335 ± 5 d) were randomly assigned to 1 of 12 bahiagrass pastures (4 heifers per pasture; 6 pastures per treatment). Each pasture received 31.8 kg of molasses and 6.4 kg of cottonseed meal (as fed) twice weekly from d 0 to 70. In Exp. 2, Braford heifers were randomly assigned into 1 of 16 drylot pens to evaluate the daily hay DMI of heifers offered SEP or SLU supplementation twice weekly from d 0 to 21. Effects of treatment and treatment × day were not detected for BW and ADG of heifers in Exp. 1 and 2 ( P ≥ 0.27). In Exp. 1, overall pregnancy rates were similar ( P = 0.55), but puberty achievement tended to be greater for SLU versus SEP heifers ( P = 0.10). In Exp. 2, G:F and hay DMI did not differ between treatments ( P ≥ 0.21). Therefore, cottonseed meal and sugarcane molasses can be offered separately rather than in a slurry form without affecting growth, forage intake, and reproductive performance of grazing replacement beef heifers during breeding season.