Figure 1.
Figure 1.

Plasma IGF-I concentrations (±SEM) of heifers receiving subcutaneous injections containing 250 mg of bovine ST (BST; sometribove zinc; n = 25; Posilac, Elanco, Greenfield, IN) or 5 mL of saline (0.9%; control; n = 25). Treatments were administered every 14 d beginning on d 14 until d 196 of the experimental period (d 0 to 210). Values obtained from samples collected on d 0 and 7 served as covariate (P < 0.01) but did not differ (P = 0.35) between BST and control heifers (50.4 vs. 48.0 ng/mL, respectively; SEM = 1.8). Therefore, results reported are covariately adjusted least squares means. A treatment × day interaction was detected (P < 0.01). Days on which treatments were administered are underlined. Treatment comparison within time: **P < 0.01.

 


Figure 2.
Figure 2.

Puberty attainment (±SEM) of heifers receiving subcutaneous injections containing 250 mg of bovine ST (BST; sometribove zinc; n = 25; Posilac, Elanco, Greenfield, IN) or 5 mL of saline (0.9%; control; n = 25). Treatments were administered every 14 d beginning on d 14 until d 196 of the experimental period (d 0 to 210). Heifers were considered pubertal once plasma progesterone concentrations were greater than 1.0 ng/mL for 2 consecutive weeks, and puberty attainment was declared at the second week of increased progesterone. A treatment × day interaction was detected (P = 0.04). Treatment comparison within days: **P < 0.01, *P = 0.03, and †P = 0.10.