Table 4.

Abundance of receptor mRNA associated with skeletal muscle growth from longissimus thoracis skeletal muscle of feedlot steers of different cattle breed types following implanting

Steers (n)	Implant and breed treatments1				SEM	P-values2
Gene3	AN-IMP	SG-IMP	AN-CON	SG-CON		Breed	Trt	B × T
	5	5	5	5
OXTR
Day 2	56.58	19.56	69.90	99.98	50.91	0.94	0.24	0.37
Day 10	0x	23.21xy	0x	88.58y	32.01	0.03	0.15	0.31
IGF-1R
Day 2	59.65	23.46	25.83	18.00	14.00	0.15	0.19	0.35
Day 10	21.75	23.01	31.87	37.65	10.08	0.72	0.19	0.80
VDR
Day 2	77.05	25.26	62.18	104.46	48.13	0.92	0.47	0.29
Day 10	6.93a	22.91a	4.66a	114.93b	22.54	0.01	0.04	0.03

Implant treatments administered on day 0 include the following: no implant +Angus (AN-CON), no implant + Santa Gertrudis (SG-CON), Revalor-S + Angus (AN-IMP; 120 mg trenbolone acetate + 24 mg estradiol) and Revalor-S + Santa Gertrudis (SG-IMP; 120 mg trenbolone acetate + 24 mg estradiol).

P-values indicate the effect of Breed, Treatment (TRT), or B × T (Breed × Treatment). Skeletal muscle biopsies were collected on day 2 and 10 post-implanting, and RNA isolation and quantitative PCR were performed as described in the Materials and Methods.

OXTR, oxytocin receptor; IGF-1R, insulin-ike growth factor 1 receptor; VDR, vitamin D receptor.

Different letters indicate a difference (P < 0.05) between time points.

Different letters indicate a tendency between time points (0.05 < P ≤ 0.10). All data are presented as the least square means ± SEM.

Italics indicate P-values for the different effects (breed, trt and trtxbreed).