Table 7.

Main effects of MS and backgrounding estradiol benzoate and progesterone on cumulative and carcass adjusted performance in steer calves fed for 168 d in Exp. 2^a

	Mature sizeb			Implantc			Pooled
Item	SMS	LMS	P value	NI	SS	P value	SEM
n, steers	79	79	–	80	78	–	–
n, pens	10	10	–	10	10	–	–
Live weight basis
Initial body weight, kg	308	371	<0.01	339	340	0.04	0.3
Final body weight, kg	587	660	<0.01	618	629	<0.01	1.9
Average daily gain, kg	1.66	1.72	<0.01	1.66	1.72	<0.01	0.012
Dry matter intake, kg	10.04	11.26	<0.01	10.48	10.83	<0.01	0.042
Dry matter intake/MBSd, g/kg	103.2	104.1	0.10	102.4	104.9	<0.01	0.34
Gain:feed	0.165	0.153	<0.01	0.159	0.159	0.78	0.0009
GEDe, Mcal/kg	5.04	5.47	<0.01	5.23	5.28	0.24	0.033
Carcass-adjusted basis
Final body weightf, kg	581	663	<0.01	616	628	<0.01	1.6
Average daily gain, kg	1.63	1.74	<0.01	1.65	1.71	<0.01	0.010
Gain:feed	0.162	0.154	<0.01	0.158	0.158	0.71	0.0009

^aShrink (3%) was applied to all body weights.

^bSMS, smaller mature size; LMS, larger mature size.

^cNI, nonimplanted during backgrounding-phase, implanted with 24 mg estradiol and 120 mg trenbolone acetate on d 85; SS, implanted with 20 mg estradiol benzoate and 200 mg progesterone on d 2 and with 24 mg estradiol and 120 mg trenbolone acetate on d 85.

^dMBS, metabolic body size, calculated as kg of body weight^3/4 (Kleiber, 1961).

^eGED, gain energy density, calculated as estimated retained energy divided by ADG.

^fCalculated as HCW divided by 0.625.