Performance and Carcass Traits of Nellore and Nellore X Angus Steers Fed Whole Shelled Corn Diets

Diets with high proportion of concentrate or even diets without inclusion of forage began to be used on larger scale in South America feedlots. Moreover, number of Angus and Nellore crossbred steers is increasing in Brazil to produce better quality beef. Therefore, the objective of this study was to evaluate performance and carcass traits of Nellore and Nellore x Angus steers fed whole shelled corn diets. Thirty-two animals, with average BW of 353 ±25.3 kg were housed in individual pens and used in a completely randomized design using a 2 x 2 factorial arrangement (2 breeds and 2 diets). One diet containing 80% whole shelled corn and 20% of a pellet based on soybean meal and minerals (WSC; 15.1% CP and 2.84 Mcal/kg of ME). The other diet had 74% whole shelled corn, 20% of the same proteic-mineral pellet and 6% of sugarcane bagasse (WSCB; 14.7% CP and 2.75 Mcal/kg of ME). Feeding period was 116 d, with 20 d of adaptation period and 96 d of experimental period. Steers were fed individually and initial and final weighing was measured after 16 h of fasting. At the end of the feedlot, steers were slaughtered using cerebral concussion and slitting of the jugular vein and then carcass traits were measured. Statistical model included the effects of breed, diet and breed x diet interaction. Nellore x Angus steers had greater DMI, ADG, LM area and backfat thickness (BF; Table 1). However, Nellore steers had greater dressing percentage (DP; Table 1). Steers fed WSCB had greater DMI and tended to have greater ADG (Table 1). In conclusion, Angus x Nellore steers have greater ADG than Nellore, but they are not more efficient. The use of bagasse in WSC diets increases DMI and therefore ADG in feedlot steers. Funded by Fapemig and CNPq.

Table 1. Performance and carcass traits of Nellore and Nellore x Angus steers fed whole shelled corn diets.

Item	Nellore		Angus x Nellore		SEM	P Value
	WSC1	WSCB2	WSC	WSCB		Breed (B)	Diet (D)	B*D
DMI, kg	6.75	7.87	7.60	8.89	0.35	0.01	<0.01	0.82
ADG, kg day-¹	0.841	0.901	0.959	1.196	0.07	0.01	0.06	0.25
G:F	0.122	0.114	0.125	0.134	0.008	0.15	0.90	0.30
HCW, kg	246.18	246.44	247.25	253.87	6.90	0.53	0.61	0.64
LMA (cm2)	72.17	68.10	75.89	77.17	3.12	0.04	0.65	0.39
BF (mm)	6.80	5.55	8.20	7.77	0.58	<0.01	0.15	0.48
DP, %	57.90	56.41	54.88	53.63	0.53	<0.01	0.01	0.82