Table 3.

Effect of dietary Lys concentrations on growth performance of beef steers

	Treatment				P-value
	CON*	POS†	RPL||	SEM$	Trt
Body weight¶, kg
Day 0	307	308	307	4.0	0.98
Day 56	412a	391b	396b	6.3	0.05
Day 180	640a	610ab	602b	11.7	0.04
ADG**, kg/d
Days 0 to 28	1.78	1.73	1.66	0.14	0.80
Days 28 to 56	2.11a	1.43b	1.65b	0.14	0.01
Days 0 to 56	1.95x	1.58y	1.66xy	0.11	0.06
Days 56 to 180	1.81	1.77	1.66	0.08	0.27
Days 0 to 180	1.87a	1.70ab	1.66b	0.06	0.04
DMI††, kg/d
Days 0 to 56	8.9	8.1	8.5	0.36	0.39
Days 56 to 180	11.3	11.0	10.7	0.36	0.43
Daily NEg‡‡, Mcal/d
Days 0 to 56	12.0	10.4	11.4	-	-
Days 56 to 180	16.0	15.0	15.1	-	-
Metabolizable Lys supply||||, g/d
Days 0 to 56	44.7	51.5	55.4	-	-
Days 56 to 180	57.0	66.1	65.7	-	-
Metabolizable Lys balance||||, g/d
Days 0 to 56	−14.7	−2.0	−1.3	-	-
Days 56 to 180	−1.3	7.6	7.6	-	-
Gain:Feed
Days 0 to 56	0.230a	0.192b	0.193b	0.008	0.01
Days 56 to 180	0.160	0.161	0.155	0.006	0.76

*CON—diet formulated to be deficient in Lys.

^†POS—diet formulated to meet Lys requirements through feedstuffs.

^||RPL—diet formulated to meet Lys requirements through AjiPro-L (Ajinomoto Animal Nutrition North America, Eddyville, IA).

^$Standard error of the mean.

^¶Days 0, 56, and 180 BW are averages of two consecutive day weights. A 4% pencil shrink has been applied to all weights.

**ADG—average daily gain.

^††DMI—dry matter intake.

^‡‡Daily NE_g is the product of calculated NE_g and DMI.

^||||Daily metabolizable Lys supply and balance determined used the NASEM Beef Cattle Nutrient Requirements Model (2016).

^a,b,cMeans with different superscripts in the same row differ (P ≤ 0.05).

^x,y,zMeans with different superscripts in the same row tend to differ (0.05 < P ≤ 0.10).