Table 3.
Effects of deleting Lysine (Lys), Methionine (Met), and Threonine (Thr) levels in corn–soybean based TMR on the growth performance of heifers aged seven to nine months old (n = 72).
| Items 1 | Treatments 2 | SEM | p Value 3 | |||||
|---|---|---|---|---|---|---|---|---|
| PD–Lys | PD–Met | PD–Thr | PC | T | M | T × M | ||
| BW, kg | ||||||||
| Average | 273.7 | 273.9 | 276.3 | 274.8 | 2.98 | 0.4798 | <0.0001 | <0.0001 |
| 6 mon | 227.5 | 227.0 | 229.9 | 228.5 | 4.08 | 0.4647 | ||
| 7 mon | 258.0 | 257.8 | 259.3 | 257.6 | 4.00 | 0.7016 | ||
| 8 mon | 282.7 | 284.3 | 282.5 | 280.3 | 4.52 | 0.3667 | ||
| 9 mon | 326.4 | 326.8 | 333.4 | 333.0 | 4.02 | 0.0997 | ||
| ADG, kg | ||||||||
| Average | 1.04 | 1.09 | 1.09 | 1.11 | 0.029 | 0.1566 | <0.0001 | <0.0001 |
| 6–7 mon | 0.98 | 1.02 | 0.94 | 0.95 | 0.075 | 0.2848 | ||
| 7–8 mon | 0.95 | 0.95 | 0.90 | 0.89 | 0.079 | 0.4946 | ||
| 8–9 mon | 1.21 c | 1.30 bc | 1.44 ab | 1.48 a | 0.080 | 0.0013 | ||
| DMI, kg | ||||||||
| Average | 7.15 | 7.16 | 7.16 | 7.05 | 0.050 | 0.1073 | <0.0001 | <0.0001 |
| 6–7 mon | 6.25 | 6.20 | 6.26 | 6.28 | 0.091 | 0.2942 | ||
| 7–8 mon | 6.99 | 6.98 | 6.94 | 6.84 | 0.089 | 0.0916 | ||
| 8–9 mon | 8.21 | 8.28 | 8.16 | 8.25 | 0.088 | 0.2297 | ||
| Feed conversion rate, G/F | ||||||||
| Average | 0.146 | 0.152 | 0.152 | 0.156 | 0.008 | 0.1452 | 0.0001 | 0.0002 |
| 6–7 mon | 0.156 | 0.164 | 0.151 | 0.155 | 0.011 | 0.2138 | ||
| 7–8 mon | 0.135 | 0.134 | 0.127 | 0.130 | 0.010 | 0.5009 | ||
| 8–9 mon | 0.147 c | 0.158 bc | 0.176 ab | 0.181 a | 0.012 | 0.0057 | ||
1 BW=body weight, ADG=average daily gain, DMI=dry matter intake; 2 Treatments: PC = theoretical amino acid balance TMR; PD–Lys = 30% Lys deleted TMR; PD–Met = 30% Met deleted TMR; PD–Thr h = 30% Thr deleted TMR; 3 T = Treatment, M = Month of age, T × M = The interaction between treatment and month of age; a,b,c values within the same row with different superscripts are different (p < 0.05).