Table 1. Age at first calving, body weight prior to the first calving, and average daily gain from birth to first calving.
| AFC group * |
|||||
|---|---|---|---|---|---|
| Young (n = 23) |
Moderate (n = 67) |
Old (n = 52) |
Very old (n = 27) |
P-value | |
| Age when body weight reached 350 kg; months | 11.0 a (10 to 13) |
12.0 ab (10 to 14) |
12.0 ab (10 to 15) |
12.0 b (11 to 14) |
0.025 |
| Body weight at 12 months of age; kg | 375.0 a (342 to 436) |
368.0 ab (331 to 421) |
366.5 ab (307 to 446) |
355.0 b (321 to 409) |
0.040 |
| Age at first calving; months | 21.9 a (20.8 to 22.4) |
23.3 b (22.5 to 23.9) |
24.6 c (24.0 to 25.4) |
26.1 d (25.6 to 28.7) |
< 0.001 |
| Age at first calving; days | 666.0 a (634 to 684) |
709.0 b (685 to 728) |
747.5 c (730 to 775) |
793.0 d (779 to 872) |
< 0.001 |
| Body weight before the first calving; kg | 620.0 a (577 to 662) |
648.0 b (536 to 729) |
664.0 b, c (561 to 769) |
695.0 c (587 to 803) |
< 0.001 |
| Average daily gain from birth to first calving; kg per day § | 0.87 a (0.81 to 0.93) |
0.86 a (0.72 to 0.97) |
0.84 b, c (0.67 to 0.96) |
0.81 c (0.70 to 0.93) |
< 0.001 |
* Young, < 22.5 months; moderate, 22.5 to < 24.0 months; old, 24.0 to < 25.5 months; very old, ≥ 25.5 months of AFC. § Value = {(bodyweight of heifer before first calving) – (bodyweight of newborn calf)} ÷ AFC. a, b, c, d Values with different letters are significantly different (P < 0.05).