Table 2. Longevity traits and lifetime productivity until the end of the third lactation for the four AFC groups *.
| AFC group * |
|||||
|---|---|---|---|---|---|
| Young (n = 23) |
Moderate (n = 67) |
Old (n = 52) |
Very old (n = 27) |
P-value | |
| Proportion of cows with three or more calving | 60.9% (14) | 41.8% (28) | 34.6% (18) | 33.3% (9) | 0.154 |
| Number of parities § | 3.0 e (1 to 3) |
2.0 ef (1 to 3) |
1.5 f (1 to 3) |
2.0 ef (1 to 3) |
0.090 |
| Productive period; days | 693.0 (50 to 977) |
601.0 (0 to 1,038) |
315.5 (0 to 1,041) |
481.0 (0 to 878) |
0.123 |
| Non-productive period; days | 844.0 ab (661 to 1,047) |
785.0 a (691 to 1,062) |
770.5 a (730 to 1,206) |
907.0 b (779 to 1,277) |
<0.001 |
| Cumulative actual milk yield of life (kg) | 24,682 (1,282 to 28,633) |
17,401 (784 to 32,127) |
10,074 (395 to 34,896) |
15,020 (2,443 to 28,391) |
0.256 |
| Overall lifetime milk yield (per day, kg) | 14.3 (1.8 to 16.4) |
11.9 (0.0 to 17.2) |
8.7 (0.0 to 18.4) |
9.9 (0.0 to 16.6) |
0.090 |
* 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. a, b Values with different letters are significantly different (P < 0.05). e, f Values with different letters tended to be different (P < 0.1). § The maximum value was set to 3.