Table 4.
Performance indicators and blood metabolites (adjusted least squares means: 4 wk intervals) of first lactation Holstein-Friesian dairy cows within three fat-to-protein ratio scores in milk during early lactation (1–20 WIM).
| WIM/Item 1 | n | FPR score 2 | s.e.m | p-Value | ||
|---|---|---|---|---|---|---|
| <1.0 | 1.0–1.5 | >1.5 | ||||
| Weeks 1–4 of lactation | ||||||
| DMI, kg/day | 1639 | 13.4 ba | 13.7 a | 13.0 b | 0.38 | <0.001 |
| ECM, kg/day | 1603 | 22.0 c | 25.6 b | 27.4 a | 0.55 | <0.001 |
| Milk fat, g/kg | 1639 | 34.0 c | 43.3 b | 54.1 a | 0.55 | <0.001 |
| Milk protein, g/kg | 1639 | 36.9 a | 34.5 b | 33.4 c | 0.36 | <0.001 |
| BCS, units | 1097 | 2.67 | 2.65 | 2.66 | 0.039 | 0.387 |
| BW change 3, kg/wk. | 1246 | −2.72 a | −5.32 a | −9.67 b | 0.947 | <0.001 |
| lnBHB 4 | 845 | 0.38 b | 0.44 b | 0.55 a | 0.024 | <0.001 |
| lnNEFA 4 | 843 | 0.32 c | 0.39 b | 0.45 a | 0.029 | 0.001 |
| EB 5, MJ of ME/day | 1554 | −6.89 a | −19.3 b | −39.4 c | 4.712 | <0.001 |
| Weeks 5–8 of lactation | ||||||
| DMI, kg/day | 1884 | 16.0 a | 15.9 a | 15.5 b | 0.36 | 0.021 |
| ECM, kg/day | 1881 | 26.4 c | 28.4 b | 30.3 a | 0.55 | <0.001 |
| Milk fat, g/kg | 1884 | 32.1 c | 40.2 b | 49.1 a | 0.38 | <0.001 |
| Milk protein, g/kg | 1884 | 32.5 a | 32.1 b | 31.3 c | 0.28 | <0.001 |
| BCS, units | 1384 | 2.56 | 2.56 | 2.58 | 0.034 | 0.084 |
| BW change, kg/wk. | 1839 | 2.71 a | 1.45 a | −2.16 b | 0.686 | <0.001 |
| lnBHB | 1034 | 0.41 c | 0.46 b | 0.52 a | 0.040 | <0.001 |
| lnNEFA | 1037 | 0.32 b | 0.34 b | 0.38 a | 0.030 | 0.009 |
| EB, MJ of ME/day | 1851 | 3.53 a | −9.16 b | −23.7 c | 4.44 | <0.001 |
| Weeks 9–12 of lactation | ||||||
| DMI, kg/day | 1889 | 17.1 a | 17.0 a | 16.1 b | 0.40 | <0.001 |
| ECM, kg/day | 1889 | 26.5 c | 28.4 b | 29.5 a | 0.55 | <0.001 |
| Milk fat, g/kg | 1889 | 32.9 c | 40.0 b | 47.5 a | 0.42 | <0.001 |
| Milk protein, g/kg | 1889 | 33.3 a | 32.5 b | 31.5 c | 0.29 | <0.001 |
| BCS, units | 1385 | 2.52 | 2.52 | 2.52 | 0.032 | >0.500 |
| BW change, kg/wk | 1860 | 4.06 a | 2.19 b | −0.55 c | 0.633 | <0.001 |
| lnBHB | 881 | 0.38 b | 0.43 a | 0.43 a | 0.020 | <0.001 |
| lnNEFA | 878 | 0.25 | 0.26 | 0.28 | 0.032 | >0.500 |
| EB, MJ of ME/day | 1869 | 14.6 a | 3.74 b | −13.6 c | 4.17 | <0.001 |
| Weeks 13–16 of lactation | ||||||
| DMI, kg/day | 1816 | 17.2 ba | 17.3 a | 16.8 b | 0.42 | 0.011 |
| ECM, kg/day | 1816 | 26.4 c | 28.2 b | 29.4 a | 0.54 | <0.001 |
| Milk fat, g/kg | 1816 | 33.3 c | 40.5 b | 47.7 a | 0.43 | <0.001 |
| Milk protein, g/kg | 1816 | 34.0 a | 33.3 b | 32.2 c | 0.30 | <0.001 |
| BCS, units | 1358 | 2.51 | 2.51 | 2.51 | 0.030 | >0.500 |
| BW change, kg/wk | 1789 | 3.08 | 2.12 | 0.40 | 0.661 | 0.101 |
| lnBHB | 563 | 0.35 b | 0.43 a | 0.46 a | 0.024 | <0.001 |
| lnNEFA | 562 | 0.20 | 0.23 | 0.23 | 0.040 | 0.226 |
| EB, MJ of ME/day | 1796 | 14.1 a | 7.05 b | −6.82 c | 4.07 | <0.001 |
| Weeks 17–20 of lactation | ||||||
| DMI, kg/day | 1645 | 17.3 | 17.5 | 17.0 | 0.42 | 0.051 |
| ECM, kg/day | 1644 | 26.5 c | 27.7 b | 28.8 a | 0.65 | <0.001 |
| Milk fat, g/kg | 1645 | 34.7 c | 40.9 b | 48.8 a | 0.53 | <0.001 |
| Milk protein, g/kg | 1645 | 34.5 a | 33.7 b | 32.5 c | 0.28 | <0.001 |
| BCS, units | 1296 | 2.53 a | 2.53 a | 2.48 b | 0.026 | 0.017 |
| BW change, kg/wk. | 1628 | 2.45 | 1.74 | −0.23 | 0.711 | 0.136 |
| lnBHB | 377 | 0.38 b | 0.48 a | 0.48 a | 0.064 | <0.001 |
| lnNEFA | 377 | 0.21 | 0.19 | 0.22 | 0.040 | 0.481 |
| EB, MJ of ME/day | 1637 | 14.3 a | 10.2 a | −0.92 b | 3.461 | <0.001 |
a,b,c Means within a row with different superscripts differ (p ≤ 0.05) within FPR scores; 1 weeks in milk/ stage of lactation; ECM—Energy-corrected milk; FPR—fat-to-protein ratio; 2 FPR score—fat-to-protein ratio in milk; <1.0 = ‘Low’; 1.0–1.5 = ‘Normal’; >1.5 = ‘High’; 3 BW change represents the difference between current and previous BW at each week postpartum; 4 values for blood metabolites were natural log transformed; 5 EB—energy balance estimated according to equations within ‘Feed into Milk’ [36].