Table 4.
Results of mixed effects ordinal regression models for the effect of type of ration, calving number, season, lactation phase and energy corrected milk (explanatory variables) on mean amounts of myristic (C14:0), palmitic (C16:0), stearic (C18:0), oleic (C18:1), saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) and short chain fatty acid (SCFA) (g/100 g fatty acids) (dependent variables) in milk samples from dairy cows in Galicia (NW Spain). The regression coefficients—provided with their 95% confident intervals (CI)—indicate the likelihood of being in a higher category of the dependent variable when each category of explanatory variables is compared with the reference one (base). Random-effects cluster variance is provided (along with standard deviation (SD)).
| C14:0 | C16:0 | C18:0 | C18:1 | SFA | MUFA | PUFA | SCFA | |
|---|---|---|---|---|---|---|---|---|
| Variance (SD) |
Variance (SD) |
Variance (SD) | Variance (SD) | Variance (SD) |
Variance (SD) | Variance (SD) | Variance (SD) | |
| Herd | 0.90 (0.95) | 0.60 (0.77) | 0.68 (0.83) | 1.06 (1.03) | 1.20 (1.09) | 1.18 (1.08) | 0.92 (0.96) | 0.65 (0.80) |
| Herd:animal | 1.45 (1.20) | 1.40 (1.18) | 1.34 (1.16) | 1.31 (1.15) | 1.65 (1.28) | 1.69 (1.30) | 1.37 (1.17) | 0.86 (0.93) |
| Coefficients (CI) |
Coefficients (CI) |
Coefficients (CI) |
Coefficients (CI) |
Coefficients (CI) |
Coefficients (CI) |
Coefficients (CI) |
Coefficients (CI) |
|
| Feeding † | ||||||||
| Grass silage | 1.45 (0.50—4.16) |
1.26 (0.52–2.99) |
0.56 (0.22–1.41) |
1.42 (0.42–4.75) |
0.76 (0.26–2.19) |
|||
| Corn silage | 3.73 ** (1.30–10.65) |
5.54 ** (2.33–13.12) |
0.40* (0.16–1.00) |
4.76 ** (1.43–15.78) |
0.16 ** (0.05–0.45) |
|||
| Grass/Corn silage | 4.02 ** (1.40–11.46) |
3.61 ** (1.52–8.52) |
0.34 ** (0.13–0.84) |
3.66 ** (1.10–12.13) |
0.16 ** (0.05–0.47) |
|||
| Calving number ‡ | ||||||||
| 2nd | 0.99 (0.83–1.17) |
1.46 ** (1.23–1.71) |
0.87 (0.74–1.02) |
0.66 ** (0.55–0.77) |
1.81 ** (1.52–2.14) |
0.68 ** (0.57–0.81) |
0.74 ** (0.62–0.87) |
1.30 ** (1.10–1.52) |
| 3rd or higher | 0.57 ** (0.47–0.68) |
1.04 (0.87–1.23) |
1.21 ** (1.02–1.44) |
0.76 ** (0.63–0.89) |
1.68 ** (1.40–2.02) |
0.78 ** (0.65–0.94) |
0.99 (0.84–1.18) |
1.63 ** (1.39–1.91) |
| Season§ | ||||||||
| Summer | 2.20 ** (1.91–2.51) |
1.92 ** (1.68–2.18) |
1.12 (0.98–1.28) |
0.97 (0.85–1.10) |
1.45 ** (1.27–1.66) |
0.83 ** (0.72–0.94) |
0.59 ** (0.52–0.67) |
0.37 ** (0.32–0.42) |
| Autumn | 2.32 ** (2.05–2.61) |
1.81 *** (1.61–2.03) |
0.52 ** (0.46–0.58) |
0.75 ** (0.67–0.84) |
1.50 ** (1.33–1.69) |
0.69 ** (0.61–0.77) |
0.24 ** (0.21–0.27) |
0.97 (0.85–1.09) |
| Winter | 1.36 ** (1.21–1.52) |
1.36 ** (1.22–1.51) |
0.53 ** (0.47–0.59) |
0.52 ** (0.46–0.57) |
1.39 ** (1.25–1.65) |
0.58 ** (0.52–0.65) |
0.40 ** (0.35–0.44) |
0.78 ** (0.69–0.88) |
| Lactation phase ¶ | ||||||||
| Fresh (BHB ≥ 0.10 mM/L) | 0.27 ** (0.13–0.55) |
0.46 ** (0.29–0.73) |
4.40 ** (1.61–11.97) |
4.84 ** (2.92–8.00) |
0.24 ** (0.14–0.39) |
5.72 ** (3.42–9.55) |
0.32 ** (0.21–0.46) |
0.06 ** (0.03–0.10) |
| Peak | 13.90 ** (11.01–17.5) |
9.15 ** (7.52–11.12) |
0.04 ** (0.03–0.05) |
0.14 ** 0.11–0.16 |
6.94 ** 5.70–8.45 |
0.15 ** 0.12–0.18 |
0.30 ** 0.25–0.36 |
1.73 ** 1.41–2.11 |
| Mid | 116.56 ** (91.85–147.65) |
18.88 ** (15.59–22.86) |
0.01 ** (0.00–0.07) |
0.05 ** (0.04–0.06) |
16.23 ** (13.38–19.68) |
0.06 ** (0.05–0.07) |
0.19 ** (0.15–0.22) |
1.48 ** (1.22–1.78) |
| Late | 126.28 ** (98.58–161.08) |
9.23 ** (7.57–11.25) |
0.01 ** (0.00–0.05) |
0.07 ** (0.06–0.09) |
9.17 ** (7.50–11.21) |
0.11 ** (0.08–0.13) |
0.23 ** (0.19–0.27) |
1.03 (0.84–1.25) |
| Energy corrected milk yield (Kg) | 1.05 ** (1.04–1.05) |
1.00 (0.99–1.00) |
0.96 ** (0.95–0.97) |
0.95 ** (0.93–0.95) |
1.03 ** (1.02–1.04) |
0.94 ** (0.93–0.95) |
0.99 ** (0.98–0.99) |
1.05 ** (1.04–1.06) |
† Pasture is the base; ‡ 1st is the base; § Spring is the base; ¶ Fresh (BHB < 0.10 mM/L) is the base; * p ≤ 0.05; ** p < 0.01; *** p < 0.001.