Table 2.
Description of the variables used to estimate yield efficiency and causes for inefficiency in Manchega sheep milk (n = 967).
| Variable | Description | Units | Mean | S.D. |
|---|---|---|---|---|
| Yield efficiency | ||||
| CY (Y1) | Curd yield | g/100 mL | 26.80 | 6.10 |
| DCY (Y2) | Dried curd yield | g/100 mL | 11.18 | 2.34 |
| WR (Y3) | Water retention (CY-DCY) | g/100 mL | 15.71 | 4.11 |
| Fat (X1) | Fat content in milk | g/100 mL | 6.48 | 1.84 |
| CP (X2) | Protein content in milk | g/100 mL | 5.69 | 0.81 |
| Random factors | ||||
| Flock (F1) | Flock of origin | 1 to 4 | - | - |
| Fixed factors | ||||
| SOL (F2) | Stage of lactation | 1 to 3 | - | - |
| Syneresis (F3) | If A60 < Amax | Yes or no | - | - |
| Prolificacy (F4) | Number of lambs | 1 to 3 | - | - |
| Season (F5) | Season of lambing | Autumn or spring | - | - |
| Parity (F6) | Lactation number | 2 to 5 or more | - | - |
| Covariable factors | ||||
| DMY (F7) | Daily milk yield | mL | 1.093 | 474.3 |
| pH (F8) | pH | −log[H+] | 6.61 | 0.29 |
| SCS (F9) | Somatic cell score | log10 (103 cells/mL) | 5.24 | 0.62 |
| WTS (F10) | Whey total solids | % | 11.19 | 2.47 |
| TS (F11) | Milk total solids | g/100 mL | 17.95 | 2.36 |
| Lac (F12) | Lactose content in milk | g/100 mL | 4.88 | 0.38 |
| Cas (F13) | Casein content in milk | g/100 mL | 4.51 | 0.69 |
| RCT (F14) | Rennet clotting time | min | 21.39 | 11.48 |
| A60 (F15) | Curd firmness at 60 min. | mm | 38.26 | 11.11 |
| Amax (F16) | Maximum curd firmness | mm | 42.14 | 9.16 |
| k20 (F17) | Rate of curd aggregation | min | 24.72 | 12.40 |
| L* (F18) | Lightness | [0, 100] | 82.66 | 2.34 |
| a* (F19) | Red/Green value | [−60, +60] | −2.55 | 0.81 |
| b* (F20) | Blue/Yellow value | [−60, +60] | 5.51 | 1.65 |
| C* (F21) | Chroma or saturation | (a*2 + b*2)1/2 | 4.67 | 2.05 |
| h* (F22) | Hue | tan−1 (b*/a*) | −0.55 | 0.28 |