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. 2019 Jun 12;97(8):3399–3414. doi: 10.1093/jas/skz200

Table 7.

Effect of increasing SID CP on milk yield and milk composition at 3, 10, 17, and 24 DIM (n = 72)

Dietary treatment, SID CP g/kg1 DIM P-value2,3
92 107 116 125 135 149
Item 1 2 3 4 5 6 SEM 3 10 17 24 SEM Trt DIM Trt × DIM Lin Quad
Milk yield, kg/d4 11.4b 12.3ab 12.5ab 13.1a 12.8a 12.9a 0.53 7.0c 13.0b 14.9a 15.1a 0.53 <0.01 <0.001 <0.05 *** *
DM, % 17.7 17.9 18.4 18.3 18.0 18.0 0.35 19.1a 18.2b 17.6c 17.3c 0.35 0.22 <0.001 0.37 NS †
Lactose, % 5.20 5.15 5.11 5.12 5.15 5.13 0.05 4.96d 5.07c 5.23b 5.30a 0.05 0.30 <0.001 0.25 NS NS
Fat, % 7.29 7.35 7.63 7.47 7.01 6.96 0.35 8.10a 7.63a 6.94b 6.47c 0.35 0.13 <0.001 <0.10 NS †
Protein, % 4.35e 4.62d 4.76cd 4.90bc 5.10ab 5.27a 0.11 5.34a 4.59c 4.62c 4.78b 0.11 <0.001 <0.001 <0.001 *** NS
Casein, % 3.28e 3.57d 3.69cd 3.84bc 4.04ab 4.14a 0.10 4.19a 3.54c 3.57c 3.74b 0.10 <0.001 <0.001 < .001 *** NS
Urea, mg/dL 6.29bc 6.48abc 6.05c 6.52abc 7.24ab 7.49a 0.28 4.68c 6.46b 7.79a 7.78a 0.18 <0.01 <0.001 < .05 *** †
Energy, MJ/kg5 4.72 4.80 4.94 4.90 4.80 4.80 0.13 5.24a 4.89b 4.65c 4.53c 0.13 0.37 <0.001 0.26 NS †
Concentration, g/100 g CP
 Total AA 89.9 89.5 90.3 90.2 90.2 90.4 0.50 90.3 89.7 90.3 – 0.41 0.63 0.24 0.15 NS NS
 EAA 40.8b 40.7b 41.5ab 41.7ab 42.0a 42.3a 0.30 42.3a 41.1b 41.1b – 0.20 <0.001 <0.001 <0.001 *** NS
 NEAA 49.1 48.8 48.7 48.6 48.2 48.2 0.31 48.0b 48.6b 49.2a – 0.24 <0.10 <0.001 0.56 ** NS
Response Model6 DIM BP7 Equation P-value8
 Milk yield, kg/d LB 17 120 ± 6.9 Yi = 15.5 − 0.09 × (120 − Xi) for Xi < 120 <0.05
LB 24 125 ± 10 Yi = 15.9 − 0.08 × (125 − Xi) for Xi < 125 0.06
 Fat, % LB 10 116 ± 8.3 Yi = 8.01 − 0.04 × (Xi − 116) for Xi >116 <0.05
 Protein, % L 3 Yi = 5.2 + 0.009 × (Xi − 92) for Xi > 92 <0.05
L 10 Yi = 4.0 + 0.02 × (Xi − 92) for Xi > 92 <0.001
LB 17 138 ± 4.5 Yi = 5.1 − 0.02 × (138 − Xi) for Xi < 138 <0.001
L 24 Yi = 4.3 + 0.02 × (Xi − 92) for Xi > 92 <0.001
 Casein, % L 3 Yi = 4.1 + 0.007 × (Xi − 92) for Xi > 92 <0.001
L 10 Yi = 2.9 + 0.02 × (Xi − 92) for Xi > 92 <0.001
LB 17 135 ± 4.0 Yi = 3.97 − 0.02 × (135 − Xi) for Xi < 135 <0.001
L 24 Yi = 3.3 + 0.02 × (Xi − 92) for Xi > 92 <0.001
 Urea, AU9 LB 10 118 ± 7.8 Yi = 5.84 + 0.07 × (Xi − 118) for Xi > 118 <0.05
LB 17 115 ± 9.5 Yi = 7.07 + 0.05 × (Xi − 115) for Xi > 115 <0.05
LB 24 111± 9.5 Yi = 7.12 + 0.04 × (Xi − 111) for Xi > 111 <0.05
 EAA, g/100 g CP L 10 Yi = 39.9 + 0.04 × (Xi − 92) for Xi > 92 <0.01
LB 17 132 ± 4.8 Yi = 42.0 − 0.06 × (132 − Xi) for Xi < 132 <0.01

abcdWithin a row, values without common superscript letters, differ (P < 0.05).

1Treatments 1 through 6: The calculated mean SID CP content for the dietary treatment fed to sows in the given treatment group.

2 P-values for the dietary treatment (Trt) and DIM are from the ANOVA test using the MIXED procedure of SAS.

3Orthogonal polynomial contrasts were used to evaluate linear (lin) and quadratic (quad) effects of SID CP: NS = not significant, †<0.10, *<0.05, **<0.01, ***<0.001.

4Milk yield was estimated using equations from Hansen et al. (2012).

5Gross energy of milk was estimated, using the equation: GE (MJ/kg) = (38.9, MJ/kg × milk fat, % + 23.8, MJ/kg × milk protein, % + 16.3, MJ/kg × lactose, %)/100%, given by Chwalibog (2006)

6Best fitting model, L = linear line, LB = linear broken-line.

7BP = breakpoint for the linear broken-line.

8The P-value for the slope where P-values below 0.15 were accepted.

9Urea in milk was measured in arbitrary units (AU) because the instrument was not calibrated.