Table 3 Comparison of production efficiency in breeding pig farms with different PRRSV infection statuses

Sow death rate (%)

4.61 ± 3.45^c

7.06 ± 5.98^a

7.94 ± 4.66^b

−2.45

−3.33

−0.88

5.197 × 10^–15***

Repeat breeding rate (%)

6.07 ± 5.65^b

6.23 ± 5.12^b

7.37 ± 5.93^a

−0.16

−1.30

−1.14

0.003^**

Number of healthy piglets per litter

12.12 ± 1.14^a

12.16 ± 0.99^a

11.72 ± 0.77^b

−0.04

0.40

0.44

9.70 × 10^–9***

Number of stillbirths per litter

0.33 ± 0.20^b

0.38 ± 0.30^b

0.41 ± 0.29^a

−0.05

−0.08

−0.03

0.04^*

Stillbirth rate (%)

2.46 ± 1.39^b

2.70 ± 1.96^b

3.05 ± 2.05^a

−0.24

−0.59

−0.35

0.02^*

Number of mummies fetuses per litter

0.23 ± 0.09^c

0.28 ± 0.14^b

0.34 ± 0.19^a

−0.05

−0.09

−0.06

2.23 × 10^–11***

Mummies fetuses rate (%)

1.69 ± 0.65^c

2.01 ± 0.96^b

2.52 ± 1.43^a

−0.32

−0.83

−0.51

2.04 × 10^–12***

Delivery rate (%)

89.87 ± 5.91^a

88.82 ± 7.34^a

86.15 ± 9.68^b

1.05

3.72

2.67

1.11 × 10^–7***

Average weight of healthy piglets (kg)

1.36 ± 0.29^b

1.39 ± 0.33^a

1.35 ± 0.10^c

−0.03

0.01

0.04

1.06 × 10^–8***

Litters/mated female/year

2.12 ± 0.40

2.12 ± 0.45

2.19 ± 0.33

0.00

−0.07

−0.07

0.21

Healthy piglets/mated female/year

27.52 ± 6.33^a

27.73 ± 5.63^a

24.87 ± 6.90^b

−0.21

2.65

2.86

4.73 × 10^–7***

Mortality in the farrowing room (%)

6.79 ± 9.85^b

6.36 ± 8.01^b

7.78 ± 10.07^a

0.43

−1.01

−1.42

0.01^*

Number of weaned piglets per litter

11.23 ± 2.06^a

11.31 ± 1.39^a

10.68 ± 1.23^b

−0.08

0.55

0.63

2.74 × 10^–7***

Preweaning mortality by batch (%)

14.87 ± 9.97^ab

13.47 ± 8.40^b

15.27 ± 8.38^a

1.40

−0.40

−1.80

0.005^**

Average weaned weight (kg)

6.19 ± 0.49^c

6.54 ± 0.48^b

6.67 ± 0.43^a

−0.35

−0.48

−0.13

2.20 × 10^–16***

Weaned piglets/mated female/year

25.52 ± 5.90^a

25.88 ± 5.91^a

23.02 ± 6.43^b

−0.36

2.50

2.86

3.04 × 10^–7***

Weaned piglet cost (¥/head)

430.11 ± 57.54^b

438.64 ± 107.15^b

514.84 ± 208.61^a

−8.53

−84.73

−76.20

1.97 × 10^–6***