Table 1 Reproductive parameters (WEI; LBP, live born piglets; SBP, stillborn piglets; MM, mummies) and reproduction indicators (ER, estrus rate; FR, farrowing rate; FEI, farrowing efficiency index; LPI, live piglet index) for both treatment groups (C-group, control group, n = 289; P-group, peforelin-treated group, n = 279) and different parity groups (gilts, 1st parity sows, 2^nd–4^th parity sows and 5+ parity sows), expressed as means ± SEM and their significance level

WEI overall

6.11 ± 0.33

6.82 ± 0.44

P > 0.05

WEI ≤ 7 d pw

5.08 ± 0.26

5.10 ± 0.34

P > 0.05

LBP

14.7 ± 0.20

14.4 ± 0.19

P > 0.05

 LBP – gilts

13.76 ± 0.49

13.95 ± 0.47

P > 0.05

 LBP – 1^st parity

14.47 ± 0.61

13.39 ± 0.53

P > 0.05

 LBP – 2^nd–4^th parity

15.07 ± 0.22

14.73 ± 0.23

P > 0.05

 LBP – 5+ parity

13.40 ± 0.079

13.83 ± 0.54

P > 0.05

SBP

0.18 ± 0.07

0.80 ± 0.08

P > 0.05

MM

0.38 ± 0.07

0.28 ± 0.04

P > 0.05

ER

87.2 %

93.2 %

P < 0.05

FR

81.3 %

85.7 %

P > 0.05

FEI

70.9 %

79.9 %

P < 0.05

 FEI – gilts

42.9 %

82.6 %

P < 0.0001

 FEI – 1^st parity

65.5 %

74.2 %

P > 0.05

 FEI – 2^nd–4^th parity

78.5 %

82.5 %

P > 0.05

 FEI – 5+ parity

71.4 %

68.5 %

P > 0.05

LPI

1032

1151

P < 0.01

 LPI – gilts

590

1152

P < 0.0001

 LPI – 1^st parity

948

994

P > 0.05

 LPI – 2^nd–4^th parity

1183

1215

P > 0.05

 LPI – 5+ parity

957

947

P > 0.05