Projektinformation
Beskrivning (abstrakt)
We hypothesized that prolonged farrowing decreases subsequent fertility, that is, pregnancy rate. Furthermore, we hypothesized that prolonged farrowing causes retention of placentae and metritis, delays uterine involution and perturbs follicular growth after weaning. We also hypothesized that sows that undergo prolonged farrowing release less oxytocin at subsequent estrus in response to boar stimulation.
We determined the farrowing duration (time between expulsion of first and last piglet) of sows and explored whether there is a negative effect on subsequent post-weaning pregnancy rate (n = 148). We explored the relationship between farrowing duration and placenta expulsion (n = 142), and postpartum uterine size and intrauterine fluid (n = 99). For that, placenta expulsion was observed until 24 h after birth of the last piglet and ultrasonography was used during the first week postpartum to examine the uteri of the sows. Uterine size and intrauterine fluid were used as indicators for initial uterine involution and puerperal metritis. Furthermore, we determined the farrowing duration of sows (n = 30) and monitored the subsequent follicular development using transrectal ultrasound twice a day between the third day after weaning and ovulation. At estrus, blood samples were collected in the presence of a boar in order to determine the endogenous oxytocin concentrations and release patterns.
The results show that sows with a prolonged parturition (> 300 min) were 3.4 (P = 0.027) more likely not to be pregnant. Sows that experienced total (no expulsion of placental parts; 3%) and partially retained placentae (no expulsion of placental parts after birth of the last piglet; 3%) had longer farrowing durations (1009 ± 275 and 734 ± 136 min) than sows without retained placentae (369 ± 202 min; P = 0.021 and P = 0.004). Farrowing duration conformed to a quadratic relationship with the number of expelled placental parts (P = 0.001), placental expulsion duration (time between expulsion of first and last placental part; P = 0.002) and time between expulsion of last piglet and last placental part (P = 0.024). Use of oxytocin increased number of expelled placental parts (3.8 ± 0.2 vs. 2.9 ± 0.3, P = 0.035), decreased the placental expulsion duration (172 ± 44 vs. 328 ± 26 min, P = 0.011) and time between expulsion of last piglet and last placental part (148 ± 48 vs. 300 ± 24 min, P = 0.025). Furthermore, prolonged farrowing (β ± SE, Wald χ2, Odds; 2.0 ± 0.5, 13.1, 7.6; P = 0.001), obstetrical intervention (1.5 ± 0.7, 4.4, 4.3; P = 0.036) and two or more stillborn piglets (1.4 ± 0.7, 3.8, 3.9; P = 0.052) increased the risk of having enlarged uterine size whereas oxytocin administration ( 1.5 ± 0.7, 4.7, 0.2, P = 0.040) decreased the risk. Two or more stillborn piglets (2.6 ± 0.9, 8.7, 13.7; P = 0.003), obstetrical intervention (1.8 ± 0.8, 5.0, 6.0; P = 0.025), prolonged farrowing (1.7 ± 0.8, 4.3, 5.7; P = 0.039) and impaired placenta expulsion (3.3 ± 1.7, 4.0, 26.9; P = 0.044) were associated with intrauterine fluid. After weaning, OT concentrations were higher in sows with prolonged farrowing than in sows with shortened farrowing (28.0 ± 7.7 vs. 20.6 ± 7.7, P < 0.01). OT concentrations correlated with diameters of the follicles measured 5 d after weaning and when the follicles reached their maximum size after weaning (r = 0.61, P < 0.01 and r = 0.57, P < 0.01, respectively).
We determined the farrowing duration (time between expulsion of first and last piglet) of sows and explored whether there is a negative effect on subsequent post-weaning pregnancy rate (n = 148). We explored the relationship between farrowing duration and placenta expulsion (n = 142), and postpartum uterine size and intrauterine fluid (n = 99). For that, placenta expulsion was observed until 24 h after birth of the last piglet and ultrasonography was used during the first week postpartum to examine the uteri of the sows. Uterine size and intrauterine fluid were used as indicators for initial uterine involution and puerperal metritis. Furthermore, we determined the farrowing duration of sows (n = 30) and monitored the subsequent follicular development using transrectal ultrasound twice a day between the third day after weaning and ovulation. At estrus, blood samples were collected in the presence of a boar in order to determine the endogenous oxytocin concentrations and release patterns.
The results show that sows with a prolonged parturition (> 300 min) were 3.4 (P = 0.027) more likely not to be pregnant. Sows that experienced total (no expulsion of placental parts; 3%) and partially retained placentae (no expulsion of placental parts after birth of the last piglet; 3%) had longer farrowing durations (1009 ± 275 and 734 ± 136 min) than sows without retained placentae (369 ± 202 min; P = 0.021 and P = 0.004). Farrowing duration conformed to a quadratic relationship with the number of expelled placental parts (P = 0.001), placental expulsion duration (time between expulsion of first and last placental part; P = 0.002) and time between expulsion of last piglet and last placental part (P = 0.024). Use of oxytocin increased number of expelled placental parts (3.8 ± 0.2 vs. 2.9 ± 0.3, P = 0.035), decreased the placental expulsion duration (172 ± 44 vs. 328 ± 26 min, P = 0.011) and time between expulsion of last piglet and last placental part (148 ± 48 vs. 300 ± 24 min, P = 0.025). Furthermore, prolonged farrowing (β ± SE, Wald χ2, Odds; 2.0 ± 0.5, 13.1, 7.6; P = 0.001), obstetrical intervention (1.5 ± 0.7, 4.4, 4.3; P = 0.036) and two or more stillborn piglets (1.4 ± 0.7, 3.8, 3.9; P = 0.052) increased the risk of having enlarged uterine size whereas oxytocin administration ( 1.5 ± 0.7, 4.7, 0.2, P = 0.040) decreased the risk. Two or more stillborn piglets (2.6 ± 0.9, 8.7, 13.7; P = 0.003), obstetrical intervention (1.8 ± 0.8, 5.0, 6.0; P = 0.025), prolonged farrowing (1.7 ± 0.8, 4.3, 5.7; P = 0.039) and impaired placenta expulsion (3.3 ± 1.7, 4.0, 26.9; P = 0.044) were associated with intrauterine fluid. After weaning, OT concentrations were higher in sows with prolonged farrowing than in sows with shortened farrowing (28.0 ± 7.7 vs. 20.6 ± 7.7, P < 0.01). OT concentrations correlated with diameters of the follicles measured 5 d after weaning and when the follicles reached their maximum size after weaning (r = 0.61, P < 0.01 and r = 0.57, P < 0.01, respectively).
| Status | Slutfört |
|---|---|
| Gällande start-/slutdatum | 01/01/2013 → 30/06/2017 |