C. Vanderhaeghe

A cross-sectional study to collect risk factors associated with stillbirths in pig herds

The aim of this study was to identify risk factors for stillborn piglets at herd level in commercial pig herds. A written questionnaire, containing semi-open questions directly or indirectly related to stillborn piglets, was sent to 250 randomly selected pig herds (>150 sows) in northern Belgium. In total 111/250 questionnaires were returned (response rate of 44.4%) and 107 were valid for analysis. The average reported frequency of stillbirth was 7.5% (S.D. 2.8%). The relationship between risk factors and stillbirths was evaluated with a generalized linear effects model with the percentage of stillborn piglets as outcome variable. Type of breed used on the farm was significantly (P<0.01) associated with the percentage of stillborn piglets. A high temperature in the farrowing unit (> or =22 degrees C compared to <22 degrees C) was associated with significantly (P<0.01) more stillbirths, whereas showering sows with warm water before parturition resulted in significantly less stillbirths (5.8%) than no showering (7.7%) (P<0.01) and was not significantly different from showering with cold water (7.0%) (P=0.26). When supervision of farrowing was performed occasionally, significantly more stillbirths (8.1%) were observed in comparison with no attending to farrowing (6.5%) (P<0.01) or frequent supervision of farrowing (6.9%) (P<0.01). Significant interactions were found between breed and showering sows prior parturition or supervision of sows at parturition, and between temperature in the farrowing unit at parturition and showering procedure of the sows. In conclusion, this study has clearly demonstrated that breed is a major factor involved in the frequency of stillbirth. Additionally, some management practices before or at parturition may reduce the number of stillborn piglets.

Longitudinal field study to assess sow level risk factors associated with stillborn piglets.

The aim of this study was to identify risk factors for stillborn piglets at sow level in commercial pig herds in northern Belgium. In total, 545 sows of 22 pig herds were included in the study. Stillborn piglets were observed in 48.3% of the litters and the mean stillbirth rate of the sows was 7.5%. Two multilevel logistic regression models were used to investigate the risk factors for stillborn piglets. One included the stillbirth occurrence at previous farrowing, while the other one did not. In both models, sows with lower back fat levels (<16mm) at parturition had an increased risk for stillbirth compared to sows with medium back fat levels (16-23mm). Vaginal palpation during farrowing was associated with stillborn occurrence as well. Sows that farrowed during the day were more likely to have stillborn piglets than sows farrowing overnight and each unit increase in total litter size significantly increased the risk for stillborn piglets. Parity was significantly associated with the risk for stillborn piglets when stillbirth occurrence at previous farrowing was taken into account. The risk for stillbirth was 2.5-times higher among sows with >1 stillborn piglets at the previous farrowing compared to sows without stillbirth in the previous parity. In conclusion, high parity sows, large litters, sows with low back fat levels and sows with >1 stillborn piglets at previous farrowing require special attention due to an increased risk for stillbirths. Finally, all practices performed in the farrowing unit should be conducted carefully and without disturbance of the sows during the parturition process.

Risk factors associated with postpartum dysgalactia syndrome in sows.

The aim of this study was to investigate management and strategy-related risk factors for the occurrence of postpartum dysgalactia syndrome (PDS) in commercial pig herds. A questionnaire was sent to 250 pig herdsmen. Of the responding herdsmen (n=110), 37 reported occurrences of PDS, whereas 73 reported no cases of PDS. Data were then analysed using logistic regression. After univariate analysis, eight variables associated with PDS (P<0.2) were retained and these were used to construct a multivariable logistic regression model. Four significant risk factors were found: (1) moving pregnant sows to the farrowing unit 4 days or less before expected farrowing (Odds Ratio [OR] 6.272); (2) farrowing induction (OR 4.804); (3) feeding sows ad libitum during lactation (OR 3.149) and (4) frequent farrowing supervision (OR 0.085). This study has demonstrated that a considerable number of modern pig herds still suffer from problems with PDS, and that control measures should include optimising management and feeding practices.

Incidence and Prevention of Early Parturition in Sows

A retrospective study, based on 60,990 farrowing records from 35 commercial herds, was performed to determine the incidence of early parturition (<114 d) and to investigate the relationship between early parturition and total number of piglets born, number of piglets born alive and percentage of stillborn piglets per litter. The mean gestation length was 115.4 ± 1.62 d, and early parturition occurred in 10% of all farrowing records. Sows with early parturition had significantly more stillborn piglets and a larger litter size compared to sows with a normal gestation length (114-117 d). Sows with a gestation length <114 d were 1.2 times (95% CI: 1.19-1.21; p<0.001) more likely to have an early parturition at the subsequent parity. A second study was performed in four herds (n=329) to investigate the efficacy of altrenogest administration on 110-112 d (T112) or 111-113 d (T113) of gestation for preventing early parturition and to investigate the effect of this treatment on the reproductive performance of sows. The interval between the last altrenogest treatment and the onset of parturition was 3.3 ± 1.32 (T112) or 2.0 ± 0.89 (T113) days. The gestation length of sows of the altrenogest group (T112 + T113) (115.3 ± 1.23 d) was significantly longer compared to gestation length of the non-treated sows (114.7 ± 1.69d) (p<0.01). Altrenogest treatment had no negative effect on the reproductive performances of the sows. In conclusion, the administration of altrenogest in late gestation is an effective and safe method to prevent early parturition and can counteract the reproductive losses because of premature farrowing, which may occur in a substantial part of the farrowing events.

Non-infectious factors associated with stillbirth in pigs: A review

The main objective of this review is to provide current information regarding non-infectious risk factors associated with stillborn piglets. These factors can be roughly categorized as genetic, maternal, piglet and environmental factors, but also interactions exist between several factors. An understanding of this multifactorial problem should help practitioners and farmers implementing a more effective farrowing management to obtain a high reproductive efficiency. From the papers studied in this review, it can be concluded that litter size, parity, sows body condition and farrowing supervision/birth assistance seems to be the most relevant risk factors associated with stillborn piglets.

Comparison of oral versus parenteral iron supplementation on the health and productivity of piglets

The aim of this study was to compare oral iron supplementation in feed with a standard iron injection and assess the impact on the health and productivity of pigs. The reliability of a quick test (HemoCue) for the measurement of blood haemoglobin concentration was also investigated. Three pig herds, with a total of 88 sows and their piglets, were included in the study. Piglets in treatment group O were fed a special iron-rich feed on days 2 to 4, 5 to 7 and 8 to 12 of lactation using a specially designed feeding device. Piglets in group IM received 200 mg of an iron dextran complex intramuscularly at three days of age. Haemoglobin concentrations and performance of the piglets were compared between groups. The mean haemoglobin concentrations in pigs at weaning were 131.4 and 116.4 g/l for pigs in groups O and IM, respectively (P<0.01). Daily weight gain (253.9 v 248.8 g/day) and piglet mortality (11.4 v 12.2 per cent) were slightly better in group O than in group IM (P>0.05).

Influence of postpartum cloprostenol treatment in sows on subsequent reproductive performance under field conditions.

During the previous decade several studies focused on postpartum treatment with prostaglandin for improvement of reproductive performance in sows. The aim of the study was to investigate the effect of administration of a prostaglandin F(2 alpha) (PGF(2 alpha)) analogue in sows within 24-48 h after farrowing on sow and litter performance. In five commercial farms, the sows were randomly assigned to either treatment A (2 ml cloprostenol, Planate) or treatment B (2 ml physiological saline solution, i.m.). Fifteen per cent of all sows were at random selected for progesterone analysis. Litter performance was assessed by measuring pre-weaning mortality and average daily weight gain (ADG). Sow performance was assessed by measuring weaning-to-oestrus interval (WOI), the percentage of sows returning to oestrus and litter size during subsequent farrowing. Administration of a PGF(2 alpha) analogue within 24-48 h postpartum had no effect on the rate of progesterone decline measured over 24 h compared with that of the controls. Litter performance and WOI were not affected by treatment. The subsequent litter size in sows of parity seven and more showed a significant difference of 1.98 piglets (p < 0.01) between both groups, to the benefit of the cloprostenol group. In conclusion, administration of a synthetic PGF(2 alpha) analogue, cloprostenol, within 24-48 h after farrowing improved litter size at next farrowing in older (>or=7 parity) sows.