Lena Rangstrup-Christensen

Sow-level risk factors for stillbirth of piglets in organic sow herds.

In Danish organic pig production, one-third of total born piglets die before weaning, and stillbirth has previously crudely been estimated to account for 27% of the total preweaning mortality. The objective of this study was to evaluate season, litter size, parity and body condition of the sow as risk factors for stillbirth in nine commercial Danish organic pig herds. The study was conducted over a 1-year period, and the data included registrations on 5170 farrowings with 82 906 total born piglets. The average number of total born piglets per litter was 16.0, and the number of stillborn piglets per litter was 1.1. A significant effect of season was seen with an odds ratio for stillbirth of 1.15 during summer (May to August) compared with the remaining part of the year. A non-linear effect of litter size was seen where an increase in litter size from 11 to 16 resulted in an odds ratio of stillbirth of 1.11. An increase in litter size from 16 to 21 resulted in an odds ratio of stillbirth of 1.45. A significant interaction between body condition and parity was present. In first parity sows, an increase in body condition score from 2 (thin) to 3 (moderate) and from 3 to 4 (fat) increased the probability of stillbirth with an odds ratio of 1.23 and 1.36, respectively. In sows with parity above 4, an increase in body condition score from 2 to 3 and from 3 to 4 decreases the probability of stillbirth with an odds ratio of 0.68 and 0.79, respectively. In conclusion, increasing litter size and being born during the summer months of May to August were found to be risk factors for stillbirth. Furthermore, an interaction between body condition and parity showed that thin sows with parity above 4 had a substantially increased risk of stillbirth compared with normal and fat sows with parity above 4. In contrast, for parity 1 sows risk of stillbirth was increased in fat sows.

Causes of preweaning mortality in organic outdoor sow herds

The aims of the current study were to identify the causes of preweaning piglet mortality and investigate the effect of season and parity on the proportions of mortality causes. The study was conducted in nine herds over a one-year period, and dead piglets were collected for necropsy once during each of the four seasons. In total, 2672 piglets were necropsied of which 60% were live-born but died post-partum (pp), 32% were stillborn and 8% were euthanised. Intra-partum deaths accounted for 88% of stillborn piglets. Eighty-one percent of necropsied live-born piglets died within four days pp. Half of these had a body weight of <1u202fkg at the time of death. Crushed and starved piglets accounted for 83% and 9% of mortalities until day four pp, respectively. Thirty-three percent of the crushed piglets (age zero to four days) had not suckled prior to death and the proportion of these piglets was lower in summer compared to the remaining part of the year (ORu202f=u202f0.6, 95% CI [0.5;0.9]) and was higher for multiparous sows compared to first parity sows (ORu202f=u202f1.7, 95% CI [1.1;2.6]). In conclusion, sow parity and season affected the proportion of crushed piglets before four days of age. Furthermore, the group of crushed piglets was heterogeneous and consisted of both heavy well-fed piglets and small piglets with empty stomachs. Thus, management implementations to lower mortality may differ depending on sow parity, season and individual piglet characteristics.

14. Increase sustainability of organic pig production with more vital piglets

About every third piglet dies before weaning within the Danish organic pig production, making the organic piglet mortality higher, than what is seen in the conventional indoor production. The high piglet mortality is in conflict with both the idea of increased animal welfare and the organic principles. As most of the piglets die within the first days after farrowing, improving the thermal conditions around the time of farrowing is important, since the thermal environment in many cases may be a significant contributor to piglet death also for piglets that are categorized as crushed or starved to death. nThis paper describes a subproject under the larger Danish VIPiglets project with the overall aim to reduce piglet mortality in Danish organic pig production. The subproject described in this paper has three overall aims concerning 1) ways to improve the thermal environment around the time of farrowing 2) how the temperature and humidity inside the farrowing hut relate to piglet mortality 3) how temperature affects farrowing duration and inter birth interval. nStudies concerning aim two and three are still ongoing and so no results are presented. In the study concerning aim one the average total litter size was 17 piglets and total piglet mortality was 31%. The study showed that providing sows with access to poplar trees (a shaded area) significantly affected paddock use compared to sows without a shaded area (control sows), by increasing the use of the paddock before farrowing and day zero and one post partum (pp) (F4,218=2.91, p<0.05) and the paddock use particularly increased at hot temperatures. Furthermore the sows with access to poplar were lying more when outside compared to controls (29 % vs 18 % respectively; F1,70=15.13, p<0.0005). In general the sows were seen lying more in the paddock at high temperature compared to low temperature particularly before farrowing, on day 0 and 1 pp and again after day 11 pp.