Piglet birth weight could be key to reducing pre and postnatal mortality
Piglet birth weight can influence both prenatal and postnatal mortality rates under outdoor conditions, so genetic approaches to optimise birth weight offers pig breeders and producers an opportunity to improve pig welfare and enterprise profitability.
These were two of the key findings of a study to gain a better understanding of the risk factors for different causes of piglet mortality in order to help to design strategies to minimise losses.
“Outdoor farrowing system account for 27% of breeding sows in England, and it is therefore important to understand the factors affecting their production efficiency,” Newcastle University’s Sandra Edwards told delegates at this year’s British Society of Animal Science annual conference.
“Piglet mortality is a significant economic and welfare issue, with farrowing and preweaning losses in commercial outdoor herds currently averaging 19% of all pigs born. Since sophisticated environmental and human interventions at the time of farrowing are infeasible in these systems, risk factors may differ in importance from those seen in indoor systems,” she added, explaining the rational behind her team’s work, carried out in conjunction with the SAC and the Grampian Country Food Group.
As part of a large genetic research programme, data were collected on 17,191 individually identified piglets from sows farrowing over three parities in individual outdoor paddocks on Scottish units during a 15-month period.
For each piglet, litter information, gender, birth weight, fostering history and survival were recorded. All piglets that died before weaning were subject to post-mortem investigation to determine cause of death. The data were used to investigate the influence of different factors on prenatal mortality and postnatal mortality. A risk factor analysis was carried out.
“We found that, from a mean total litter size of 13.6 piglets, overall survival at birth was 97.3% and survival during the nursing period was 90.15%,” said Professor Edwards. “The major cause of postnatal mortality was crushing, accounting for between 73% and 84% of all identified causes of death in different parities. Low vitality, starvation and scour each accounted for less than 10% of losses per parity.
“The pattern of mortality risk with month/parity was inconsistent. Male pigs were at greater risk of stillbirth and greater risk of subsequent mortality than females. Risk of both prenatal and postnatal mortality reduced progressively for each 0.1 increment in birth weight between 0.5kg and 2.3kg and increased progressively for each 0.05 increment in within-litter standard deviation between 0.10 and 0.65. And both parameters increased with sow parity,” she added.
Presented to the British Society of Animal Science Annual Meeting, March 31 to April 2, 2008, Scarborough, UK.
Full details: Shrestha NP, Roehe R, Smurthwaite KM, Jarvis S, Lawrence AB, Edwards SA: “Risk factors for piglet mortality in outdoor farrowing systems.”
Presented to the British Society of Animal Science Annual Meeting, March 31 to April 2, 2008, Scarborough, UK.
Proceedings of the British Society of Animal Science, pp159 http://www.bsas.org.uk/Publications/Annual_Conference_Proceedings
PDF of Powerpoint presentations available at http://www.bsas.org.uk/Members_Area/
summary (pdf )
