Submitted to: Veterinary Record
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/20/2006
Publication Date: 8/15/2006
Citation: O'Reilly, K.M., Harris, M.J., Mendl, M.T., Held, S., Moinard, C., Statham, P., Marchant Forde, J.N., Green, L.E. 2006. Factors associated with preweaning mortality on commercial pig farms in England and Wales. Veterinary Record. 159:193-196. Interpretive Summary: In commercial pig production a breeding sow produces 10-12 piglets per litter and has approximately 2 - 2.4 litters per year. A small proportion of the litter (0.5 pigs / litter) may be stillborn and not all live-born piglets survive until weaning. The average pre-weaning mortality is between 11-13 percent but there is a wide variation. This variability indicates that reduction in pre-weaning mortality is possible on many farms. We are currently engaged in a long-term epidemiological study to identify risk factors associated with pre-weaning mortality in a variety of commercial farrowing systems. In order to generate hypotheses for this long-term study, we carried out exploratory analysis on pilot data collected from 68 farms. We found that the average pre-weaning mortality was 10.7%, with a range of 2% to 16%. The distribution had two peaks at 9% and 15%, and these peaks were associated with weaning age. Factors associated with decreased mortality included the provision of bedding in a piglet creep area, an overall pen size of between 4.0-5.0 m^2, the presence of the stockperson during farrowing and the fact that the farm was a breeding only unit. The results have highlighted some areas on which to concentrate in the long-term study but they already indicate housing and husbandry factors that may help producers to impact mortality on their unit, to increase productivity and piglet welfare.
Technical Abstract: This paper presents a pilot study of factors associated with preweaning mortality in pigs. Data from 68 pig farms were used to generate hypotheses for further research into risk factors for pre-weaning mortality (PWM). The data came from 68 farms with a total of 96 farrowing systems. The median PWM reported by the farmers was 10.7 percent (inter-quartile range 8.5 - 13.6 percent). There was a significantly higher (P<.05) PWM when pigs were weaned at an older age. Having adjusted for this, PWM was significantly lower (P<.05) in crated systems compared with indoor loose, Solari and outdoor systems. Other factors associated (P<.05) with a lower PWM rate were a pen size of 4 - 5 m^2, compared with larger or smaller pens, presence of bedding in the creep area, natural ventilation and presence of the stockperson during farrowing. Factors associated (P<.05) with a higher PWM rate included buildings greater than ten years of age, use of bedding in the pen (excluding the creep) and infra-red lamps compared with other forms of supplemental heat. We hypothesize that presence of the stockperson, the type of farrowing system, the size of the pen within a system, hygiene in the farrowing house and provision of extra heat and bedding are all associated with PWM.