It’s possible to breed for improved piglet pre-weaning survival
Breeding could be the key to improved piglet pre-weaning survival in alternative farrowing systems to the crate. A recent study, carried out by the SAC, Newcastle University and Grampian Country Food Group, has shown that there is potential to breed for high survival in alternative farrowing systems.
“Recent estimates of total pre-weaning piglet mortality range between 16% and 19%,” the SAC’s Emma Baxter told delegates at this year’s British Society of Animal Science annual conference. “A different approach to effectively address piglet survival is needed. Genetic breeding programmes implemented in alternative farrowing systems could prove a viable option,” she said.
To test this theory, behavioural and physiological indicators of pre-weaning piglet survival were measured on both gilts and their piglets in a genetic selection group bred for high (postnatal) survival (HS) and a control group (C) farrowing in indoor loose-housed and outdoor farrowing systems in a two-by-two design. The gilts were offspring from a previous generation selected for survival traits and bred under outdoor conditions.
In the outdoor environment total mortality tended to be higher in the control litters than the high survival litters – 18% compared to 12% – and this tendency was even lower in live-born mortality at 13% compared to 10%. In the indoor environment there were no significant differences in either total mortality or live born mortality.
Regardless of environment or genotype, important indicators of prenatal survival were body shape and size, farrowing birth order, and placental efficiency. Birth weight and behavioural development were the most important indicators of postnatal survival and, although indicators were independent of environment, there were genotype interactions with temperature and time to udder as survival determinants.
Gilt behaviour affected piglet postnatal survival. Piglets that died had mothers that were more careless with their posture changes, crushed more and were more aggressive. When comparing survival indicators at a litter level, regardless of environment, the control gilts showed more crushing incidents – both fatal and non fatal. In the indoor environment, high survival gilts were more aggressive towards their offspring and were the only genotype to show savaging – 40% of the high survival indoor gilts mouthed or bit piglets.
“The mortality results in the indoor environment illustrate the genotype by environment interactions and the potential to further improve survival,” explained Miss Baxter. “Indicators of prenatal survival were generic across systems, with piglet shape being the most important survival indicator.
“Postnatal survival indicators included birth weight and behavioural development,” she added. “In both systems, control gilts showed more crushing behaviour than high survival gilts. However, there are potential undesirable side-effects of selecting for high survival gilts in the indoor system, as they showed heightened aggression towards their piglets.”
Presented to the British Society of Animal Science Annual Meeting, March 31 to April 2, 2008, Scarborough, UK.
Baxter E, Jarvis S, Sherwood L, Farish M, Robson S, Smurthwaithe K, Roehe R and Edwards S: “The influence of genetics and environment on indicators of piglet pre-weaning survival.” Proceedings of the British Society of Animal Science, pp11 http://www.bsas.org.uk/Publications/Annual_Conference_Proceedings
PDF of Powerpoint presentations available at http://www.bsas.org.uk/Members_Area/
summary (pdf) Presentation_011baxter (pdf)
