Recently, I have found myself being asked on farm when is the right age to wean, writes Maisie Lord.
While I stress that the cross compliance rules for welfare standards are quite clear on the minimum weaning age of piglets, beyond this, the ideal weaning age will be a trade-off between the potential performance of the sow and her piglets, and the unit’s own goals.
I encourage producers to look at their data and at benchmarks to see what works well on their unit and where the potential for improvement lies. Essentially, weaning must strike a balance between getting the sow back into production and minimising post-weaning check in her litter.
The sow’s subsequent reproductive performance needs to be optimised. If the lactation length is too short, her uterus lining will not have been given enough opportunity to recover from the last litter. If her lactation is too long, she will be required to produce milk for larger piglets. She may struggle to do this. Bodyweight loss and reduced pregnancy rate in the subsequent lactation can be a knock-on effect.
A study posted on the National Hog Farmer website looked at data from 750,000 farrowing records and demonstrated that an increased lactation length resulted in increased numbers born in the subsequent litter. However, this levelled out at lactation lengths of 21 days.
A 14-day versus a 21-day lactation for parity 2 females resulted in an increase in average litter size from 12.93 to 13.98. But the data showed little improvement beyond this.
However, it is a balance. For the piglet, the weaning process should be as stress-free as possible, and with minimum check, to help maximise post-weaning genetic growth potential.
Bear in mind that feed intake of creep under the sow is minimal (approximately 100g/pig) before 14 days old. Piglets weaned at 28 days, as opposed to 21 days, will have had an extra seven days to adapt to new feed. Further research demonstrates that for each day of lactation above 17 days, a weaning weight increase of 0.25kg/day/pig is possible. And Cargill trials have shown that an extra 0.8kg in weaning weight equates to an extra 3.9kg at slaughter.
If you have a typical target of 210kg weaned/sow/year, this could be achieved by ether 35 piglets at 6kg weaned or 28 piglets at 7.5kg. Theoretically, we would look to wean as big a pig as possible and as many as possible.
We can promote this via elements of sow nutrition that improve birth weights and by correct lactation feed intake and supplementary milk feeding of piglets to boost piglet weight gains. In most cases, there will be a likely compromise to be had between numbers born and weight weaned.
I have always given ‘a politician’s answer’ to the question of best weaning age, because there are too many farm-specific factors. To determine the weaning age for your unit, look at the data on farm and consider the factors that contribute to the weaning age and to your goals, in terms of weaning weight and sow productivity.
Maisie Lord is a pig nutritionist for Cargill. Based in North Yorkshire, she worked at Cargill’s innovation centre in the Netherlands before joining the UK team