Large litters and pre-weaning mortality

I last touched on this in my second Blog for Pig World in December 2013. That was when litters of 16 were appearing regularly and beginning to surprise people, especially those who were starting to get them!

Since then, the view has emerged that large litters are bound to get result in pre-weaning mortality (PWM). Some producers seemed to be salving their conscience in claiming that, in these days of much bigger litters, 12% PWM isn’t necessarily the badge of shame that the pundits claim.

“PWM hasn’t moved down much in 30 years” has often been said in the past, and I still hear vets saying so today at meetings.

Inevitable?
I don’t like percentages in pig stats. The difference between 12% and 6% of piglets born alive is 0.6 of a piglet surviving in a litter of 10, and near one whole piglet more in one of 16. Allowing for some deaths later towards finish weight, for the big litters of the future this means selling 2.2 more finished pigs per sow per year, or about 170kg of saleable meat per sow – a lot of moolah for virtually the same cost of production, as the sow still has to be housed, fed and managed whatever the outcome.

So, do these large litters mean that a higher PWM is inevitable? Two years ago, stimulated by my own blog needing farm figures to support this view or not, I set about trying to collect some.

Just being there
I questioned 14 clients and it soon emerged that being present at farrowing was a major factor in securing a low PWM. Typically with a 12% PWM, one piglet snuffs it in the first 24 hours from farrowing and another one to weaning at, say, 23 days. One lost in the first day and only one more across the next 22! To reduce that 12% figure, then saving those last-born weak and anoxic (short-of-oxygen) piglets must be critical in any litter, large or small. So being there is important and it’s even more vital with big litters.

More time with the baby pigs
So, for the future we must face up to this; sufficient time must be allowed for the farrowing barn staff to be present with the baby pigs, especially in those first punishing 24 hours. Several surveys suggest that out of the 2,600 man hours/year labour availability, the time allocated to the baby pig is only 8%. Not nearly enough. It should be more than double this; something like 18%.

To test this out, since 2013 in quizzing my clients whose records showed some in and around the 12% PWM mark and some near the 6% PWM level, I asked them to estimate how much time was spent with the baby pigs. Two things stood out:

  1. The time allowed was significant whether the litter numbers were average or high.
  2. Those who spent as little 8% labour availability with the baby pigs were mostly at 12% PWM or more, and most of those who spent at least 16% got their PWM down to 7% or less.

This conclusion from this exercise is that spending more time with the baby pigs (I suggest not less than 18% of labour load) and being there at farrowing (cue prostaglandins, and on large farms a nightshift, especially with hyperprolific genetics) are important ways to break that stubborn 12% PWM/170kg lost meat barrier.

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About The Author

John Gadd, who has spent 60 years' involvement in pig production, has had more than 2,800 articles about pigs published and has written three best-selling pig textbooks. With hands-on experience that includes managing a grow-out herd at 1,800ft in Banffshire, Scotland, and 20 years in the allied industries with Boots' Farm Department, RHM Agriculture and Taymix, he set up his own international pig management consultancy in the mid 1980s and has now visited more than 3,000 pig units in 33 countries as a pig management adviser. (Photo courtesy Bournemouth Daily Echo)