By Maisie Lord, Cargill pig nutritionist
Average litter size has increased by 1.5 piglets every five years, thanks to advancing genetics, and litters of 13 or 14 piglets are now typical.
However, the sow’s milk yield has not necessarily followed the same proportional increase and she may need some additional help.
But, first, it’s a good idea to look at the sow’s capability and make sure we’re managing her well enough so she can perform to her maximum potential. It’s estimated that a sow can provide for 90kg to 100kg of pigs at four-weeks-old on her milk and dry creep feed – equivalent to 12 piglets weighing 7.5kg to 8kg at weaning.
To achieve this, the sow needs to be consuming the right amount of energy in a balanced diet. A typical figure of 30MJ of energy drives 1kg litter weight gain. If each piglet gains 6.7kg during the lactation period and there are 12 piglets suckling, then the sow needs to be eating at least 8kg a day of a high-spec lactation ration of 14MJ/DE.
Beyond this she will be using her own body reserves to drive her milk yield. While some weight loss during lactation is desirable, a loss of more than 6% of the sow’s total body weight can be detrimental.
A study published in the journal Reproduction of Domestic Animals in 2012 showed that a body weight loss of more than 15% in sows was associated with a lower number of viable foetuses and a 10% reduction in foetal survival.
There are many nutritional interventions that can be used to encourage sow feed intake in lactation to prevent weight loss and drive milk yield.
The amount of feed offered must be carefully balanced when the sow enters the farrowing crate – not so low to cause an issue with constipation but low enough to drive intake after farrowing.
Conventional sow management will encourage gradual increases in feed intakes to a maximum level by 14 days post-farrowing. New approaches are also available, but we must monitor and record how much she is eating throughout her lactation.
We will then know if her intakes could be improved and what additional piglet supplementation is required – key to maximising kilos at slaughter.
Differences in weaning weights are magnified five-fold by their slaughter weight – a 1kg difference in piglet weaning weight becomes a 5kg difference in slaughter weight – or a longer rearing time.
Recent research has shown the significant benefit of using a milk supplementation and liquid pre-starter supplementation, which leads to an increase in weight of 0.5kg/weaned piglet and a 5% reduction in pre-weaning mortality in litter sizes of 16 piglets.
Creep feed pre-weaning is also imperative, not only to ensure maximum growth to meet the deficit between sow milk and the growth potential, but also to ensure piglets transition correctly at weaning.