Increasing numbers born to improve breeding herd productivity makes sense, but higher litter size is only part of the equation. Producers must be able to rear these extra piglets if they’re going to raise production and prospective profits. Jane Jordan has been finding out why little pigs offer big potential
Modern dam lines can produce large litters and rear them given the right environment and care. However, as prolificacy increases and litters become larger, it’s inevitable that the proportion of small pigs born in each farrowing will increase. And this is where the quest to wean more pigs per sow becomes a little unstuck.
To maximise the number of pigs weaned, producers must minimise pre-weaning losses, and perhaps the greatest challenge for most herds is to reduce neonatal deaths. Many fatalities are recorded as non-viable, but what determines piglet viability: is it birth weight, body condition, health, vigour, or the level of care needed to look after such small animals?
It’s probably a combination of all these factors, although many draw a line at birth weight. Common advice suggests piglets weighing less than 900g at birth are unviable, and more than half of them will die before they are weaned.
But does this argument stack up when the drive for higher numbers born means that a significant proportion of the pigs delivered may arrive below a target birth weight of say 1,200g?
If removing these ‘mini’ piglets from the start is justified – as a way of avoiding potential problems and additional costs – how does this benefit herd productivity in the long term and the challenge to wean another three or more pigs per year?
Target tinies
Rearing tiny piglets, rather than writing them off, is not as difficult or expensive as it may seem and it’s worthwhile. For the past three years, Robin and James Brice have been achieving brilliant results from low birth weight piglets born in their 750-sow breed-to-finish herd in Suffolk. The policy has raised sow productivity by 1.45 piglets weaned per litter, which mirrors the extra 1.45 piglets born due to the increased prolificacy of the Rattlerow dam lines they use.
Sows are now producing 11.8 pigs/litter, while pre-weaning mortality remains at around 8%. Robin says it demonstrates that although numbers born are increasing steadily – up annually by about 0.35 pigs – this extra production is being preserved through to weaning.
He says target pre-weaning mortality at 10%, no matter how big the litters, as there’s no point having the extra production offered by increasing prolificacy if you can’t maintain it.
“Most herds, whether you are producing 16 pigs a litter or just 10, would benefit from more supervision and greater attention to detail at farrowing and with neonatal routines,” he adds. “It’s about reducing loss and providing smaller piglets with what they need to get on and grow.”
Producers tend to forget that small piglets are genetically programmed to perform well, and given the right environment they will.
The Brice unit operates a three-week batch system. Farrowing sows are monitored 24-hours a day with a high level of supervision during the birth process (see BPEX website photo stories night farrowing checks: http://www.bpex.org.uk/news/photo-library/photostories/nightfarrowingchecks.aspx). This has significantly reduced neonatal deaths, but it’s how small pigs are managed and a steadfast commitment to rear anything with a ‘bite for life’ that has really helped to boost overall productivity.
“We produce more pigs now than ever and have few problems rearing them because we are tackling variability right at the start, in the farrowing house,” says Robin. “By minimising potential losses pre-weaning, and by rearing small pigs rather than removing them, we have continued to improve productivity year on year since 2010.”
And the only real cost to the business has been in terms of labour time and the increased attention devoted to critical periods during farrowing week.
Proactive piglet care
All small piglets are proactively managed from birth to provide them with the best opportunity to thrive, survive and grow. Specific rearing techniques are used to ensure small ones do suckle and consume as much colostrum as possible. Competition is also eliminated with smalls fostered onto freshly farrowed gilts as soon as possible after birth. Gilts are preferred because the udder line is low and teats are small and more suitable for tiny mouths.
“We grade our piglets into smalls – which are the mini pigs – and good smalls. We usually get between six and nine litters of small pigs in every batch, and anything that has the urge to suck gets a chance,” says Robin. “If you take away the competition and make sure these little piglets get a good feed, they’ll soon get going.”
Small pigs only tend to stay with their natural mother for between four and six hours, which again counters popular advice to leave offspring with their dam for 24 hours. However, gilt colostrum is nutritionally better than that produced by older sows, so fostering these little piglets onto gilts makes sure they receive the best nutrition available.
“We give Baycox to piglets at about four days of age and by then you can really see a difference,” Robin adds. “They’re vigorous and thriving, and when we introduce creep at 14 days they’re growing well with a keen appetite.”
Viable performance
Critics say investing considerable time and resources in rearing small, ‘underweight’ piglets is unlikely to pay dividends at the farm gate, but again James and Robin disagree. Their records show that litters comprising piglets with birth weights between 670-850g are as viable post-weaning as their larger litter mates, and they account for valuable revenue.
They have tracked a number of ‘mini pig’ litters through their production system and found performance trends are the same as those achieved by larger progeny (see table).
Weaning weights at four weeks of age are between 5-8kg, with average daily growth while suckling between 170-229g/day. Pre-weaning mortality for these litters averages 8%, and although the weaners may be on the light side, they are vigorous, have good feed intakes and excellent conformation.
Post-weaning growth rates are between 340-460g/day with a liveweight at 12 weeks of between 24.5-31.9kg. During the subsequent finishing period (12 weeks in straw-based pens), they continue to grow well with an average daily gain between 770-860g. End weights fall on the lighter side of the contract at 89-98kg, but the pigs grade and sell well.
What’s more, the business has seen no change to rearing herd performance as a consequence of rearing these smaller pigs. Mortality rates post weaning to 35kg averages 1.3%, and for the finishing period is 1.7%.
As Robin says, tackling pre-weaning mortality and looking after smaller pigs is not rocket science, it’s about identifying how loss can be minimised through careful management and better stockmanship.
What happens in the farrowing house sets a precedent for all subsequent productivity. Reducing pre-weaning mortality, by keeping more piglets that are born alive, living and thriving through to weaning, could be a more realistic option for many herds, rather than aiming for higher prolificacy.