Litter size has increased in the past 10 years, but so have piglet losses, according to Steve Jagger, senior pig nutritionist at feed company ABN.
The challenge for pig farmers is to improve piglet survival while maintaining sow nutrient balance.
Dr Jagger sets out why this problem has arisen, and Chris Opschoor, global nutrition services manager at genetics company Topigs Norsvin, and Kristian Juul Volshoj, technical manager (pigs) at neonate nutrition specialist AB Neo, offer practical advice on how to overcome it.
See also: Guide to managing big pig litters
What causes higher mortality?
Higher losses are caused by:
- a reduction in average piglet birthweight
- a higher proportion of smaller piglets (less than 1kg) with a lower chance of survival
- lower colostrum intake a piglet (as colostrum is finite)
- a reduction in passive immunity.
How are sows affected?
Bigger litters mean sows have a greater nutrient requirement to maintain condition and are more likely to lose condition during lactation.
“If you move from 11 to 14 pigs a litter reared, milk production is increased by about 25%,” says Dr Jagger.
“This is accompanied by a loss of protein, fat and minerals from the sow if nutrient intake is inadequate.
“It can also lead to an increase in the weaning-to-service interval and a reduction in size of the next litter.”
What do gilts and sows need for optimum production?
Adequate colostrum is key for the neonatal development of piglets, says Chris Opschoor.
So, the daily requirements of sows during lactation must support milk production.
Nutrition must also be sufficient to avoid high bodyweight loss, which has a big impact on follicle development, affecting oocyte quality and embryo survival in the next pregnancy.
Mr Opschoor recommends seeking advice from your pig genetics supplier about daily requirements.
While total bodyweight increases during gestation, in practice most sows lose maternal weight as they approach farrowing and foetal weight gain accelerates. This is undesirable for the longevity of the sow.
“Improvement in bodyweight development of sows to support litter quality starts with gilts.
“Limit weight losses during lactation, especially first parity sows,” advises Mr Opschoor.
Weight loss of more than 12% of the gilt’s bodyweight can result in 2.2 fewer piglets being born alive in the second litter, according to research published in the journal Biology of Reproduction (“Consequences of negative energy balance on follicular development and oocyte quality in primiparous sows”, 2019).
“This is low-hanging fruit,” says Mr Opschoor. “If we’re able to manage this, it will have a big positive impact [on production].”
To support optimum production, he advises:
- Improving bodyweight development during gestation – young sows have a higher lysine requirement but a lower feed intake, so a higher lysine to energy ratio is needed
- Ensuring levels of vitamins C, D and E, calcium and phosphorus, and electrolyte balance, L-carnitine and fatty acids are sufficient.
What is a healthy sow?
Kristian Juul Volshoj advises focusing on the basics of managing large litters, ensuring colostrum intake and using techniques to enhance survival.
A healthy sow is the cornerstone to success, he says. A healthy sow:
- has a sound appetite
- has no signs of abnormal discharge
- has mammary glands that are not hard or red
- has a normal temperature (38.6-39.5C)
- gets up and lies down without problems
- has a high milk yield
- urinates clear or light-yellow urine.
“Make sure you can say yes to all these points – they are essential for high efficiency in the farrowing house.”
How can I reduce piglet mortality?
Post-mortem examinations of more than 1,300 piglets from 50 herds showed that nearly 70% of mortality occurred within the first four days of life.
Almost half (46.6%) of these deaths were caused by crushing; a further 18.5% were a result of weakness at birth, and 17.7% were from hunger.
Find out why piglets are dying on your farm. Work with your vet: collect dead piglets for a week, write their ages on their backs and send them for post-mortem.
One of main reasons for crushed piglets is “the climate crisis in the farrowing crate,” according to Mr Volshoj.
If they are too hot, they will move out from the heat lamp into the pen.
Too cold, and they will move towards the sow because she is warm and comfortable. You want them to spend their energy suckling instead of trying to keep warm.
- Teach the piglets to stay in the creep area (see “Split-suckling”, below)
- Aim for 34-37C in the creep area – you can measure the temperature, but start by using your eyes: if pigs are lying on top of each other, for example, they are clearly too cold.
Ideally, the piglets should spend the first 12 hours with their mother to ensure they get enough colostrum.
This is easy to say but harder to practise, says Mr Volshoj, so consider the following:
- If a piglet has a dry umbilical cord, it’s ready for cross-fostering
- If you are checking the sow at night, and she has started giving birth, mark the piglets already born – they will be old enough for moving by the morning
- Waiting too long leads to higher mortality as the smallest piglets won’t have enough milk.
Mortality is highest among the smallest piglets, so invest most time taking care of them. Mr Volshoj suggests three ways to do this:
One way to ensure high colostrum intake is split-suckling. This method is often used in Denmark and is a way of supporting the smallest piglets in large litters.
- Ensure the 10-12 smallest piglets get enough colostrum by confining the larger ones to the creep area for up for 45 minutes
- Do this once or, at most, twice during the first day of birth before cross-fostering.
Aim to have litters fixed by day five. Look at all the sows that have given birth and choose one to take care of all the piglets weighing less than 700g or 800g.
- The ideal is a second-litter sow with good-sized piglets of her own. Replace these with the smallest piglets collected from the other sows
- The best time to do this is just after feeding when the sows are calm and will accept the pigs more easily
- Match the number of piglets to be fostered to the number of functional teats the foster sow has
- If you’re using a milk-cup system, allocate one or two additional piglets to the foster sow.
3. Two-step nurse sow
Again, this is normal practice in Denmark with litters of 18-20 piglets, where action needs to be taken to ensure their survival.
- Step one: a nurse sow – one that farrowed four to eight days ago and was feeding her own piglets very well – receives excess newborn piglets from other litters. It’s best to give her the biggest piglets from these litters to stimulate the sow.
- Step two: the nurse sow’s piglets, in turn, go to an intermediate nurse sow, with pigs ready for weaning (older than 21 days). Check her teats are accessible to the piglets and don’t give her more piglets than have just been weaned.
Steve Jagger, Chris Opschoor and Kristian Juul Volshoj were speaking at the Pig & Poultry Fair online forums on 12 May