10 October 2022
Importance of Piglet Colostrum Management
As piglets move from the safe environment of the womb and into the perilous world, they are faced with many challenges that can prove deadly. For one, they are born with minimal energy reserves and must get their first meal… fast! Their newborn bodies lose heat fast so, if they don’t make it to a teat, their core temperature will soon drop, making them torpid, slow, and disengaged with their environment. They also need to compete against their peers for their place in the udder and the sow’s heat. In modern pig farming, it is common for there to be more piglets than teats.
To make matters worse, piglets are born without immunity, susceptible to different viruses, bacteria, and parasites. In fact, many microorganisms that would never stand a chance against a normal immune system can wreak havoc in the newborn piglet in a matter of days, if not hours.
As piglets become weaker due to chilling, lack of energy and disease, they are at a greater risk of crushing by the sow. Crushing is one of the leading causes of death in piglets and, contrary to previous opinion, maternal ability has little to do with it; piglets get crushed because they react slowly and simply fail to get out of the way on time.
Thankfully, there is a simple, natural way for piglets to cope with the dangers of their neonatal hours: colostrum, the ‘first milk’, which is packed with energy and antibodies.
Colostrum intake and immunity
Why are piglets born without immunity? Wouldn’t that be a significant design flaw? To answer this question, we need to understand a bit more about the immune system.
We can divide the immune system in three sub-systems: innate immunity, non-specific immunity, and specific immunity.
The innate immunity of piglets
It is not strictly true that piglets are born totally defenceless. The skin creates a barrier that impedes pathogens from attacking the underlying tissues. The mucosae produce mucus that traps bacteria, the cilliae in the trachea clear the airways of debris and microorganisms, and the acid pH in the stomach also serves as a barrier. Together, all these protection mechanisms are called ‘innate immunity’.
The non-specific immunity of piglets
The immune system proper has several tissues that can attack invaders and inactivate their pathogenicity mechanism. Cells such as macrophages can devour any strange or suspicious particles. To aid them in their task, there are Y-shaped proteins (type G, A immunoglobulins or IgG and A antibodies) that stick to invaders and signal to macrophages that an invader is present. Some of these immunoglobulins can clump around pathogens and inactivate them, these are called ‘agglutinins’.
Piglets are born with a somewhat significant amount of these defences. However, most important pathogens have developed sophisticated ways to avoid these immunity mechanisms.
The specific immunity of piglets
To fight against the most dangerous pathogens, animals have developed incredibly complex mechanisms to recognise and destroy invaders. Lymphocytes, for example, are cells that can recognise harmful bacteria and induce them to self-destroy. Other lymphocytes harness the strength of the immune system and direct it towards a specific invader (T cells). Others (B cells) produce antibodies that recognise specific proteins (antigens) in the cell walls of pathogens. These IgG and IgM antibodies are very powerful. They can activate proteins that can poke holes in the cell walls of harmful bacteria, they can signal to diseased cells to self-destruct when they express viral or cancerous proteins. Finally, a type of B-lymphocyte (Memory cells), can recall previous pathogens and mount a response much faster.
Animals cannot survive without specific immunity, and piglets are born without it! The reason is that, for specific immunity to work, it must first be exposed to pathogens. Unfortunately, piglet immunity is too immature to mount a proper response.
What is passive immunity transfer?
As piglets are exposed to pathogens, they slowly start mounting a response; this is called ‘active immunity’. However, they would die before they are able to fight disease; so, somehow, they must acquire immunity from another source. Since they don’t produce this immunity, it is called ‘passive’.
This is where colostrum comes in. The ‘first milk’ is packed with IgG and IgM antibodies that allow piglets to fend off most attacks until they are able to mount their own response. Furthermore, colostrum contains the sow’s own antibodies, so these are specific to the pathogens that are circulating in that farm. This is why there is no ‘design flaw’ in mammals; even if they had a mature immune system in the womb, piglets would not be able to produce antibodies for the pathogens they will face in the outside world. By getting the specific antibodies from their dam, they are literally given a chance at life. Colostrum contains not only antibodies, but also immune cells and other factors, important for defence mechanisms of new-born piglets.
The placenta of pigs
Why not transfer the maternal antibodies from within the womb? Well, if the prenatal piglets were in direct contact with the sow, its own immune system would attack the strange tissues (after all, they are half-foreign). Therefore, there is the need for some sort of interface that modulates the interaction between the sow and its piglets in the womb: this is the placenta.
Mammals have developed different types of placentae. Some are better than others at keeping the fetal tissues separated from the mother’s. For example, in the case of primates and rodents, there is significant contact between maternal and fetal tissues, and there is more passive immunity transfer from within the womb. But it the case of calves, foals, and piglets, the placenta is very efficient and there is practically no passive immunity transfer at all. This is the reason why, in these species, colostrum intake is a matter of life and death.
When, for whatever reason, the newborn piglet does not drink sufficient colostrum, it won’t benefit from its dam’s antibodies and we call this ‘passive immunity transfer failure’.
There is a small window of opportunity for colostrum intake in piglets
The gut lining does not normally allow for large, complex proteins (such as antibodies) to pass from the gut to the bloodstream. However, during the first 20 to 40 first hours of life, neonatal gut is permeable to maternal antibodies and immune cells, so piglets can acquire specific immunity quickly.
However, the gut may close as early as 24 hours and, after that, there is effectively no more immunity transfer. The composition of colostrum also changes and, by 20 hours after farrowing, it is chemically closer to milk.
Optimal conditions for the sow for colostrum production
To produce good quality colostrum in fair amounts, sows need adequate nutrition, water, and the ability to express some crucial behaviours.
Sows that don’t recover well from their last farrowing and reach a new cycle with low body scores are likely to have lower antibody levels, so their colostrum will be lower quality. Sow diet in the nursery is crucial to avoid significant weight loss during lactation. Dehydration is a problem in the days leading to farrowing, as sows decrease their food and water intake.
As farrowing approaches, keen farmers can detect the changes in the udder, this is the time to move sows to the farrowing pens. The mammary glands filter sow plasma and this is how circulating antibodies get to the colostrum. This process occurs around day 105 of pregnancy (Farmer et al., 2006). In nature, sows build nests as farrowing gets closer. Nesting triggers a chain of hormonal events that eventually result in colostrum descending. When sows farrow, there is an important release of oxytocin which stimulates prolactin and thus, the life-saving colostrum arrives at the teat just in time for the piglets to suckle. Furthermore, suckling reinforces colostrum release and milk production; this is especially important in gilts, so they should be given a piglet for every available teat.
As farrowing approaches, sows attempt to build a nest. This behaviour reinforces several hormonal pathways that lead to better lactogenesis (milk production).
Restrictive farrowing crates prevent the sow from expressing the nesting behaviour. However, how much this affects colostrum quality is not clear. Stress (especially heat stress) can interfere with the hormonal chain of events, which could lead to poor colostrum production or premature colostrum spilling. Infectious diseases such as porcine reproductive and respiratory syndrome virus (PRRS) can cause agalactia (poor or no colostrum production), which is disastrous for the piglets.
To sum up, sows need good body score at the end of lactation, adequate nutrition, hydration, the ability to express nesting behaviours, and a low stress environment to produce optimal colostrum quantities, with optimal quality.
How to ensure adequate colostrum intake
In this section, we will discuss a few general conditions that must be met to prevent problems in colostrum intake. It is important to ensure a conducive environment to passive immunity transfer before attempting specific colostrum management techniques such as split suckling and cross-fostering.
The first step every farm needs to take is to make sure that farrowing unit workers are aware of the importance of colostrum intake. This is perhaps the most important factor in colostrum management success.
Workers should be able to identify piglets that are at risk of passive immunity transfer. These are:
- Low weight piglets
- Smaller piglets from large litters
- Orphans
- Low viability piglets
High piglet mortality has a very negative impact in the morale of workers, so they are usually happy to do everything in their power to reduce it. Nevertheless, overmanaging can also be counterproductive. For example, cross-fostering piglets from litter to litter, trying to milk sows and tube feed piglets, or spending an inordinate amount of time with a few, very weak piglets, are all recipes for disaster. Colostrum management is best in the golden middle: not too much, not too little. Workers should also be diligent and mark piglets as they drink colostrum; simple steps like these save time and make management easier at one of the busiest times in the whole production chain.
There should be no last-minute scrambling in the farrowing area and every single piece of equipment needed during farrowing should be made ready in advance. Farrowing is labour intensive, so farm managers can assist by adapting a batch-farrowing system ; synchronisation is another option to achieve this goal.
Colostrum and immunity transfer
One of the main goals of proper colostrum management is to make pigs immune to the most significant pathogens. By inducing immunity in the sow, we can indirectly confer protection to piglets at the moment of passive immunity transfer.
To achieve this, sows are usually vaccinated several weeks before farrowing. Each farm should have its own vaccination programme, and this is something you should discuss with your veterinarian. As standard procedure nowadays, vaccination against neonatal diarrhoea pathogens (E.coli complex and C. perfringens C,A) is requested. Vaccination is very important in replacement gilts that come from another facility. Since they have not been exposed to the circulating pathogens, it should not be assumed that its piglets will be protected, even if they drink enough colostrum.
Declerck et al. (2017) studied the sow and piglet factors that impact colostrum intake. They found that intake per piglet decreases in larger litters and with oxytocin administration to assist farrowing. Stillbirths also have a negative impact on colostrum intake. On the contrary, there is a positive impact by greater piglet body weight and shorter time between birth and first suckling. In litters with pronounced body weight differences between piglets, there is a greater likelihood that the runts won’t get sufficient colostrum.
Protecting piglets from common pathogens
These are some of the most common pathogens of piglets, which can be reduced through colostrum management.
Escherichia coli
E. coli is the most common cause of scour in piglets. The disease can begin in the first day of life and it usually produces a watery diarrhoea that quickly leads to dehydration. E. coli is somewhat opportunistic, so it is very easy to improve results with correct colostrum management. E.coli causing neonatal diarrhoea (ND) contains specific adhesins (usually F4, F5 and F6) characteristic for the strains and ND.
Rotavirus and coronaviruses
These viral diarrhoeas of piglets appear during the first week. These are very common pathogens that are almost impossible to eradicate. Usually, sows have good defences against these viruses, so disease is mild and mortality is low when there is proper colostrum management. The exception is transmissible gastroenteritis (TGE), a coronavirus disease of pig that can cause up to 100% mortality in naïve herds.
Clostridia
Clostridia are bacteria capable of producing some of the most toxic substances in the world. These pathogens are opportunistic and are normal features of the soil and gut microbiome. However, when gut ecology is altered, Clostridia become quite dangerous and can quickly kill a large number of pigs.
These pathogens affect piglets as they near weaning or supplementary feed is introduced.
Through sow vaccination and colostrum management, Clostridia (C. perfringens type C) cases can become quite rare. On the other site, one of the most frequent and prevalent pathogen, causing diarrhoea during the first days of life, is C. perfringens type A producing Alpha and Beta2 toxin (reference).
Coccidia
Coccidia are one-cell parasites that invade and destroy the gut lining. Infected pigs shed oocysts that are very resistant in the environment. There is no commercial vaccine available against coccidia, so we can’t rely solely on colostrum. If coccidia are circulating in the farm, then the sow will have some immunity. Nevertheless, due to the impact of coccidiosis in pig production, it is better to take prophylactic measures against this disease on the positive farms.
Porcine respiratory and reproductive virus
PRRS can affect pigs in two different ways. In sows, it causes abortions, reduces the viability of pigs, and can cause agalactia. As we have discussed, PRRS can wreak havoc in the farrowing area, which is why vaccination, biosecurity and all-in/all-out schemes also play a role in reducing piglet mortality.
In piglets, PRRS manifests as a respiratory disease. This virus can infect piglets before they are born, so the disease can manifest as early as the first hours of life.
Salmonella enterica
Salmonellosis is an important scour of piglets that affects slightly older piglets, usually after the second week. However, piglets with passive immunity transfer failure are much more likely to develop this disease.
Farrowing conditions for passive immunisation
When farrowing finally arrives, there three main actions you can take to ensure that the largest number of piglets gets enough colostrum.
Litter equalisation
Having more piglets than teats is a common problem in modern pig farming. To prevent the weakest pigs in this litters from dying due to lack of colostrum, several litter equalisation techniques have been developed, cross-fostering being the most widespread.
It is important to equalise litters within the first 48 hours, after that, there is not much chance that we can help with passive immunity transfer.
The first step is to identify large litters and vulnerable piglets. If possible, piglets that are about to be moved to another sow should suckle some colostrum from their dam. It is important to mark piglets and to keep records. A common pitfall of cross-fostering is overdoing it.
A key to success is to have a clear cross-fostering policy and make sure that all personnel are kept in the know.
Litter equalisation reduces piglet mortality and improves growth in heterogeneous litters.
However, every attempt should be made for piglets to get colostrum from their dam.
Split suckling
Stronger piglets have a clear advantage to the detriment of the runts of the litter. Split suckling consists in dividing the litter in two groups, one of heavier piglets and the other with the runts. One group is kept in the creep area while the other is allowed access to the sow.
Once the weaker pigs have had their share, they are moved to the creep area, where there is also a heat source that prevents chilling.
There are several schemes, but one of the most successful is giving the runts 90 minutes with the dam, and 60 minutes to the strongest group.
Manual feeding and teat training
The least viable piglets simply won’t feed on their own, even we remove the competition by split suckling and litter equalisation. In these cases, it might be necessary to milk the sow and feed the piglet with a syringe.
It is fair to ask if this is economically viable. In commercial farms, milking sows and paying so much attention to a few piglets is usually not cost effective. However, smaller farms can attempt it. Muns et al. (2015) found no improvement in mortality through colostrum supplementation of low weight piglets. However, there was a positive effect in early weight gain in runts from primiparous dams when given a high energy supplement. There is a case to be made for energy supplementation in low weight piglets, since this can enhance the chances that they will get colostrum on their own. This result was confirmed by Declerck et al. (2016) who also found a decrease in mortality through energy supplementation.
It is also possible to supplement low weight piglets with cow colostrum, though that would require a very recent calving. Obtaining extra colostrum is a challenge on its own, so some farmers can choose to keep frozen cow colostrum, which is easier to get. Cow colostrum can be frozen and kept for months at a time.
In general, manual feeding techniques are not cost effective. Teat training, on the other hand, is extremely easy and financially sound. It consists of guiding the piglet to the teat. In most cases, with a little help from us, event low viability piglets can get passive immunity and have a better shot at life.
Keys to success
We must bear in mind that litter equalisation is a necessity of modern pig farming that is meant to minimise the negative effects of sow prolificacy (large litters). Alexopoulos et al. (2018) studied what factors influence the success of litter equalisation:
- Avoid cross-fostering piglets before 12 hours, every attempt should be made for piglets to get colostrum from their dam.
- Passive immunity transfer is most effective before 6 hours, so split suckling should be done as a matter of course in heterogeneous or large litters.
- Evaluate teat availability at farrowing.
- After 24 hours, cross-fostering should be kept to a minimum.
References
Alexopoulos, J. G., Lines, D. S., Hallett, S., & Plush, K. J. (2018). A review of success factors for piglet fostering in lactation. Animals, 8(3), 38. https://doi.org/10.3390/ani8030038
Cabrera, R. A., Lin, X., Campbell, J. M., Moeser, A. J., & Odle, J. (2012). Influence of birth order, birth weight, colostrum and serum immunoglobulin G on neonatal piglet survival. Journal of Animal Science and Biotechnology, 3(1), 1-10. https://doi.org/10.1186/2049-1891-3-42
Declerck, I., Dewulf, J., Decaluwé, R., & Maes, D. (2016). Effects of energy supplementation to neonatal (very) low birth weight piglets on mortality, weaning weight, daily weight gain and colostrum intake. Livestock Science, 183, 48-53. https://doi.org/10.1016/j.livsci.2015.11.015
Declerck, I., Dewulf, J., Sarrazin, S., & Maes, D. (2016). Long-term effects of colostrum intake in piglet mortality and performance. Journal of Animal Science, 94(4), 1633-1643. https://doi.org/10.2527/jas.2015-9564
Declerck, I., Sarrazin, S., Dewulf, J., & Maes, D. (2017). Sow and piglet factors determining variation of colostrum intake between and within litters. Animal, 11(8), 1336-1343. https://doi.org/10.1017/S1751731117000131
Farmer, C., Devillers, N., Rooke, J. A., & Dividich, J. L. (2006). Colostrum production in swine: from the mammary glands to the piglets. Pig News and Information, 27(1).
Muns, R., Manteca, X., & Gasa, J. (2015). Effect of different management techniques to enhance colostrum intake on piglets’ growth and mortality. Animal Welfare, 24(2), 185-192.
Muns, R., Silva, C., Manteca, X., & Gasa, J. (2014). Effect of cross-fostering and oral supplementation with colostrums on performance of newborn piglets. Journal of animal science, 92(3), 1193-1199. https://doi.org/10.2527/jas.2013-6858
