An intricate matrix of inter-related factors leading up to farrowing and continuing through the parturition process influence piglet performance and quality. Collectively, these factors are described as Sow Peripartal Syndrome (Figure 1), and this condition presents several threats to piglets. Four of the most critical factors influencing the potential of a sow’s litter are: being born alive, adequate birth weight, adequate colostrum intake and piglet vitality. Below, we focus on piglet vitality and some practical, research-based approaches to mitigate the threats reduced piglet vitality presents to animal performance and producer economics.

When researchers speak about “piglet vitality”, they are referring to the vigor and strength of piglets at birth. Multiple methods are used to quantify piglet vitality. Most of these methods focus on the first minutes of post-natal life and assess a piglet’s time to first breath, time to stand, muscle tone, heart rate, oxygen saturation rate, and blood pH. While these measurements are relatively labor-intensive and difficult to measure, other measurements consider indirect parameters such as time between birth and reaching the sow’s udder; or time between birth and first suckle. Even these indirect metrics can be challenging to implement in commercial conditions outside the controlled research environment.

Efforts are ongoing to help farmers efficiently identify piglets with reduced vitality or at risk of reduced vitality. Evaluative tools and methods can help commercial pig producers identify which piglets will need extra support to avoid production losses stemming from reduced gain, disease or mortality. In the absence of widespread methods for assessing vitality in commercial conditions today, the challenge falls mainly on the farmer’s eye – for example assessing a piglet’s udder stimulation and its number of movements in the enclosure.

Why vitality matters – suckling time, mortality and weaning weights

Vitality at birth can influence a piglet’s performance across its lifetime. Directly or indirectly, reduced piglet vitality results in production losses (Figure 1). In contrast, good vitality sets the stage for piglet growth and health while minimizing risk of production losses. Good vitality enables a piglet to quickly reach the sow’s udder, be competitive and start suckling. In turn, suckling allows the neonate piglet to maintain body temperature and reach a positive energy balance. If suckling is not initiated, the piglet is at risk of starvation and may be unable to maintain body temperature. This can set in motion a spiral of negative consequences ending in production losses via reduced growth, disease development and/or mortality.

Using time between birth and first suckle as an indirect measure for piglet vitality, research has shown that when piglets began suckling within 30 minutes following birth, the pre-weaning mortality rate was 6%, compared to a 21% mortality rate for pigs that initiated suckling more than one hour after birth. Also, piglets taking more than 1 hour to start suckling had a 5% lower pre-weaning daily weight gain compared to piglets starting suckling within 30 minutes if corrected for birth weight and colostrum intake. The fact that colostrum intake is partially determined by piglet vitality leads to a prolonged effect of piglet vitality on complete lifetime performance.

Reduced piglet vitality – Hypoxia and extended farrowing

Among the many risk factors that threaten piglet vitality, most are also factors for piglet hypoxia at birth. Hypoxia is generally agreed to be one of the most important parameters determining piglet vitality. A long duration of the expulsive phase of farrowing and dystocia is a major risk factor for intrapartum asphyxia. Therefore, avoiding a prolonged duration of farrowing is very important for piglet vitality. Environmental, and physiological conditions that may contribute to extended farrowing duration include farrowing pen design, high back fat levels on sows, constipation, a high number of total born piglets, decreased gestation length, and increased fear levels for humans.

The impact of hypoxia during birth on piglets’ early life and long-term performance was illustrated in a recent study where typical measures of vitality such as umbilical cord blood pH and lactate were recorded at birth. When piglets were grouped according to these measures, the piglets with the highest lactate and lowest blood pH values, evident of serious hypoxia, had 100 g lower colostrum intake and 0.5 kg lower weaning weights compared to litter mates with normal blood values. The effects of a piglet’s conditions at birth were also seen over the long term: piglets with serious hypoxia gained 9% less (664 g/d vs 721 g/d) from wean to slaughter.

Close supervision of farrowing generally leads to fewer stillborn piglets and a lower neonatal mortality. This outcome is due to timely farrowing assistance when dystocia occurs. Next to manual assistance, oxytocin can reduce farrowing duration although not all studies confirm this effect. Apart from the time-consuming and labour-intensive aspect of birth assistance, there is the biosecurity risk to consider. Human assistance could potentially increase the risk of developing mastitis, metritis, agalactia (MMA) especially when hygienic standards are not followed. This will result in further weakening of the piglets and even increase pre-weaning mortality. Furthermore, indications of increased incidence of peripartal hypophagia with prolonged parturition have been reported, again resulting in reduced sow milk production and lower levels of piglet performance.

Although piglet vitality is mainly determined by the level of hypoxia, it is not the only parameter reducing vitality. Other factors hindering vitality include cold stress, physical abnormality like splay-leg, and conditions in the intra-uterine environment such as placental development, the latter which strongly influences the birth weight and maturity of the piglet at birth.

Sows’ diets and piglet vitality

The sow’s diet can also influence her piglets’ vitality. Supplementing the sow’s diet during gestation with n-3-long chain polyunsaturated fatty acids has been shown to increase piglet vitality at birth due to the docosahexaenoic acid which results in better organ maturation and brain development. However, not all studies have shown this effect.

Researchers are considering how the sows’ gestation diet may support intrauterine conditions related to piglet vitality. Insights from different breeds suggest that genetic factors play a role in vitality. For example, piglet vitality is positively correlated with body weight at birth (BWB), but genetic factors beyond BWB may also play a role here. While Meishan piglets are very small at birth, this breed demonstrates an exceptionally high vitality. A better placental vascularization in Meishan piglets could partially explain the breed’s high vitality even when birth weights are rather low within this breed due to uterine crowding. Arginine supplementation in the gestation diet of the sow improves placental vascularization by enhancing placental angiogenesis, although once again, not all studies have found positive effects of arginine supplementation.

Nutrition innovation improves piglet oxygenation during farrowing

Inspired by new insights on the dynamics that occur in sows and piglets around farrowing, researchers at Trouw Nutrition Swine Research Centre pioneered an additive for the preparturient sow’s diet. Gestawean OxiLiv is a patented drinking water additive dosed in the sow’s drinking water from 5 days before farrowing until the sow has farrowed.

The additive’s water application eliminates the need for manual labour associated with the use of alternative products such as top dresses and ensures consistent delivery to the sow. This product’s mode of action improves oxygenation to piglets during the farrowing process, helping reduce stillbirths and asphyxia damage. An interesting effect of Gestawean OxiLiv is its role in maintaining sows’ blood calcium levels. In the hours before farrowing, a sow’s calcium levels begin to decline to prepare for intrauterine contractions and colostrum secretion. Researchers compared the stillborn rates of sows with litters containing no stillborn piglets to sows with stillborns. The research showed sows that were able to maintain their calcium levels during farrowing did not experience stillborns.

Validated on farms to support more live piglets

A series of field trials on commercial farms throughout Europe and in Canada, among pigs of various genetics, showed the use of Gestawean OxiLiv reduced stillbirths and helped produce +0.4 extra piglet born alive per litter. Some studies achieved 0.5 to 0.7 extra piglet born alive per litter. Farms experiencing higher stillbirth rates saw an increased benefit from product use compared to their counterparts, which historically had relatively low stillbirth rates.On selected farms where assessment of pre-weaning survival was possible, researchers observed an extra 0.2 to 0.4 piglet survived to weaning. Piglets from sows treated with Gestawean Oxiliv significantly increased colostrum intake by 6%, corroborating for the increased vitality at birth and consequently the better survival of piglets from sows receiving Gestawean OxiLiv. In this group, the percentage of piglets having a colostrum intake below 250g was 7% compared to 14% in the control group. A minimum intake of 250g colostrum per piglet is known to be a critical threshold for piglet survival and lifetime performance.

Potential Can Be Influenced Pre-Farrowing

Piglet vitality influences lifetime performance and is interrelated to many other factors including sow nutrition and practices during the farrowing process. Trouw Nutrition understands the importance of piglet vitality during the neonatal period and aims to improve vitality by tackling the underlying causes even prior to farrowing. This approach to addressing root causes and developing targeted interventions aims to improve the profitability of production without increasing farm labour. A primary cause of reduced piglet vitality at birth is hypoxia. To help manage this threat, it is critical to create conditions for a smooth farrowing. Appropriate farrowing interventions leading up to and during the farrowing process can start preparing piglets prenatally for the postnatal life and identify piglets at risk upon farrowing.

*References available upon request

References (for others, see phd Vila, Ruben, Cools and paper Edwards 2002)

Piglet behavior as a measure of vitality and its influence on piglet survival and growth during lactation. R. Muns, E. G. Manzanilla, C. Sol, X. Manteca, J. Gasa. Journal of Animal Science, Volume 91, Issue 4, April 2013, Pages 1838–1843, https://doi.org/10.2527/jas.2012-5501

Perinatal mortality in the pig: environmental or physiological solutions? S.A. Edwards* Livestock Production Science 78 (2002) 3–12 10.1016/S0301-6226(02)00180-X

Investigating the behavioural and physiological indicators of neonatal survival in pigs, E.M. Baxter, S. Jarvis, R.B. D’Eatha, D.W. Ross, S.K. Robson, M. Farish, L.M. Nevison, A.B. Lawrence, S.A. Edwards. https://doi.org/10.1016/j.ther...