Dr. Hannele Kettunen, R & D Manager
The third webinar presentation was given by DVM, PhD, Adjunct Professor Claudio Oliviero from the University of Helsinki, Finland. Check my previous blogs for an overview of the other 2 presentations:
"The relevance of gut integrity and a hypothesis on how resin acids can strengthen the intestinal barrier: a broiler chicken example" by Dr. Filip Van Immerseel (Ghent University)
"Late gestation feeding of sows and its impact on sow and piglet performance" by Dr. Peter Kappel Theil (University of Århus)
Dr. Oliviero started by noting that for the past 25 years, the litter size of sows has been increasing steadily, and has reached the average of 18.6 piglets per sow on 2018 in Denmark. During the same time period, the average farrowing duration has increased from two to nine hours.
The development has unfortunately had a negative effect on the size and livability of piglets, and on the availability of colostrum per piglet. For each additional piglet born there is a decline of 35–43 g in average birth weight. The hyperprolific sows thus give birth to a high number of relatively small piglets.
Nest building is hormonally driven and precedes farrowing by 12–24 hours. Whenever possible, the sow should be provided with nest materials such as straw, sawdust or paper, and allowed to move within the enclosure. Fulfilling the need to build the nest favorably affects the hormonal balance and shortens farrowing duration, which then reduces the percentage of stillborn piglets.
The hormonal changes before and during the farrowing are essential for a successful parturition. During the nest-building phase, the progesterone levels in blood serum need to drop and prolactin levels go up. Too high progesterone levels at the onset of farrowing also down-regulate lactose synthase activity, prolactin and oxytocin receptors on mammary epithelial cells, and thus lead to an insufficient production of colostrum. Moreover, the prolactin peak at prepartum is essential for the initiation of lactation.
An abundance of nesting material in a free pen allows an optimal hormonal balance, while the stress related to farrowing crates and insufficient or non-existing nest materials inhibits these hormonal changes and leads to a longer farrowing duration.
The farrowing duration itself is also important for the future performance of the piglets. Research conducted in professor Oliviero’s group has shown that each extra minute of farrowing decreases the total production of colostrum by an average of 2.2 g, which is a remarkable drop considering that the farrowing of hyperprolific sows can take more than 500 minutes.
Large litter size is also a challenge for the immunity of piglets. The effect is multifactorial, starting from abovementioned birth characteristics, leading to an insufficient colostrum intake and therefore also a low intake of maternal antibodies. On the other hand, psychosocial stress due to crowding and competition with siblings, as well as possible regrouping, increases the cortisol levels in the serum of the piglets. Both the high cortisol level and low intake of colostrum have a negative effect on intestinal maturation, making the affected piglets prone to intestinal disturbances, and lowering their immunological status.
According to professor Oliviero, measures to increase sow’s immunity have a positive effect on the immunity of piglets, because a high immunoglobulin G (IgG) concentration in sow’s blood serum results in a high IgG concentration in the blood of the offspring. Such measures include nutritional feeding strategies, e.g. high fiber content, dietary resin acids, yeast derivatives, live yeast, or conjugated linoleic acid. It is important to ensure that the sow has adequate energy reserves and a positive glucose metabolism at the time of farrowing. Housing and management strategies that allow the sows to move and build a nest with abundant nest materials also help to improve the immunity of piglets and ensure them a good start in life.
Have a look at the article describing the impact of resin acids on sow colostrum yield and quality:
Hasan, S., Saha, S., Junnikkala, S., Orro, T., Peltoniemi, O., Oliviero, C., (2018). Late gestation diet supplementation of resin acid-enriched composition increases sow colostrum immunoglobulin G content, piglet colostrum intake and improve sow gut microbiota. Animal. 1–8.