Maternal pheromone has positive influences on weaned Pigs

The broad objective of this work is to improve the health and welfare of commercial pigs. One critical moment in the production cycle is the abrupt weaning of 3-week-old pigs from their mother. Most weaned pigs experience a very high level of stress after weaning. Few or no therapies are available to blunt this stressful experience. The laboratory in which I worked, had discovered a maternal pheromone that might improve the health, production and welfare of weaned pigs. The objective of this thesis was to determine a singular application type for the maternal pheromone for newly weaned piglets. Maternal pheromones in mammals aide in the survival of newborns, help piglets find a food source (identification of the nipple for nursing), and stimulate a maternal – offspring bond (May et al., 2015b). This maternal olfactory presence is diminished once piglets are transitioned to a nursery pen during weaning. The studies laid out in this thesis promote the concept of extending the maternal presence in the environment after the time of weaning. Study 1 primarily focused on placement of the pheromone in the nursery pen. Olfactory (but not physical) contact with the pheromone proved sufficient to extend the following studies with indirect contact of the pheromone to the piglet. Study 2 furthered the idea of the design of the pheromone by evaluating the standard Myristic Acid formula to Myristic Acid Methyl Ester. These results determined the formula presented to piglets in study 3. Study 3 focused on providing answers on the dilution detectable by the piglet such as how concentrated the pheromone can be and still produce adequate results. Lastly, study 4 finalized the applicator style by testing which plastic type will release the pheromone in the environment in ample supply for the piglet.
Study 4 results were validated by the solid phase microextraction (SPME) polymer fibers that detected the skatole in the pheromone in an air sample from the nursery environment. The detected molecules via SPME were then analyzed by gas chromatography-mass spectrometry (GCMS) to identify the skatole molecule within the air sample. Of the two treatment types in study 4, Ethylene Vinyl Acetate (EVA) and Nylon, EVA showed an increased area under the curve compared to the nylon plastics. These results were seen in both the evaluation of 1 gram of each treatment as well as the comparison of release pheromone after 24 and 48 hours in a nursery setting.
Overall, the conclusion based off the results found in this thesis states that by applying the swine maternal pheromone to piglets during the first 48 hours of weaning increased growth rates, increased immediate feeding behavior, and decreased aggression behaviors. Further research ought to expand the parameters of the maternal pheromone by extending its boundaries to see if it works in a commercial setting and to see what positive influence the maternal pheromone can have through each stage of the pig's life.