To determine if lactating sows can be fed diets containing less protein in order to reduce the quantity of nitrogen excreted into the environment. To determine if sows fed reduced CP diets improve their lactation performance when housed under hot environmental temperature.

How research was conducted:
Lactating sows were fed different diets that contained lower amounts of protein and their nursing piglets were weighed and the milk was analyzed for nutrients. The amount of protein in the sows body was also measured to ensure that the diets fed would provide her with the protein that they needed. Sows were also housed each in small rooms where the temperature could be well controlled and increased to resemble the summer temperature. When animals are fed large amounts of proteins, it may result in more heat produced by the animal, which in turn is not desirable during hot weather. The amount of heat produced by sows that were fed diets with different levels of proteins was calculated by measuring how much oxygen was consumed and carbon dioxide was produced by the sows. The amount of nitrogen produced in the sows’ urine and the ammonia in the air was also measured.

Research findings:
Sows fed reduced CP diets as low as 12% and containing crystalline amino acids maintain lactation performances and decrease the quantity of nitrogen excreted in the urine, which in turns decrease air emission of ammonia. Sows house in hot environmental conditions produce more heat however reduced CP diets do not reduce the heat produced by the sows and their piglets. When crystalline amino acid prices are favorable over protein feed prices, overall cost of production could be reduced if nitrogen excretion becomes regulated.
What these findings mean to the industry:
When amino acid prices are competitive with feed prices, feeding reduced CP diets with crystalline AA supplementation can be implemented for multiple parity lactating sows on the basis of reduction in N excretion and ammonia emission without impacting lactation performance and return to estrus.
Contact information:
Nathalie L. Trottier
Department of Animal Science
Michigan State University