By employing various models and adjusting their underlying assumptions, we can reveal previously hidden aspects of complex systems, such as animal populations. Different models indicate that nitrogen utilization efficiency varies significantly between individual animals and herds. Specifically, amino acid and protein levels optimized for individual pigs do not necessarily enhance overall production unit efficiency. Additionally, our newly developed mathematical models offer improved accuracy in describing the physiological responses of pregnant sows to lysine and protein intake. Our findings suggest that at low lysine levels, sows may increase their litter size at the cost of their body condition and piglet quality. Conversely, higher dietary lysine levels result in a reduced litter size but improve piglet quality, survival, and sow longevity. The dynamics elucidated by our models help explain the observed trend in the U.S. of increased litter sizes coupled with decreased piglet and sow survivability. By employing advanced models to assess amino acid requirements, we not only enhance our understanding of nutritional efficiency but also gain critical insights for optimizing animal health and productivity, addressing key challenges in swine production.
