Which factor does NOT contribute to reduced animal productivity on farms?

High-quality feed plays a crucial role in enhancing animal productivity on farms, rather than reducing it. Proper nutrition is foundational for optimal growth, reproduction, and overall health in livestock. When animals receive balanced and nutrient-rich feed, they exhibit improved performance metrics, such as weight gain, milk production, and reproductive success.

In contrast, factors like infectious diseases, environmental stressors, and genetic predisposition can negatively impact productivity. Infectious diseases can lead to health issues, reduced growth rates, and increased mortality, all of which detract from an animal's productive capacity. Similarly, environmental stressors such as extreme temperatures, inadequate housing, and poor management practices can stress animals, leading to lower productivity outcomes. Lastly, genetic predisposition can influence traits such as growth rate and disease resistance, and unfavorable genetics can hinder an animal's ability to thrive and produce efficiently.

In summary, high-quality feed is essential for promoting animal productivity, while the other factors mentioned tend to diminish it.