This podcast episode is based on a technical article examining the limits of conventional Holstein breeding strategies under extreme climatic conditions. It analyzes a dairy operation in Arizona where bulls with very high indexes for milk production and type perform poorly under heat stress, particularly in terms of fertility and hoof health. A comparison of winter and summer data indicates economic losses of up to $360 per cow, largely driven by declining reproductive performance. In response, the herd’s breeding strategy has shifted toward sires with positive daughter pregnancy rates, more moderate type traits, and improved body condition. For certain cow families, targeted ProCROSS crossbreeding is also used to increase resilience and adaptability within the herd. With comments on a "The Bullvine"-article (March 10th, 2026) vy Andrew Hunt: https://www.thebullvine.com