Imported Holstein Friesian and imported Jersey
cows showed higher milk yield than farm born cows.
The animals of temperate regions maintained under
tropical conditions cannot behave similarly in both the
environments (Javed et al., 2002). The herd under study
was imported from temperate zone (United States of
America) and kept in the subtropical environment of
central Punjab, Pakistan, where ambient temperature
often rises around 45°C in summer months. The import
of temperate breeds to tropical environments is often