Figure 3. Responses in milk production to environmental variables for different sires A.

Predicted response in daily milk production of daughters to temperature humidity index (THI) for the two most extreme sires from the data set. In a climate change scenario where the THI increases significantly, sire 2 should be selected for breeding as the milk yield of his daughters is relatively insensitive to THI. B. Predicted response in daily milk production of daughters to herd average daily milk production (HTDMY), a surrogate for the level of feeding, for two sires from the data set. With low levels of feeding, eg. low inputs of grain, sire 2 could be considered as his daughters produce more milk than the daughters of sire 2 at very low levels of feeding.