Historical selection programmes within the Holstein breed focused mainly on milk production, while largely ignoring functional traits. The subsequent decline in these functional traits within the Holstein population, especially fertility and health, has now been well documented. The use of alternative breeds (breed substitu-tion) and crossbreeding have been suggested as strategies by which some of these problems may be overcome.
The potential of these two approaches have been examined in a number of studies undertaken at AFBI-Hillsborough, and on commercial dairy farms in Northern Ireland, with these studies conducted under predomi-nantly low input management scenarios. Breed substitution studies have involved comparisons of Holstein and Norwegian Red cattle, while crossbreeding studies have involved comparisons of Holstein with first cross Jersey crossbred cattle, and Holstein with three-way crossbred dairy cattle (Swedish Red x Jersey x Holstein). These studies have compared milk production and composition, fertility, health, longevity and profitability of the different breeds and genotypes.