Fredrik Andersen's doctoral research has used data from the national dairy cattle control authority to reveal the connection between the shape of the lactation curve and the incidence of mastitis and pregnancy in Norwegian dairy cattle.

The study shows that a steep curve puts udder health at risk but at the same time promotes early pregnancy. The main reason for this is that a high intake of energy via feed results in a higher volume of milk, which then increases the risk of mastitis. An optimal energy balance is also essential for initiating ovulation after calving.

The quality of feed is decisive

The energy supply provided by feed has a decisive effect on milk production and therefore also on the shape of the lactation curve. Andersen's field work, carried out in collaboration with The Norwegian University of Life Sciences in Ås, Norway, has demonstrated that feed strategy in the first phase of lactation is important in order to promote the cow's milk production, health and fertility.

Too little or too much energy during this period will lead to lower fertility and the development of diseases which result in lower milk output and impair animal welfare.

Applying the results

Andersen's study shows that the shape of the lactation curve can be used to monitor the feed strategy and energy balance in dairy cattle. By means of modern milking equipment, the daily milk output can be measured and used to plot lactation curves. By applying the findings of this doctoral research, the curves can then be used in production control in order to identify feed strategies which promote fertility and udder health.

Furthermore, the parameters of the lactation curve shape can be used in future breeding programmes in order to achieve a slacker lactation curve. This lowers the risk of mastitis, despite a high-energy intake through feed, which in turn promotes milk production and fertility during the first lactation phase.