SAC Research

The project will determine whether increased lifespan, health and welfare can all be delivered through the inclusion of traits related to robustness in a broader breeding index. It will also assess whether cows selected in this way would display undesirable behavioural temperament traits such as overt aggression.

There are a number of candidate traits that may underlie robustness:

• Lifetime Energy Balance (LEB): the amount of body fat carried, and the way it is mobilised during lactation varies between cows. Traits underlying robustness, such as health and fertility, are compromised when body fat levels are extremely low during early lactation. Therefore a means of quantifying body energy change is required and we will be investigating new approaches.

• Maturity: During the first lactation, heifers are still growing, but must also sustain a first lactation and a second pregnancy, and eventually replenish lost body fat. We will investigate whether or not achieving a greater degree of maturity in body size by first calving contributes to robustness. 

• Behaviour: A robust animal must be able to gain access to sufficient feed, water etc, without becoming stressed, overly aggressive, or by becoming completely non-reactive to the environment. We will be investigating the behavioural characteristics of robust and less robust families.

• Health traits and physical characteristics: A wide range of type traits and other physical characteristics may also contribute to robustness and we will study the relative importance of these in this research.

Robustness may differ across the range of environments that currently exist, and may exist in future. Information will be gathered from farms and national databases to determine what the relevant features of the ‘environment’ are for dairy herds. The performance and welfare of bulls’ daughters will be compared within and across environmental categories, to determine whether some bulls are ‘generalists’ (i.e. well adapted to many production environments) and some are ‘specialists’ (i.e. adapted to only some production environments) with respect to environment.

Robust cows should deliver more profitability for farmers through a reduction in health and fertility costs, and culling rates, which will also reduce environmental impact. From the cow’s point of view the use of a selection index that places a higher emphasis on health will be of benefit to welfare.