great scot

Great Scot: healthy, fresh milk!

The opportunity to work and travel overseas saw AbacusBio consultant Grace Johnstone investigating the fatty acid profile of milk at the Scottish Rural College (SRUC)'s Roslyn campus near Edinburgh, from August to December 2012.

The research project involved the use of mid-infrared spectrometry to estimate the fatty acid content of milk. This recent technology is a fast, efficient and accurate alternative to traditional methods of measuring fatty acids.

Grace was primarily involved in using statistical modelling to understand effects of factors including diet, genetics, season, lactation stage and correlations with milk yield and body condition score.

“We observed large variation in the profile of fatty acids throughout lactation, and diet also had a significant effect. Cows fed a by-product based diet with some palm kernel oil supplement, produced milk with a lower saturated fat content than a herd fed on homegrown forage rations.” She added “there was also a divergence between a high-yielding genetic line and a control line suggesting that present breeding goals are resulting in milk with higher saturated fat content.”

Grace explains that consumption of saturated fatty acids is associated with adverse effects on cholesterol status, blood pressure and consequently, cardiovascular disease risk. In most developed countries around the world, cardiovascular disease is the leading cause of death and dairy products are the major source of saturated fats. Therefore, lowering the saturated fat content of our milk supply could have significant benefits on the health of our population. In addition, lowering the ratio of saturated fats to unsaturated fats is a natural way to produce differentiated products such as more spreadable butter.

Grace suggests that while the fatty acid profile of fresh milk is not currently regulated for New Zealand farmers, the industry or legislature may introduce some ceiling levels for saturated fat in the future. This is already the case in the United Kingdom, where a leading supermarket chain, Marks & Spencer, has worked with suppliers to reduce saturated fat content levels in its dairy supply and offers a premium for milk specially produced to have reduced saturated fat levels.

Beyond the potential to help produce healthier milk, the research programme also aims to explore the use of spectral data to guide herd and cow management decisions. For example, the fatty acid profile of milk is correlated to energy balance so spectral data could be used as an early indicator of likely body condition loss. This would allow the herd manager to act before significant deterioration in body condition occurs.

“My stay in Edinburgh was a fantastic experience”, Grace reflects. “It was exciting to be involved in a new and growing field of dairy research and great to be part of the continuing relationship between AbacusBio and SRUC.”