Recent work conducted by groups including partners in the GplusE project shows that milk based biomarkers have a great potential to improve the efficiency of breeding and management of dairy cows.
Because traits relating to fertility and health of dairy cows are complex and very difficult to measure on an individual basis, the genetic progress in breeding for robust dairy cows is slow. Similarly, traits such as energy balance or methane emissions are also hard t]o assess on an individual basis, which hampers the capacity of farmers to manage their animals in a cost effective and environment friendly way.
Milk composition is potentially an important source of information on such traits and mid-infrared (MIR) spectroscopy allows to measure milk-based biomarkers in each individual cow at a reasonable cost.
A collaborative study between Teagasc in Ireland and the Walloon Agricultural Research Centre in Belgium demonstrated that the accuracy of predicting residual feed intake (a commonly used proxy for feed efficiency) from milk MIR spectra was 0.62 in cross validation. The accuracy of predicting methane emissions was 0.87. Accuracy is the correlation between the predicted and the actual values.
Another study conducted at the University of Liege showed that the measurement of a combination of various fatty acids traits (e.g., C18:1 cis-9 and C10:0) could be used to breed for fertility. MIR-predicted acetone and β-hydroxybutyrate contents in milk are useful for breeding cows less susceptible to ketosis. A number of MIR-predicted phenotypes related to the disease response of the cow (e.g., lactoferrin); to the reduced secretory activity (e.g., lactose); and to the alteration of blood-milk barrier (e.g., minerals, citrate) can also be potentially considered for predicting susceptibility to mastitis.
The results from both studies were obtained from limited data sets and have therefore to be confirmed on higher number of animals. This will be achieved in the research studies that are currently performed within the GplusE project.
More information can be obtained from papers 10, 11 and 13 presented in J. Anim. Sci. Vol. 93, Suppl. s3/J. Dairy Sci. Vol. 98, Suppl. 2. You may also contact Nicolas Gengler: nicolas.gengler[at]ulg.ac.be.