Purna Badhra Kandel

Thématique

The general objective of this thesis is to study the relationship between the environmental impact traits like methane and the fine composition of milk and their genetic quantification at individual cow and sire level. This thesis is conducted through the ITN Marie Curie GreenHouseMilk project and SPW-DGO3 Methamilk Project.

Enteric methane emission is one of the largest sources of methane emission in animal agriculture and there is considerable drive to estimate the individual cow emissions which will have great impact to select low methane emitting cows. Due to difficulty to collect large number of phenotype from conventional methane measurement from individual animals, alternatives are sought. Consequently, some studies have focused on the use of traits indirectly related to the methane emission and easily recorded at large scale, as milk fatty acids (FA). Milk FAs can be accurately predicted by milk Mid-infrared (MIR) (Soyeurt et al., 2011) and these FAs has shown indirect link with methane emission (Chilliard et al., 2009, Dijkstra et al., 2011). It has been shown that direct quantification of CH4 emissions by mid-infrared spectroscopy (MIR) from milk samples is possible (Dehareng et al. 2012).With large recorded MIR spectra from Walloon Region of Belgium and from another GreenHouseMilk partner (TEAGSAC, Ireland); an accurate estimation of genetic parameters for environmental traits seems possible. Before adding new trait like methane emissions on multi-trait animal selection program, estimation of genetic correlation between this trait and other traits and quantification of their predicted selection response is important which are the parts of this thesis.