Quentin has explored how optimisation of grazing during summer could affect the milk production of dairy cows and enteric methane emissions (eCH4) by replacing indoor grass silage with grazed grass in dairy cow’s diet. To investigate the emissions between cows grazing and cows fed silage indoors, he used a unique setup, two machines that measure eCH4 emissions directly from cows, which were installed outdoors and indoors.
Quentin is based at the Norwegian Institute of Bioeconomy Research (NIBIO) and his project has been carried out in collaboration with SLU in Umeå with SustAinimal’s Mårten Hetta as the head supervisor. He has experience collaborating in projects on animal behaviour and precision farming, has a passion for grazing and is very eager to promote it. The thesis consists of four different papers with four different experiments:
Day or night-time grazing in in Röbäcksdalen Umeå
A grazing experiment on the effects of day or night-time grazing in a part-time grazing system on milk production, animal behaviour, and eCH4 emissions.
Herbage quality on methane production in Tjøtta experimental station (NIBIO) in Norway
Partly an in vivo and in vitro experiment with a modelling approach to estimate CH4 production, estimate intake, feed digestibility, and rumen fermentation patterns based on two different qualities of Italian ryegrass pasture grazed by sheep.
Morning or afternoon new strip on a commercial organic dairy farm in Halland county
A grazing experiment investigating the effect of time of fresh pasture’s allocation on milk production and behaviour of dairy cows in a full-time grazing system.
Exercise or production pasture access in Mære Agricultural School in in Trøndelag
A grazing study investigating the effect of two contrasting uses of pasture, production or exercise pasture, in a part-time grazing system on milk production and eCH4 emission of dairy cows in a farm with an automatic milking system (AMS).
The results showed that forages in the diet, including grass silage and fresh grass, made up over 58 percent of the cows’ total feed during summer. Diets with 20 to 76 percent grazed grass could be an efficient strategy on performances of different dairy barn systems. Even farms with automatic milking systems could rely on grazing for over 50 percent of the cows’ summer diet whilst simultaneously maintaining the production performances compared to only indoor feeding (with exercise paddock). In the second experiment, the quality of the grass was shown to affect the fermentation pattern, with less digestible grass resulting in higher predicted methane emissions per quantity ingested by the sheep.
When grazing was more prevalent in the diet, night-time grazing improved milk quality by 10 percent. Cows naturally grazed longer in the evening and offering new fresh feed at this time provided promising results. At the same time, replacing grass silage with fresh grazed grass reduced eCH4 emissions by 20 to 28 percent whilst maintaining milk performances. Overall, the thesis underscores the positive potential of providing pasture for dairy cows, which not only enhanced animal welfare but also reduced eCH4 emissions whilst maintaining milk performances. This approach could help to reduce the climate footprint of the dairy sector in Scandinavia.
