Short project description

Dairy cows considerably contribute to greenhouse gas (GHG) emissions by eructating methane, a natural product of microbial fermentation in the rumen as well as a powerful GHG. Among the available tools to reduce enteric methane emission by targeting rumen metabolism and inhibiting methane producing microorganisms, the feed additive 3-Nitrooxypropanol (3-NOP) is considered the most promising, and large scale implementation in Danish commercial dairy farms is planned (https://fm.dk/nyheder/nyhedsarkiv/2024/april/bredt-flertal-i-folketinget-fordeler-ca-5-mia-kroner-fra-det-groenne-raaderum/).

However, manipulating the mature ruminal microbiome in favour of reduced GHG emissions or increased production efficiency has proven challenging. Accordingly, recent studies have examined 3-NOP as a candidate to early-life dietary intervention to modulate microbial establishment in the gastrointestinal tract of young dairy cattle. Although, its effects on the behaviour of young dairy cattle are unknown.

As part of a large experiment investigating the effects of several doses of 3-NOP on performance and emissions of Danish Holstein heifers conducted in the departmental resident Danish Holstein herd of Aarhus University (Tjele, Denmark), this thesis project will examine the undisturbed behaviour of dairy heifers feed-supplemented with one of four doses of 3-NOP (0, 50, 100, 150 mg/kg DM) over several months of age. The student will help develop an ethogram, label behaviour from video recordings, and analyse original data.