A study into the effects of a Coriander based additive inclusion on dietary intake, nutrient balance, animal productivity, ruminal fermentation, Methane emissions and ruminal microbial community structure

Abstract

After Carbon Dioxide (CO2), the second most significant anthropogenic and abundant greenhouse gas (GHG) is methane (CH4). This study considers the global importance and measurement of methane, the approaches applied, as well as the available technology to help mitigate the issue of methane emissions in ruminants. The main area of interest, to assist with this mitigation, is through the use of an essential oil blend additive in the diet. In dairy cattle, essential oils have been shown to lower the daily CH4 emissions (g/d) and CH4 relative to dry matter intake (g/kg DMI), by up to 15%. It has also been shown to influence the rumen microbiota and therefore favourably alter the CH4 emissions relative to the milk production, in terms of per unit milk as well as milk quality. In order to investigate this, four main in vivo trials were undertaken that utilised data for methane emissions for both dairy cows and growing lambs (investigate effect of additive on methane emissions per day g CH4/d; per DMI g CH4/kg DMI and CH4 relative to bodyweight increase (g/kg BW). 18 ewe lambs and 8 periparturient dairy cows were used for the short-term/exploratory trial (Chapters 3 and 4, 12 weeks and 3 months respectively) and the entire University dairy cow herd (circa 450 dairy cows) for the long-term trial (Chapters 5 and 6, 6 months). The purpose of the initial/exploratory trials was to investigate the potential quantity of the essential oil additive, Agolin Ruminant, required to lower methane emissions in ruminants, develop a procedure for a long-term study and to develop the optimum method for DNA/RNA extraction of the rumen samples. Results from the initial/exploratory studies of both cows and sheep (0,0.5,1 and 2.5g/h/d; 0,100 and 200ug/h/d respectively), showed little in the way of significant difference in the microbial population (p>0.05). However, many numerical differences were seen that could have potentially led to differences being seen in the data over the long-term. This was confirmed in the long-term trial, showing significant differences for lower methane emissions (6%), lower methane emissions per kg milk produced (19%); and an overall increase in productivity data (10%) for the animals receiving 1g/h/d of Agolin was seen. To conclude, over a long period of time, Agolin Ruminant affects the rumen microbiota to increase the productivity of the animal whilst lowering the methane emissions.

Date of Award	2020
Original language	English
Awarding Institution	Aberystwyth University
Supervisor	Jamie Newbold (Supervisor), Kenton Hart (Supervisor) & Eric Jean-Yves Roger Pinloche (Supervisor)