Essential Oils and Methane Production

Oregano

Cow belches release methane into the air, which leads to air quality concerns since methane is considered a greenhouse gas.  Ionophores, like Monensin, have been used to alter the rumen fermentation and reduce methane production along with providing other benefits.  However, ionophores have been banned in Europe and who knows what the future is for these products in the US.  Therefore, researches have tried to find naturally occurring substances that could have the same effect as ionophores.

Like ionophores, essential oils alter the rumen fermentation of feeds by changing the populations of the different kinds of rumen bacteria.  They essentially act like antibiotics in the rumen and kill certain kinds of bacteria.  In the rumen, there are numerous different kinds of bacteria and if one is inhibited another one will flourish.  Since different kinds of bacteria produce different end products (volatile fatty acids, methane, ammonia, etc.) from their fermentation changing the populations will change what is produced from the overall rumen fermentation process.   

Some of the common essential oils that have been studied so far are garlic oil, cinnamaldehyde (from cinnamon oil), eugenol (from clove bud), capsaicin (from hot peppers), and anise oil.  All of these oils have been shown to reduce methane production, modify protein degradation, and increase propionate production in the rumen.  Propionate is the main energy source for milk production so one benefit to feeding essential oils could be increased milk production.  Modification of protein degradation could reduce the amount of ammonia produced in the rumen.  Ammonia produced in the rumen is converted to urea in the blood, is excreted in the milk and urine, and is the main source of excess nitrogen in manure.  Therefore, reducing ammonia production could have both air and water quality benefits.  Reducing methane production would have direct positive impacts on air quality since it would result in less methane being belched out.

Researchers at Penn State have also waded into the area of study and have looked at oregano as a feed additive to reduce methane production.  Dr. Alex Hristov is the main investigator and he began this work by evaluating different supplements in the lab.  He then moved his research to animal studies and found that feeding oregano reduced methane production in dairy cows by 40% and increased milk production by 3 lbs/day.  Because methane production represents an energy loss to the animal it is not surprising that reducing methane production would also lead to an increase in milk production.  The future of this work is to determine what specific compound in the oregano is actually eliciting the response.  Determining the basic compound is essential to get this type of research out onto the farm because basic compounds are easier to make consistently and would be cheaper for farmers to buy.

Although many of these products show promise, how well they work and if they alter the rumen fermentation in a positive manner is highly variable.  These products work on a broad range of rumen bacteria so truly manipulating rumen fermentation on a fine scale will be difficult.  Also, essential oils are very pH dependent meaning that they work differently at low versus high pH.  Therefore, the type of animal and diet fed to that animal will greatly impact how well essential oils reduce methane production.  What dose to feed, how to incorporate into rations, and what combination of oils is the best are all things that are yet to be determined. 

Water Conservation

This summer has been a dry one for many folks in Pennsylvania and around the northeast.  This has lead to major losses in crop production because many farmers in this part of the state do not irrigate their crops.  In other parts of the country irrigation is the norm, but in Pennsylvania there is usually enough rainfall to not warrant irrigation.  This year was an exception. 

Although drought has the most noticeable impact on crop production other areas of the farm can be impacted as well.  Farm animals need a lot of water and if the water supply to the farm is not adequate to sustain them through dry times animal production can also suffer.  A person uses about 62 gallons of water per day, much of which is water that we are using for washing and other activities, and not directly consuming.  However, a dairy cow needs about 30-35 gallons of water a day just to drink, beef cows and horses need about 15 gallons per day, and 100 chickens need about 10 gallons of water per day.  Many farms are supplied by wells or springs and both can give out during extended dry seasons.  Springs are more likely to give out than wells, assuming the well is dug deep enough, so they should be monitored more closely.  Monitoring the well, regardless of how deep it was dug, is always a good idea because if it is getting close to giving out you will have time to plan for an alternative water source.  Well monitors cost between $250 and $1000, but if that is the main water source for a farm it is well worth the investment.

There are a number of simple things that can be done to conserve water in the home and on a farm and many good suggestions can be found at the Penn State Extension Water Resources web page.

Tracking MUNs to Limit Ammonia Emissions

Milk urea nitrogen (MUN) is an affective and easy tool for farmers to track how well their cows are utilizing nitrogen from the feed, but it can also be a tool to evaluate air quality on farms. 

Milk urea nitrogen on well managed farms ranges from 8 mg/dl up to 12 mg/dl.  Values higher than 12 indicates that there is nitrogen being wasted and the ration formulation needs to be evaluated.  There are two things that should be looked at in the ration when MUNs are running high.  The first is the amount of protein in the ration.  If the cow is fed more protein than she needs that protein will first be converted to ammonia in the rumen.  Ammonia is then absorbed into the blood stream where it is converted to urea due to the toxicity of ammonia to the cow.  Much of this urea is then excreted as a waste product in the urine, but some will also go into the milk.  Therefore, MUN is a good indicator of how much urea is excreted in the urine.  The other thing to look at in the ration is the amount of available energy.  If there isn't enough energy for the level of protein the protein will be broken down without subsequent microbial protein production and ammonia will be formed.

From a farmer perspective high MUNs indicate that money is being wasted on protein that is not being used for milk production.  From an environmental perspective urea that is excreted in the urine is quickly converted back to ammonia by the urease enzyme found in the feces.  This ammonia creates air quality concerns for the farm and the surrounding area.  It is estimated that 25% of the nitrogen that ends up in the Chesapeake Bay comes from the air as ammonia.