Grouping Animals for Better Water Quality

What does grouping animals have to do with water quality?  Initially they may not seemed connected, but grouping animals can have big impacts on local water quality.  Cows can be grouped by age, pregnancy status, or stage of lactation.  Although all grouping strategies have benefits, grouping cows by stage of lactation is the most beneficial for water quality.

Cows at different stages of lactation have different levels of milk production.  When cows first calve their milk production is relatively low, but rapidly increases and peaks around 60 days post calving.  After that, milk production declines at a slower rate until the cows are dried off around 300 days post calving.  Because milk production is the main driver of feed and nutrient intake, cows at a similar stage of lactation will have similar nutrient requirements.  Therefore, if a herd is grouped based on stage of lactation rations can be created for each specific group that more closely matches the needs of that group.  

Rations are formulated based off of the average milk production of a group plus two standard deviations.  This is the best compromise to meet the requirements for the highest producing cows while decreasing the amount of overfeeding to the lower producing cows.  However, the tighter the range of milk production in a group of animals the lower the standard deviation and the more precisely the ration can be formulated to meet the needs of the group without overfeeding the lower producing cows in the group by such a degree.  The overfeeding of nutrients, specifically nitrogen and phosphorus, are major contributors to local water quality concerns because when more nitrogen and phosphorus is fed to the cow than she needs the extra is excreted in the feces and urine.

Grouping cows is generally more economical as well because feeds can be used most efficiently.  Larger dairy farms have been grouping cows for a while, but it is more difficult for smaller farmers to have enough animals in a certain stage of lactation and/or the facilities to group animals.  However, it can be done with some creativity and smaller farmers should consider grouping as a way to increase feed efficiency and reduce nitrogen and phosphorus loss from the farm.

Challenges to Implementing BMPs on a Farm

Why don't farmers implement certain best management practices (BMP) on their farms?  For those who are not farmers, it may seem obvious going onto a farm that a certain BMP should be implemented.  The farmer may even agree with you but yet there is no plan to implement that BMP on the farm.  The biggest reason BMPs are not implemented is the economy.  Farmers have no money to spare so even if there is cost sharing available there just aren't the matching funds from the farm perspective to make the BMP go forward.  Everyone has been hit by the overall economic crisis, but farmers were hit especially hard with low milk prices that will take many years to recover from.  In short, most farms are in survival mode and extras are just not going to happen.  Unfortunately there is no good solution to this issue until the milk price and the overall economy improve.

The other reason I see why farmers don't implement a specific BMP on their farm is that they don't know what to do. With limited funds they don't know what BMP would be most beneficial to them, and they may not be aware that some BMPs are actually required.  For example, farms in Pennsylvania have been required to have a conservation plan and a manure management plan since the 70's but there are many farmers that do not know that they are required to have these two plans on file.  If we want farmers to improve nutrient management and soil conservation on their farm we need to be very specific about what they need to do. 

The Miner Institute, A Great Resource

Miner Institute Dairy Facilities

The Miner Institute is a privately funded research institution located in Norther New York.  It has a working dairy farm and equine facilities that allows it to do a great deal of research in many different areas and one of those is environmental issues.  The institute also publishes an informative and entertaining monthly newsletter entitled the "Farm Report" on current topics and research updates.  

The October issue just came out and there are two interesting environmental focused articles related to manure application and the carbon footprint of milk.  The manure article emphasizes the importance of spreading manure as thin as possible to avoid environmental consequences.  The article also makes the point that in many situations traveling a little further to spread  manure instead of just going to the field next to the barn will pay off.  Many farms assume that the gas and time is not worth traveling further to spread manure, but the improved yields from those fields will offset the cost of travel in many situations.  

The other article of interest summarized a study published in Food and Nutrition Research that evaluated the carbon foot print of various drinks (milk, soft drinks, orange juice, beer, red wine, mineral water, soy drink, and oat drink) relative to the nutrients provided by those drinks.  The results of the article showed that milk had the lowest climate impact relative to the amount of nutrients provided.  Milk is a very nutrient dense product so what environmental impact it has is offset by the nutritive value of the product. 

I encourage everyone to check out the Miner Institute's Farm Report.  It will be well worth the time. 

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. 

Protein Utilization on Pasture

Although we tend to worry about cows getting too much protein from the pasture during the lush spring months, the fall bump can also lead to too much protein intake on pasture. Good quality pastures tend to provide more protein than energy in general, but during the spring and fall growing seasons that ratio tilts even further towards protein. Therefore, supplementing either grain, corn silage, or a total mixed ration (TMR) is usually necessary to improve production in grazing herds and increase the utilization of protein from the pasture.

The energy component of the diet can greatly influence how the protein from the pasture is digested. This is because when a cow eats she is not only eating to support her own needs, but also the needs of the microbes in her rumen. When there is energy and protein available at the same time these microbes break down the feed (energy and protein) and use the end products to produce more of themselves (microbial protein). They then pass out of the rumen serving as a protein source for the cow. However, if there isn’t enough energy available, as is the case on pasture, the protein in the pasture will still be broken down, but instead of being converted to microbial protein, feed protein is broken down to ammonia. Ammonia is absorbed into the blood where it is converted to urea. This urea in the blood is the source of milk urea nitrogen (MUN) and urea nitrogen in the urine. Since MUN is coming from the same blood urea nitrogen pool as urea in the urine it is a good indicator of urea excretion and utilization. Excessive urea production and excretion in urine can lead to water and air quality concerns.

Also, from the cow’s standpoint, the production and excretion of excess urea takes energy. There is a paper out of Penn State by Kolver and Muller that estimated excess urea excretion cost the cow almost 4 lbs of milk/day! This is because it takes energy for the cow to convert the absorbed ammonia, which came from excess protein supply in the rumen, to urea. Ammonia is toxic to the cow so this conversion to urea is a necessary energy utilizing process, which cannot be eliminated, but can be reduced through lower protein rations and appropriately matching ration protein and energy concentrations. Are you willing to leave 4 lbs of milk on the table knowing that not only did you lose milk production, but you also lost feed efficiency and it could have been prevented if MUN had been tracked and maintained within the recommended 8-12 mg/dl?

One way to improve nitrogen efficiency from the pasture and decrease MUN is to supplement the pasture with a partial TMR. A study from Penn State supplemented pasture with a partial TMR and saw an 8 lb/day increase in milk production and a 3 mg/dl decrease in MUN compared with pasture supplemented with 19 lb of concentrate. Supplementing with a grain mix or corn silage are also options, but a mixture is usually better at providing digestible energy that is not too fermentable in the rumen.

Although the pasture may be supplying a large portion of the dry matter, supplementing the pasture is necessary to maximize its full potential. Total mixed ration supplementation of pasture allows for better capture of protein from the pasture the nitrogen utilization will be increased, which can be tracked though MUN values. For all the effort that goes into developing and maintaining high quality pastures lets be sure we are getting all we can out of these efforts.