Rayner Reckons

Mar 19

Know the risks of Nitrate & Prussic Acid in your feed

Posted on Tuesday, March 19, 2019

Feeding stock is a task that requires some prior preparation.  While most feeds can be provided to ruminants, it doesn’t mean that you can feed them without following a few simple rules.  

 

The rumen is a living environment, which hosts the micro-flora, fungi and other organisms that actually work to break feed down so that it can be absorbed and used by the animal.  Sudden changes in feed type, lack or roughage and reduced water intake can all create a situation where the environment of the rumen becomes unhealthy to the micro-flora and results in digestive upsets and illness.

 

Mostly the rumen remains fairly stable as livestock select diets that allow the rumen micro-flora to thrive and do their job of breaking down material for absorption and digestion.  Problems start to arise when diets and rations are offered that create unhealthy rumen environments. 

 

As mentioned before common issues are changes in feed types, particularly to including grains that have high levels of starch.  It also occurs when fibre is lacking or if rations are less than the animal requires and as it becomes hungrier it eats plants that may contain toxins that can result in illness or death.

 

Poisoning is a risk that many producers have had to consider this year. Common issues have been weeds that have been eaten as hungry stock eat whatever they can chew.  It also has been an issue as new weeds arrive in drought feeds. Stock may consume plants that are poisonous simply because they have never seen them before.  

 

However the biggest issue has been with sorghum crops that have been grazed or cut for fodder.  The cause has been either from Nitrate poisoning or from Prussic Acid.  

 

What is Nitrate Poisoning?

 

Nitrogen is needs by plants for growth.  They absorb nitrogen through the soil and root system.  Young plants and leaves have high levels of nitrates as they are growing. However when plants are stressed or not growing at a rate that allows the nitrogen to be used, the plant stores this as nitrate.  Some plants are more prone than others to do this (they are known as ‘nitrate accumulators’), but most plants will accumulate nitrates to some degree if stressed.

 

The issue for livestock is that when the material is eaten that Nitrate is converted to nitrite.  This chemical change allows the nitrite to be quickly absorbed from digested feed into the blood system where it attaches to hemoglobin.  These nitrites replace oxygen cells in the blood and cause rapid impacts on the animal.  

 

Within 15-20 minutes symptoms like staggering, difficulty breathing, spasms and foaming at the mouth start to occur. Many affected animals will lie down while some may thrash about.  I’ve had it described to me that the cattle looked drunk.  

 

Its mainly sheep and cattle impacted in this way.  Horses and pigs are less affected by nitrate because they don’t convert it to nitrite. If levels are high though, the nitrate can damage the lining of their gut.

 

According to a number of sources, most of the species commonly grazed in Australia can cause nitrate poisoning if stressed.  These are species that include oats, sorghum, maize, sudan grass, Johnson grass, canola, lucerne, kikuyu, turnip and sugar beet tops, soybean, wheat, barley and a range of weeds.

 

It’s essential that you consider feed testing any fodder that you purchase to see what level of nitrate is in the feed.  Ask a few questions from the vendor?  Was it treated with a big application of fertilizer or manure?  Was it stressed before bailing?  These questions can help you decide if it is suitable to feed to livestock

 

Prussic Acid

 

Prussic acid is a major concern for producers who graze or rely on sorghum varieties for fodder.  It is present in most sorghum, although some varieties will have lower levels.   

 

At a chemical level within the plant, prussic acids exist as a non-poisonous chemical called Dhurrin.  This chemical can react with another plant-based material known as Emulsion.  Under the right conditions, these two materials will react and create Prussic Acid.  It’s also known as Hydrocyanic Acid.  In simplest terms this is Cyanide Poisoning!

 

Damage to the pant through mechanical impact, environmental stress, trampling and even insect damage results in the mixing of these materials and the release of Cyanide.  

While sometimes this can evaporate from the plant, it doesn’t all disappear.  It also means that further damage, such as harvesting, or grazing will result in more Cyanide being released. 

 

The concern with Prussic Acid is its high level of toxicity.  Feed Central suggests that amounts greater than 0.1 percent (1000 ppm or mg/kg) of plant dry matter is considered highly dangerous. Some levels from the Washington State University place that level even lower at 750 ppm.

 

The effect on animals is very similar to that of nitrate poisoning. The acid is readily absorbed into the bloodstream and it then attaches to the hemoglobin and displaces oxygen.  

 

Since many producers look to graze or use sorghum forage there are some basic considerations to be factored into the decision making process.  Remember that: 

  • Leaf blades normally contain higher levels than leaf sheaths or stems
  • Younger (upper) leaves have more prussic acid than older leaves
  • Tillers and branches (“suckers”) have the highest levels, because they are more leaf than stalk

 

Most sorghum should be grazed when they are more mature.  Often this is over 3ft in height.  As plants mature, there are more stalks than leaves in the overall plant causing prussic acid content in the plant as a whole to decrease.

 

With so much drought-affected crops its important to remember levels will be much higher as the pants are mostly leaves. Sorghum grown in drought may retain high levels of prussic acid, even if made into hay or silage.

 

My advice to all producers thinking about using or grazing sorghum is to get it tested first!  Know the levels before you feed it out.  There may be alternative uses to this feed. 


If you do have concerns, or you want some more advice, then get in touch with me. Asking questions can save you a lot of risk and the potential of stock losses.

Sep 05

Have you really considered what you are feeding?

Posted on Wednesday, September 05, 2018

NSW is now categorized as 100% drought affected.  As the state emerges from winter and looks towards a hotter drier spring and summer, there are many producers considering what options they have available.  

For many the decisions include choosing to continue destocking, with the goal of retaining a core group to focus on.  Other producers have spoken to me about their plans to keep feeding and maintain numbers.  For a large portion of people the decision is a mix of selling and feeding.

None of these decisions are easy.  Having spent close on the last 12 months advising producers on strategies, I know how hard choices can be.  However, regardless of the difficulty, you must make decisions, and build a plan to help manage the direction you want to take.

Perhaps the hardest part of this process has been for producers who are choosing to feed, and have started to draw on uncommon feeds to support their herds. 

By uncommon feeds, I mean choosing options outside of the usual products that include grains, hay, silage, plant based meals and prepared products like pellets. 

As these feeds become more difficult to source, or more expensive to source, producers have looked to alternatives.  In the past few weeks I’ve spoken to producers feeding products that have included;

Scrub cut on farm

Pumpkins

Potatoes

Grape Marc

Bread

Orange Pulp

I’m sure there are plenty of other things being fed to cattle and sheep.  These are just the ones I’ve come across lately.

While these options can be useful feeds, its essential you use them after considering the risks associated with these feeds.  Not all of these feeds are as useful or as good as they might be made out to be.

The important things you must consider are:

Residues:  Chemical residues are one of the great risks in feeding unusual feeds.  Many products from the horticultural sector may have been treated with chemicals for pest control or grown in soil that has a chemical risk.  These products might be fine for use on horticultural products, but in meat these same chemicals may be prohibited.

You need to consider if there is a risk with products that may have been treated or grown in soil.  Products like potatoes, pumpkins, and sugar cane tops can contain soil which may lead to a residue issue.  So its important to ask a few questions about the background of the product before you feed it to stock.

Dry Matter:  All products contain some water.  However the amount of water will vary considerably.  If a product is 50% Dry Matter (DM) that means half its actual weight is made up of water. 

The implications are that in transporting that feed, half the weight in the load is water, so you wont get as much as you were expecting to be delivered!

Secondly it means that the amount you actually feed out will be twice the amount of product.  In simple terms, if your co requires 10kg/ DM/ day you would need to feed 20kg of feed to meet those requirements. 

Often variations in Dry Matter mean ration amounts are not meeting livestock requirements and causing nutritional issues for stock.

Variable Feed Quality:  In a drought we are really aiming to provide the energy (Mega Joules – MJ) that animals require for their daily intake.  This needs to be balanced with an appropriate level of Crude Protein (CP%) for their production needs.  In addition the amount of fibre in the feed will impact both on energy levels and the amount an animal can physically eat each day.

Some unusual feeds can be reasonable in their energy levels, but very low in protein.  Others may have reasonable levels of protein but it is unavailable to the animal as the protein is tied up in tannins within the feed.

Protecting Yourself

For many people these unusual feeds help keep their program in place.  There’s noting wrong in using these feeds. 

However you need to use them in the full knowledge of the risks they may have. 

If you are going to use them, there are some things you must absolutely do.  These are:

Request a Commodity Vendor Declaration. The Commodity Vendor Declaration or (CVD) outlines the product source, the chemicals it may have been treated with and its suitability for feeding to livestock in regards to exposure to restricted animal materials (RAM).

If you cannot obtain a CVD you must record the feed stuff, where it came from, the amount, the date your received it, when you started feeding it and to what stock you fed it to.  This is all part of the standard records required for your LPA accreditation anyway.  I also tell my clients to keep copies of the invoice and supplier details.

Get a Feed Test DoneA feed test will tell you the quality of the feed you are intending to use.  If it has sufficient energy, protein and fibre.  The results of a test will help you decide if it is product that can be fed on its own, or if it requires something else blended to balance the ration for your stock. 

Either way, once you know, you can then decide how best to use it.

There are other practical considerations.  For example, feeding scrub is a commonly used source of roughage.  However you need to consider how you will feed it.  Don’t forget your own safety in cutting scrub!  We are not all NINJA warriors able to leap around trees lopping limbs!  So you need to be realistic as well.

Other products sue to their bulky nature, water content or size may pose limitations to how much your animals can physically eat, and therefore reduce the usefulness of the feed source.

If you are thinking of going down the path of using unusual feeds, then do some research.  Consider the risks and evaluate the true value of the feed and its usefulness to your program.  Remember one size doesn’t fit all! If you do want to talk through your options, please feel free to get in touch 

Mar 07

How do you prioritise risk?

Posted on Wednesday, March 07, 2018

Its vey common to hear how much risk there is in agriculture.  I know I hear the phrase “farming is a risky business” fairly frequently.  To some degree that’s true.  There are risks with the weather and the markets.  There are risks associated with production from diseases and pests.  There are the risks working with machinery, animals and working in isolation. 

However choosing to focus on the negative side of risk is also a risk.  Choosing not to do something, simply as a reaction to a perceived level of risk might actually be the wrong thing to do for your business or for yourself.

Lets face it; risk is part of life! There are risks with everything we do.  The way we manage those risks depends on our experiences, our knowledge of similar or past events.  It includes an appreciation of the situation and a decision to way up the possible outcomes of that response.  So risk management is something we all do!

In day-to-day life making risk management decisions needs to happen in our head, and often quite quickly!  However for a business, making risk management decisions on the fly, often leads to missed opportunities or costly mistakes that time and money to correct.

So how do you look at risk?  How can you plan for risks and develop a business structure that is robust enough to respond to risk and capitalize on opportunities that often come along?

One of the tools I find most useful comes from the work health and safety industry.  Called a risk score calculator, its basically a way to plot the level of risk to an activity or an event.

The tool plots the Likelihood of something occurring.  

There are five levels, from Almost Certain to Rare.  

The way I use these levels is to look at the data I’ve collected on the business.  Has it happened before, is it happening often, does it happen all the time?  In my mind, that’s the whole point of collecting data!

The second step is to decide what are the consequences of an event happening?  Is it Catastrophic – which if you prefer is an easy way to say if this occurs will someone die, or will huge losses occur?  And then through Moderate to insignificant consequences. 

When you determine that level it’s fairly straightforward to decide if the risk you are considering is extreme, high, medium or low. 

Effectively using this tool helps you prioritize your actions and future plans.  Extreme risks are the ones you need to fix straight away.  

Quite simply you need to consider what can you change to lower that risk?  Is it a change to the way you operate?  Is it a physical change to infrastructure?  Does it require you to invest in skills and training?

Setting priorities is a huge part of risk management.  You can’t do everything at once!  And while there are always jobs to do, some of them are probably less important and can wait a while. 

I reckon the real value of using this tool comes from actually sitting down and having a rational and objective assessment of the situation.  As I said previously, your data will help you decide if the situation is likely to occur or not.  The consequences of the event help set its place on your list of priorities.

I’ve recently been working with a producer using this tool to evaluate the impact of weather extremes.  Their farm data shows clearly rainfall is coming in more intense events and the periods between rainfall is growing.  

The pasture data shows changes in growing days as well.  That data shows that it is likely they can no longer rely on certain species of temperate pastures to finish cattle for their traditional market. 

The consequence of that is major impact on the business.  The risk to that business is rated as High.  So we have been working to develop pastures that suit the changes recorded, with more sub tropical species introduced into the mix.  We have also started focusing on alternative markets so that cattle hit the specifications.

These are all big business changes.  But we are making them to respond to a clearly determined level of risk.  More importantly with my clients, we have a set of priorities to focus on.  In sitting down to discuss the ways to respond, we were able to look at opportunities and new directions before choosing the best option for this business.

It also highlights the importance of collecting good data.  I like using data to drive innovation on farm.  Responding to and lowering risk needs some innovative ideas!  If your data can’t help with those decisions, then you really do need to rethink how you are operating.

Over the next month I’m visiting several new clients to look at their programs and offer some advice.  One of my first questions will be how do you manage risk?  You can be sure we will go through this exercise and work up a few priorities! 

Don’t forget if you want a hand to help set your priority list in order or to look over the data you need, I’m always happy to come and ask the questions and get you going!



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