Nov 3, 20219 min read

TRAC Beef & Sheep Newsletter - Spring 2021 Edition

As consultants we are regularly questioned on what it is like elsewhere, often the answer is “it’s all relative”, relative to rainfall, stocking rates, and farming practices adopted.

The Red Meat industry continues to spiral to new heights in 2021. Spring is delivering finishing rains in many parts with the perfect storm for livestock producers in the southern and marginal zones. Appearing as a similar result for many, as seen in 2020, prompting further thought on how to capitalise on opportunities.

Identifying opportunity is driven by a range of factors; physical, financial, environmental, and sometimes just by human nature and the desire to do better. In spring 2020 we explored the opportunity to get More from Winter Pastures, Effects of Moulds and Yeasts in Forages, and discussed Rumen Development in young lambs.

As Spring 2021 unfolds and presents some early signs of weather challenges for forage conservation, we consider the process of making silage, and the opportunities and value of fodder crops with wet conditions in the high rainfall areas. The TRAC team led by Owen Rees has been delivering silage workshops throughout SA and VIC this year focusing on Factors affecting animal performance, encouraging all who attended to review their systems and increase their desire to do better.

Our Nutrition Team is available as we look towards the summer months of feed budgeting and ration formulations, with forage sampling equipment onboard to assist - give us a call.

GRAZING SUMMER CROPS

Whether it is part of your pasture rotation or a designated crop to “finish’’ animals on, many farmers this year have planted forage brassica, turnips, and herbs.

Normally we would see people wait for the crop to mature, then round up a mob of sheep/lambs or cattle and push them in and shut the gate and away we go. If we are lucky, they might get a bale of hay.

Planting summer crops is a costly exercise, but what can be done to make sure that your animals are making the most out of it?

The animal requires a feed source or ration that is balanced however they will normally only select for water, salt, and energy. This means that the first 2 weeks they are in the paddock they eat the leaf tips and then the following 2 weeks they eat some leaf and stem, then the last 2 weeks they graze stem only, ‘cos that is all that is left.

In the first 2 weeks, the leaf tips are full of protein and have little fibre; in the middle two weeks, the ration is better balanced; and in the last 2 weeks; the stems are high in fibre and the animals don’t have enough energy.

So what management strategies can we put in place to help make the ration as balanced as we can?

Strip/Block Grazing

We need the animals to eat more of the “whole” plant in one sitting. The leaf, stem, and in some cases the bulb will provide more of a balanced diet than a leaf only pick. The is largely due to the bugs in an animal’s guts will thrive on a constant stream of nutrients that are balanced to optimise growth and/or production. Another benefit of strip/block grazing includes back fencing once the animals have left so that the area allows the plant regrowth potential to order to have something on offer in the next rotation.

Feeding an Energy Source

With most summer crops being extremely in high crude protein %, the addition of extra energy will be required for the animal to utilise all that available protein, as excess protein results in lost energy. Feeding a small amount of cereal grain, as a starch and energy source, will help the animal convert the protein that would be unavailable without the addition of an extra energy source

Salt and Minerals

Crops that are very digestible by the animal will limit the amount of minerals that the animal will be able to extract before it turns to manure. Adding a tub of TPM loose-lick minerals will help keep animals nutritionally balanced. On crops, we can see some negative mineral interactions and some deficiencies occur that limit stock performance - remembering that Zinc is an important requirement while grazing brassica.

Poor Ensilaging Conditions

Silage can be tricky to nail at the best of times. What makes great silage is multifactorial in the parameters we are chasing, such as dry matter, neither too high nor too low; fibre fractions; energy content; sugars; a low pH and high silage acids, but in no scenarios do we want butyric acid.

This year we may face the challenge of either cutting early and accepting the loss of quality from rain, or letting silage go a bit too long but hoping for better curing conditions – neither of which is what we hoped for. Similarly, what we saw in many areas last year. However, as with all things in farming, there is a gamble and what makes us continue moving forward is the ability to re-plan, adapt and make the most out of a scenario. The best chance we have of achieving our desired results of weight gains, high pregnancy rates and healthy animals, is understanding what can go wrong and how, and then putting in place mechanisms to use the silage in the most efficient way.

How does fermentation work in silages?

The difference between silage, hay and fresh-cut grass, is that silage has high moisture and has gone through a fermentation process to allow long term storage while retaining many of the nutrients. To create the acids to preserve and retain the nutrients, the silage goes through several phases where acids, temperature and O2 levels change.

When the grass or crop is cut, the plant is still respiring and using up sugars and energy. The faster the stomata close the more nutritional value is retained, this is where conditioning and tedding facilitates this process. When the forage is layered into the pit, the most crucial component is reducing the amount of oxygen throughout the forage – this means thin and well-compacted layers.

Phase 1:

Phase one is the aerobic phase, this begins immediately after cutting and early on after being ensiled. This is where respiration and proteolysis occur. During respiration, sugars and O2 get converted into carbon dioxide, water and energy for the microbes. This will continue as long as substrate and oxygen are available. When looking at the time on the ground it is estimated that there will be 5% nutrient loss per day - so it is a high priority to shorten this phase. In this phase, the sugars are used by aerobic bacteria, causing oxygen to drop when in a closed stack. The other main factor in this phase is that we will see a rapid increase in temperature.

If the temperature goes too high there will be more nutrients used and result in an increase in NDF, ADF and drop in energy– the increase in fibre as a percentage is because we are losing other components. Overheating can also lead to degradation of protein quality where we see high levels of soluble protein and it can also increase undesirable bacteria, yeasts and moulds. Proteolysis is the second portion of phase one, where we can see protein breakdown resulting in high levels of ammonia (also from excess O2) or high temperature. The longer the silage is exposed to air, the greater protein loss will be observed.

What causes higher temperature?

Too much oxygen from a poorly compressed stack
High dry matter (>50%)
Poor spreading over stack – uneven compressing
Long paddock time

Phase 2:

Phase two will start when all of the oxygen has been used and we begin fermentation. Acetic acid will begin to be formed and pH will start to decline, however, there is only weak acids at this point and high nutrient losses can be observed. This phase should typically only take 1-3 days. An important time to consider regarding relocating baled silage! by moving the silage we will be again adding oxygen and the entire process will begin again, losing more nutrients, so make sure to relocate them ASAP. Toward the end of phase two, lactic acid will begin to be produced and pH will continue to drop towards 4. The higher the sugar content to begin with, the stronger the fermentation that can occur as this is food for the microorganisms.

Phase 3:

The silage is now at a stable state with a constant temperature and no more fermentation is taking place. Generally, we allow 6 weeks to reach this phase. It is only when oxygen is introduced back to the silage that fermentation can begin again - think of moving baled silage, accidental tears to the plastic and opening the face of the stack to feed out, all problems that can restart the process, however, if the oxygen is not eliminated such as taping the holes, it will never reach phase two and continue to lose nutrients and grow mould.

There has been so much work that goes into making silage, it is important to maintain the integrity of the feed when we go to feed it out, such as face management or the time that either pit or baled silage is sitting in the paddock exposed to air. This is the ideal growth area for moulds, yeast, aerobic bacteria and risks significant dry matter loss and loss of nutritional quality – we can lose up to 50% of the nutritional value!

A few areas where we can preserve quality:

Inoculants have been shown to increase silage intake and performance, up to 14% in beef
Density is king
Use good quality plastic, and many layers for bale wrapped silage
Plan for the quality you are targeting - DM %, density and chop length
Move silage bales out of the paddock the same day they are wrapped
When feeding out bales – feed as close to the time the animals will consume feed (within 24 hrs)
Plan the size of the stack and minimum quantity that will be fed out per day for stacks
Move through 30 cm of silage face in a pit per day - Face too big? Feed off from left side one day, then from right side next day
Remove silage from top to bottom – lifting a bucket upwards can lift portions of the stack and allow air to enter
Only pull back plastic cover enough to remove 1 days feed
When it is warm or humid, consider the time it will take animals to consume the silage and the impact to mould growth.

What we can’t control: What happens when silage gets wet?

This will depend hugely on what stage the crop was, how soon after cutting the rain was, frequency and quantity of rainfall. What we do know (fairly certainly), is that rain significantly increases the risk of mould – and mould can impact dry matter intake, fertility and growth rates. Fortunately, this we can control through toxin inhibitors in rations and through loose lick minerals and dilution of feed If needed. The other thing we aren’t so certain about is which areas might be challenged from rained on forage.

When there is rain or external water sources on the forage, it can increase the length of respiration and the plant uses its reserves of sugars and other soluble carbohydrates. This can also result in the leaching of proteins, soluble carbohydrates, and some minerals. Challenging conditions can cause leaf shattering, loss of energy from respiration and microbial activity and an increase in fibre percentage.

Be sure to get a feed analysis before any purchases and for all home-grown forage, to plan for the year ahead and how to manage any unwanted surprises. Get a mould and yeast count before purchasing, or have one done prior to feeding.

10 - 10,000	Relatively safe
10,000 - 100,000	Transition zone
100,000 - 500,000	Relatively safe - watch for clinical signs, consider feed management options
500,000 - 1 million	Discount nutrient value by 5%, feed with caution
1 million - 5 million	Dilute feed, and include feed management options
Over 5 million	Avoid feeding
Over 10 million	DO NOT FEED

Adapted from Hoffman(2009), Adams(2013) & Penn State Extension by Feedworks AU

Depending on where your count sits, there are ways we can often still utilise the feed:

Dilution is key – the risk will be reduced if the animals are eating less of the problem.
Do a risk assessment on the group you are choosing to feed, if they are rams being prepared for joining, joining animals or animals actively giving birth, choose a lower risk group.
If you need to feed the forage (or grain) and are concerned about the impacts, or seeing clinical signs, there are mycotoxin inhibitors that can be fed with grain or with loose lick minerals.

A mould and yeast count will take 5-7 days from receival in Bendigo. Take a sample as normal for a feed analysis preferably with a corer, place it in a plastic zip loc bag clearly labelled and do not freeze. Post with your submission form via express post. For a nutritional analysis of silage, select the A1 Plus to receive silage acids. Alternatively – give us a call to come help.

While we can’t control the weather, we can control how we manage weather affected feed and how we offer it to animals. Give your local TRAC consultant a call to discuss a forage plan for your business and to discuss allocating feeds to specific classes of stock for the greatest return.

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