Molly Kuchel
- Mar 2, 2023
- 8 min read

TRAC Beef & Sheep Newsletter - Autumn 2023 Edition

Evaluation, goal setting, tools and execution are all very important tasks that need to be performed to achieving a profitable result.

Total Result Ag Consulting [TRAC] and TRAC Performance Minerals combine to offer products, service and advice to the ruminant sector on a daily basis and we love what we do.

Information is part of the evaluation and goal setting, TRAC Autumn Edition of our Beef & Sheep Newsletter discusses Utilising Forage Brassicas This Summer and Micro Minerals In Autumn Lambing Ewes. Plus we share where Sean & Mark of the TPM Team will be during the 2023 Field Days season.

If a skim read sparks a question or an idea, as always our consultants are available for a chat, it’s what we do!

UTILISING FORAGE BRASSICAS THIS SUMMER

By Owen Rees, Senior Ruminant Productivity Consultant, Total Result AG Consulting

Growing forage brassicas can help provide your stock a fast growing, highly nutritional feed stuff over the Summer & early Autumn period when most of the permanent pasture species have turned reproductive and lost quality. Brassicas and leafy turnips are a high protein, high energy, low NDF feed source that is available around the same time as spring lambs are starting to be weaned. Brassicas can also be used to increase growth rates of store cattle that are waiting to be finished or to keep dairy heifers on their growth curve, but after I have sown my crop, how do I make the best use of my investment?

When looking through all the research of live weight growth rates on summer crops, we see a wide range; 60g - 320g of LWG per day in lambs and 0.7kg to 1.2kg LWG in cattle. We must ask ourselves the question, why such a range? Is it stocking rate, crop type and stage of maturity and/or year? These all have an impact on the performance of the animals, but the nature of the plant itself has a big effect on the animals that are grazing it.

When we are putting weight on young animals like lambs and weaner cattle we have a protein requirement of 16% CP in the total diet. At this level the animals requirement to build muscle is being met without any adverse effects from excessive protein. Many summer crops, especially brassica have a total plant crude protein level way above the animals requirements. “So what” I may hear you ask, or even “the more the better”, well not in the case of protein. When the animal starts to digest the crude protein from the plant, nitrogen in its different forms are released into the rumen, where the rumen bugs consume it as food. If there is too much or there is not enough bugs in the rumen, the nitrogen levels will increase to the point where it is unsafe for the animal. The animals safety mechanism is enacted and the nitrogen is sucked through the rumen wall into the blood stream where it is sent to the liver to be converted into urea. Some urea is then recycled through the animals saliva and the rest is excreted through the urine back onto the pasture or crop. Changing the form of nitrogen into urea in the animals liver comes at a huge energy cost. This energy could have been better used for live weight gain.

If we looked at a 36kg lamb it has the potential to eat 1.8kg DM of crop per day and put on 370g per day of live weight, so why don’t all lambs grow at this high rate? Well if we use the industry calculation of what the energy cost is to recycle the extra protein, we end up with a more realistic growth rate. Protein levels in the leaves of brassicas have been tested at 32% CP +

0.18MJ per % of CP over 16x intake

0.18MJ x 16 x 1.8 = 5.1MJ per head per day

So now there is only enough energy for our lamb to put on 200g live weight per day and this is a figure more commonly seen by farmers on their farms. So, what can be done on a farm level to minimise the loss of production?

Grazing management can play a big part in getting the animal to eat the leaf and the stem together. Forage tests show that the stem of the plant has a vastly reduced protein content than the leaf. If we can get the animals to eat them both together, the total protein content is much closer to the animals requirement and we minimise the over allocation of nitrogen in the animal and thus reduce the amount of protein recycling the animal has to do.

o Strip grazing or block grazing paddocks with temporary electric fencing will put pressure on the animals to eat more of the whole plant in the one sitting.

If we don’t have the ability to increase the grazing pressure, we need to supplement the animals with hay/straw that is highly palatable and that they will freely eat over the crop. This can be very hard to find as most days animals will prefer to eat green leafy material over dry stemmy straw.

o If this is the case and your animals refuse to eat the fibre source, then providing them with a salt regulated loose lick that has added bentonite will slow the rate of passage down allowing the animals more time to digest the crop before it passes through them. TPM Boost Go is such a product with its high salt content the animals will actively consume it and the added bentonite will help slow the rate of digestion down, added minerals will also help to balance the diet for maximum growth potential for your animals.

Feeding the animals an energy source like cereal grains whilst grazing the brassica crop can also help balance the high protein from the brassica.

If you would like help getting the best out of your summer brassica crops,

please call one of our Experts In Ruminant Productivity

to tailor an individual plan for your animals this year.

MICRO MINERALS IN AUTUMN LAMBING EWES

By Mark Facy, Business Productivity Consultant, Total Result AG Consulting

As ewes get closer to lambing their energy requirement significantly increases far beyond what stubble and dryland can provide in both energy and protein, then during lambing the transition onto grass can throw a huge curveball as it introduces a major change to the diet during a critical period where consistency is preferred. Growing a lamb and then going through birth puts immense stress on the animal that utilises large stores of minerals. It is vital to set the ewe up to lamb and then replace lost minerals for longevity of the flock. Macro and Micro Minerals in ruminants are required in varying amounts with the Macro mineral levels required in their diet as a percentage of intake and usually in grams/kg of Dry Matter Intake, whereas micro minerals are required in much smaller levels, mostly measured in parts per million (ppm).

Availability of macro and micro minerals is dependent on many factors, some of which are environmental and influenced by dietary interactions, as well as levels of availability for which the elements are being utilised. Many of these determining factors are challenged and documented by many as to the availability being either dietary or supplemented sources, however what is recognised is ruminants require them.

The term ‘Oxidative Stress’ is used when discussing the pressure on ruminants when their micro mineral requirements are essential, for example when ewes are either being mated, carrying early pregnancies, or lambing, paired with the low levels of availability of macro minerals in many non-supplemented dryland grazing systems. For autumn lambing ewes in the southern grazing systems of Australia, access, and availability of these micro minerals through late summer is often low and ewes are potentially at high risk of Oxidative Stress depending on where in the production cycle they are and the potential consequences this poses to the longevity of the flock.

This is highlighted in the following graph:

Reference: “Practical implications of mineral and vitamin imbalance in grazing sheep”

- Underwood Memorial Lecture, July 2018. David G Masters.

As previously mentioned, macro and micro mineral availability and in what amount is extremely variable, it is recognised that some minerals are present in diets to meet requirements and do not require supplementation, but levels of others are often below production requirements, for example: Iron, Copper, Zinc, Cobalt, Manganese, Iodine and Selenium.

Functions of these micro minerals can be identified but not limited to the following:

Iron (Fe) – Increased requirement during pregnancy, bleeding increases requirement as does heavy intestinal parasite loading.

Copper (Cu) - Beneficial for reproduction and fertility, bone formation, immune system and cell respiration.

Zinc (Zn) – Plays an essential role in the immune system, cell membrane structure and cell functions, as well as the involvement in mobilisation of Vitamin A from the liver.

Cobalt (Co) - Pivotal in enzyme reactions, immune response, and the overall health of the nervous system, required daily for rumen microbes to manufacture Vitamin B12.

Manganese (Mn) – Has significant roles in formation of connective tissue, cartilage, bone development and tissue respiration.

Iodine (I) – A major component in manufacturing thyroid hormones, in turn impacting growth, development and reproduction, as well as muscle function, all significant during the lambing process.

Selenium (Se) - Involved in and enhances immune response, a natural anti-oxidant and has a role in resistance to viral infection.

Typical functions of micro minerals being the regulation of cell replication and differentiation and immune support. Both are critical elements to reproduction and foetal development, closely followed by early immune support of lambs through colostrum. In addition, minerals are in demand during the late stages of pregnancy for maintaining placenta, uterus and uterine contents.

Minerals, the Silver Bullet?

Not always, when we consider livestock production systems the objective is to ensure a correct balance of Macro and Micro Minerals are available at critical times to balance the immune system, support structural soundness and the efficient conversion of protein energy and fibre providing a healthy animal to underpin a profitable Livestock enterprise.

Requirements depend on age, growth rates, stage of pregnancy, immune challenges, heat stress and other such physical and environmental challenges as discussed.

When searching for answers to what may seem probing questions around mineral supplementation considerations of implementation, percentage, active levels, ratios, and the grazing environment are recommended. TPM’s Boost range of High Density Loose Lick mineral supplements are cost effective, with excellent water repellency qualities ensuring supplementation is available during challenging weather, often coinciding with high animal requirements. Our TRAC Consultants are equipped to assist.

To discuss how we can apply this information on your farm

please get in touch with one of our Experts In Ruminant Productivity

to tailor an individual plan for your animals this lambing.

Phone the TRAC Office on 08 8733 1888