Video 10 minerals in sheep
A lift in the weather means things are looking up with ewes and lambs out grazing. Sheep nutrition is a cornerstone of a healthy flock. With energy balance being the key driver to flock performance. This is why we need to monitor ewe body condition throughout the season. Key times for this are a month out from breeding and six weeks out from lambing.
Another key driver to nutritional performance is protein especially for ewes approaching lambing (colostrum quality) and for the lactating ewe. After this, our flocks want to balance minerals and vitamins at key times of the year.
Remember
- When we talk about supplementation we need to balance key minerals. It is important we want to avoid deficiencies and also be mindful of over supplementing or causing toxicities
- We can’t manage what we don’t measure so having an idea of the flock and farm mineral status is a great starting point. With a couple of key measurements, we can assess farm mineral status like forage, grass analysis and blood samples Prelambing.
Watch the VIDEO above where I look at minerals in our flock at key times.
So here is a shortlist of some of the key minerals we need to manage in our flocks
Calcium
This is a macromineral or large mineral which is a key mineral to manage in the ewe Prelambing. Low blood calcium can cause issues from muscle weakness and collapse Prelambing.
The symptoms are ewes in the extreme will be down and unable to stand. This can often be associated with or confused for twin lamb disease (related to lack of energy).
While we treat these with injectable or oral calcium we should aim to have less than 2% of the flock affected.
Balancing calcium and magnesium intakes Prelambing is key here.
Magnesium
When ewes feeding lambs (milking) at grass one disease which poses a real risk is grass tetany or staggers. This deficiency is very acute meaning we often have little time to act. Magnesium is involved in nerve function and with more magnesium requirements in lactation, it is critical that we get daily intakes.
Sheep won’t store magnesium or at least have it readily available on a daily basis. We need to be aware of interactions and other factors may also affect intakes.
- Dry matter intake (can be affected by a number of things like adverse weather )
- Potassium(too high)
- Sodium (too little)
- Ammonia or nitrogen high
- Not enough fibre
- CLA fats in spring grass can affect magnesium uptake
During these risk periods, we must ensure ewes get daily supplementation with magnesium
We must remember also it is estimated ewes only ingest/absorb 20% of magnesium (average) so we must look at ensuring supplementation at-risk period is optimal.
In grazing systems potassium can be high in both grass and forages. This is down to the use of slurry and potash fertilizers.
Selenium
This mineral is required by the ewe but it is not made in the animal. It plays a key role in the immune response (function) and iodine metabolism. Grazing animals may be at more of a risk to deficiency.
Its main role in the body is as an antioxidant enzyme glutathione peroxidase. We can measure this in the blood to help look at mineral status (long term) while plasma serum levels are used to measure short term intakes.
It has been linked to a disease called white muscle disease. With reduced growth rates and ill thrift in lambs.
It may also play a role in fertility and in the production of healthy sperm in the ram.
This is a mineral where we must carefully match supply to needs. Oversupply can lead to toxicity with several side effects.
It can be closely linked to vitamin E also which plays a key role in immune function as an antioxidant. Deficiencies of both can look similar, so must be considered together.
Iodine
Plays an important role in thyroid function and thyroid hormone production. Selenium enzymes are also involved in this. This is why these two mineral are often linked.
Thyroid hormones can play a key role in immune defence, muscle function and have been linked to reproduction suppressed oestrus.
They also play an important role in metabolism leading to stillbirths or weak lambs.
Cobalt
This is a very important mineral in young growing lambs. Cobalt plays an important role in B12 formation, which plays a key role in energy metabolism. Cobalt is really important for the rumen microbes to synthesise vitamin B12. Cobalt is also believed to play a role in certain enzyme reactions. Sheep are more prone to cobalt deficiency, particularly young growing lambs. This can be attributed in part to it being involved in wool growth.
It is key to understand that vitamin B12 plays a key role in energy metabolism. This is important in the production of glucose.
It usually is poorly retained within the animals so needs a regular supply at key times.
Zinc
This trace element plays a key role in a lot of enzyme systems. It can also play a role in immune function and keratin production and hoof health. While most animals have a high tolerance for zinc in their diet.
Pastures typically have adequate levels of zinc; however, hay and straw are said to have lower concentrations.
Zinc also plays a role in sperm health in rams.
Copper
Copper plays an important role in cellular function and immunity
There is a narrow range when supplementing with copper meaning getting it to optimum levels are essential. Sampling can be difficult as blood can be difficult to interpret and liver samples are the premium method of doing this. A good plan is to take liver samples from culls or lambs at slaughter for analysis.
Remember low copper can be an issue but also over-supplementation (toxicity) is a big problem in some flocks.
It has been associated with swayback and changes in hair coat and wool. It can also when low effect immunity and may cause infertility. As it is involved in glucose metabolism.
While we can get copper deficiencies due to low copper they are rare. They usually occur because of complex interactions or are locked up by other minerals.
The key minerals involved in this are iron, sulphur and molybdenum. This begins with simple interactions in the rumen and then the blood that locks up copper making it not freely available for use within the body. These form substances called thiomolybdates which will give the appearance of deficiency but can be due to lock up.
These animals will not be low in copper in their diet but because it is locked up may not be freely available.
In lambs, they digest copper through their intestine.
With copper toxicity or oversupply we can see animals getting weak, listless and experience a haemolytic crisis. This haemoglobin is broken down and excreted in plasma and urine.
There are a number of ways of measuring copper in the blood, but liver sampling (major reserves) are the premium animal-based tests for copper. This can be done by liver biopsy or checking livers from culled animals in the factory.
Conclusion
Minerals play an important role in our flocks
Some key things is we must establish a mineral status for the flock. We need to supplement at key times and know the farm-specific risks
Watch the video above as I talk about key risk periods.
Thought for the day
In challenging times the mind can race and we can become unproductive and in some cases quite overwhelmed. Practice being mindful in these times. Meditation can be used as a powerful tool to control our thoughts and focus on being present.
If people feel I can help them in any way my email is info@tommythevet.ie
Big thanks to Nettex for their support in helping me make #50in50 happen
Happy safe farming
For a full range of minerals for your flock check out https://www.rumenco.co.uk/products/sheep