Minerals for Animals

Magnesium

Blurb: magnesium plays a key role in muscle and nerve function in ruminants. Deficiencies are very rapid and can be fatal.

It is stored in low levels in the cows body and requires regular daily intakes. Magnesium can play a key role in enzymes, muscle and nerve function. In ruminants the main problem we see is tetany (deficiency) and death. This is one of the most serious deficiencies because of the speed of onset to collapse and death.

When animals begin lactating the demand for magnesium can rise quickly. Sodium also helps in the digestion transport of magnesium from the gut into blood.

There are a number of things that affect magnesium uptake

• Dry matter intake (can be affected by a number of things)
• Potassium(too high)
• Sodium (too little)
• Ammonia or nitrogen high
• Not enough fibre
• CLA fats in spring grass can affect magnesium uptake

Magnesium also plays a vital role in calcium metabolism.

We must remember also it is estimated cows only ingest/absorb 20% of magnesium (average) so we must look at ensuring supplementation at risk period is optimal.

We often call this deficiency grass tetany as it occurs at grass. It can occur at other times where intakes are affected. This can be weather related or in stressful conditions like weaning time for suckler cows.

Magnesium is stored poorly in the body meaning that anything that effects intakes or absorption can cause the symptoms of hypomagnesia.

In cows it is absorbed from the rumen and high potassium levels will affect its uptake, remembering both slurry and fertilzers can contain potassium.

With a high risk in grass based systems and also with very little time when animals become deficient, we must manage this mineral.

Copper

Blurb; 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 bloods can be difficult to interpret and liver samples are the premium method of doing this.

Remember low copper can be an issue but also over supplementation (toxicity) is a big problem on some farms.

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 blood that lock 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 calves and lambs they digest copper through their intestine.

With copper toxicity or over supply we can see animals getting weak, listless and experience haemolytic crisis. This haemoglobin is broken down and excreted in plasma and urine.

There are a number of ways of measuring copper in 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.

When measuring copper on farm like other minerals you must look at all potential sources.

Micro

Selenium

Blurb: plays a key role in immune function and is closely linked to vitamin E.

This mineral is required by the animal but it is not made in the animal. it plays a key role in 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 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 illthrift.it can also play an important role in poultry and pigs.

It may also play a role in fertility and in the production of healthy sperm in the male animal.

It has been linked to retained placentas in cows, however it is a minor contributor in these cases. It must however be factored in and ruled out after negative energy and low blood calcium.

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.

Supplementation is set at a maximum level of 0.5mg/kg

Iodine

Blurb: This mineral plays a key role in thyroid function.

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 calves and lambs.

Cobalt

Blurb: this is a really important mineral for the formation of vitamin B12 in the rumen of cows

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. While it can be hard to get exact inclusion rates 0.1mg/kg has been quoted. 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 the key roll in energy metabolism. This is important in the production of glucose. This is important around calving time for the cow around energy metabolism.

It usually is poorly retained within the animals so needs a regular supply at key times.

Zinc

Blurb: this mineral plays an important role in enzymes, immune function and healthy skin.

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 high tolerance for zinc in their diet.

Pastures typically have adequate levels of zinc; however, hay and straw are said to have lower concentrations.

Deficiency can be seen in young growing calves. You can see issues with skin (alopecia) and poorer skin health. some authors have suggested it may play a role also in hoof health.

Zinc also plays a role in sperm health in bulls and rams.

We can measure blood levels but this may be rarely done. Often farms will supplement with zinc at 50mg/kg

Iron

A lot of this can be combined with protein in the body. It also plays a role in haemoglobin (red blood cells) and other important pathways. It is another mineral when excess has complex interactions with copper.

iron deficiencies can be seen in rapidly growing animals although rare. weakness and lack of appetite are often some of the early symptoms. They will have pale mucous membranes due to the anaemia caused by low haemoglobin.

It has been said to be an issue found in veal calf units occasionally.

Iron toxicity can occur but it rarely occurs.

Calcium

Calcium is a one of the most important minerals in ruminants. It plays a key role in muscle function and immunity particularly around calving time.

Probably one of the most important macro minerals, especially around calving time. The cow will have a big demand on calcium before calving and especially during milk production. Older cows are more prone to issues with calcium around calving. This is due to their reduced ability to flush calcium from bone around calving time.

Calcium plays a key role in muscle function and immune function. Some breeds like jersey and Guernseys may be more susceptible to deficiency.

Milk fever or your down cow is the obvious clinical signs of the disease, but is only the tip of the iceberg within the herd in relation to calcium.
Low blood calcium (subclinical milk fever has serious effects on cattle). This low blood calcium can affect muscles like the uterus and rumen. This may lead to poor involution (repulsion of the placenta) and lower dry matter intake (slower rumen function)

Calcium also has complex interactions with other minerals pre-calving. For example we actually want low levels of calcium pre calving in the diet. High levels of magnesium and also low levels of potassium.

Also metabolic alkalosis will predis pose cows to milk fever around calving time. This is where we must balance the dietary cations and anions in the pre – calving diet

Calcium is one of the most important minerals around calving. It has several interactions with other minerals meaning that e ffort is needed to balance these in a cow’s diet. In grass – based systems this is why we put emphasis on pre-calving diets high in magnesium

Sulphur

Blurb : plays an important role in proteins, minerals and vitamins.

This is mainly in the body in the form of proteins, but can be a component of hormones, minerals
and vitamins. Urea when being fed may cause issues with sulphur defacing and
affect important
amino acids like cysteine and methionine.
Although rare sulphur deficiency can affect rumen function and thrive.
Excess dietary sulphur can cause problems rumen motility and nerve function. The main challenge
with excess sulphur is in its
role locking up copper with molybdenum or on its own

Vitamin A is necessary for normal vision in animals, maintenance of healthy epithelial or surface tissues and normal bone development.

• Vitamin A is a protective substance for the entire ectoderm and important for the development, the protection and the regeneration of skin and mucosa.
• Vitamin A has a special function in the visual process.
• Vitamin A is additionally of great importance for growth, skeletal development and fertility of animals.
• Vitamin A contributes substantially to the functionality of cell membranes and various enzymes.

All ruminants require cobalt in their diet for the synthesis of vitamin B12. Vitamin B12 is essential for energy metabolism and the production of red blood cells. B vitamins are eight nutrients essential to health, growth, or reproduction.

Lactating cows consuming vitamin B supplemented feed during the whole lactation period showed higher milk production and milk components, sustainable productivity, improved feed efficiency and lower culling rates