June grass low in minerals with effects seen in livestock – Agriland.ie

It is not unusual to observe signs of mineral deficiencies in livestock, with some of these more severe than others, depending on the mineral and the level of deficiency.

Calves with discoloured coats, cattle observed eating stones and licking objects, as well as excessive salivation, poor skin/hoof health, reduced disease resistance, reduced fertility and growth rates can all be symptoms of mineral deficiencies in livestock.

In severe cases, mineral deficiencies can result in livestock deaths and so, close attention should be paid to any potential risks of mineral deficiencies in cattle.

Irish grass mineral analysis conducted on a number of farms in June by technical manager at Uniblock, Dr. Amanda Dunne, found grass was very low/deficient in the following important nutrients:

• Sodium;
• Magnesium;
• Zinc;
• Copper;
• Cobalt;
• Selenium;
• Iodine.

The Minerals Matter June newsletter from Uniblock noted that June was mainly cool and dry, with an average temperatures of 13°C.

It added that the large volumes of rainfall in the earlier spring months “may have had a negative impact on soil health which can compromise grass quality in terms of its nutrients”.

A total of 75% of the grass samples taken were found to be in the ‘very low’ (Livestock with a sodium deficiency can oven be observed eating stones, soil, briars, licking urine and many other objects, a condition known as PICA.

The Minerals Matter newsletter noted that high potassium levels were observed in 50% of grass analysed, which “increases the risk of PICA as it locks up sodium”.

In situations where salt (sodium mineral supplementation) doesn’t make a difference to pica, the deficiency could be due to low levels of phosphorus in the grass.

Grass and blood samples can help detect this, according to Dr. Amanda Dunne.

A combination of low magnesium and sodium alongside high potassium levels in most of the samples is a recipe for grass tetany or ‘staggers’ in both cattle and sheep.

The newsletter recommends 24/7 access to high-magnesium lick for livestock placed close to water source and noted that high nitrogen (N) in grass can also cause grass tetany.

It outlined that minerals such as zinc, selenium, cobalt and copper “are largely associated with immune function, and most grass samples in June “showed low levels of these vital nutrients”. 

The Uniblock technical manager outlined other symptoms and deficiencies for farmers to keep an eye out for:

• Signs of zinc deficiency include reduced feed intake and growth rate, excessive salivation, poor skin/hoof health and reduced fertility in cows and bulls;
• A selenium deficiency can lead to white muscle disease, reproductive failure, increased incidence of retained placenta in dairy cows, increased calf mortality and reduced calf weaning weights, and immune suppression;
• Cobalt’s primary role in ruminants is a building block for vitamin B12. Signs of cobalt deficiency include reduced appetite and growth, pale skin and mucous membranes and reduced disease resistance;
• Copper deficiency can result in impaired fertility and reduced growth rates. Often copper deficiency can be observed in adult cattle and quite often is a result of antagonists – Sulphur, Molybdenum and Iron.

“These ‘antagonists’ can lock up the copper, making it unavailable to the animal. On average, our samples showed ‘high’ levels of sulphur and molybdenum and 75% of samples were in the ‘low’ category for copper,” Dr. Dunne said.

The Uniblock technical manager said: “Grass is very changeable in terms of mineral status on a month-to-month basis, regardless of whether it looks to be growing well or not.

“In addition, animals too are changeable in terms of their nutritional requirements throughout the year depending on what stage of growth they are at from birth to adulthood or stage of pregnancy or lactation.

“Therefore, it is vital to monitor and supplement where necessary to fulfil demand to achieve optimum results.”