Pregnancy Requirements | Vitamins | Trace Elements | Major Minerals

Suckler Nutrition

Suckler cows and their calves are valuable assets yet cow diets are often short of energy, vitamins and trace elements with only the magnesium requirement fully met. It is crucial to feed cows economically. Failure to meet the cows requirements results in poorer returns from calves and/or greater replacement costs.

The main cause of infertility is shortage of energy but trace element deficiencies also play a role. Cows should be maintained at a condition score between 2 and 3. Fertility suffers if cows are too fat or too lean.


An SAC survey in 2005 showed that 31% of suckler culls were due to infertility with less than 1% due to staggers.


Magnesium Requirement A lack of magnesium can cause staggers, which can kill. Cows cannot store magnesium, therefore it is important to ensure they get an intake of 15—30g of magnesium every day. Cold wet weather and any stress on the cow can increase the risk of staggers.

Dry Matter Intake As cows approach calving, their appetite drops dramatically so they must be in good enough condition to cope with this or they need a more nutritionally dense diet at calving. Post calving it takes time for their appetite to recover.

Hormone Changes cause appetite depression before calving & also suppress the cows immune system making her more susceptible to infection & reducing the antibodies in her colostrum. Good nutrition helps relieve this, particularly good levels of vitamin E & selenium. Lifeline buckets are a good option, they contain Mannan Oligosaccharides which increase the production of immunoproteins & antibodies in colostrum, boosting disease resistance of both cow and calf. (Proven by SAC)

Post Calving If the nutrition is not right, cows are more susceptible to milk fever, lameness, mastitis, retained cleansings and displaced abomasums. All can be reduced by good nutrition.

Energy 14 days pre-calving a 600kg suckler cow requires around 88MJ of energy, 14 days post calving the same cow requires 120MJ of energy, failure to feed her adequately results in excess condition loss, less milk for the calf and reduced fertility. Cows short of energy often seem more susceptible to staggers than cows receiving adequate energy.

Protein Over the same 28 day period her requirement for protein rises from 1,500g to 2,000g. Often cows receive protein form non protein Nitrogen in treated straw or from grass and grass silage with high rumen degradability. Recent work with sheep at the SAC showed feeding better quality protein gave benefits from; enhanced immune response, lower faecal worm count, and higher birth weights with no increase in lambing problems, better appetite in ewes. Although the work was carried out on sheep there is every reason to expect similar benefits if your sucker cows are fed better quality protein.

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Vitamins are involved in metabolic functions, immune response and provide vital antioxidants.


Vitamin A Maintains mucus membranes in healthy condition vital for bone formation and eyesight. Fresh grass has a high beta-carotene content which is metabolised to vitamin A, silage has some and hay has virtually none.

Vitamin D3 Essential for calcium and phosphorus metabolism, required for good skeletal development. Virtually absent from forage, cattle require sunlight to form their own vitamin D3 which is restricted in winter. Extra supplementary vitamin D3 is essential in winter.

Vitamin E The role of vitamin E as an antioxidant and its synergy with selenium is very important both within cells and in the cell wall. Adequate vitamin E is crucial to both cow and calf, vitamin E is vital for calf vigour at birth. Good grass is high in vitamin E.

Vitamin B12 Crucial in energy metabolism, important in cobalt deficient situations.

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Biotin An important B vitamin which is involved in metabolism and helps harden hooves.

Trace elements are crucial for a cows metabolism and act as enzyme activators.

Copper Crucial for blood haemoglobin and its effect on enzymes in metabolism means that shortages result in poor growth, infertility and scouring. Don’t confuse dead hair in the spring with brown coat caused by copper deficiency and don't wait to see “spectacles” around the eyes.

Molybdenum In the rumen both molybdenum and iron combine with sulphur and lock up copper; molybdenum is more active at locking up copper than iron. If the molybdenum level is very high and gets into the blood it can bind copper from enzymes. Ensure there is adequate rumen active copper in your diet if your forage is high in molybdenum. Molybdenum content over 3mg/kgDM is high. However due to the interactions check copper availability in diets where the forage has a content of iron over 250mg/kgDM, molybdenum is over 1mg/kgDM and sulphur is over 25g/kgDM.

Selenium An antioxidant, it works in conjunction with vitamin E. Deficiency can result in; retained cleansing, poor muscle function (white muscle disease), poor fertility, reduced immune response, more mastitis, poor growth.

Iodine Required to produce Thyroxin (growth hormone). Shortage of iodine results in irregular oestrus, foetal death/abortion, poor metabolism and heat regulation, weak calves that die rapidly and may be hairless in extreme cases.

Zinc Crucial for a healthy immune system. It aids wound healing and disease resistance. Zinc is involved in metabolism, reproduction, growth and development. Zinc is also required for hoof condition and teat canal lining, the first line of defence against mastitis.

Cobalt Ensures that the rumen bugs can produce vitamin B12. The source of cobalt has to be available to the bugs and there must be enough but not too much or vitamin B12 production can actually be switched off.

Vitamin B12 is essential for energy metabolism.

Manganese An important enzyme activator, crucial for fertility. Our forages are high in manganese but there is evidence feeding more available manganese improves fertility and work in America points to poor maternal manganese status being associated with “knuckling under” in calves.

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These major minerals are essential for healthy teeth and bones, muscle function, nerves, fluid balance and milk supply.

Salt effects nervous function and maintains electrolyte balances within the body.

Calcium shortages are associated with milk fever but it also causes suppressed appetite and impaired muscle function (resulting in more difficult calving, more retained placentas and increased displaced abomasums). Remember the calf relies on calcium from its mother while it is on milk.

Phosphorus is associated with infertility but, phosphorus is also crucial for milk yield and growth of the calf.

Sulphur is required when there is a high level of non protein nitrogen in the diet, rumen bugs need sulphur to turn this into microbial protein, they also need an adequate supply of available energy.

Potassium is a major cause of milk fever when fed excessively pre-calving (beware of high potash spring grass or silage).

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