PASTURE and cereal grazing crops are usually an inconsistent source of nutrients for cows, which need to be carefully managed in both the pre-calving and pre-joining stages.
That's because of continuous changes in the composition and availability of nutrients in pastures and crops, which can affect the supply of key minerals to the animals.
Dry matter intake of grazed pastures can also vary quite considerably due to changes in weather conditions. Not only will this affect the supply of energy and protein to the animals, but the mineral supply will also be reduced.
This can lead to a number of metabolic disorders i.e. grass tetany and milk fever, which fortunately can be managed through some nutrition-based strategies.
Cow deaths which occur in the last trimester are often due to one of three problems: pregnancy toxaemia, hypomagnesaemia (lack of magnesium) or hypocalcaemia (lack of calcium).
It is important to look at all of these factors to help protect our breeding herd and also improve the percentage of live calves that hit the ground.
Magnesium has a positive impact on muscle function and helps with the ease of calving. It also helps reduce the effects of stress and is important for lactating cows as they delete large amounts of calcium and magnesium from their bodies in their milk.
High potassium in green feed and supplementary feed also interferes with mobilisation of calcium and magnesium from bone reserves, which needs to occur before calving.
Cows cannot physically eat enough calcium or magnesium to meet their needs during and after calving from green feed or supplementary feeds.
Magnesium along with vitamin D and phosphorous helps improve the efficiency of calcium use, providing a stronger, healthier animal and a more viable calf.
Effective fibre is also critical prior to calving to enable the rumen to work efficiently and allow feed to be digested properly.
Where there is limited feed or where there is some green feed starting to appear, good quality hay should be offered to slow rumen flow and increase available energy to the animal.
Magnesium is an essential mineral required for grazing animals due to the risk of the stock developing grass tetany.
Grass tetany occurs predominately in winter and spring because of:
- High potassium, which reduces the plant's uptake of magnesium.
- High nitrogen, which reduces magnesium absorption in the rumen.
- Low sodium levels, which affects the magnesium absorption process in the rumen.
Winter and spring pastures are also deficient in other important trace elements like copper, selenium, zinc, iodine, vitamin D, calcium and phosphorus.
Note that balancing the magnesium and calcium ratio to prevent milk fever is also essential.
Failure to supplement with these critical elements can result in poor conception rates, anoestrus, risk of metabolic disorders and a decline in growth rates, consequently resulting in an economic loss.
What's the cost
The reality is all reproductive females need to optimise their mineral reserves to function at peak capacity.
Alltech's Supplamins HiMag and Supplamins MidMag and Blueprint SuperMag and Blueprint Lift, have been specifically formulated with particular focus on providing the essential ingredients to combat grass tetany, assist in reducing stress during transport, and during pre-calving.
Supplamins Mid Mag is recognised as the effective supplement to provide four to six weeks prior to calving.
It has high levels of magnesium, calcium, vitamin D3 (to assist with bone deposition of calcium) and levels of zinc, vitamin E to enrich colostrum and selenium to assist with cold stress in the calf, among other critical minerals.
Supplamins HiMag/MidMag and Blueprint SuperMag are water proof and available in a 25kg bag.
Intakes are designed to be 50-100 grams/head/day with a cost of 10c-40c/head/day. All of these products are easy to use, self limiting and are fed out in open troughs.