13 August 2012
Herbage testing for herd nutrition assessment
Total nutrition including energy, protein, macro and micronutrients during calving and early lactation is critical to
cow health while also determining milk production both this year and next.
Animal Nutrition Manager from farm nutrition company Altum, Jackie Aveling, says that an energy deficit in this period
could impact cycling and conception rates, so it is important to provide a high quality balanced diet to meet nutrient
needs.
“One of the best methods to determine if a herd is consuming adequate nutrients is herbage testing to pinpoint any
limiting factors in the diet in combination with analysis from other supplementary feeds.”
Dairy pasture data collected over the last five years from thousands of Altum clients has been statistically analysed to
a 95% confidence interval by region, element and month to confirm seasonal trends:
Potassium levels are higher over winter and spring, then trend down over summer.
Magnesium and calcium — both key elements for the lactating cow — trend lower in winter and spring.
The majority of trace elements trend lower over the spring period as pasture growth increases, with a few exceptions.
“In a forage based diet, pasture potassium levels exceed the needs of calving and lactating cows.
“Potassium can negatively impact the availability of magnesium in the cow which increases the risk of milk fever.
Identifying pasture potassium and magnesium levels will help farmers plan an effective supplementation programme,” says
Jackie.
“A robust supplementation programme includes a combination of methods including high quality magnesium directly provided
to the herd through water, dry cow molasses lick blocks and pasture dusting.”
Sodium can increase magnesium uptake in cows and provides other health benefits.
“For optimal health and maximum production balance is the key. These are just some of the factors that a pre-calf and
early lactation herbage analysis can pick up.
“Detailed analysis of the herbage test taken at the correct time will assist in identifying a direct supplementation
programme, which then can be implemented to remedy the shortfalls and give the herd a better chance of reaching its
optimum production potential.”
Mrs Aveling says this can also be linked to a fertiliser programme, which provides a method to introduce a background
dose of important elements such as magnesium and selenium for stock.
ENDS