From dry to damp: getting your pastures ready
New Zealand farmers know that pastoral fortunes can shift rapidly once summer’s extreme dryness gives way to cooler, wetter autumn conditions.
He says while trace elements play a vital role in herd health and production, they can be tricky to manage.
The five main trace element deficiencies identified in New Zealand pastoral systems are copper, zinc, cobalt, selenium and iodine. And the cost of not having enough of these five trace elements in the cow’s diet can be very high.
“Serious effects can include elevated empty rate and/or in-calf rate, lost days in milk, impaired herd genetic improvement and reduced longevity. The serious financial impacts on productivity and profitability from these potential consequences are well documented,” says Butler.
He points out that, longer term, sub-clinical deficiencies in trace elements such as iodine, zinc and cobalt can go unnoticed. “But if these shortages become the norm in your herd, the result can be significant negative effects on energy metabolism, impacting growth and milking performance in the background,” he says.
“Therefore, the potential financial risk of not getting your trace element balanced for your herd is worth the time and investment to get it right.”
Butler adds that trace elements can all be difficult to provide to cows solely through a pastoral diet, as their levels can vary significantly by pasture, by season and by region.
“The functions of these trace elements broadly fall into three categories - reproductive performance, energy metabolism and production, and immune support. These three drivers are key determinants of a dairy herd’s overall performance,” he says.
Identifying whether the herd is deficient in these vital elements is not an easy task. Today’s high performance, high-BW dairy herds have set a new benchmark based on their size and performance, says Butler. There is a significant gap between traditional trace element standards, set many years ago, and the demands of our modern herd sizes and productivity levels.
“Trace element demands for modern, high performing dairy stock are now many times higher than the needs of historic New Zealand animals and production systems.
“We really need to be addressing this critical issue of trace element deficiency if we want to see our herds perform at their highest levels,” cautions Butler.
He says at its simplest, identifying the levels of the trace elements in your pasture can be done through an herbage test.
“If your levels for the five key trace elements are at the lower end of medium, it’s a clear sign that pasture levels are deficient in trace elements, and your cows won’t be getting what they need.
“Herbage testing can identify particularly deficient pasture Additionally, secondary deficiencies can occur due to the presence of elements such as sulfur and molybdenum in soil, or during periods of high soil iron ingestion such as grazing winter crops.”
