New Zealand is a leader in the world’s dairy industry. Sophisticated animal breeding practices, farming techniques, temperate climate and innovative processing have led to New Zealand supplying some 30% of world dairy exports. Efficiencies and economies have been developed throughout the industry and one relatively recent innovation is the use of PKE for feeding dairy cows.

Traditionally, New Zealand farmers rely on fresh grass to feed their cows and grow/make their own supplementary hay, silage and forage crops for times when there is less grass. Traditionally the use of supplementary feeds like corn and dried distiller grain is very small. This changed about 10 years ago when New Zealand dairy farmers ‘discovered’ PKE. Since then PKE imports have grown enormously and are now run at more than one million tonnes per year as the table shows. According to the United States Department of Agriculture Foreign Agricultural Service this is over a third of the 4.86 million tonnes global trade of PKE .

Nutritional content

PKE is very suitable for feeding dairy cows as the table of composition shows

Moisture content of PKE is just 10% so it keeps well in temperate climates, but must to be kept dry to avoid going mouldy. At 10.5-12.5 Mega Joules/kg dry matter, PKE is comparable to energy obtained from cereal grains. PKE fibre is highly digestible (60% is digested in 30 hours so the cow gets good nutritional benefit even from the fibre. The fibre encourages acetic and butyric acid production and this helps with milk fat production. A cow should also eat feed that has long fibres such as grass and hay to ensure good rumination.

New Zealand border control

New Zealand is isolated and free and from many agricultural pests and diseases; rabies and foot and mouth disease for example, so biosecurity issues are taken very seriously.

The general requirements are:

1. Shipments must be fumigated before or during shipment
2. Must be free from contamination e.g. animal products, recognised pests and viable seeds
3. If our border control people find some biosecurity risk the shipment must be treated, sent elsewhere or destroyed.
4. Needs official documentation on handling, storage and inspection prior to export and these standards are steadily climbing. New requirements are for longer phosphine fumigation and an increased sampling by our border control staff.

Distribution in New Zealand

Farmers order PKE from their local supplier. They can pay a spot price or contract price and can lock in a price as well .The biggest supplier is a company called RD1, which is owned by Fonterra our biggest dairy company. Fonterra has some 90% share of the imports and they buy from Wilmar who operate plantations in both Malaysia and Indonesia. Most farmers order PKE as they need it and use it up within 40-50 days. PKE is delivered to farms in bulk truck or truck and trailer loads of 10, 20 or 30 tonnes.

Usage in New Zealand

About 50% of dairy farmers are now buying PKE. They start feeding it at the rate of 0.5 kg per cow per day to accustom them to the smell and taste. Mixing with other feeds like silages and/or molasses helps palatability. Later, PKE can be fed as a single food and the daily feed rate can be increased gradually to 2 – 3 kgs/day. During times of serious feed shortages cows can be fed up to 6kg dry matter per day, but they have a high refusal at this level. Some farmers add proprietary blends of minerals to the PKE.

PKE is fed from troughs or meal feeders and some farmers cut off 200L drums and use those. Other farmers put PKE on the ground and let the cows lick it up.

Limiting factors for PKE consumption are palatability and dustiness. The cow’s nostrils are close to the mouth and they can inhale dusty feed when they eat. This can put them off eating it.

Copper in animal feeds

PKE has 20mg of copper per kg dry matter. This is significant as it is twice the daily requirement for cattle and four times the daily requirement for sheep. The copper content of PKE is not as high as Distiller’s dry grain (residue from the brewing process).

Copper is an essential mineral and farmers give cows proprietary mineral supplements that include copper when the animals cannot get enough through their diet. In larger concentrations however, copper can become toxic.

The normal copper concentration in cattle liver is 25 to 100 ppm. Concentrations greater  than 200 ppm start to be toxic . Many mineral supplements are well marketed and relatively cheap, so there is a tendency to over supplement.

Management of copper intake for cattle, sheep and deer

The key message is that farm animal copper intake needs to be managed when feeding PKE.

Calves can be feed a 50/50 PKE and grain based meal mix at age 10 – 12 weeks. PKE should be restricted to young calves as they absorb higher levels of copper so are more susceptible to copper toxicity than adult cattle.

Sheep are more susceptible to copper toxicity than cattle, so copper management is very important for them.
The brown Jersey cows are highly efficient absorbers of copper and so are more susceptible to copper toxicity than the black and white Friesian cows.

Recommended procedures for monitoring copper in cattle

•  Avoid copper and selenium supplementation while feeding PKE
•  Analyse copper content of the grass to find out the background level 
•  Analyse copper content of the animal’s liver once a year
•  Mix PKE with other feeds to dilute the copper content

Conclusion

PKE has developed sustained popularity on New Zealand dairy farms.  So long as copper levels are managed, PKE is an economic supplementary feed that helps maintain dairy farm productivity.