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In autumn, lice populations on cattle increase. This is due to temperature and humidity levels becoming more favourable for lice survival on the animals. Lice populations rise to reach their peak in winter and early spring. 

In New Zealand, there are two types of lice, a sucking species which pierces the skin and feed on tissue fluids, and a biting lice which feeds on the surface debris of skin. Both cause irritation to the animal resulting in rubbing or licking, hair loss, and damage to the hide.

Damage to fencing or troughs is often a result of excessive rubbing by cattle. The most visible areas of hair loss are generally on the neck, shoulders and along the flanks. As temperatures cool down and coat thickness increases, the environment for lice is more favourable for population increases. With increased numbers, the frequency and intensity of rubbing behaviour by cattle escalates.
Lice can’t fly and need close animal to animal contact to spread in a herd. They don’t survive long off the animal. This is important in the management of lice as all animals need treating, especially if mixing of mobs is occurring.

When treating animals for lice, it is best to start in late summer or early autumn when lice numbers are lower and coat thickness is less, allowing greater amounts of chemical exposure to the lice population. 

There are three chemical groups that are currently registered for use in cattle in New Zealand. Pour On organophosphates (for example Destruct) or synthetic pyrethroids (for example Blaze or Delmax) target lice and nuisance flies. On the other hand, Mectin based products target both internal worms and lice, for example Cydectin, Dualmax.

It is important to note that when any of these products are applied in winter, on animals with full coats or covered in mud or faeces, only suppression of lice numbers will be achieved at best. Lice numbers rebuild again over six to eight weeks, often requiring another treatment. This is due to some lice escaping a lethal dose of drugs in thick coats, and none of the drugs having an effective persistent effect on lice or killing eggs.

The take-home message for lice management is to treat animals early when lice numbers are low, so population control is managed better. For further information call into your local PGG Wrightson store or talk to your local Technical Field Representative.

We all know that weeds in pastures are undesirable, but a recent study sponsored by the Ministry for Business, Innovation and Employment¹ has reported that we have likely been underestimating their full cost to New Zealand agriculture. 

The study estimated that the total cost for just 10 common pasture weeds was likely to be over $1.3 billion a year in lost production, while Californian thistle alone takes over $700 million per annum 
from farmers. 

Farmers need to get on top of weeds to protect pasture yields, and fortunately they have some good tools at their disposal like Tropotox™ Ultra. Tropotox Ultra is a selective, grass and clover friendly herbicide that controls many broadleaf weeds in pasture, peas, clover and grass seed crops. It has a broad spectrum of activity with strength on thistles, buttercup, and seedling docks.

Tropotox Ultra contains 25 grams a litre MCPA and 375 grams a litre MCPB in a soluble concentrate formulation. It is a member of the phenoxy herbicide group, which were first discovered back in the 1930s, developed and commercialised in New Zealand in the 1980s, and still form the backbone of many of our pasture weed control programmes today.

Phenoxy herbicides mimic the natural plant growth regulator auxin in plants, causing abnormal growth, twisting of stems and cupping of leaves in susceptible species followed by plant death. However, monocots (for example grasses) are largely unaffected by the rates of phenoxy used, but many dicot plants (for instance broadleaves weeds) are highly susceptible. 

Tropotox Ultra is absorbed into foliage of growing plants where it moves to the growing points and interferes with key plant functions. Visible symptoms, such as twisting and curling of foliage, can be seen in a day or two but death of weeds can take several weeks. Clover, and some other legumes, lack the mechanisms that converts the product to the herbicidal active form, and once clover has at least two true trifoliate leaves it is tolerant to Tropotox Ultra.

Best use guides:

• Apply Tropotox Ultra to small, actively growing weeds once clovers have passed two true tri-foliate leaves.
• Do not apply to weeds under stress for example drought, water logging.
• Use the higher rate where weeds are more advanced.
• Avoid spraying where rainfall is expected within two hours of application.

For more information on how to get the best out of your pastures by using Tropotox Ultra, talk to your local PGG Wrightson Technical Field Representative.

Supplied by Agritrade
¹Saunders JT, G. G. (2017). The economic costs of weeds on productive land in New Zealand. International Journal of Agricultural Sustainability.

The business relationship between Nelson contractors Kevin and Andrew Fry (K & A Fry Contracting) and PGG Wrightson has grown so strong over the last five years, that both parties now promote and refer one another to new farmers in the district.

Established in 2002, K & A Fry Contracting are the biggest agri-contractors in the local area, offering hay silage, groundwork, feed conservation and spraying services. What started as a one-man business with a tractor and a seed drill, has grown to a sizeable partnership between Andrew and his father, Kevin. They now have a fleet of five tractors and a spray truck, operating with a team of six full-time staff. 

Andrew notes that spray contracting is the biggest part of their business and being able to rely on PGG Wrightson Technical Field Representative, Andrew Young, helps with inputs, advice and daily support in both their agri-contracting business and cropping ventures. 

“Andrew (Young) is outstanding for both his service and knowledge. We’re in constant communication with him for advice when we’re out on a job, and we talk to him daily about spraying.

“In many instances, we’re working for PGG Wrightson customers, but sometimes not. That doesn’t matter to Andrew, he’s always happy to help.

“He knows what he’s talking about and gives us sound advice. He’s quick to respond, and if there’s something he’s not sure about, he’s upfront in telling us that he needs to do some research first.”
The Fry’s also have 75 ha of crops under irrigation, growing maize for PGG Wrightson Seeds and Lucerne for baleage. They’ve recently added 11 ha hops, too. With the contracting business, Kevin and Andrew are not on the farm a lot of the time. Here, they rely heavily on Andrew Young to monitor the crops and regularly revise their crop management plans. 

 “Andrew is probably here at least three times a week checking on the crops and keeping things on track,” says Andrew Fry. “That gives us real peace of mind.”

He adds that they order everything through PGG Wrightson, “we find PGG Wrightson to be consistently reliable. We rarely have to wait for a product. Andrew normally delivers it too, unless it’s a big volume.

“We’re loyal to PGG Wrightson, but they’ve earned that loyalty. We consistently get good deals and Andrew’s support is invaluable in all areas of our business.”