34 minute read
Research
by AgriHQ
Massey University doctoral student Aaron Yang has been researching digital dermatitis in dairy herds for his studies. He visually assessed 59,849 cows in 127 herds.
Hoof disease reveals mysteries
ANNE BOSWELL
NEW Zealand’s unique position with bovine digital dermatitis (DD) puts it in good stead to manage the disease in future, Massey University student Aaron Yang says.
He gained many insights into the disease, which was previously thought to be absent or at least extremely rare here because of the unique pastoral dairy system, while doing his masters degree and doctorate.
Studies have been done overseas but limited information was available on DD in NZ.
DD is the most important infectious cause of cattle lameness in confined systems, particularly in the northern hemisphere. Once in a herd DD typically becomes endemic and is eradicated from few herds.
It can result in loss of production and increased animal health management time and cost. It also raises concerns of animal welfare because it causes varying levels of discomfort and pain.
Yang’s interest was encouraged by hoof health expert Neil Chesterton.
“Neil brought a project to Massey when I was doing my masters, which was a pilot study of DD in Taranaki,” he says.
“I thought it was a very interesting study as no one else had really looked at this disease carefully in NZ. I took the project as my masters dissertation and then DD research became part of my life over the past five years.”
He found the disease is rare, at least in Taranaki. Farms where more DD cases were detected were generally related to loose biosecurity management.
However, there was no information about it in the other parts of the country and he was to discover the mystery of DD in NZ where the dairy system is different to other major dairy production countries.
Yang adopted novel methodological approaches and investigated the distribution, risk factors, climate effect and transmission dynamic of DD.
He visually assessed 59,849 cows from 127 herds in Waikato, South Canterbury, West Coast and Manawatu.
He chose those regions to provide a cross-section of farming systems: Waikato for its 3000-herds, South Canterbury to represent large herds and irrigated pastures, West Coast for its unique geography and predominantly self
Digital dermatitis is an animal welfare issue because it can be painful and results in a loss of production and increased animal health management time and cost.
contained farms and Manawatu for its proximity to Massey.
During milking he hosed the cows’ feet and visually inspected them, screen testing for DD lesions large enough to be seen without lifting the hoof.
He also asked farmers to complete a questionnaire on their management systems and biosecurity practices.
Yang found the disease is still in the early stage of establishment in NZ though it is widely present on most dairy farms.
Factors associated with increased cases are mainly hygiene and biosecurity related, including hoof-trimming equipment and animal movements. However, lameness is rarely associated with the disease, an insight he has yet to understand.
The strong overseas risk factor of housing cows is not associated with cases of DD here, even on farms with herd homes or stand-off pads. However, Yang says absence of evidence does not imply evidence of absence and that needs more investigation.
DD lesions in NZ are very different from classical presentations overseas. Yang saw very few active clinical cases but small, grey, rubbery lesions that disappeared within six weeks.
There was also evidence of faster transmission in early lactation with the rate decreasing over time. The curve flattened druing lactation, like the much-publicised covid-19 flattening of the curve, with the number of new cases eventually lower than recovered cases.
Finally, climate observations were also surprising. Overseas, cases were higher with humid weather associated with rain but in NZ cases decreased as rain increased.
Yang says the only explanation he has is increased rain appears to make hooves cleaner and the environment more hygienic.
The disease profile here is starkly different to overseas.
“In the northern hemisphere I don’t think they had comprehensive research of DD at its early stage of establishment,” he says.
“Some overseas experts say NZ today is like the Netherlands was 20 years ago.
“The only thing that didn’t surprise about the findings was the low number of affected cows in most of the herds, that pattern was consistent across all regions.”
Yang’s chief supervisor Professor Richard Laven interpreted all the research results and authored all the associated publications, Professor Cord Heuer supervised his masters degree, technician Megan Moss collected most of the Taranaki data, Dr Kristina Muller and Dr Carolyn Gates co-supervised and Professor Wesley Johnson and Professor Geoff Jones provided statistical insight.
Yang also worked closely with staff from Vetent, Totally Vets, West Coast Vets and Southern Rangitikei Veterinary Services.
Despite his research Yang is reluctant to make a prediction about the future of DD here.
He is, however, cautiously optimistic.
“In general I will say this disease is still at a manageable condition but we currently lack an efficient and accurate method to detect the disease.
“At this stage it is being overlooked and underreported and the consequence of this is that the future is uncertain.
“The good news, however, is that we can do something to possibly eradicate the disease or at least keep it at this manageable condition for years and years depending on the ambition of the dairy industry.
“We need to develop and use an accurate, rapid method of testing a herd four times a season to determine what sort of cows are at risk.
“The wise thing to do at this stage would be to at least detect the disease in dairy herds and keep an eye on it, monitoring its pattern over time. I think precaution is a good idea.” n
Despite 99.5% of dairy herds being vaccinated against lepto 26.5% are shedding non-vaccine strains, which indicates new strains are emerging and putting dairy farmers in the high-risk category.
Lepto on the rise
SAMANTHA TENNENT
LEPTOSPIROSIS notifications are on the rise and dairy farmers are at high risk of being hospitalised if they contract the disease.
Leptospirosis is a disruptive disease that can affect people for a long time.
A Massey University team led by Associate Professor Jackie Benschop is half way through a four-year study on the disease.
“I think people thought it was done and dusted after the vaccination was introduced but it’s a dynamic disease that continues to emerge and re-emerge worldwide. It is classified as a neglected disease,” Benschop says.
“While the vaccination is effective against the strains it covers there are others that aren’t covered and other ways people can be exposed to the disease other than through cattle.”
Between 2017 and 2019 the average number of patients notified with leptospirosis was 140 a year compared with 74 a year from 2012 to 2016.
The severity of disease appears to be increasing, too, with 60% of notified cases in 2017 hospitalised.
Veterinary studies student Maryna Sokolova said dairy farmers are at an increased risk of being hospitalised if they get the disease.
“When compared with other occupations dairy farmers are more often needing hospitalisation,” Sokolova says.
“This could be because they have more opportunities to come in contact with the disease, reluctance to get checked and stop working and remoteness of farms.
“And despite 99.5% of dairy herds being vaccinated against lepto 26.5% of dairy herds are shedding non-vaccine strains, which indicates new strains are emerging.”
The study is funded by the Health Research Council and seeks to address gaps in leptospirosis knowledge that will inform control strategies. It has been interviewing people who recently contracted the disease and 20 of the 33 people interviewed reported contact with dairy cattle.
Patients are asked questions about animal exposure, rodent sightings, outdoor activities, symptoms and workplace compensation. The study will answer questions about risk factors, disease severity and duration, how ACC works for patients with leptospirosis and will identify practices used for animal vaccination and personal protection.
One dairy farm worker described his experience, which involved chronic relapses, severe fatigue, headaches and flank pain. His symptoms were worse than any chronic fatigue patient his doctor had seen and the disease was having a huge impact on his family and mental health.
Earlier research looked at notified cases in 2015. Of the 63 cases 36 were farmers or farm workers, nine worked in the meat processing industry and five others worked in close contact with animals.
“We need to work together for research beyond just the disease and do research specific to the social impacts,” Benschop says.
“Lepto can have a big impact on communities and we need to raise awareness and understanding.”
Leptospirosis is caused by bacteria that live in kidneys of animals. It is passed from their urine into the environment, surviving for extended periods in damp soil and water and spreading rapidly in flood conditions.
In NZ domestic and wild animals that host the disease include cattle, sheep, deer, pigs, possums, hedgehogs and rodents. People can be infected with the disease by direct or indirect contact with infected animal urine, including contact with damp soil and water.
There are also risks people can contract it from animals not normally considered hosts, for example a dog. The bacteria get in through the body’s mucus membranes or cuts and abrasions.
There are typically two phases to the disease in humans. The early phase at five to seven days is characterised by flu-like symptoms of fever, muscle aches and headache and the late phase from four
Research into the increasing incidence and severity of leptospirosis cases is being led by Associate Professor Jackie Benschop at Massey University.
to 30 days is characterised by prolonged fever and a range of possible systemic complications including fatigue, jaundice, renal failure, respiratory insufficiency and confusion, which is probably a result of fever.
Up to 30% of those with acute disease suffer long-term effects such as depression and chronic fatigue.
The prevalence of the disease can be severely underestimated because there are no specific clinical signs for a patient with leptospirosis and the disease might be self-limiting, so doctors are not always aware of or suspect the disease.
The Veterinary Association developed Leptosure, a risk management programme, in 2002 that is aimed specifically at dairy farmers to protect staff and other farm visitors. Vaccination programmes work well for the leptospirosis strains in the vaccine but several strains are not covered and the best protection against them is to minimise the risk.
“Reducing contact with infected animal urine is the key way to minimise risk. We want people to be aware of leptospirosis and protect themselves, their families and their staff,” Benshop says. n
MORE:
The team wants anyone who gets leptospirosis to contribute to the study by contacting study coordinator Shahista Nisa s.nisa@massey.ac.nz.
0508 Animate (264 6283) nzsupport@pahc.com
Buttercup killers elusive
Dense infestation of giant buttercup in a Takaka dairy pasture.
TIM FULTON
RESEARCH on giant buttercup has highlighted the risk of herbicide resistance from a narrow range of weed control treatments.
Scientists at AgResearch, Landcare Research and Lincoln University are working together on biocontrol options for giant buttercup (Ranunculus acris), a weed avoided by dairy cattle because of its acrid taste.
It is estimated to cost dairy farmers $200 million a year in lost production.
Giant buttercup, a native of Europe, has been in New Zealand since the early days of pastoral farming. Genetics research suggests it had multiple introductions from different parts of Europe.
Its seeds are easily spread by stock, agricultural equipment, floods and in hay. Rhizome fragments are also spread by stock, machinery and floods. The longevity of the seed in the soil varies depending on soil moisture and other climate conditions. The rhizome enables the plant to readily survive drought and sub-zero temperatures.
AgResearch principal scientist Dr Graeme Bourdot leads a national team of scientists addressing some of the big weed management issues facing the pastoral sector including herbicide resistance evolution, biological control, internal biosecurity, sleeper weeds and weed control economics.
The Lincoln-based researcher has been working on giant buttercup since the 1990s when dairy farmers began reporting poor control from the herbicides they have relied on since early 1950s.
His research showed the buttercup evolved resistance to the phenoxy herbicides (MCPA, MCPB, 2,4-D) on many farms as a result of regular exposure to the herbicides, which, until the late 1990s, were the only mode of action available for selective weed control in pastures.
In Europe it occurs across a very wide climatic range from the Mediterranean to the Arctic Circle. It is prevalent on dairy farms in South Auckland, Hawke’s Bay, Southland, Taranaki, Wairarapa, West Coast and Tasman and all other regions are at risk because of their climatic suitability.
The plant is particularly troublesome in Golden Bay where Bourdot and colleagues have worked closely with farmers on two Sustainable Farming Fund projects since 2014.
Scientists are yet to make the breakthrough needed for successful biological control though other discoveries are being made.
Experiments in Golden Bay from 2014 to 2017 in 18 different dairy pastures compared the effectiveness of a common fungus, Sclerotinia sclerotiorum formulated as a mycoherbicide with all the synthetic herbicide active ingredients on the NZ market and with pre-graze mowing, liquid nitrogen fertiliser and gibberellic acid on wet and dry soils.
Sclerotinia is a naturally occurring fungus that can kill giant buttercup in dairy pastures.
It turns the plants into a slimy, rotting mess. It has the same effect on lettuces, carrots and celery and many other plants.
AgResearch principal scientist Graeme Bourdot says one of the challenges in the fight against giant buttercup is a lack of information on its precise origins.
It causes the brown rot often seen in the refrigerator. Grasses and clovers are unaffected.
Experiments in the past three years have quantified the effects of timing (preor post-graze) and frequency of mowing on giant buttercup and on pasture drymatter yield.
Observations made in Golden Bay indicate giant buttercup is more likely to invade paddocks that are pugged in winter.
The experiments in the 18 pastures show soil drainage, gibberellic acid, nitrogenous fertiliser (growth promoters) and the experimental mycoherbicide have no effect.
But the herbicides aminopyralid and aminopyralid+triclopyr gave substantial and long-lasting reductions in the cover of the weed but also substantial temporary reductions in clover.
Flumetsulam, thifensulfuron methyl, MCPA, MCPB and MCPB+bentazone were less effective against the buttercup but also less damaging to the clovers.
Pre-graze mowing reduced the cover of giant buttercup as the frequency of mowing increased and showed promise as an alternative to herbicides.
For all herbicides there was a 1:1 replacement of giant buttercup by grasses and clovers. The effectiveness of the herbicide treatments varied greatly between pastures, possibly due in part to differences in evolved resistance.
The study showed repeated use of the same synthetic herbicide or those with the same mode of action is not sustainable, Bourdot said.
Across the more than 40 branded herbicide products registered in NZ with label claims for giant buttercup there are only seven active ingredients belonging to only four different mode-of-action (MOA) groups giving farmers a relatively small set of MOAs to rotate between to help avoid resistance.
“Repeated use of a single MOA is likely to result in resistance to that MOA and this possibly explains many of the poor results from farmers’ herbicide applications,” Bourdot said.
Sheep don’t seem to mind the acridtasting plant but it is generally not palatable to cattle unless mown before grazing. When the intact plant is wounded or eaten the toxin protoanemonin is produced by enzymatic breakdown of the glucoside ranunculin, contained in the plant’s foliage.
While only seven of NZ’s 17 dairy regions are known to have significant populations of giant buttercup, AgResearch modelling indicates all regions are climatically suitable for the weed.
Bourdot said one of the challenges for a classical biological control programme for giant buttercup is a lack of information on its precise origins.
“It almost certainly came from Europe, probably in the bush-burn seed mixes sown by the early colonists, but we don’t know precisely where in Europe.”
Giant buttercup in NZ has a variety of lineages as determined from the maternally inherited DNA found in plants’ chloroplasts.
“Manaaki Whenua Landcare Research scientists working with us in the project
AgResearch science staff, from left, Sarah Jackman, Mike Trolove and Shona Lamoureaux inspecting the data collected from the herbicide experiment at one of the 18 sites in Takaka in September 2015.
discovered that there are seven different chloroplast cytotypes of giant buttercup in NZ and one is far more common in dairy pastures than all the others. And that’s the one we haven’t yet been able to trace back to its European origin.”
Without that trace information it is not possible to look for a natural enemy that might have potential as a biocontrol agent.
“It’s found on the coast of France by the Mediterranean right up to the Arctic Circle so where do you go looking?”
Nonetheless, that impediment hasn’t completely closed the door on a biocontrol programme.
“With further research we could discover the European origin of our dominant lineage of giant buttercup, enabling targeted exploration for its natural enemies.” n
Giant buttercup plants in the AgResearch shadehouse at Lincoln.
Striking initial effect two months after treatment with one of the herbicides (treated plot in centre, untreated on right) in the field experiment at Takaka. AgResearch technician Sarah Jackman at back of the plot.
Kiwi products tick credence boxes
TONY BENNY
OVERSEAS consumers are prepared to pay a 24% premium for dairy products that are carbon-neutral, according to research funded by Our Land and Water National Science Challenge and AgResearch.
Co-author of a paper called Impact of delivering green dairy products onfarm in New Zealand Dr Wei Yang says an analysis of international academic papers and empirical research confirmed consumers are prepared to pay more for so-called credence attributes.
“The way we define credence attributes is something that as a consumer we could not observe or identify or ensure the existence of.
“It doesn’t look like colour or taste that we can tell. It’s the kind of thing we cannot tell except by food labelling,” Yang says.
As an economist now lecturing at Lincoln University she was invited to participate in the study because of her understanding of the market and market signals.
Credence attributes were first raised in the mid 1990s and have been widely studied by academics as well as marketers since then. Yang spent two months searching and analysing the existing literature published since the 1990s.
She was careful to include only peerreviewed studies that were objective rather than grey literature that might be compromised as authors look for the positive results their funders hoped for.
In addition to academic studies she included those focusing on hypothetical decisions but they also provided monetarised estimation of consumer willingness to pay.
There are three possible motivations for consumers to consider credence attributes, Yang says.
“One is more from a food safety and health perspective. They’re worried about the food safety issue and so they pay more for the credence attributes.
“The second motivation is about
New Zealand dairy products produced in an environmentally friendly way are popular with overseas consumers.
the environmental or so-called social responsibility so they feel like they are responsible for all those environmental issues and they are willing to pay more.
“The third category is a kind of mix of the other two so it’s really hard for the consumers to tell if it is driven by their personal interest or if’s driven by the social responsibility.”
Whatever the reason, researchers have concluded consumers are prepared to pay more for products they believe have credence attributes.
Because the issues of carbon neutrality is relatively new in the marketplace they use environmentally friendly as a proxy.
It showed consumers are prepared to pay a 24% premium for environmentally friendly attributes.
But in a list of seven credence attributes, environmentally friendly actually ranked lower than organic, for which consumers would pay a 35.8% premium, as well as country or region of origin, food safety, hormone or antibioticfree, animal welfare and grass-fed.
Though other businesses along the value chain would all take their share Yang used historical United States data to calculate 30% of the premium could be returned to farmers.
After including carbon-neutral
Lincoln University lecturer Dr Wei Yang says studies show overseas consumers are prepared to pay more for dairy products produced in New Zealand.
certification fees and the cost of offsetting emissions that are impractical or impossible to eliminate on-farm, such as biogenic methane, the results show producing carbon-neutral dairy products can increase farmer profit by up to 15%, assuming the gas offset cost is $25 a tonne. n
It’s never too late to be fire safe
WE’RE well and truly into single figure temperatures these days.
That said, it’s never too late to make sure your home is fire safe. At FMG, fires in fireplaces make up 20% of house fire claims and electrical fires make up 30%.
New Zealand’s rural insurer has shared some checks people can do to make sure their homes are fire safe. • Last year FMG had $13.5m worth of house fire claims; • Half of them were from winter with most in June; • Fireplaces and chimneys were the leading cause of winter fires and; • Electrical fires in heaters continue to be a common cause.
Check electrical wiring, switchboards and appliances.
Significant fires can start behind appliances. It’s a good idea to check the cords, plugs and sockets of large appliances like dishwashers, ovens and fridges.
FMG also suggests checking smaller appliances like electric blankets, heaters, irons and toasters.
Check only one appliance is connected to each socket, whether to a single power point or a multi-board and power points are not overloaded with double adapters.
People concerned about any electrical wiring or switchboard in a house should ask a qualified electrician to examine it and replace if needed. People are at greater risk of fire in houses not upgraded with new electrical wiring and switchboards, such as those over 60 years old.
Rural properties are twice as likely to use wood fires and the damage caused by rural house fires is often worse because of the extra time it takes for emergency services to arrive. Fires often start because a fireplace has no fireguard. The fire can spread to nearby items such as rugs and carpets that start to burn. A fireguard helps to prevent sparks, embers and logs rolling onto the floor when a door is opened.
Inspect and clean fireplaces and chimneys. If people are concerned they
should get a certified expert to inspect fireplaces and chimneys for deterioration. Chimneys should be swept regularly to remove any debris and build-up of creosote, soot and ash.
Fire and Emergency has found in 80% of house fires it has attended smoke alarms were either not properly installed or not working.
And people should make sure emergency services can access properties should a fire occur. Now is a good time to clear driveways of low branches and other obstructions. n
MORE:
House Fires Advice Guide on the FMG and Fire and Emergency websites.
From human bits to whole animals
SAMANTHA TENNENT
DEALING with bits and pieces of people in the form of body tissue samples finally took its toll on Matt Collier who was craving interaction with living human beings.
When a chance to work for himself and build relationships with dairy farmers arose he left a 17-year career in medical science where he had been a manager in human histology and pathology laboratories, dealing with cancer diagnoses and the like to join forces with his father, Chris Collier, who launched Probiotic Revolution at the end of 2015.
Working with farmers has been a big learning curve.
He had some connections to dry stock farming through family when he was growing up and did six months on a farm when he left school but his career was focused on human medicine.
“I still consider myself a student in the game in terms of agriculture, animal management and the seasons of agriculture. Understanding dry stock doesn’t mean a lot when it comes to what’s involved in a dairy farm season,” Collier says.
“I love getting out and having a conversation with a farmer and not just jumping straight into business. I’m learning heaps from my clients and enjoying the relationships, which is absolutely key for us.”
As a townie he has always appreciated the beauty of rural New Zealand and understands how much farmers value their animals and land. He is enjoying stretching his legs in the countryside.
“I think a point of difference for what we’re doing is we want to be a face, not a product. We don’t stock our product on shelves as we want to work alongside our farmers to uncover their goals and help match solutions through our products.
“And there are benefits from having the personal relationships as we get to hear
Matt Collier left his medical science career to work in probiotics, which are used to build the strength of the immune system of animals and increase growth and production naturally.
what’s happening. We get feedback and photos from clients and they refer us to other farmers.”
There are strong movements internationally to reduce the reliance on antibiotics in feed-producing animals, largely because of the dangers of antimicrobial resistance. Collier promotes probiotics to build the strength of the immune system of animals and increase growth and production naturally.
Bacteria outnumber body cells 10 to one. Most of the bacteria live in the gut and most are quite harmless. Probiotics are live micro-organisms, a certain type of friendly bacteria that provide health benefits when eaten.
Probiotic research and the understanding of the role of microorganisms in humans and farm animals has increased dramatically in the last five years.
“We have the international science and our on-the-ground experience from our clients to build our understanding of the role probiotics can play in the farm system.”
The product range covers calves, cows, horses, goats and dogs and the first product was Calf Xtreme.
“We got over 130,000 calves on it in the first three years. Initially, we focused on Taranaki and Waikato but now have got clients in Bay of Plenty, Manawatu, Hawke’s Bay, Northland and all over. We are also starting to expand into the South Island.
Progress has probably been a bit slow since we are the service on the ground but we are happy with how we are tracking and referrals from happy clients are expanding our reach.”
Collier does not have any regrets about his career change. He enjoyed medical science but finds working with dairy farmers meets his needs for interaction and he loves helping farmers and their animals. n
Milk fever is commonly caused by a calcium deficiency in cows that takes many forms and affects many processes critical to early lactation.
Managing calcium deficiency
CHRIS BALEMI
ALL farmers will recognise a downer cow by the symptoms presented and they know the disease is caused by low calcium in the blood during stress.
It is commonly called milk fever.
What farmers won’t always recognise is cows with clinical symptoms are just a small part of a much bigger issue.
That is why most researchers use terminology such as hypocalcemia because the broader term better conveys the true issue of calcium deficiency and that the disease takes many forms and affects many processes critical to early lactation.
For every downer cow there will be many more cases where cows stay on their feet but suffer the wider effects of the deficiency. They commonly have calving problems, metritis, retained fetal membranes, mastitis, poor immunity, poor conception and the list goes on. Few are as dramatic as a downer cow yet are equally important.
Most feeds supply more than adequate calcium yet it is among the most poorly absorbed elements. The body controls calcium uptake very tightly because an imbalance can lead to serious complications. That is done through the release of hormones, particularly parathyroid hormone and vitamin D and calcium storage is controlled by another hormone, calcitonin. The body’s hormonal system responds quickly to manipulate the available calcium based on demand. This system works really well provided the diet is right and the cow has not been subject to longer-term deficiencies and is not under or over conditioned because such cows are not as good metabolically at regulating the hormones.
On New Zealand farms our high reliance on large amounts of pasture during early lactation presents the biggest challenge for calcium management.
Pasture supplies very high levels of potassium, normally more than 3%, when the cow’s nutritional requirement is about 1.1%. The large over-abundance of potassium doesn’t just compete with calcium for uptake, it also seriously affects the acid/alkaline balance of the blood. Increased pH in the blood interferes with the release of the hormones required to control calcium balance. High blood pH effectively stops the release of parathyroid hormone.
Over the years farmers have used many strategies to treat milk fever with varying levels of success. Many of the common ones have shown very inconsistent results and methods that prove successful in one
situation can often fall totally on their face in another.
Here is a run-down on common methods used to combat calcium deficiency in dairy cows: • Reducing the levels of calcium in the diet. This is probably the most common method used over the last 40 years. It can work well as long as no pasture is fed but to work well pasture must be almost totally removed and replaced with a feed that has low calcium, potassium and sodium. Maize silage is one of the few feeds that fits the criteria and where large quantities of maize silage have been added to the diet this approach has worked well. It is, however, important the cows are very well supplemented with extra calcium during lactation otherwise the induced calcium deficit can have serious consequences. • Injectable calcium or calcium boroglucinate has always been used as the last line of defence for this disease. This formulation floods the bloodstream with readily available calcium along with boron, which further increases calcium absorption.
In desperation some have adopted this method as their primary means of control, simply treating the cows showing clinical symptoms, giving either intravenously or under the skin. This approach never works satisfactorily. While a bottle of calcium boroglucinate usually gets a cow back on her feet she will often go down again later. In many cases when she does seem to recover she will remain sub-clinically calcium deficient throughout much of the early lactation.
Another issue is many sub-clinical cases of calcium deficiency are not picked up. It can be common to have anywhere from 25% to more than 50% of cows suffering sub-clinical calcium deficiency at calving and well into early lactation. As well as producing less milk these cows will be more susceptible to mastitis and uterine infections as well as poor reproductive outcomes. Interestingly, a number of scientists report injecting calcium solutions can seriously interfere with a cow’s ability to balance her calcium status longer-term, struggling to regulate and control the calcium metabolically in subsequent seasons.
Flooding the body with calcium in the form of lime flour is another option that has gained some traction over recent years, sometimes with large quantities of vitamin D. This approach can work on some farms, however, success is very reliant on keeping the levels of ongoing calcium supplementation very high. That can be challenging. If the levels fall below an often poorly defined point the cow will then be metabolically incapable of activating any of the calcium reserves in her body.
The high levels of lime flour have the added disadvantage of buffering the blood pH to the point where parathyroid hormone release can no longer be activated. This approach means a farmer relies solely on the body’s ability to absorb its calcium from the diet yet, because of the pH buffering of the blood, the body is doing everything it can to shut down the absorption of calcium and could be triggering calcium storage through calcitonin release.
So, is there a better option available?
Over the last five years Agvance Nutrition has worked intensively to develop and apply its own specific version of the anionic (negative DCAD) diet designed to be practical in a NZ dairy system.
We believe, based on the many hundreds of farms we formulate these blends for, we have developed a combination of the DCAD salts that suit NZ conditions and provide a better option to combat calcium deficiency.
During this time we have learned how this system can be applied to local conditions where pasture normally makes up at least part of the diet. We have also formulated ways that better match requirements based on the make-up of the diet and that target specific deficiencies more prevalent under different crop feeding situations. The poor palatability of these salts is often mentioned in the literature and removing this issue has also been given much time and effort. It is no good making up a good blend of minerals if the cows won’t eat it. n
Chris Balemi is the managing director of Agvance Nutrition.
THE DESTINATION FOR RURAL REAL ESTATE
Land is the biggest asset to any farming business – so it pays to stay up-to-date with the market.
One last word …
ASTUNNING cow mural has become a popular stop along the well-travelled Rai Valley roads in the Marlborough Sounds and the story behind the artwork is equally as heart-warming as the spectacular mural.
What do you get when you combine a roadside cow shed, a family holiday and a relief milker with an artistic hand and big heart?
For dairy farm owners John and Lynne Small the answer was an appropriately themed mural, or should we say mooral, turning an ordinary shed wall into a vehicle-stopping work of art.
The funky mooral is a popular stop along the well-travelled Rai Valley roads in the Marlborough Sounds.
Following the birth of their first grandchild the Smalls hired a relief milker to stay on the farm while they went to America to spend time with their newest family member.
“We knew the artist through a mutual friend before he started on the farm so we thought he might be keen to milk cows as well as paint a mural,” John says.
The humble artist-turned-milker used the time around his farm schedule to create the masterpiece on the shed.
The element of surprise was key for the artist, who started with simple outlines, as he refused to disclose his vision to both the Smalls and curious passers-by who would stop to query exactly what the mural was going to depict.
The finished product is bright and striking. Located near the top end of the valley, it continues to attract attention from those travelling the Rai Valley roads, with passers-by often stopping to admire the artwork and take a picture.
Winter has definitely arrived with storms and snow in parts of the country. This is usually a good time to wrap up in front of the fire with a good read but, unfortunately, the farm work never stops with maintenance and cleaning as well as feeding out and shifting stock.
And, of course, calving is just around the corner so many are preparing for the season ahead. I have yet to hear of any early calves so cows appear to be holding on. But as farmers know, cows love to drop their calves when the weather is at its absolute worst.
Good luck for the new season.
Sonita
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Dairy Diary
July 2020
July 1 – DairyNZ
Smaller herds wintering discussion group, Southland. Ivan and Denise Hopper have finished their second season with robotic milking technology. They have five robots and peak milk 340 cows on their Woodlands farm. Info at www.dairyevents.co.nz
July 1 – DairyNZ
Organic discussion group, Waikato/Bay of Plenty. Converting a hill-country dairy farm to organics. Visit the Sheehy’s farm west of Otorohanga. Info at www.dairyevents.co.nz W T F S
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July 2 – Dairy Business of the Year Awards on Sarah’s Country
The awards evening has been cancelled and will be replaced with an online event live on a special edition of Sarah’s Country. The Leaders Optimisation Day will be postponed to later in the year. Info at www.dboy.co.nz
July 2 – DairyNZ
Muddy Waters discussion group, Waikato. Focus on the host farm’s system and seasonally relevant topics including 40ha shell bank management, how to make the most of the support block and spring feed plan. Info at www.dairyevents.co.nz
July 2-3 – DairyNZ
FeedRight 2020, Waikato. Workshop 1, transition period and early lactation. The FeedRight course includes an e-learning module assessment on dairy nutrition principles and theory and two practical two-day workshops, Workshop 2 is on mid and late lactation and dry period. Cost $750. Info at www.dairyevents.co.nz
July 4 – Dairy Industry Awards
The awards will be screened online and on national television on Saturday July 4 at 7.30pm on Country TV’s Sky Channel 81, which will be accessible to all viewers without subscription. Info at dairyindustryawards.co.nz
Dairy NZ – CalvingSmart
Various dates and locations, For new entrants with 0-3 years experience. Approach the calving season with confidence. Topics include what a normal calving looks and feels like and looking after new-born calves. Info at www.dairyevents.co.nz
DairyBase – Benchmarking
Various groups and dates, Southland and Otago. Provides insights on financial and physical performance KPIs. DairyNZ farm business specialist Robb Macbeth highlights trends in operating profit/ha, operating expenses per kg MS, pasture harvested tDM/ha, farm systems comparison. Info at www.dairyevents.co.nz
