Dairy Newsletter Autumn 2026

Managing Risk as we Head into Autumn 

As we move through another busy summer on farm, it’s a good time to reflect on the season so far and look ahead to the key focus areas for the remainder of lactation.

Summer Round-Up

Across much of New Zealand, summer has brought its usual challenges variable pasture growth, heat stress, and the ongoing juggle between maintaining production and protecting cow health. The cows are often the best indicator of how the season has truly gone. This summer we’ve observed an increase in antibiotic use on some farms, particularly for mastitis and lameness cases. While antibiotic treatment is frequently necessary and appropriate, an upward trend is usually a signal to reassess underlying risk factors.

Rapid Grass Growth, Feed Changes

Recent rain combined with warm soil temperatures has resulted in rapid pasture growth across much of the district. While this is welcome from a feed supply perspective, sudden diet changes and wet conditions can increase the risk of several diseases. Lungworm (Dictyocaulus viviparus) thrives in warm, moist environments. Following rain, larval contamination of pasture can increase quickly. Young stock are particularly at risk, with signs including coughing, increased respiratory effort, and reduced growth rates. Ensuring appropriate drenching programmes are in place is essential to prevent production losses. Vitamin B1 (thiamine) deficiency can occur when rumen function is disrupted, often following abrupt feed changes or higher levels of rapidly fermentable feed. Affected animals may appear dull, uncoordinated, or develop muscle tremors, and in severe cases seizures. Early treatment is critical, and response is typically rapid when addressed promptly. Rapidly growing, lush pasture also increases the risk of grass staggers (hypomagnesaemia) in lactating cows and youngstock. These pastures are often low in magnesium. Clinical signs range from nervousness and twitching through to collapse. Prevention is key.

Body Condition Scoring in Late Lactation

As we approach the final months before dry-off, body condition scoring (BCS) should be a key focus. Target BCS at calving are 5.0 for mature cows and 5.5 for first and second calvers. Cows generally cannot gain BCS in the final month pre-calving. It is difficult to achieve more than ~0.5 BCS/month unless feeding high energy diets. Therefore, late lactation is the most efficient time to add condition.

Key focus areas for March – May:

• Body Condition: Identify and prioritise cows below target BCS. Consider early dry off for light cows.
• Feed Planning: Revisit your autumn feed budget. Monitor covers closely and avoid compromising condition to chase late-season production.
• Parasite Management and Trace Elements: Review youngstock animal health plans heading into winter
• Lameness: Address track damage early, manage cow flow, and treat lame cows promptly before conditions deteriorate further.
• Mastitis: Assess teat condition, milking routine, and environmental hygiene.

Preparing Dairy Youngstock for Winter: Targeted Treatments for Health & Growth

As winter approaches, dairy youngstock (particularly R1 and R2 heifers) face increased challenges including cold, wet conditions, nutritional stress and parasite exposure. A proactive treatment plan protects health, supports growth rates and helps replacements reach mating weight and condition targets.

Internal parasites such as roundworms, tapeworms and fluke can significantly reduce weight gain and resilience in youngstock. Ninety percent of parasite larvae are on pasture, so managing parasite exposure as well as treating animals is crucial. Effective parasite control involves both pasture management and strategic drenching. Reducing larval intake through grazing rotation and avoiding heavily contaminated paddocks is just as important as choosing the right product. Drench choice should be tailored to your farm’s parasite challenge and resistance risk, so it’s a great idea to have a chat with your vet to choose the best product for your specific system. With rising drench resistance in parts of New Zealand, we also recommend strategic drench timing and, where appropriate, faecal egg count monitoring to ensure treatments are effective and sustainable. The Wormwise website has some good information on sustainable parasite management, focusing on using the right drench at the right time while protecting future effectiveness.

At the clinic, we stock a wide range of combination oral and injectable drenches and can advise on the most appropriate option for your herd’s parasite profile.

Vaccinations play an important role in winter disease prevention. Clostridial vaccines (eg 5-in-1 or 7-in-1), leptospirosis and BVD protection are commonly recommended, depending on age and farm risk. We carry a full range of vaccines and can advise on primary and booster schedules.

Trace element supplementation, particularly selenium, cobalt, and copper, supports immunity and growth when pasture quality declines. Products such as MULTIMIN® provide rapidly available trace minerals to support immunity, growth and fertility. MULTIMIN can be used in calves from day one of life and at weaning, and strategically in heifers before high-demand periods such as winter and mating. We stock MULTIMIN alongside other injectable and oral trace element options to suit your system. Beyond treatments, remember that nutrition and parasite exposure on pasture also affect winter performance. Grouping lighter animals for targeted feeding, maintaining body condition, and keeping yards clean and dry all help maximise the benefit of your treatment plan.

Heading into winter is the ideal time to review your youngstock plan. Speak with our team to tailor a practical, costeffective programme that keeps your replacements growing, healthy and on track for the season ahead.

What’s Happening at the Teat End? Teat Scores & Milking Management Visits

The teat end is the cow’s first line of defence against mastitis. Damage such as cracking, dryness or hyperkeratosis makes it easier for bacteria to enter the teat canal and cause infection. Poor teat condition is strongly linked with increased clinical mastitis and rising bulk milk somatic cell counts (BMSCС), particularly as the season progresses. Maintaining smooth, healthy teat ends is essential for udder health, cow comfort, milk quality and overall farm profitability. Two of the most common causes of teat end damage are excessive vacuum pressure or overmilking. High vacuum levels increase congestion and swelling at the teat end, leading to thickened rings and roughened skin. Overmilking where cups remain on after milk flow has finished puts prolonged stress on the teat tissue, reducing blood flow and preventing the teat end from closing properly after milking. These changes leave the teat canal open for longer, increasing the risk of bacteria entering between milkings.

Regular teat scoring is a simple but powerful tool to monitor teat end condition and identify these issues early. Teat score farm visits allow us to objectively assess teat health across the herd, track changes over time, and make recommendations before problems escalate.

If BMSCC is climbing or mastitis cases are increasing, a milking management visit provides more in-depth assessment. These visits are carried out during milking and look closely at machine function and settings, cow flow and behaviour, cluster alignment, removal timing, liner condition, and teat spray coverage. We often see significant improvements with small adjustments for example a decrease in the vacuum.

What to Watch for in the Shed

• Rough, thickened or raised teat end rings, particularly worsening as the season progresses
• Red or blue discolouration of teat ends immediately after cluster removal
• Cows slow to let milk down or restless during milking, suggesting discomfort
• Frequent overmilking, especially where milk flow has clearly finished
• Clusters slipping, indicating vacuum or liner issues
• Uneven teat spray coverage or poor skin condition between milkings
• Increase in mastitis cases

If these signs are becoming common, early investigation can prevent longerterm udder health issues. Together, we can develop a practical, farm specific plan to improve teat health, reduce mastitis risk, and support consistent milk quality throughout the season.

Leptospirosis: Protect Your Herd & Family

It’s never been a better time to check that you have control measures in place to protect your farm from Leptospirosis, an infectious disease that can cause severe disease in both people and animals. The human health effects of Lepto can be significant with symptoms ranging from a mild flu to lifethreatening kidney and liver damage.

Lepto can cause severe disease in livestock, with possible symptoms including abortion, weak or stillborn calves, mastitis, drop in milk production, and sudden death in youngstock. Pets can also become severely ill or die from Leptospirosis.

People can catch Lepto when they are exposed to leptospires (the infectious bacteria) passed from animals in urine. Leptospires thrive in wet conditions, especially when it’s warm and wet, and can be transferred to people via their eyes, nose, mouth, or skin wounds. There are different types of Lepto bacteria, known as serovars, which behave differently so it is important to understand the most common Lepto serovars to protect your farm.

The most common Lepto serovar in both humans and livestock in NZ is called Hardjo; apparently healthy cows can be infected with Hardjo, and their urine can be infectious to people for up to 2 years. Vaccination of livestock, use of personal protective equipment (e.g. wearing waterproof gear), and personal hygiene (e.g. covering cuts, washing hands) are simple but effective ways to protect people on your farm against Hardjo infection.

Recent research from Massey University has identified an increase in the number of human Lepto cases caused by the Ballum serovar since 2008, and Ballum is the second most common Lepto serovar in people. Ballum is carried by pest species such as rats, mice, and hedgehogs rather than livestock, so an effective pest control program is another crucial piece of the Lepto control puzzle. Remember that Lepto can survive well in wet environments, so protective equipment and personal hygiene are an important line of defence against Ballum.

These researchers have also identified another Lepto species, now named Pacifica, in NZ livestock. However, they have not found any cases of Pacifica causing disease in animals and there are no accurate figures to show how common this species is among people with Lepto. Pacifica is part of the Tarassovi “group” of Lepto bacteria; around 1 in 10 Lepto cases in people may be caused by Tarassovi “group” of Lepto bacteria and these case numbers have not increased over the last 15 years.

Cattle, pigs, sheep, deer, goats, and dogs can all be vaccinated against Lepto. Success of your farm’s vaccination plan depends on using an effective vaccine, vaccinating animals before they get exposed to Lepto, and keeping up with booster vaccinations every year. Risk of Lepto infection is highest when the environment is wet, but changing weather patterns can make this hard to predict, so it is important to use a vaccine that will protect your animals in for a full year. Ultravac® 7 in 1 and Leptoshield® are both proven in clinical trials to protect for 12 months against Leptospirosis infection by the most important Lepto serovar, Hardjo.

To minimise the risk of Leptospira infection and subsequent shedding, calves should be vaccinated early, before they are exposed to the organism.

Under Zoetis vaccination protocols, calves should receive an initial two-dose primary course, with the first vaccination typically given from 4-6 weeks of age, followed by a second dose 4-6 weeks later (depending on product label directions). Protective immunity is not fully established until after completion of this primary course, so early timing is critical.

Vaccinating calves at this stage helps:

• Reduce the risk of clinical disease
• Prevent establishment of renal infection
• Reduce or prevent urinary shedding, which is a key source of human exposure

Once calves have completed their primary course, they should then be integrated into the farm’s whole-herd annual booster programme.

How does this differ from herd booster vaccination?

• Calf vaccination focuses on building initial immunity before first exposure, particularly during high-risk wet periods or when calves are first mixed, grazed off-farm, or introduced to contaminated environments.
• Herd booster vaccination involves annual revaccination of all adult stock to maintain immunity and reduce long-term shedding, particularly for Hardjo, which can persist in apparently healthy cattle for up to two years.

For optimal protection of both people and livestock, calf priming and annual herd boosters must work together as part of a whole-farm Leptospirosis control programme, alongside pest management and good hygiene practices.

Always consult your veterinarian to tailor vaccination timing to your farm system, risk profile, and product label requirements.

References Zoetis New Zealand Limited. Tel: 0800 963 847; www.zoetis.co.nz. Ultravac & Leptoshield are registered trade marks of Zoetis. ACVM Nos. A6935, A3734, A7426.ESR Notifiable Diseases in New Zealand Annual Reports 2010-2022 Nisa, S., et al., Diverse Epidemiology of Leptospira serovars Notified in New Zealand, 1999-2017. Pathogens, 2020. 9(10). Wilkinson, D.A.,et al., Identification of pathogenic Leptospira species and serovars in New Zealand using metabarcoding. PLoS One, 2021. 16(9): p. e0257971. Yupiana, Y., et al., Emerging Leptospira strain poses public health risk for dairy farmers in New Zealand. Prev Vet Med, 2019. 170: p. 104727.