The Country
  • The Country home
  • Latest news
  • Audio & podcasts
  • Opinion
  • Dairy farming
  • Sheep & beef farming
  • Rural business
  • Rural technology
  • Rural life
  • Listen on iHeart radio

Subscriptions

  • Herald Premium
  • Viva Premium
  • The Listener
  • BusinessDesk

Sections

  • Latest news
  • Coast & Country News
  • Opinion
  • Dairy farming
  • Sheep & beef farming
  • Horticulture
  • Animal health
  • Rural business
  • Rural technology
  • Rural life

Media

  • Podcasts
  • Video

Weather

  • Kaitaia
  • Whāngarei
  • Dargaville
  • Auckland
  • Thames
  • Tauranga
  • Hamilton
  • Whakatāne
  • Rotorua
  • Tokoroa
  • Te Kuiti
  • Taumurunui
  • Taupō
  • Gisborne
  • New Plymouth
  • Napier
  • Hastings
  • Dannevirke
  • Whanganui
  • Palmerston North
  • Levin
  • Paraparaumu
  • Masterton
  • Wellington
  • Motueka
  • Nelson
  • Blenheim
  • Westport
  • Reefton
  • Kaikōura
  • Greymouth
  • Hokitika
  • Christchurch
  • Ashburton
  • Timaru
  • Wānaka
  • Oamaru
  • Queenstown
  • Dunedin
  • Gore
  • Invercargill

NZME Network

  • Advertise with NZME
  • OneRoof
  • Driven Car Guide
  • BusinessDesk
  • Newstalk ZB
  • Sunlive
  • ZM
  • The Hits
  • Coast
  • Radio Hauraki
  • The Alternative Commentary Collective
  • Gold
  • Flava
  • iHeart Radio
  • Hokonui
  • Radio Wanaka
  • iHeartCountry New Zealand
  • Restaurant Hub
  • NZME Events

SubscribeSign In
Advertisement
Advertise with NZME.
Home / The Country

Jane Lacy-Hulbert: Should waste milk go to your calves?

By Jane Lacy-Hulbert
Hawkes Bay Today·
25 Sep, 2019 11:16 PM2 mins to read

Subscribe to listen

Access to Herald Premium articles require a Premium subscription. Subscribe now to listen.
Already a subscriber?  Sign in here

Listening to articles is free for open-access content—explore other articles or learn more about text-to-speech.
‌
Save

    Share this article

Whatever you do, don't feed waste milk to bobby calves. Photo / File

Whatever you do, don't feed waste milk to bobby calves. Photo / File

Waste milk has traditionally been fed to calves to dispose of milk that can't be sent for supply, but is this a good idea?

With an increased focus on the responsible use of antibiotics, questions are being asked about waste milk's value as a feed source for calves, and the risks this practice might pose to the wider environment.

Waste (or 'red') milk is the milk produced by lactating cows when they're sick and receiving antimicrobial treatment for diseases such as mastitis. It also applies to the milk produced in the withholding period, which can be three to four days after treatment.

Bacterial growth and antibiotic resistance

Exposing a bacterial population (such as the calf's developing digestive tract) to low concentrations of antibiotics may encourage bacterial growth with existing resistance genes. It could also lead to other bacteria mutating and developing new ways to resist antibiotics.

Advertisement
Advertise with NZME.
Advertisement
Advertise with NZME.

The risk is that calves consuming this milk will shed antibiotic- resistant faecal bacteria into the environment. This could have unintended consequences for your calves, and for the future usefulness of the antibiotic.

This is backed up by a substantial review published in the European Union in 2017. The review found that shedding was more pronounced for younger calves (2-3 weeks old), compared with 6-7-week-old calves.

Fortunately, this shedding wasn't observed in calves fed colostrum from cows previously treated at dry-off with long-acting dry cow antibiotic products. Unfortunately, pasteurising waste milk won't deactivate the residues, as most antibiotics are heat-stable.

Advertisement
Advertise with NZME.

Calf health and growth

Although there are few studies on this aspect, it's likely that antibiotic residues would interfere with calves establishing good gut bacteria, or that pathogens and viruses from older, sick cows could infect the young calf. If there are more antibiotic-resistant bacteria present in the gut, these issues would be harder to control.

Although waste milk may be a convenient feed for calves, is it worth the risk for the health of the replacement calf, or to the environment?

One thing is certain — it cannot be fed to bobby calves, as the calf's gut is likely to absorb the antibiotic residues and cause the carcass to be rejected.

Discover more

Robotic feed pusher turns in results

25 Sep 10:43 PM

Next step for Far North water project

25 Sep 10:47 PM

Taking responsibility for farm plastic

25 Sep 11:02 PM

Find out more about calf care at dairynz.co.nz/calves

• Jane Lacy-Hulbert is a senior scientist with DairyNZ

Save

    Share this article

Latest from The Country

The Country

'Some of the worst we’ve seen': Huge pile of concrete dumped illegally

12 Jul 12:00 AM
The Country

'Merry hell' in Mamaku: Village held 'to ransom' by hoons

11 Jul 06:00 PM
The Country

'Massive milestone': Rare native geckos, parrots return amid pest-control success

11 Jul 06:00 PM

From early mornings to easy living

sponsored
Advertisement
Advertise with NZME.

Latest from The Country

'Some of the worst we’ve seen': Huge pile of concrete dumped illegally

'Some of the worst we’ve seen': Huge pile of concrete dumped illegally

12 Jul 12:00 AM

Cleaning up the concrete and other waste is expected to cost between $25,000 and $30,000.

'Merry hell' in Mamaku: Village held 'to ransom' by hoons

'Merry hell' in Mamaku: Village held 'to ransom' by hoons

11 Jul 06:00 PM
'Massive milestone': Rare native geckos, parrots return amid pest-control success

'Massive milestone': Rare native geckos, parrots return amid pest-control success

11 Jul 06:00 PM
Opportunities in America for NZ red meat

Opportunities in America for NZ red meat

11 Jul 05:01 PM
Solar bat monitors uncover secrets of Auckland’s night sky
sponsored

Solar bat monitors uncover secrets of Auckland’s night sky

NZ Herald
  • About NZ Herald
  • Meet the journalists
  • Newsletters
  • Classifieds
  • Help & support
  • Contact us
  • House rules
  • Privacy Policy
  • Terms of use
  • Competition terms & conditions
  • Our use of AI
Subscriber Services
  • NZ Herald e-editions
  • Daily puzzles & quizzes
  • Manage your digital subscription
  • Manage your print subscription
  • Subscribe to the NZ Herald newspaper
  • Subscribe to Herald Premium
  • Gift a subscription
  • Subscriber FAQs
  • Subscription terms & conditions
  • Promotions and subscriber benefits
NZME Network
  • The New Zealand Herald
  • The Northland Age
  • The Northern Advocate
  • Waikato Herald
  • Bay of Plenty Times
  • Rotorua Daily Post
  • Hawke's Bay Today
  • Whanganui Chronicle
  • Viva
  • NZ Listener
  • Newstalk ZB
  • BusinessDesk
  • OneRoof
  • Driven Car Guide
  • iHeart Radio
  • Restaurant Hub
NZME
  • About NZME
  • NZME careers
  • Advertise with NZME
  • Digital self-service advertising
  • Book your classified ad
  • Photo sales
  • NZME Events
  • © Copyright 2025 NZME Publishing Limited
TOP