Dairy cows: Managing mastitis in heifers

Find out how to manage mastitis infections in heifers by optimising management and husbandry. 

Back to: Reducing the risk of mastitis in heifers

Mastitis management strategies 

Mastitis management should focus on prevention, paying particular attention to managing the environment in which your heifers are reared and calved. On this page, we advise on the environmental and husbandry aspects you can control to minimise the risk of mastitis infections, including living conditions, adequate nutrition and age at first calving.  

Segregating close-to-calving heifers away from dry and calving cows 

Avoid mixing in-calf heifers and dry cows prior to calving, as this has been associated with an increased risk of mastitis in heifers. 

Milk fresh heifers first, using clean milking equipment. Good mastitis control in the main herd will also help, as contagious mastitis is more likely to spread to heifers if there is a high incidence of mastitis on the farm.  

It takes up to two weeks for most heifers to settle into the milking routine. It’s important to be patient and gentle during this period to maximise production, minimise milking times and reduce the risk of injury. Taking care when adjusting first-calvers to the milking routine will also reduce the risk of mastitis. 

Environmental management of pre-calving heifers 

Before calving, give your heifers adequate space, with good access to feed and water, and clean, dry housing or pasture. It’s also important to provide a clean calving environment and to minimise stress around calving.  

The hygiene and cleanliness of heifers before calving is just as important as it is for dry cows. We recommend:  

  • A bedded lying area in straw yards of 1.25 m2/1,000 litres of milk/cow (herd annual milk yield)  
  • A loafing area of at least 2 m2/cow  

At grass, only keep animals in the same lying area (pasture, paddock, field) for a maximum of two weeks, followed by at least four weeks’ rest for that area.  

Read ourDry cow management guide for more recommendations on space requirements and environment management when animals are housed and at pasture.

Heifer feeding and nutrition 

To rear heifers for successful calving at 24 months, you will need to maximise weight gains without allowing animals to become overfat. To do this, we recommend:  

  • Setting appropriate rearing targets for calving at 24 months and monitoring progress regularly  
  • For Holstein-Fresian heifers, a growth rate of 0.8 kg/day is recommended to achieve the required body weight for calving at 24 months  
  • Feeding to meet these targets from birth to calving  
  • Using proper transition feeding to reduce the risk of negative energy balance before and after calving  
  • Avoiding heifers getting overfat  
  • Ensuring they receive adequate nutrition, especially vitamins and minerals  and, in particular, vitamin E and selenium  

Review pre-calving feeding regularly, paying particular attention to dry matter intake, energy density and mineral supplementation to meet your targets.  

Age at first calving 

Heifers should calve for the first time between 22 and 26 months of age and, ideally, at 23 to 24 months old.  

The age at first calving has been shown to relate to higher risks: 

  • Too young  a higher risk of requiring assistance at calving 
  • Too old a higher risk of poor performance in the first lactation and risk of culling 

Research: How does first calving age affect UK herds?

Nottingham University researchers looked at data from 437 UK herds, containing records from over 18,000 first-lactation heifers. The average age at first calving was 29 months, with just over half calving at more than 28 months and over a third calving at more than 30 months old. 

The optimal age at first calving was 23 to 24 months old. The risk of a heifer being culled in first lactation increased significantly for heifers calving at more than 30 months, compared with those calving at 23 or 24 months. 

Sherwin, V. E., Hudson, C. D., Henderson, A., Green, M. J. (2016). 'The association between age at first calving and survival', Animal, 10 (11), pp. 1,877–1,882.


Overconditioned heifers are more at risk of requiring assistance at calving, which may increase the risk of udder oedema and mastitis infections around the time of calving.  

Ideally, 90% of your heifers should have a body condition score (BCS) between 2.5 and 3.5 at calving (BCS 3 for Holstein-Friesian heifers). Find out more in ourBody condition scoring factsheet.  

Useful links

Controlling heifer mastitis

Treating mastitis in heifers

Preventing mastitis in heifers 

If you would like to order a hard copy of the Control of contagious mastitis guide, please contact: Emailpublications@ahdb.org.uk or Telephone: 0247 799 0069