Monitoring health and welfare when wintering at grass

Managing animals over winter at grass presents specific health and welfare challenges. See our tips on preventative management.  

Monitoring stock when wintering at grass is essential as some animals may not cope as well as others and require housing or managing differently.

Before wintering, assess BCS. Any thin animals should not be wintered outside.

Young animals should be grazed separately to ensure allocation is correct and account for growth requirements.

Potential health issues:

• Loss of body condition
• Internal and external parasites
• Infectious disease, particularly where stocking density or management may increase the risk of transmission
• Eye problems, including infectious keratoconjunctivitis

Preventative management:

• Body condition score (BCS) regularly, every 3–4 weeks
• Faecal egg counts (FEC) for parasite burdens
• Biosecurity for incoming/new livestock
• Use of sheltered fields during bad weather
• Vaccinate for clostridial disease
• Monitor nutritional status and investigate suspected deficiencies with appropriate veterinary advice and testing

During a wet winter, the high water content of the grass can contribute significantly to water intake.

However, water requirements vary with forage DM content, weather, animal class and the inclusion of concentrates or conserved forage. Water supply must therefore be sufficient at all times and increased where necessary. 

Keep fields with piped water available for late pregnancy where possible, when water requirements may increase.

When feeding concentrates and conserved forage, be aware of their lower water content and ensure the water supply reflects this. 

Removing concentrates from the diet may also remove a source of trace elements. Discuss this with your vet and, if a deficiency is suspected, use appropriate blood and/or forage sampling to investigate.

Blood tests can provide useful information about the nutritional status and can help identify potential problems when interpreted alongside animal condition, diet and forage analysis.

They can include:

• Beta-hydroxybutyrate (BHB): an indicator of negative energy balance and increased fat mobilisation
• Urea: can provide information about protein supply and rumen nitrogen status, but is influenced by diet and timing of feeding
• Serum albumin: can provide information about longer-term nutritional status, but is influenced by factors other than dietary protein

Discuss any blood test results with the vet and make changes to the diets or groups as necessary. Blood testing can be done through the farm vets, or for BHB, new on-farm tests are available.

The figures below have been supplied by the Moredun Institute and should be interpreted alongside the original guidance and the laboratory's reference ranges. 

BHB is a ketone produced by the liver when ewes are mobilising body reserves to compensate for insufficient energy supply:

• Higher levels indicate greater mobilisation of body reserves; excessive mobilisation during late pregnancy can increase the risk of pregnancy toxaemia 

• Normal level: less than 1.1 mmol/litre

Urea is influenced by protein supply and rumen nitrogen status:

• It can vary considerably depending on diet, energy supply and when the last feed was provided 

• Normal level: 2–3 mmol/litre

Serum albumin is a protein made by the liver:

• Low levels can indicate poor nutritional status but may also be associated with other factors
• Normal level during late pregnancy: 26–30 g/litre