Winter Nutrition and Minerals for Deer

As winter tightens its grip, feed quality and availability drop, just as stags are coming off a nutritionally demanding period, and as hinds are heading into an increased requirement for foetal growth as well as setting themselves up for lactation during summer. Even when bodyweight does not change much through winter, the right balance of energy, protein and minerals is critical to maintain condition, support immunity and set animals up for strong velvet growth and healthy fawns in spring.

Stags after the rut: replacing fuel, not just weight

The rut is a costly time for stags. Voluntary reduced feed intake, increased movement and high stress commonly strip fat reserves and leave animals running on a nutritional deficit. Through winter, the goal is to restore energy status and muscle tone while keeping the rumen stable. A stag can look settled, yet still be short of the fuel and nutrients needed to support immune function over the winter and to prepare adequately for velvet initiation and growth as day length increases from late August.

Prioritise consistent energy: winter pasture can be bulky but low in usable energy. Where needed, add supplementary feed gradually to avoid digestive upset.

• Do not neglect protein: Adequate dietary protein supports tissue repair and helps set up spring antler/velvet growth. Very poor-quality roughage can limit intake and performance even if animals appear full.
• Feed for rumen health: Keep a fibre base and introduce any supplementary feed slowly over 10–14 days, with steady access rather than “boom and bust” feeding.
• Winter crops: It is well worthwhile having any winter crops analysed for nutritional value. A couple of years ago we found a winter kale crop with a protein level of 9% (lower than the fodder beet paddock next door for cows).  At this level we had to balance the diet with good quality silage to meet protein requirements.
• Monitor condition: Use body condition scoring and observe dominance behaviour — subordinates often miss out when feed is limited.

Hinds in winter: building a calf on a tight budget

For hinds, winter nutrition is about more than holding condition. Pregnancy places a steadily increasing demand on energy, protein and key minerals, with requirements rising most sharply in late gestation as foetal growth accelerates. If a hind is short through this period, she may still carry to term, but the hidden costs can show up as lighter calves, slower early growth, poorer milk production and a harder recovery post-calving. Replacement fawns’ future productivity can also be impacted by poor nutrition. Mammary tissue development of the foetus starts occurring at about two months of gestation, and there is a significant influence on mammary development in the fawn for two months before and two months after birth – the da’s nutritional status is therefore going to play a significant role in the future production of replacement hinds.

• Maintain (or gently lift) condition: Aim for steady condition rather than rapid gain – sudden changes in diet can cause setbacks.
• Manage competition: First-calvers and lighter hinds benefit from separate mobs so they are not pushed off feed.
• Plan the late-winter pinch point: The period when pasture is at its lowest often coincides with rising pregnancy demand – budget supplements early.
• Think ahead to lactation: A hind that enters spring underfed is behind before fawning even starts.

Minerals: small quantities, big consequences

Mineral needs do not stop in winter – if anything, shortfalls are more likely because intake can be limited and forage mineral content can be variable, plus there is possibly greater antagonisation due to low pasture covers and the likelihood of more soil exposure. Getting minerals right supports bone development, immune function, fertility, and (in stags) the foundations for antler/velvet growth. The best programme is one that matches your forage, soils, water and class of stock – so consider testing pasture/supplements and working with your veterinarian.

• Calcium and phosphorus: Essential for skeletal growth and antler mineralisation; keep the balance appropriate, especially if using grain-based feeds.
• Magnesium: Supports nerve and muscle function; risk periods can occur when diets change or when pasture quality shifts quickly.
• Sodium (salt): Drives appetite and helps maintain hydration; it also improves uptake of some loose-lick mixes.
• Copper, zinc and selenium: Commonly discussed trace minerals in deer systems due to roles in immunity, reproduction and growth (note that deficiency and toxicity can both occur — dose matters).
• Iodine and cobalt: Involved in metabolic function (thyroid and vitamin B12 pathways) and can influence overall thriftiness where soils are low.

In practical terms, minerals can be delivered in a multitude of ways. The “best” option is the one whereby animals will be reliably supplemented at the intended rate. Talk with your veterinarian about testing to see what may be needed and the best method for correcting any deficits that might be identified.

Animal health: winter is a good time to tighten the programme

Nutrition and animal health go hand-in-hand. When feed is tighter and animals are under more pressure (post-rut stags, pregnant hinds, young stock), small health issues can quietly erode performance. Winter is often a practical time to review your herd health plan with your veterinarian and to line up any treatments so that animals are set up for spring.

• Trace mineral supplementation: If deficiencies are known or suspected, options include oral minerals (licks, boluses), injectable trace minerals, or slow-release boluses. The right product and timing depends on your risk profile (soil/forage, class of deer, stage of production). Avoid stacking multiple sources without calculating total intake – copper and selenium in particular can be harmful if oversupplied.
• Vaccinations: Review what diseases are relevant to your area and system, and whether boosters are due. Where vaccination is part of your programme, good timing matters – aim to vaccinate ahead of predictable stress periods (e.g. late pregnancy/lactation, major diet changes, weaning, yarding) so that immunity has time to develop.
• Parasite control (drench) if required: Where possible, treat based on need rather than habit. Use faecal egg counts (and/or veterinarian advice) to decide whether to drench, which product to use, and whether resistance is a concern. Prioritise higher-risk groups (young stock, lighter animals) and remember that nutrition strongly influences resilience to parasites.

Whatever you choose, keep records (date, mob, product, dose rate, withholding) and build treatments into a whole-farm plan rather than one-off fixes.

A well-fed winter herd does not necessarily look “fatter” – it looks settled, resilient and ready. By targeting energy first, supporting protein for repair and growth, and keeping a sensible mineral programme in place, you give stags the platform to express velvet potential and help hinds deliver strong, vigorous fawns when spring finally arrives.