Grazing animal tactics in cold weather

Grazing animal tactics in cold weather

As the cold snap of winter rolls in across the country, our grazing animals showcase a diverse array of adaptations, evolved over time to contend with plummeting temperatures and the reduction in leafy vegetation cover across Kent’s nature reserves.

Thick fur and wool

The primary function of fur and wool is to provide insulation. The dense hair or wool traps a layer of air close to the animal’s body. Much like when we put on a puffy coat, the trapped air reduces the conduction of heat to the external environment helping the animal stay warm in cold weather. The master of coat insulation has to go to the highland cow – known for its double coat, the outer layer of a highland cow's coat is made of long, course guard hairs (up to 13 inches!) which are designed to repel water and keep the animal dry in wet weather.

This water-resistant quality helps prevent the soft dense undercoat becoming saturated, maintaining its ability to trap air close to the animal’s body. This incredible insulating ability allows the cows to withstand extreme wet and cold weather in the highlands as well as provide an economical benefit for farmers as there is little need for shelters and barns - the cows will simply get too hot indoors!

A herd of highland cattle looking at the camera.

© Jessica Allam

Cows employ a unique thermoregulatory mechanism by adjusting blood flow to their core horn structure. The horn itself is comprised of bone tissue with a central blood supply which is encased in a layer of keratin. As temperatures drop, blood flow is restricted and channelled away from the extremities towards the animals’ core, ensuring internal temperature stability. In the summer however, cow horns fill with blood and dissipate heat through the horn structure into the external environment. This intricate adaptation highlights the cow’s ability to regulate its body temperature based on environmental conditions.

Manx sheep grazing in snow and frost.

© Alison Ruyter

Manx wool has high lanolin content, a natural wax which is produced by the sheep’s skin and found in their wool. The Lanolin has moisturising and water-resistant properties, making their wool more resilient against the elements. Like the highland cow, manx also have a double fleece which helps them stay warm. You can see in the picture where the snow has settled on the manx's wool. The fleece has such good insulation that even the snow takes longer to melt due to the lower levels of heat loss. 

Our konik and exmoor ponies are also excellent examples of developing a thick and fluffy coat for the winter! Below you can see the difference in coat length and thickness between the summer (left) and winter (right). 

When these coats are shed in the spring, they become valuable nesting material for birds. The rolling, rubbing, and scratching they do to remove the coat plays an important part in shaping the microclimates of a site, from dust bowls to breaking down (or re-)coppice trees.

Increased movement and food selection

During the colder months, grazing animals will become more active to maintain their body temperature and will also increase their metabolic rate and burn more calories to generate heat. A brilliant example of this is with our 8 longhorn cows at Heather Corrie Vale in Sevenoaks.

Presented below are two heat maps capturing the cows’ activity across the reserve during challenging weather – specifically wet (A) and cold (B) conditions. The image on the left (A) depicts the cows hunkering down and taking refuge in the coniferous wooded area, strategically seeing shelter to stay dry during rainfall. As the weather improved the next day, the cows exhibited heightened mobility; actively moving across the reserves open spaces and engaging in foraging activities to maintain warmth (B).

However, the animals are not just moving more for thermoregulatory reasons; the increased range opens up a wide pantry for the animals to munch away on, with each plant meeting specific nutritional needs. Top choices of grazing animals in the winter are gorse with its 17% high protein content whilst English broom has an impressive 21%. Holly leaves, bracken and sweet chestnut are also on the menu as they are high in calories, with bracken in particular being high in iron and magnesium. Ponies, sheep, and goats also strip tree bark from species such as Willow, Ash, and Alder to gain valuable vitamins, minerals, and fibre.

The changes made to these winter food sources by grazing are great for wildlife. The holly responds to grazing by getting thornier, keeping predators out. The dead wood and flaky bark on the stripped trees become home for wood-boring beetles, whilst the gorse sends out lots of new side shoots which will be full of flowers in time.

Behavioural adaptations

When it comes to finding food in the winter it can be difficult – especially if it snows. Each grazing species expresses a different level of object permanence, aka ‘out of sight, out of mind’ ability.

Cows have a basic level of this skill. They can recall the location of food sources and navigate their environment based on past experiences. Yet when everything is covered in a sheet of white, it can be hard to find and remember where the grass was. During this time, you will most likely see cows turn to browsing leaves from the trees – a visible food source amid the winter landscape. On the other hand, ponies, sheep, and goats showcase a notable proficiency in object permanence skill, remembering locations and navigating obstacles to reach hidden food sources beneath the snow. You will regularly see these animals pawing at the snow to uncover the grass beneath as well as ponies using their hooves to crack the ice covering water troughs and shallow ponds.

The wildlife follows along behind. Birds such as robins and even buzzards forage in the open areas of grass and disturbed ground uncovered by the sheep and pigs, while all animals benefit from the ponies opening up water supplies.

You can find out more about our approach to conservation grazing here!