Stress is a physical or mental factor that causes tension to the body and/or mind of both people and animals. Stress is a reaction that initiates, usually, the “fight or flight” response, composed by both endocrine and neurologic factors (adrenaline and noradrenaline). Stress provoking factors may come from the outside (the environment and psychological or social situations) of the body or from the inside (illnesses, medical procedures…).
Each individual responds to stress in a different way. For animals, the response to stress may depend on their species, breeds and life conditions.
Animal stress can have different causes
The stress response includes several changes that may have negative effects on livestock. These effects include changes in the immune function and increased susceptibility to disease, decreased feed intake and rumination, inhibition of oxytocin release and reduced fertility, among others. These factors not only impact on the animal’s welfare but also on the productivity of a farm. On both levels it is in farmers interest to assess and anticipate animal stress and manage it appropriately.
There are a number of phases inherent to the farm animal’s life which may represent a stressful moment, e.g. transition phases, like weaning, can be a delicate period for a piglet for instance; or giving birth and lactation for nursing sows, who will need supplements of energy to better care for their newborns. Other common stressful situations for domestic animals include, health care procedures, among others. Stress induced by handling agitates and excites animals, which increases body temperature and heart rate, raises corticoid levels in their blood (adrenaline) and reduces immune functions, leaving the animal more susceptible to diseases. Animals accustomed since their birth to human proximity will have a less intense physiologic response than animals that have been raised in a pasture with little human contact.
Environmental stress has an impact on livestock too. All animals perform better at their “thermal comfort” zone, which varies among species. This kind of stress may be managed by providing adequate nutrition and hydration in each case, with proper management practices (shelters, ventilation, etc.) and health care when needed.
Avoiding handling the animals as much as possible would be almost the perfect solution in every developed farm. That is why in some places around the world, farmers have begun to implement some advanced measures as far as finances allow: for instance, with automated milking robots, cows enter whenever they want and there are no pressures for them to be herded through the farm in order to be milked!
Apart from facilities and general shelter, nutrition also plays an important role; therefore, nutritional strategies can help animals to cope with eventual challenges coming from their surroundings, improving their welfare.
For instance, to avoid loss of appetite and therefore undernutrition of newborn piglets, farmers will choose flavourings to increase the palatability of the diet after lactation and then stimulate the animals’ appetite.
Feed additives in particular may be important also in maintaining footpad/hoof health. Together with animal health care these contribute to stronger joints and support the immune system of animals by maintaining gut health, resulting in increased resilience to stressors and infectious diseases.
Giving high caloric feeds in winter to animals may help to cope with low temperatures along with an adequate heating system for the enclosures and the avoidance of cold air flows. On the other hand, providing low caloric feed in summer can help to tackle the effect of high temperatures, avoiding the fact that the animal may generate more body heat itself; this should be accompanied by adequate shaded areas around the enclosures, an adequate ventilation in the indoor facilities and the availability of fresh water sources in different formats –drinking water in the case of cattle; showers for pigs.
Also for cattle and dairy cows, one thing that seems to help them de-stress are brushes to scratch their backs! Who doesn’t like a nice back massage?