When renovating or designing a new stable for all cattle age categories, it is important to remember one crucial criterion: the issue of animal welfare. In 1993, the British Farm Animal Welfare Committee (FAWC) approved a codex of five basic freedoms that have been accepted worldwide, not excepting the Czech Republic. One of these is ensuring an adequate breeding environment and providing protection for the animals against adverse microclimate - removal of physical or thermal discomfort factors (Manteca et al., 2012).
Quality ventilation systems of stables buildings play a key role in this respect. The biggest risk to animal welfare in cattle farming is keeping animals in a stable with inadequate air exchange - ventilation (air humidity ↑, concentration of gases in stables ↑, temperature ↑ but also ↓ = cold and heat stress etc.). Any short-comings in the quality of the stables or the breeding environment significantly increase the risk of animal disease (such as respiratory diseases) and have a negative effect on a number of physiological processes in the body which are closely related to yield and reproduction of the stock.
An organism experiences thermal comfort when the thermal condition of the body is optimal and the animal has to expend only a negligible amount of energy to maintain its physiological functions when within a certain temperature range and with other physical aspects being constant. This range of external temperatures is called the thermal neutral zone (Doležal et al., 2004). The thermal neutral zone for cows is between -6 °C and + 19 °C and for calves between +10 and +25 °C (Staněk, 2016).
Considering the course of temperatures in the last few years, summer months tend to be a period of heat stress in cattle, especially among high-producing cows. Cows are under heat stress when the temperature of the surrounding environment rises to a level where the animals can no longer efficiently conduct heat to the outside of the body. Heat stress in cows results in the activation of a number of thermoregulation mechanisms which aid them in releasing excessive heat from the body. Externally, heat stress most commonly manifests in the form of an increased respiratory rate, increased salivation, reduced feed consumption, increased fluid consumption, seeking of shaded places, reduced rest time with increased time spent standing (load on the limbs) and, in some cases, attempts to cool down by laying down in wet/cool walking corridors.
The threshold of heat stress in cows generally occurs approximately when air temperature exceeds mere 21 °C. However, it is important to note in this respect that heat stress is usually a combination of not just ambient temperature but relative humidity as well. As temperature and relative humidity increase, the risk of the outset of heat stress grows significantly. The immediate effect of heat stress is usually not just a decrease in milk production, but also noticeable changes in milk composition; breeders also often encounter issues with cow reproduction (decreased pregnancy rate, reduced signs of rutting, early embryonic mortality, etc.).
The consequences of the effects of high ambient temperatures - heat stress - are long-term, in the order of several weeks. In the case of cold stress, the situation is markedly simpler since it is easier for cows to produce metabolic heat in the rumen (feed intake ↑) than it is to release it. On the other hand, stables face the issue of water or technologies for slurry removal freezing up during frosty and arctic days. Stables with minimal air exchange may struggle with high relative air humidity, water condensation, etc.
Ensuring an adequate breeding environment is the primary task of every cattle breeder and must be taken into account already during the construction or renovation of the stable. The trend in recent years has been to build structurally simple stables which ensure an adequate environment for breeding by their design. Today, efficient air exchange in the stables is most commonly resolved by open side walls with rolling canvases combined with a high-quality ridge vent on the roof. It is also worthwhile for breeders to install a weather station to automatically control the microclimate in the stable.
The station can be interconnected with not just the side ventilation walls and ridge vent, but also forced ventilation technology, evaporation cooling and the
lighting system controls. Fully digitally controlled microclimate in the stable is a modern innovation trend that not only contributes to better breeding comfort for the animals, but also makes animal husbandry more economically efficient.