Animal welfare: a comfortable stall
For some time animal welfare has become an important parameter for the design and management of modern stalls. Plans must take into account rotary brushes for ensuring healthy epidermal conditions as well as systems for air circulation and climate control. There are also technological solutions for bedding which must guarantee rest for animals in sound hygienic conditions
It is now widely confirmed that the comfort of dairy cows strongly conditions their state of health and production. This means that the most recent stalls are equipped with furnishings, also as regards the plant system, for the purpose of improving the well-being of the animals.
Rotary brushes for epidermal health
Plastic polymer bristles mounted on a rotary base of galvanized or stainless steel rotate slowly for a gentle massage applied to the hide of the cow to remove parasites, surface incrustations and old hide. The results lower the tendency to scratch, improve epidermal transpiration and regulate peripheral blood circulation. It has been determined that the use of these rotary brushes increases milk production by up to1 kg/day. The most simple brush massages only the animal’s back and a double brush is used for working also on the flanks. The stiffness of the bristles must be carefully selected because though they must not irritate the hide, they must be sufficiently resistant to avoid permanently ruining their shape too quickly. The configuration of these brushes varies from cylindrical, suitable for work on the flanks, to an hourglass shape adopted for the animal’s back. The brush can be cylindrical, the shape most suitable for work on the animal’s flanks, or have an hourglass shape, the most well adapted for the back. Moreover, the brush can be fixed or mobile; the former applies more pressure on the cow and the latter could be subjected to jerky movements which frightens a single cow or the entire herd. For this reason, some models rock back and forth and are equipped with locks to prevent complete rotations.
The device is started by a movement sensor activated by the cow via a CPU which manages the motor. The operation can be allowed for as long as the cow is in contact with the brush or set for a programmable predetermined period of time. To limit permanently curvature of the shape of the bristles and ensure more regular wear, some models are equipped to change the direction of the brush rotation with each start up. For correctly guaranteeing safety in operation there are usually sensors for controlling motor temperature and excess voltage in the electric network. The electrical components are effectively protected against water to make the bush easy to wash. To ensure maximum hygiene, they can be cleaned with a jet of water or pressure washers. A single brush is sufficient for herds of 50-60 cows; more brushes are required for larger herds installed in various areas of the stalls directly on the walls or on posts.
Care of climate control
Also climate control has considerable influence on the efficiency of the herd for the production of milk as well as increasing the weight of beef cattle. This means that maintaining the temperature in the stalls at thermal neutrality is important and varies from case to case; an example is for Holstein-Friesian cattle used to produce milk in lactation the temperatures are from 0 a 24°C. In real conditions, this range is influenced also by other factors such as atmospheric humidity, the velocity of the air flow and possible exchanges of heat. The main production problems, less in winter cold, are caused by the heat of summer, especially when this heat is accompanied by high levels of humidity. Among other issues, the air exchange inside the stalls must be in keeping with the concentrations of dust and harmful gas. The ventilation parameters vary according to the season: the advised flow of air in the summer is 4-5 m/s whereas in the winter, the velocity should be reduced to 0.25-0.5 m/s to minimize the dispersion of the animals’ body heat. For this latter case, natural ventilation is sufficient because of the chimney or wind effects. Especially the chimney effect causes a strong rise of hot air which tends to rise naturally from the ground to purpose-built vents in the roof of the stalls. This movement brings in fresh air from the outside to create natural circulation. On the other hand, the effect of the wind benefits from analyses of the prevailing currents in the area and by creating, or adding afterward, special openings to facilitate the circulation of air. In summary, what is important in the planning the construction of the stalls is to take ventilation openings into account, vents above and air intakes under the eaves. In detail, the ventilation openings can be equipped with mobile shutters to alter the flow of air entering for varying climatic conditions. The openings above, which can be installed only in barns with a two-layer roof, favor the chimney effect and must ward off rain and wind which could lessen or nullify efficiency. On the other hand, vents under the eaves are always open to ensure ventilation also in the winter. These solutions outlined are passive in that they work in various ways on the natural movement of masses of air. Especially in the summer, these arrangements are not sufficient for ensuring satisfactory climate control. For these conditions, there is recourse to electric helicoidal fans. The number, size and power of the equipment to install are defined in the planning phase. For this purpose set out are the HPU (Heat Producing Unit) and thermal power at about 1000 W which is the equivalent of a cow of live weight at 630-640 kg at 20°C.
The fan can be directed by the motor or connected to gears or a belt for varying the transmission ratio. It can run as an on/off type or with a regulator for speed of rotating with an inverter, for example, and also regulated for the air temperature and humidity level.
Ventilators can operate by blowing a flow of air or by aspiration. In the first case, air pressure is produced inside the structure whereas with aspiration, air is withdrawn from the natural openings in the stalls. The former type is no longer used in that it was used only in tethered stalls and because it reduces the current of air directed to the animals. On the other hand, ventilation is reduced in free stalls, especially during feeding and while awaiting milking. The typical ventilators installed are axial, from about ø 1 m with a flow of air of some 15-30° toward the floor. The direction of rotation of the ventilator must provide aspiration of the wall of cool air.
For increasing the efficiency of fresh air a combination can be used, forced ventilation with an evaporator for nebulizing humidity in the air current into droplets of water or removing damp directly off the cow. Nubulation can be used by fitting one or more nozzles to each ventilator which, at pressure of 7-15 bar, generate droplets small enough for immediate evaporation to quickly avoids excess heat. Also in this case, the device can be activated manually or automatically via temperature and humidity sensors.
For direct aspersion, low pressure nozzles at 2-3 bar are used by locating them mainly in the feed area. In this way, the animal receives a sort of refreshing shower which also cools the floor. In this case, the floor must be non-slippery and dried quickly/ This solution requires 50-300 lt/day per head compared to 10-20 lt/day per head with nebulation which, however, requires dedicated plant with pump and related distribution installations.
An alternative to normal axial ventilation is the use of big vertical axle ventilators with diameters greater than 4 meters and equipped with many blades, up to 10-12. These are installed on the ceiling and run at very low speed of rotation, some 60 rotations/min. This system provides a great flow of air but at low velocity and does not cause a load problem for the animals. Furthermore, the power used is substantially reduced; a motor of little more than 500 W is sufficient for running a ventilator with a fan of about 7 meters to ensure some 200,000 m³/h of air, five or six times the flow produced by an axial ventilator with the same electric power. The costs of acquiring and installing the system are substantial because to guarantee gradual startup an inverter must also be installed.
Advanced beds
The real well-being of animals is ensured by good rest which, in turn, is conditioned by the type of litter in the bed. Other than straw other traditional materials are adopted because they is easy to supply, they protect the joints, curb the proliferation of coliform bacteria if 2 kg/day per head are applied two or three times a week and are good for absorbing water; in the United States sand is used in quantities of about 5 kg/day per head and replaced every ten to 15 days. These solutions have the advantage of greatly reducing cases of mastitis and hide lesions but they are difficult to manage with conventional cleaning plants, pumps, augers, etc.
A recent alternative to natural materials are carpets and mattresses in synthetic materials which undoubtedly improve the well-being of the animals and their hygienic and health conditions but involve the production of waste liquids and non semisolids.
The carpets are fairly thin, no more than 15 to 35 mm thick; they are highly resistant and most of them are models with non-slipping surfaces in contact with the animals. If they are single they are fixed to the floor with special stops but they can also be linked by using PVC profiles or with channels formed on their sides. Other models are made of less rigid polyethylene foam or foam rubber for greater comfort. The thickness of these materials is substantial, up 30 to 110 mm; they can be single or multi-layered and covered with polyethylene or rubber and the inside made of foam rubber, latex or polyurethane foam of various densities. Other than being impermeable, their surfaces almost always have an ant-slipping profile.
