When cows are forced to rest in poorly designed cubicles or on a hard surface it results in shortened resting periods, which have a negative effect on production and thus cause poorer economic performance of the herd. Nowadays this need not to be a problem since there is a wide variety of soft beddings available and also cubicle design has improved to assure easy movement of the cow without constructional limitations.
Resting periods of up to 14 hours are advantageous to production because it stimulates blood circulation in the udder and thus milk synthesis. Resting also intensifies saliva production, which is beneficial to a stabile pH in the rumen. And of course, resting also relieves the legs. Investments in resting comfort therefore are useful and quickly show a positive return on investment.
With increasing herd sizes in the free stalls, walking comfort is becoming almost as important as resting comfort. In a free stall with separate areas for feeding, drinking, milking and resting, the mobility of the cows leads to smooth functioning of the housing system. The floor surfaces between the separate areas are important since they not only are needed to go from one area to another, but must also provide enough walking comfort for cows to be able to express natural behaviour.
What is walking comfort?
Walking comfort can be described as the natural walking behaviour of the cow. Preconditions for natural behaviour are healthy claws and a non-skid surface, similar to the conditions of the original habitat of cattle.
Today the flooring in free stalls merely supports the technical demands of management and does not take into account the behavioural demands of the cow as lameness and culling of cows due to claw problems is increasing year after year. Apart from claw care, other reasons such as production, genetics, feeding, age and race make the importance of the role of the floor indisputable.
To detect the needs of cows and to implement these needs for further improving the cows’ comfort, simple observations of the animals are sufficient. It is remarkable that even cows that show signs of lameness when walking inside move more easily in the pasture. When the cows go from the barn to the pasture they always choose the softer part of the road to walk on, such as the wayside or rubber coating if provided.
Why cows choose soft surface?
The reason why cows choose an elastic surface can be explained by their anatomic conditions and the biomechanics of locomotion. Walking is the result of shifting the balance point forward by a push of the hind legs. The front leg is then moved forward to balance the push of the hind leg. To be able to do this smoothly a cow lacks a collarbone, but the front legs are attached to the body through a brawny mounting with the shoulder blade. A similar shock absorbing construction for the hind legs would mean a needless loss of power. That is why the hindquarters have a fixed attachment to the body skeleton.
The difference in anatomy between front and hind legs has a significant impact on the load the claws have to deal with as intermediate between body and surface. The absence of a shock absorbing construction in the hind legs implies a stronger burden on the legs and claws. This physical difference also explains the findings in the field where most of the time the claws of the hind legs cause locomotion problems.
An additional effect to deal with is the biomechanical differences between the inner and outer claw. The slightly unsteady walk of a cow results in an extra pressure load on the outer claw when moving the body weight from one leg to the other. On a hard floor the claw cannot sink into the surface and will carry most of the weight. The distribution of weight within and between the claws change, especially on the rear feet and legs. The outer back hoof carries 60% of the weight in a mature cow. Outside claws continuously correct changing weight loads. The change in weight distribution is believed to be the cause of rapid horn growth and high incidence of outside claw disorders.
Step length
A soft floor changes animal behaviour in the free stall, especially locomotion. Research at the
Comparing step length on pasture and on concrete slats with and without rubber coatings also showed significant differences. On pasture the average step length is 81 cm. Here the cow with her hind claw steps into the imprint of the forefoot. This way the cow can transport the visual controlled step of the forefoot onto the hind claw. The cow also takes maximum advantage of a layer of very soft shock absorbing horn in the ball segment of the claw.
In the passageways of today’s housing systems long swinging steps provide a higher risk of slipping. Animals try to avoid this by adjusting their step length to an average of 58 cm. When concrete slats are covered with a rubber lining, step length increases to an average of 78 cm, which nears the length of the steps when walking on pasture and can be seen as an expression of improved walking security.
Change in behavior
Of major importance within fertility management is heat detection of the cows. Fertility problems are the second most important cause of depletion in a herd, but are usually not affected by housing. However the effect of a soft floor up to now has an underestimated impact. Through observations it could be ascertained that heat expression on a soft floor is different to that on a hard slippery surface. Frequency, but also intensity and duration of riding as an indicator of heat expression increased considerably. Locomotion problems can occur when riding cows land on a hard surface, slip or injure themselves. This risk is minimised on a soft floor.
Cows tend to clean parts of their body by standing on three legs and lick the area of the lifted hind leg, which has become an indicator for qualifying the quality of floors. Research showed that cows on a soft floor expressed this licking behaviour three times more often than on a hard slippery surface, which implies that they have more confidence on a soft floor.
Blood circulation and claw health
Walking behaviour and claw health influence each other reciprocally. Cows suffering from lameness tend to walk as little as possible. However, walking is a prerequisite for adequate blood circulation in the claws. When standing still, blood is pressed out of the claw and when the foot is lifted blood flows into the claw again, a sort of press-suck pump. Standing for longer periods is like poison to microcirculation of the blood. Not only blood circulation is too little encouraged, but also malfunctioning of the blood circulation occurs, when the sclera between the hard floor and the claw bone is bruised.
Disruptions in blood circulation have an effect on the horn building part of the claw. The quality of new horn deteriorates and a basis for knock-on effects is created. Internal bleedings and discolouring of the hoof are signs of poor blood circulation.
Claw health clearly improves when soft floors are used. Mechanical-traumatic damages on five test farms went down by 80% six months after installing rubber floor coatings. Not only occurrence, but also intensity of claw damages declined.
Contrary to hard floors, soft floors maintain soft hoof walls. The hoof wall has to carry around 60% of the animal’s weight and is supported by the heel or bulb part of the claw, which is made of a specific type of horn around a fat cushion that has additional shock absorbing properties. High producing cows often suffer from energy deficiencies and the cow has to mobilise its body fats, also from the heel of the claw, which decreases the shock absorbing properties of the heel.
This makes the hoof wall even more important. The hoof wall takes all the weight when walking on a hard surface. The sole can only support the wall when the cow walks on a soft surface in which the hoof wall can sink a little.
Horn wear-off
In natural conditions, horn from the bulb and sole automatically peels off, which can be observed in cows walking on pastures. This is also the case on soft surfaces in the barn. The weight is evenly distributed on the wall and the sole horn is peeled off gradually from both.
When using soft floors in passageways it is often questioned if the horn wears off efficiently. Critical is the net growth of horn, where wear is a factor of influence. Any external (hard surface, disease) influence on the claw results in extra growth of horn (similar to callous growth on one’s hand or feet). This firstly occurs on the outside claws of the hind legs. Experiences with soft floors have shown that net growth is only a few millimetres of extra horn. When the weight is evenly distributed this will not result in damaging overload of the claw.
Clean and safe surface
To keep claws healthy the passageways should be clean. Urine and manure have a detrimental effect on the claws and also precondition the occurrence of diseasecausing agents. Naturally passageways should never cause additional mechanical strains to the claws.
Concrete slats should have sufficient walking surface with adjusted spacing. Concrete floors often are laid out with a specific profile, such as a diamond shape, broom sweep or grooving, which actually do not prevent slipping. When a cow slips, grooving abruptly stops the slide and can cause mechanical damage to the claw.
Soft floors
Soft floors to cover concrete floors are made of rubber mats that return to their original shape when pressure is released. The softness of the mat is achieved through a special cleated sole and the grade of softness is adjusted to the weight of the cow, so the hoof will only sink a few millimetres into the rubber. The rubber also works as an anti-slip mat.
Rubber mats are available for full concrete floors as well as slatted floors. The latter being customised cut to the pattern of the slats. Slatted floors need more cleaning, but practice has shown that because of the increased activity of cows on soft floors they ‘walk’ the manure through the openings and ‘clean’ the passageways better.
On full concrete floors the rubber mats have to be seamlessly attached to each other to enable the slurry scraper to run smoothly over the rubber surface. By connecting the mats in a puzzle-like pattern the problem of catching by the scraper is solved. This way rubber mats can also be installed in existing barns.
Conclusion
Even if claw diseases have multifactor causes, the housing system should never be an extra burden to claw health. When cows in a barn can move as they would on pastureland the danger of damaging the claws is minimised. Soft floors can imitate these positive properties of a natural pasture. Unlimited locomotion improves blood circulation of the living tissues in the claws and thus prerequisites the growth of healthy horn as a basis for healthy claws.
More information can be obtained from the author at barbara.benz@kraiburg-elastik.de
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