Lameness in dairy cows arises from several risk factors, including environment, disease, nutrition and management. Though many of these factors are being addressed by many farmers, lameness in cattle will still occur. It is no different in the human population.
Variation exists, but unlike the human population, the cow population can be culled to remove cows that are persistently troublesome, in this case, lameness.
Environmental factors include such risks as stall dimension and cow size (cow comfort), floor types, floor hygiene, and population density.
There is enough data available today to construction companies and farmers on how to build new barns or renovate old ones.
The objective is to build the most suitable stalls to give cows adequate space to stand, lie down and rise again and prevent leg and body injuries.
With the anticipation of getting hurt, cows tend to stand longer in their stalls. If the stalls are too short, for example, cows will stand with their front legs in the stall and their hind legs in the alleyway.
Not being able to lie down increases cow fatigue and therefore increases the risk of getting permanent hoof and leg injury.
This is one explanation why it is seen in studies that the prevalence of lameness in herds increases with lactation number, for example.
In a recent study (J.Dairy Sci. 91:2265, 2008), it was observed that the prevalence of lameness in cows resting in free stalls was 46 per cent compared to 25 per cent for cows kept in straw pens. Similar differences in lame cow prevalence were observed in a British study where it was 24 per cent in free stalls compared to five per cent in straw yards (J.Dairy Sci. 89:4259, 2006).
Zero to 1.9 per cent slope in free stalls increased the prevalence of lame cows from 16 per cent to 39 per cent. As to the types of surfaces cows walk and lie down on, the same study showed lameness prevalence of 31 per cent in cows kept in barns (zero-grazing) compared to 15 per cent in cows on pastures (grazing).
Another study (Vet.Rec. 138:563. 1996) showed lameness prevalence in cows during summer to be 23 per cent compared to 32 per cent in winter (ie. cows kept in the barn longer in winter than in summer).
Increased cow density and lower feed bunk space per cow also showed increased prevalence of lame cows.
Factors such as inferior passageway cleanliness and larger herd sizes but not necessarily increased population density also contributed to increased risk of foot and leg injuries and prevalence of lameness. Farms that had shorter calving cycles also had greater prevalence of hock swellings, which might be related to concentrate density in rations.
In the same and most recent investigation cited above (J. Dairy Sci. 91:2265, 2008), the authors compared 40 non-organic farms with 40 organic farms. Their results showed that organically fed cows had fewer foot and leg injuries than non-organically fed cows (37 per cent compared to 49 per cent, respectively).
This may be related to cows fed organically getting more forage in the diet and grazing longer than cows fed non-organically.
It is reported that under Swiss conditions (J. Dairy Res. 74:86, 2007), subclinical acidosis appeared to be a greater problem on organic farms than on conventional farms. These differences between organic and non-organic farms, if they occur, need more clarity and definition.
Nutritionally, cows that are fed diets high in concentrates tend to show greater prevalence in bouts of clinical and sub-clinical acidosis than cows fed diets high in forage (greater than 50 per cent forage concentrations dry matter in total mixed rations).
Total mixed rations that are greater than 48 per cent dry matter tends to increase sorting activity by cows and thereby increases the prevalence of acidosis in the herd.
When cows learn to sort, this type of behaviour is difficult, if not impossible, to cure.
These cows most often become culled due to severe lameness.
Another source of acidosis can occur as a result of retained placenta, and rations high in chlorides and sulphates which can be managed with proper nutrition management.
Other factors contributing to the increased prevalence of lameness is observed on farms where all cows are trimmed regularly twice annually, or where handlers are more aggressive and use sticks or plastic pipes to move cattle.
Bouts of acidosis and subclinical acidosis reduce the synthesis of biotin in the rumen.
Biotin is a vitamin that is necessary for the synthesis of keratin, a structural protein required for the repair and making of claw horn. It has been shown that the addition of about 20 grams of biotin in the ration may reduce the incidence of white line separation in claws from 15 to 10 per cent.
The inclusion of biotin in rations, however, does not reduce the incidence of digital dermatitis, sole ulcers and interdigital necrobacillosis (a bacterial infection between the toes).
Sole ulcers is most often caused by pinching between the sole and the distal phalanx (outside toe), which is most often seen in the hind feet. This pinching tends to increase significantly on hard surfaces and the pushing and shoving action of cows.
Keeping lameness of cows to a minimum ought to be the objective of every dairy person. Increased prevalence of lameness on farms decreases milk output and overall cow health. It is no different than the health our own feet and legs which helps us to get around from place to place and to live a full and disease-free life. Like cows, overweight people, those who do not manage their nutrition and physical well-being, or are unable to do so, or people who live or work in an unsafe environment, will be more prone to all sorts of health and work related problems.
It is up to us how we want to live and work. It is up to us how our cows produce for us. It is up to us to provide high quality barns and nutrition for our cows.
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