Lameness – not so hidden cost on a dairy farm
Lameness is a significant problem for the dairy industry as it is not only an important welfare issue but can lead to reduced profits according to CAFRE Dairying Adviser Judith McCord.
The most common cases of lameness in dairy cows are linked to painful hind limb foot lesions where sole ulcer, white line disease or digital dermatitis have been demonstrated as the predominant types.
Over recent years herd size and production trends have increased demands on dairy cows. In the last 10 years average herd size has moved from 75 to 95 cows, with average yield per cow increasing from 6225 litres to 7622 litres (DAERA Economics and Statistics). These higher yielding cows are at increased risk of all production diseases including lameness and high standards of management are essential to optimise their health and productivity.
Each incidence of lameness has a direct effect on milk production in terms of daily yield which can decrease significantly. Yield loss due to lameness is seen more commonly in cows from 2nd lactation onward and it can become all too common for the potential of a high yielding cow to be ‘lost’ when they become lame. Milk yield loss can start up to four months before being diagnosed clinically and can result in 550 litres of milk loss over a lactation. According to Judith, this is important information for assessing the economic impact of lameness and also its impact on cow health. Table 1 indicates the effect of lameness on the herd adding weight to the importance of early identification and treatment of clinical lameness.
Lameness has underlying effects on fertility and cull rates of a herd. The additional stress can have a serious impact on ovarian function and follicular development with the overall potential of poor cycling and ovulation. Reduction in feed intake starts to play a role in body condition score loss at peak times. Chronic inflammation can be associated with increased service to conception rates with lame cows nine times more likely to have an increased number of services and calving to conception interval can increase by up to 50 days.
Lameness cost varies with the type of lesion and degree of severity. Treatment cost alone at £75 to £80 per case of digital dermatitis is significant. The overall cost of an incidence of lameness however, in terms of treatment costs, loss of yield and potential for shortened productive life of the cow may be in the region of £330. When broken down the average lameness case cost is £2.20/day/cow for every day the cow is lame. A mobility score is needed to work out the overall cost on a herd basis.
Stephen Wallace, a dairy farmer at Drumanaghan Farm outside Seaforde, recently assessed his herd lameness level before turning cows out to grass. Stephen has recently rebuilt his footbath in a different location allow better cow flow and utilisation. Judith recommends making foot bathing easier for the farmer and the cows which will make it more likely to be done on a regular basis. The new bath is a 1m by 4m concrete bath with rubber matting throughout the race and in the bath.
Before use of the new foot bath the herd was mobility scored, cows had not been foot bathed for four months prior to this. Mobility scoring took place again after cows had been foot bathed for four consecutive milking’s per week for four weeks. Stephen used a copper sulphate and zinc solution. Comparing the mobility scores from Stephens herd shows that by foot bathing he has decreased mobility scores 2 and 3 (lame cows) by 31%. Within Stephens 186 cow herd this represents 58 fewer cows being classified as lame and can be quantified financially by considering the cost of £2.20 per day of a lame cow. Therefore when looking at lameness in terms of its economic impact the result of Stephen’s four week period of foot bathing reduces lameness cost by £127 per day.
Judith summarises that prevention is always preferable and suggests consideration of the following points to improve hoof health. Monthly mobility scoring can bring attention to lameness in a herd whilst regularly foot bathing and preventative hoof trimming will help to tackle lameness effectively. Ensure cubicles are sized correctly with a comfortable lying surface and 5% more cubicles than cows. Lying and standing area of 4 square metres per cow minimum, whatever the cubicle arrangement and floors should be non-slip or grooved and clean of loose stone.
Minimise standing time while cows wait to be milked (<1hr/day) and if longer, split into two groups where possible. Minimise slurry pooling in cubicle housing and passageways and have adequate ventilation. Housing for a time on straw post calving and smooth the transition of dairy heifers into the herd i.e. mixing into the main herd after evening milking or mixing with dry cows a few weeks prior to calving. Discuss hoof health and prevention of lameness in the herd with the local CAFRE dairy development advisers.