BOVINE LAMENESS IN WESTERN CANADA. Paul R. Greenough, Saskatoon

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1 INTRODUCTION BOVINE LAMENESS IN WESTERN CANADA What we can do to control lameness in dairy cows in Western Canada Paul R. Greenough, Saskatoon Producers in Alberta have expressed the opinion that lameness in dairy cows is on the increase. Accordingly, Alberta Milk convened a Hoof Health Initiative-Strategic Planning Workshop in Red Deer, Alberta in October, The participants were examining possible strategies by which an Alberta Dairy Hoof Health Project could be developed. With this in mind, I have taken some of the topics discussed at the meeting and made them the basis for exploring how such a service might be developed. COLLECTING DATA ON LESIONS A topic popular with participants at the meeting was the collection of information about lameness. A wise individual pointed out that we cannot manage what we cannot measure. Several systems for scoring bovine lameness have been developed. However, these systems are only of value if the lameness has been observed, the cause accurately diagnosed and then properly recorded. Whay et al. (2002) have found that an experienced observer will detect 2.5 times more lame cows than will an inexperienced observer. This means that the average busy producer will not likely detect a slightly lame cow, particularly in the environment of a crowded barn. It has been postulated that over 80% of lameness goes unobserved. Therefore, the modern trend is to create a data base of lesions observed by hoof trimmers in the feet of cows during routine hoof trimming twice yearly and during repeat visits. In Sweden data collection relies on lesions observed in all four claws during routine hoof trimming. Christer Bergsten observed to me in personal correspondence: Today we collect about 230,000 trimming records yearly, that means that 35% of Swedish cows are recorded 1-3 times yearly and it is increasing. With an electronic system you can expand the details of records but still it must be simple to enter and transfer data. Recording lesions provides a rich amount of information as many more than one lesion can be present in the feet of a single cow. On the other hand, not all of the lesions present in the feet of one cow may be causing it to be lame. Recording all of the lesions present in a herd may help a veterinarian or the producer to understand the relative importance of risk factors present. With this in mind, Alberta Milk has purchased a Hoof SUPERVISOR lesion recording system. This is a user-friendly, cow-side recording device that can be used by hoof trimmers during routine hoof trimming. Alberta Milk sponsored a demonstration of this device attended by 12 hoof trimmers in the province. Alberta Milk has paid $4,000 towards the cost of this device for CanWest Conference October 17 20, 2009 Page 1 of 18

2 seven of the hoof trimmers in province. Further subsidies for this equipment cannot be made unless further funding is forthcoming. The description of all of the lesions affecting the feet of cattle was extensively reviewed during the 15 th Symposium on Lameness in Ruminants held in Finland in June, These descriptors are forming the basis for coding lesions in order that they may be computerized. Table 1 sets out my own way of considering the very complicated array of lesions that affect the bovine foot. A meeting of the North American Hoof Trimmers Association was held in Red Deer in June of At this time, support for the accreditation of hoof trimmers is lukewarm. Some sort of certification would be desirable to assure that lesion recording is of a high standard. Until now, anyone can purchase the equipment needed and call him/herself a hoof trimmer. In my opinion, the hoof trimmers at the meeting and those with whom I have corresponded, seem to be very keen to become involved in contributing to a data recording system. For this reason, I believe that a very unique opportunity exists in Western Canada to make a serious contribution to controlling lameness in dairy cows. Table 1 The Most Important Lesions Affecting the Bovine Foot Primary Lesion Associated Lesion Primary Cause Associated Cause Infectious Diseases Interdigital Dermatitis Digital Dermatitis Hoof Horn Erosion Infectious agent(s) Poor Hygiene Foot Rot Toe Ulcer Sole Ulcer Sole Haemorrhage White Line Disease Double Sole Septic Arthritis Disorders Related to Subclinical Laminitis Necrosis Pedal Bone Prolonged standing Trauma Thin Sole Excessive wear Painful heel lesion Rotation Pedal Bone Subclinical laminitis Abscess Trauma Other Conditions that Can Cause Lameness Corkscrew Claw Heredity Vertical Fissure Heredity? Trauma Horizontal Fissure Nutrition Interdigital Fibroma Interdigital Dermatitis Digital Dermatitis Using lesions rather than lameness scores can bring about benefits to producers and provide help support to animal-health advisors. CanWest Conference October 17 20, 2009 Page 2 of 18

3 1) It will be possible to evaluate the prevalence of any lesion and relate it to the presence or absence of different risk factors. This will make it possible to prioritize the risk factors in the order in which they may be considered prejudicial to hoof health. 2) The data on lesions would be made available to artificial insemination services. When a lesion score data base has been compiled in Alberta, it will be possible to develop a system for identifying bulls with superior breeding values for claw health. Over the longer term this will reduce the incidence of lameness, and in so doing make Alberta-bred dairy cows more attractive to purchasers. RISK FACTORS The concept of risk factors arrived on the scene maybe a decade ago but remains to be clearly defined. For the purpose of this discussion I am going to define a risk factor as, Any circumstance that can have a negative effect on the hoof health of a dairy cow. To this I would like to add: The environment in which dairy cows are forced to exist has been created for the convenience of man rather than the comfort of cows. Britt (1993) was one of the first to take steps towards assessing risk factors through observation. Much more recently the University of Bristol Veterinary School has put in place The Bristol Lameness Control Programme (See <cattle-lameness.org.uk/programme.php>.) This system presents a list of 89 risk factors collected under 16 groups. This is intended to be a guide to producers for self assessment. The veterinary school then offers an advisory service based on the response of the producer. The Bristol system would be an excellent starting point for a similar service to be developed in Alberta. It is I believe difficult to prioritize causative risk factors, but then should we need to? Is it not a question of cause and effect? Should the effect be measured first before the cause of that effect can be investigated? For example, if the cow comfort index (CCI) is poor, it is behavior of the animals which indicates that cows do not wish to lie down. The cause of a poor CCI can then be attributed to one risk factor or a combination of risk factors. The degree to which a cow is unclean is an indication of poor hygiene. In Sweden cow cleanliness has been measured because it is related to the incidence of digital dermatitis. The cause of poor hygiene may be inadequate scraping or some mismanagement of barn cleanliness. If the complicated problem of dairy herd lameness is to be unraveled, it is necessary to try to evaluate all of the aspects of dairy cow management. Neil Chesterton (1989) summed up the contemporary situation when he told us that: Today a veterinarian faced with a herd lameness problem must consider every aspect of farm management rather than treat a series of individual lame cows. CanWest Conference October 17 20, 2009 Page 3 of 18

4 Table 2 A Holistic Perspective of Effect and Cause Groupings of Outcomes Contributing Risk Factors 1 Rumen Acidosis Inappropriate diet formulation 2 Forced Standing and Inadequate Rest. (Poor Cow Comfort Index) Social Confrontation Feed management Waiting/Crowding in holding yard Stall characteristics/bedding Placement of waterers 3 Poor Hygiene Cow cleanliness guide 4 5 Trauma and Hoof Sole Wear Poor Hoof Health (producer failure) Poor flooring/bedding and floor use management Inappropriate or lack of hoof trimming Poor identification of lameness, inadequate treatment,including absence of foot baths 6 Infectious Diseases Biosecurity 7 Poor Heifer Rearing Methods Age at 1st calving 8 Management System Tie stall, Free Stall, Yard, Pasture, Organic Farming 9 Maximum Production Inappropriate Profit Index 10 Poor Genetic Selection Inadequate weighting of functional traits I have chosen the above-mentioned ten groups of outcomes which I would like to discuss briefly. 1. Subclinical Rumen Acidosis (SARA) I don t really need to say much about the nutritional causes of SARA as this is a topic with which you are all familiar. However, I do wish to confirm that it is still the most important concern as the cause of subclinical laminitis and that probably the classic theories regarding its association with lameness are still valid. Way back in 1999, Jim Nocek proposed that it may not be possible to prevent subclincal laminitis but the disorder can be managed. This is still excellent advice. In recent years you may have read a great deal about the role of Matrix Metaloprotienase inhibitors causing clinical signs of subclinical laminitis (Tarlton et al., 2002; Tarlton and Wedster 2002). Today it is popular to support the concept that the release of Catecholamines, Bradykinins, Endothelin and/or Prostogandins immobilize the action of Matrix Metalinoproteinase (MMP) inhibitors. This process is exacerbated by the release of periparturient hormones such as relaxin. Although I cannot pretend to understand the biochemistry involved I believe that it must be taken into consideration. I still firmly believe that the classical hypothesis still holds good simply because it provides us with the main technique CanWest Conference October 17 20, 2009 Page 4 of 18

5 for managing subclinical laminitis. What I now think is that there are two forms of pathogenesis associated with subclinical laminitis. a) Damage to the microsirculation of the germinal tissues of the wall and sole of the hoof probably caused by endotoxins. This is the classical hypothesis which results in the production of soft vulnerable horn.. b) Activation of MMPs which cause relaxation of the collagen fibres inside the claw which in turn permits displacement of the pedal bone within the claw capsule. The initiating cause of this process has yet to be determined but may possibly also be associated with agents created in the rumen. There is nothing new I can add concerning the nutritional cause of SARA. However, a large number of lesions are known to be associated with subclinical laminitis. Examples are sole ulcer, white line disease, toe ulcer and sole haemorrhage. When these diseases are present, it is likely that SARA will exist. It may be possible to obtain some information about signs of SARA from computerized records such as somatic cell count or milk fat/protein inversion. Some clinical signs of SARA may be present and rumenocentesis is, of course, possible. If SARA is believed to be the major risk factor, the management protocols are quite well known. The quality and quantity of fibre in the diet remains the major issue I think. Examination of the manure is one way in which effective fibre can be evaluated. One cup of fresh manure should be placed on a wire screen with a mesh measuring 6 to 8 squares per inch (a kitchen sieve). The manure is washed under pressurized water and the material remaining should be evaluated (Hutjens, 1997). Forage particle size over 1.5 cm ( ) in length will reflect a rapid rate of feed passage. The appearance of whole or partial grains indicates poor carbohydrate utilization. The appearance of starch could be related to improper corn silage chopping, corn silage that is too mature, corn silage that is too dry, corn grain that is too coarse, corn grain that was dried too fast, the existence of a poor rumen environment, the too rapid rate of passage or a lack of a dry cow transition diet. Bubbles in the manure indicate that carbohydrate fermentation has been taking place in the hind gut. That is, the grains passed too rapidly through the rumen, possibly because of inadequate effective fibre. This indicates that there has been damage to the hind gut. In some cases gelatinous casts of mucus will be present as a further indication of hind gut damage. I have concerns about feeding corn silage. It is not that it is not an excellent feed as I certainly think it is. I believe that many producers either do not understand how to manage the crop (variety, when to harvest and how best to conserve) or they underestimate the energy value of the diet and then feed too much cereal. Be that as it may, I have found that in many herds affected CanWest Conference October 17 20, 2009 Page 5 of 18

6 by subclinical laminitis the diet is based on corn silage. I found it a good rule of thumb to add an additional 10% of good hay. In the last few years, research has been undertaken with oligofructose-induced acute laminitis (Thoefner et al., 2005; Dancher et al., 2009). Interest in oligofructose was initiated in New Zealand by Catherine Westwood (Westwood and Lean, 2001) who was developing and testing new cultivars of pasture grass and was unable to explain why cows at pasture could be affected with subacute laminitis. This may be of interest to producers who summer pasture beef or dairy cows. Grass founder is common enough in beef cows but very uncommon in dairy cows. The same applies in Australasia where the majority of cows are pasture managed. In recent years supplementary carbohydrate has been offered and subclinical laminitis is believed to occur. In Uruguay (Acuña 2002) toe ulcers have been observed in first-lactation heifers on pasture when they were fed supplementary carbohydrates. 2. Forced Standing Many lameness experts today are convinced that forced standing is more important than nutrition as a cause of subclinical laminitis. There are good reasons why a cow is forced to stand for prolonged periods. Firstly, the cow may choose not to lie down because the lying area is either unattractive or is associated with bad memories. Secondly, a cow is prohibited from lying down, for example, when she is waiting to be milked or waiting for a resource such as feed or water. Whatever the cause inadequate rest is counterproductive. A cow should lie down from 11 to 14 hours every day. Cows that are lying tend to use the time ruminating and producing saliva in copious quantities. More blood passes through the udder of a cow lying down than when she is standing, this probably means more milk. Prolonged standing is bad for foot health because when the foot is not moving there is inadequate perfusion of blood through the tissues inside the hoof. The valves within the coronary cushion function as a pump when an animal walks. Exercise is necessary for good foot health. Therefore, the willingness of a cow to lie down or is unable to do so in free stall barns are largely dependent on the design features of the housing. This is a topic I believe Dr. Weary will be discussing with you, so I will say no more about housing design. Flooring in cows barns has received a great deal of attention in recent years, particularly in Sweden (Telezhenko 2007; Telezhenko et al., 2004; Bergsten & Hultgren, 2002; Haley et al., 2000 & 2001; Phillips 2001 & 2001). Walking on hard or rough surfaces wears and traumatizes the dermal tissues of a cow s sole. Haemorrhages are seen in the sole. It is clinically impossible to differentiate between haemorrhages caused by trauma and those resulting from a subclinical laminitic insult. In practice if sole haemorrhages are encountered, it is wise to attribute them to subclinical laminitis only if the traumatic component can be eliminated. Many years ago I was lecturing to a group of veterinary practitioners in the UK. One colleague rose to his feet and commented. If you have subclinical laminitis in a herd, turn the cows into a straw yard and it will go away. It may be soft bedding or the extra fibre they get access to. Several of his colleagues agreed. Surprisingly, many years later an Italian colleague made the same comment to me. It works like a charm, he said. CanWest Conference October 17 20, 2009 Page 6 of 18

7 I believe that rubber matting is not as popular in North America as it is in Europe. There is little doubt that cows prefer to walk on rubber than on concrete. In Sweden rubber surfaces for holding yards are considered to be particularly beneficial. In some herds more haemorrhages are seen in the soles of the feet of first-lactation heifers than in mature cows. Some workers believe that this finding is more prevalent when heifers are about to calve and are suddenly introduced to concrete surfaces. This is a tricky time when they may have the stress of mixing with mature cows for the first time, have a change of feed and are under the influence of periparturient hormones. One group in the UK recommend that heifers should be mixed with dry cows in a straw yard two weeks prior to being introduced to concrete and the main herd. Changing to the milking ration must occur gradually. There is no certain way for measuring risk factors associated with housing. The cow comfort index (CCE) as described by Nigel Cook (2004) would provide useful data that could be incorporated into a computerized data recording system. However, this system does not take into consideration time spent waiting to be milked in a holding yard. In some production units waiting in line to drink is also an important risk factor that must be monitored. Some system needs to be developed by which all the factors related to housing stress can be measured and computerized. Probably a modification of the Bristol questionnaire could be created to meet the needs of Alberta by which producers could conduct a self assessment of the production unit with the help of attending veterinarians. Such an activity could be a task for the Alberta Dairy Hoof Health Project. 3. Poor Hygiene There is evidence that the incidence of digital dermatitis is more prevalent when there is a build up of slurry. Many reports in the literature use the frequency of scraping or flushing as an indicator measure of hygiene. Swedish and some North American workers are taking a different and possibly better approach. The degree of cleanliness or contamination of the flanks of the cows in the herd is considered to be a better indicator of the degree of poor hygiene. Dirty flanks resulting from too much slurry in the barns has been related to the incidence of digital dermatitis. The degree to which a cow s flanks are contaminated provides a subjective, indirect means of evaluating hygiene. I understand that some workers do use a scale to measure the degree of contamination of the flanks of cows. 4. Trauma and Wear Thin soles, it has been agreed internationally, should be considered as a lesion. However, the cause or risk factors associated with thin soles have not so far resulted in the development of a reliable system for objective measurement. One of the difficulties is the human inability to interpret changes in locomotion of a cow resulting from her reaction to a particular surface. Excellent progress in the study of locomotion on different quality of surfaces has been made in Sweden (Telezhenko, 2007). Perhaps another useful step would be to include, as lesions, the appearance of soles most frequently encountered by hoof trimmers. Information such as the CanWest Conference October 17 20, 2009 Page 7 of 18

8 following might provide valuable supplementary information to a database. To the best of my knowledge, the characteristics of the sole have not been classified. Some aspects of sole morphology have been studied, but scientific explanations of cause have been slow in coming. Normal Flat Flat and wide Flat and thin Overburdened heel Concave sole of cows at pasture. Usual degree of wear with cows on concrete. Common in dairy cows walking slippery surfaces. A thin apex of the sole if painful lesions present in heels. Thought to be associated with heel horn erosion or DD. 5. Poor Hoof Health Care Clarkeson et al., 1996 determined that lack of knowledge and skills among producers should be considered to be a risk factor. How this can be measured without offending a producer is extremely questionable? Rutherford et al., (2004) when considering the difference between normally managed and organically managed farms suggest that much depends on the attitude of the farmer. Some producers seek maximum production; some are prepared to accept optimal production. Some producers will not implement advice while others do so willingly. Some producers routinely employ the services of a hoof trimmer twice yearly or more. Others fear a negative result from hoof trimmers. Stanek et al. (1994) cited instances where hoof trimming had a negative effect on claw health. It is relatively easy for a producer to assess whether or not if a hoof trimmer is competent at his profession. As a rule of thumb, if the milk production of trimmed cows, collectively, drops by more than three litres per day and/or milk production fails to recover within three days, there is probably something wrong with the technique or methods employed by the trimmer. In the vast majority of cases, regular hoof trimming has a very positive influence on hoof health. As has been mentioned previously, Whay et al. (2002) found that unskilled individuals are 2.5 times less likely to diagnose lameness in a cow. It, therefore, follows that under normal circumstances fewer cows will be treated for lameness by unskilled producers. A negative attitude to calling in the veterinarian also occurs. Attitude and prejudice make some producers unwilling to install a footbath or other installations useful in treating lameness in cattle. 6. Biosecurity Biosecurity, so far as it affects lameness, mainly refers to measures for controlling digital dermatitis. Most workers tend to think in terms of measures to prevent replacement cattle from infecting an otherwise clean herd. Isolation and regular examination of a newly introduced animal may be impractical. However, it is not clearly understood how infection can be spread. For the moment, spread by instruments used by veterinarians and hoof trimmers cannot be excluded. CanWest Conference October 17 20, 2009 Page 8 of 18

9 7. Heifer Rearing, Culling and Longevity In Alberta the age at first calving in 1988 was 28.4 months and in 2007, 26.5 months. Rutherford et al. (2004) found that organic farmers were more likely to have a heifer calve for the first time at a significantly older age than was the case on ordinary farms. These workers proposed that early calving was associated with an increased incidence of lameness. Hirst et al. pointed out that first-lactation lameness is frequently associated with lameness in later lactations. He also pointed out that he found that heifers calving after the age of 27 months had fewer cases of subclinical laminitis than those that calved at an earlier time. Stature in dairy cows is measured to a point located on the spine immediately between the tuber coxae. Stature which can be measured objectively has been shown to be highly heritable (unlike feet and legs). However, specific withers height and body weight have been determined by dairy advisors to be a more useful guideline for breeding heifers than is their age. This can be highly counter-productive because farmers may try to advance puberty and enhance average daily weight gain by the overuse of cereals. The result is the inhibition of growth hormone production and the deposition of unwanted fat in the udder of the young animal. NRC guidelines suggest that heifers should not grow at a rate greater than 750 grams per day between the ages of 12 and 24 months. This sometimes restricts the age at which a heifer will calve for the first time and is not a popular recommendation for many producers. There is greater and greater pressure to have heifers calve before the age of 24 months. In my opinion, this practice may negatively influence the longevity (stayability) of the animal and eventually reduce the functional life of a herd. VanderHaar (1998) reviews contrary opinions about early calving in a well-referenced paper. He states, A heifer must achieve 636 Kg before calving if it is to weigh 568 Kg after calving. They must gain an average of 0.82 Kg per day if they are to calve at 24 months. This means that they should gain 0.90 Kg per day after they have been bred. High energy diets and rapid gains after breeding have little effect on milk production if calving occurs at optimal size (supported by four references). VanderHaar goes on the quote another worker who established that heifers fed a high-energy diet from seven months to 318 Kg had 32% less mammary parenchyma than those animals grown more slowly. He also quoted Capuco et al., 1995 who observed a 48% impairment of mammary development in heifers having a high intake of corn-based silage, compared with those on an alfalfa-based diet. VanderHaar poses the question, Does dietary protein make a difference? He cites a 1989 NRC recommendation that heifers from 3 6 months should have a crude protein to metabolizable energy ratio of 60 g per Mcal and 50 g per Mcal for heifers 6 12 months of age. Eleven studies are cited that positively correlate rapid mammary growth to the CP:ME ratio of the diets fed. Average daily weight gain is not as important as the maturity of the heifer (weight and age) when she is bred. A heifer s weight before calving also must be optimal if the lactation is to be successful. A very high average daily weight gain is an indicator to any investigator that the mechanisms by which these gains are achieved should be studied. CanWest Conference October 17 20, 2009 Page 9 of 18

10 Breeding age and weight has also variously been determined to be: Kg (Heindrich et al., 1988) or Kg (Clapp ).. All heifers do not have the same genetic makeup and cannot necessarily conform to the same rules established for them. Large-framed heifers, for example, have much less difficulty in meeting high criteria for weight and height at any particular age. Despite the vast amount of data that exists, it has never been determined, so far as I am aware, whether or not heifers that calve for the first time at an early age have shorter functional lives than do those calving at a more mature age. As you can see from the Table 3, in the USA on average, the failure time of dairy cows is about months after they calve (Caraviello et al, 2005). Table 3 Failure Time in the Various Regions of the USA Region of the United States No. cows No. herds Failure time days after first calving North East 382,444 2, (24 months) South East 144, Central 289,807 2, East North Central 379,470 2, West North Central 101, South 217,234 1, South West 177, North West 280, West 348, In Quebec the culling rate for feet and legs is about 11% which over the past 30 years represents an increase of 261%. CanWest Conference October 17 20, 2009 Page 10 of 18

11 Table 4.Culling And Replacement Rate In Canadian Dairy Herds Culling reason Reproduction 30% 29% 29% 29% 29% 29% 28 26% 27% 27% % Mastitis 17% 18% 19% 19% 18% 18% 18 % 18% 17% 16% Feet and Leg Problems 11% 11% 11% 11% 11% 10% 10 % 9% 9% 9% Low Milk production 10% 11% 12% 12% 12% 13% 15 % 17% 18% 20% Herd Replacment Rate 42% 45% 42% 39% 32% 38% 34 % Source: Canwest DHI and Valactia 35% 35% 37% From Table 4 it can be seen that the rate of culling for both reproductive disorders and feet and legs has increased but the rate of culling for low milk production has decreased. 8. Production As can be seen from Table 5, dairy production has almost doubled in Canada since Table 5 The history of production in Holstein dairy cows in Canada Year Milk Prod (kg) Fat Pro (kg) Fat Prod (%0 BCA Milk BCA Fat , % , % , % , % , % , % In 1970 there were 12 million cows in the USA with an average milk production of 5,085 L/annum. By 2005 there were 9 million cows in the USA, but the average milk production had increased to 9,945 L/annum. Should high production, per se, be considered a stressor? Greene et al. (2002) found that higheryielding cows are at greater risk of becoming lame that those with lower yields. Pryce et al., (1997) showed that there is a genetic correlation between production and poor leg health. However, this increased susceptibility may not occur if farm management and husbandry are appropriate for high-yielding animals (Pryce et al., 1999). CanWest Conference October 17 20, 2009 Page 11 of 18

12 Christensen et al (1998) pointed out that high production cows in an environment of intensive management are on the verge of failing to attain their genetic potential. These workers attribute this concern to the practice of selecting for production at the expense of functional traits. A functional trait may be poor reproductive efficiency, poor temperament, poor milking ease or feet and legs. Dillon and Veerkamp (2002) tell us that reproductive efficiency and increased culling rates in Ireland have been attributed partly to selection for high milk production at the expense of functional traits. This is of some concern to us as lameness and reproductive failure have been shown to be associated. The late Don Collick et al. (1989) recorded data from 17 dairy herds involving 427 cows in their fourth lactation and managed under similar conditions (See Table 6). Melendez et al. (2003) found that lame cows have a higher incidence of ovarian cysts. Stress increases plasma cortisol and induces oestradiol failure (Nanda, et al., 1990; Dobson and Smith, 2000; Noble et al., 2000). Here we have a rational explanation as to why lameness and reproductive failure may be linked. If a database of lesions is developed it would be a relatively simple matter to correlate the level of milk production to the prevalence of herd foot lesions. Kenneth Rutherford et al (2004) found that lameness was less prevalent among organically managed cattle than in normally managed herds. Although herds had very similar genetic merit, these workers also found that milk yield was less on the organic farms. It can be inferred from these findings that the cows on an organic farm are not pushed as much as they are on normally managed farms. However, I am tempted to suggest that there may be simple techniques for estimating how the genetic potential of a herd of cows matches up to its performance. For example, there must be an optimal ratio between the Kg of milk produced relative to the number of Kg of energy consumed. Table 6 Correlation between lameness and reproductive disorders Lame Normal Number of Cows 427 Lactation 4th Interval between parturition and 1 st service 72 ± 21 days 68 ± 23 days Interval between parturition and conception 100 ± ±31 Cows pregnant after 1 st service 45.9 % 56.3 % Artificial insemination index Culling rate 15.7 % 5.1 % Culled after 10 or more services 10.1 % 4.9 % CanWest Conference October 17 20, 2009 Page 12 of 18

13 9.Poor Genetic Selection Judging cattle at shows tends to rely on esthetics and subjective evaluation rather than objective measurement. Terms such as Milky Face or Fine Leg or Dairy Shape are used. The show ring has been considered to have a counterproductive influence on the development of dairy cows (Bonsma; Berg and Butterworth). The Holstein Association is largely responsible for doubling the productivity of Holstein cattle over the past 30 years. This is a highly commendable accomplishment. However, it is probable that improved productivity has been achieved at the expense of functional efficiency. I have struggled for years to understand the justification for the evaluation system. It is logical that non-production traits (functional traits) should be taken into consideration. Factors such as reproductive efficiency, predisposition to disease, milking ease and temperament, along with feet and legs are important to the dairy farmer. The World Holstein-Friesian Federation (WHFF) has described 18 traits,all of which describe anatomic or conformational characteristics, All of the traits with the exception of stature, have to be evaluated subjectively. I have yet to see scientific proof that any of the traits are related to the foot health of the cows. Today the Canadian Holstein Association incorporates some of the anatomical traits into their lifetime profit index formula. Dairy strength takes into consideration the trait stature which is 53% heritable and can be measured objectively. Feet and legs has three parts. Toe angle is meaningless unless this measurement is made at a consistent age and prior to the animal being exposed to concrete. It is judged to be only 13% heritable. A somewhat similar criticism can be made of another trait, namely rear leg rear view. This trait is judged on the degree to which the feet are pronated (turned out). This may not be a conformational trait at all but caused by overburdening of the lateral hind claws or exposure to concrete. The third trait is rear leg set. This trait determines if the animal is post legged or sickle hocked. This is a very unreliable trait as a straight leg can be seen associated with digital dermatitis and a sickle hock may be a postural change produced by sublcinical laminitis. Table 7. Lifetime Profit Index Formula: Relative Emphasis of Traits with Each Component and Each Component LPI CanWest Conference October 17 20, 2009 Page 13 of 18

14 I must say, in my opinion, the trait feet and legs is absolute nonsense, illogical and totally irrelevant. As the result of many years of study, German geneticist, Ottmar Distl, is confident that strategies for improving leg and claw quality are being developed. He states the following: Important parameters for claw and leg quality can only be identified when traits used in breeding work are closely related to claw health, longevity, life time performance and functional efficiency of the animal. This definition implies that claw and leg quality cannot be recorded by just one trait. The traits necessary seem to be more complex and may be of different importance in dependence of the exposure to environmental effects. Particularly, claw shape is a result of the interaction between individual factors and environment. Genetic components may respond differently to specific environments and in each specific environment other genetic components may play the prominent role. Distl (2003) also points out:: Using measurable claw traits in the selection of young bulls before licensing, functional longevity and foot quality of cows in dairy farms can be significantly improved. It has been demonstrated that the daughters of some bulls were more likely to suffer from lameness of digital origin than those of other sires. German workers assert that the inclusion of claw measurements in breeding programs would lead to a reduction in claw defects/diseases and, subsequently, in culling rates. According to Bertel Kon (2009) in Sweden the breeding value for claw health (BVCH) has an average of 100 (standard deviation 10). This means that bulls with a BVCH of more than 120 would be in the top 2.5% of the list. It must be noted that the combined type trait Feet and CanWest Conference October 17 20, 2009 Page 14 of 18

15 Legs is not related to claw health. Bertel goes on to point out that the Swedish Holstein bull Berte has a BCVH of 122 and a score for feet and legs of 82. Berte has an excellent daughter fertility score (131) and a very good longevity score (125). Holstein International attempts to the continued use of feet and legs by comparing it to the BVCH. The former is a subjective score based on personal preferences while the latter is much more objective and based on fact. Surely this is a case in which oranges are being compared to apples. Table 7 International bulls used in Sweden with Swedish values for hoof health and feet and legs. (Source Holstein International) NAME PEDIGREE HOOF HEALTH FEET & LEGS Aaron Luke x Mascot Addison Mountain xelton Bojer Juror x Acres Calano Juror x Cleitus Cash Sunny boy x Cleitus Forbidden Emory x Mascot Lord Lily Black Start x Rotate O-Man Manfred x Elton Ramos Rudolph x Ambition Wizarde Formation x Benchmark It may be interesting to note that INTERBULL was initiated in Sweden but so far does not appear to use the BVCH nor does the Canadian service MACE (Multiple Trait Across Country Evaluations). 10 Management System As one travels the world or even throughout North America, it is surprising how the manifestations of lameness differ along with their perceived causes. Human attitudes, feedstuffs and management systems differ from one region to another. If there is to be a common system in Western Canada for evaluating risk factors against lesions, it would be necessary to take into consideration at least management systems. Free stalls, tie stalls, straw yards, organic farms, and pasture or semi-pastured systems each have a different set of risk factors. Therefore, the record keeping system must be devised in a manner that keeps risk factors in categories compatible with the management system. CONCLUSIONS In this presentation I have offered my views on the factors that one day in the future could be taken into consideration by The Alberta Dairy Health Project. I am not claiming that my ideas could be a blue print of what is to come. I do believe that it is essential to have input from the CanWest Conference October 17 20, 2009 Page 15 of 18

16 veterinary practitioner to make it happen. I feel very encouraged that the hoof trimmers of Alberta are willing to complete records with a computerized cow-side recording system. We are half way there. Much work still remains in devising methods for objectively measuring the impact of risk factors. Once methods for measuring each group of risk factors have been established, it will then be a matter of trial and error to prioritize them in the light of the lesion database for the herd. The important issue that remains is to ensure that everyone involved is on the same wave length. This involves avoidance of interpersonal (political) differences. I am of the opinion that some form of training has to be made available, such as seminars and on-farm clinics. I also am of the opinion that the service must have a dedicated website for those who wish to seek information which will close gaps in their personal knowledge base. I would like to feel that some of my colleagues in dairy practice would be interested in becoming involved. I am strongly of the opinion that academics, such as myself, can only contribute so much. Individuals with muck on their hands as well as the ear of the producer are the only persons who can make things happen. REFERENCES Acuña R, Scarsi R 2002 Toe Ulcer: The most important disease in first-calving Holstein cows under grazing conditions. Proceedings of the XII International Symposium of Disorders of the Ruminant Digit, Orlando Bergsten C, Hultgren J 2002 Effects of a rubber-slat system on cleanliness, foot health, and behaviour in tied dairy cows. Proceedings of the XII International Symposium on Disorders of the Ruminant Digit, Orlando Britt J., 1993 What is your cow comfort index? Dairy Herd Management? Capuco AV, Smith JJ, Waldo DR et al Influence of prepubertal dietary regimen on mammary growth of Holstein heifers. Journal of Dairy Science, 78: Caraviello DZ,Weigel KA, Shook GE, Ruegg PL 2005 Assessment of the impact of somatic cell count on functional longevity in Holstein and Jersey cattle using survival analysis methodology. Journal of Dairy Science, 88: Chesterton RN 1989 Examination and control of lameness in dairy herds. New Zealnd Veterinary Journal 37: Christensen LG, Einarsson S, Rendel J 1998 Possibilities for general improvement of disease resistance, functionl traits and animal welfare. Acta Agriculturae Scandinavica, Section A Animal Science Supplement 28: Clapp HJ 1981 Starting the dairy calf. In Ontario Ministry of Agriculture and Food: factsheet Clarkson MJ, Downham DT, Faull WB, Hughes JM, Manson FJ, Merritt JB, Murray RD, Russell WB, Sutherst JE and Ward WR Incidence and prevalence of lameness in dairy cattle. Veterinary Record 138: Cook NB 2004 Lameness prevalence and effect of housing on 30 Wisconsin dairy herds. CanWest Conference October 17 20, 2009 Page 16 of 18

17 Proceedings of the XII International Symposium on Disorders of the Ruminant Digit, Orlando Danscher AM., Enemar JMD., Telezhenko N, Capio CT., Ekstrøm., Thoefner MB Oligofructose overload induces lameness in cattle. Journal of Dairy Science 92: Distl O, Huber M, Graf F et al 1984 Claw measurements of young bulls at performance testing stations in Bavaria. Livestock Production Science 11: Distl O 1994 Genetic improvement of claw and leg traits. Proceedings XIII International Symposium on Disorders of the Ruminant Digit, Banff pp Distl O 1995 Genetic improvement of traits of feet and legs as well as claw soundness in cattle. Zuchtungkunde 67: Distl O 1996 Selection on the basis of body conformation traits. KB Mitteilungen 34:23-25 Distl O 1998 Selection for limb traits in cattle. Milchpraxis 36:92-95 Distl O 1999 Breeding for soundness of feet and legs in dairy cattle. Zuchtungkunde 71: Distl O Koorn D S, McDaniel, B T et al 1990 Claw traits in cattle breeding programs: Report of the European Association of Animal Production working group Claw Quality in Cattle. Livestock Production Science 25:1-13 Distl, O 2003 Implications of health traits in breeding of livestock. Zuchtungskunde 75(5): Dillon P. Veerkamp RF 2002 The business and technology of dairying. Proceedings Teagasc National Dairy Conference, Killarney Green LE, Hedges VJ, Schukken YH, Blowey RW, Packington AJ, 2002 The impact of clinical lameness on the milk yield of dairy cows. Journal of Dairy Science 85: Haley D B, Pasille A M de, Rushen J 2001 Assessing cow comfort: effects of two floor types and two tie stall designs on the behaviour of lactating dairy cows. Applied Animal Behaviour Science 71(2): Haley D B, Pasille A M de, Rushen J 2000 Behavioural indicators of cow comfort: activity and resting behaviour of dairy cows in two types of housing. Canadian Journal of Animal Science 80(2): Henrichs AJ, and Hargrove GL 1987 Standards of weight and height for Holstein Heifers. Journal of Dairy Science, 70: Hirst WM, Murray RD, Ward WR et al 2002 A mixed-event time-to event analysis of the relationship between first lactation lameness and subsequent lameness in dairy cows in the UK. Preventive Veterinary Medicine 54: Hutjens M F 1997 Evaluating Effective Fibre. Proceedings of the 4-State Applied Nutrition and Management Conference. pp Kon B 2009 Breeding for better claw health. Hoof Health Connection 1-3. Nocek JE Bovine acidosis: Implications on laminitis. Journal of Dairy Science 80: Phillips CJC, Morris ID 2002 The ability of cattle to distinguish between, and their preferences for, floors with different levels of friction, and their avoidance of floor contaminated with excreta. Animal Welfare 11(1): CanWest Conference October 17 20, 2009 Page 17 of 18

18 Phillips CJC, Morris ID 2001 The locomotion of dairy cows on floor surfaces with different frictional properties. Journal of Dairy Science 84(3): Pryce JE, Veerkamp RF, Thomson R. Hill WG, Simm G 1997 Genetic aspects of common health disorders and measures of fertility of Holstein Friesian dairy cattle. Animal Science 65: Pryce JE, Nielsen BL, Veerkamp RF, Simm G Geneotype and feeding system effects and interaction for health and fertility traits in dairy cattle. Livestock Production Science 57: Rutherford K, Sherwood L, Haskell M 2004 Health and welfare of dairy cows in organic milk production systems. Conference Information: British Mastitis Conference, Warwickshire, UK Sejrsen K, Purup S 1997 Influence of prepubertal feeding level on milk yield potential of dairy heifers: a review. Journal of Animal Science 75: Stanek Ch, Thonhauser M-M and Schroder G 1994 Does the claw trimming procedure affect milk yield and milk quality factors. Proceedings VIII International Symposium of Disorders of the Ruminant Digit, Banff, Canada: 306. Tarlton JF, Holah DE, Evans KM Biomechanical and histopathological changes in the support structures of bovine hooves around the time of first calving. Veterinary Journal 163: Tarlton J F, Webster AJF 2002 A biochemical and biomechanical basis for the pathogenesis of claw horn lesions. Proceedings of the XII International Symposium on Disorders of the Ruminant Digit. Orlando Telezhenko E, Bergsten C, Magnusson M 2004 Swedish Holsteins locomotion on five different solid floors. Proceedings of the XII Symposium on Disorders of the Ruminant Digit, Maribor Telezhenko E 2007 Effect of Flooring System on Locomotion Comfort in Dairy Cows. Doctoral Thesis, Faculty of Veterinary Medicine and Animal Science, Swedish University of Agricultural Sciences. Thoefner MB, Wattle O, Pollitt CC et al Histopathology of oligofructose-induced acute laminitis in heifers. Journal of Dairy Science Volume: 88 Issue: 8: Valentine SC, Dobos RC, Lewis PA et al Effect of live-weight gain before or during pregnancy on mammary gland development and subsequent milk production of Australian Holstein-Friesian heifers. Australian Journal of Experimental Science VanderHaar MJ 1998 Accelerated heifer growth: Truth or Concequences. Proceedings Tristate Dairy Nutrition Conference, Fort Wayne. Westwood CT and Lean IJ (2001) Nutrition and lameness in pasture-fed cattle. Proceedings of the New Zealand Society of Animal Production 61: , Whay HR, Main DCJ, Green LE Farmer perception of lameness prevalence. Proceedings of the XIII International Symposium on Disorders of the Ruminant Digit, Orlando CanWest Conference October 17 20, 2009 Page 18 of 18