1999 May

The Majority of Lameness in Dairy Cows is Preventable

Lameness has been identified by dairy farmers in Australia and especially in the South West as one of the important health problems associated with dairy production.

The Western Branch of the Australian Veterinary Association and West Vic Dairy in conjunction with Upjohn and Boehringer Ingelheim recently invited Neil Chesterton, to deliver a series of seminars on lameness. Neil has a particular interest in lame cows. Vets and dairy farmers were stimulated by his practical approach to this serious problem.

What does lameness cost?

Reduced production
Decreased fertility
Cost of treatment
Increased rate of culling
Time involved in treating and managing lame cows.
Increased chance of antibiotic contamination of bulk milk.
Animal welfare issues.

In strict dollar terms that the average cost of a lame cow in Australia is $200.

What are the factors that effect lameness incidence?

Track factors
Construction and design
Degree of maintenance
Manner in which cows are moved from the paddock to the shed
Dairy Factors
Bail feeding
Yard design
Abrasiveness of yard surface
Effect of milker on cow movement
Cow Factors
Nutrition
Conformation
Genetics Rainfall

Chesterton's study found that 40% of the lameness could be explained by the different ways in which cows moved from the paddock to the shed.
He made a number of common sense observations on cow behaviour and movement which help explain why cows get lame.

If left to drift at their own pace cows do a number of things.
They sort themselves into groups with the dominant cows mostly in the middle and front of the mob and the less dominant cows mostly at the back.
Cows avoid touching other cows.
They will keep their heads down, accurately picking a safe place to put their front foot.
The back feet will go in the same place as the front feet.
Cows will tend to follow other cows, often placing their feet in the same places as the one in front.

If cows can walk at their own pace there will be a minimum of lameness.

There are two things which commonly affect this orderly walking pattern of a herd.

Condition of the track.
Patience of the person following the cows.

A poorly maintained track has two effects

Direct: Bad tracks are likely to increase damage to cows feet regardless.
Indirect: Bad tracks slow a herd down, thus increasing the chances that cows will be hurried along by an impatient herdsman.

What signs suggest that Cows are being "Pushed" rather than allowed to "Drift"?

Cows at the back of the herd begin to move from one side of the track to the other, rather than follow the cows in front of them.
Cows will be seen pushing one another. Drifting cows rarely touch one another.
Cows will have their heads raised over the back of others.
Cows will shorten their stride.

All of these signs result in unplanned placement of feet and an increased abrasive effect on the hoof.

The Transition Period - Fitting in with your farm

The transition period is the time from about 2-3 weeks prior to calving to the first week after calving. This is a tumultuous time for the cow's metabolism and the most critical period in her lactation cycle. Traditionally this period has been approached by limiting pasture intake, providing ad lib hay and the use of vitamin D3 injections if required. These measures will help in the control of metabolic diseases.

A lot of producers are now targeting higher levels of per cow production. In this case the traditional transition management is not appropriate. Further measures can be taken which will fit in with the goals of the farm.

Information regarding the best way to manage the cow through the period from late pregnancy to early lactation has been widely available. So much information is now available that it makes it difficult to decide on the management strategy that will best suit your operation.

There is an ideal way to manage the transition cow and this would be recommended to ensure the highest level of production and minimise animal health problems related to this period. For most farms the transition cow is managed using a compromise of the ideal situation. With this in mind we should look at the aims of good transition management and the best ways to make decisions on its management.

Maintain Dry Matter Intake (DMI)

In the average Friesian cow the last 7 days of pregnancy means a decrease in DMI from 12 kg per day to 6 kg per day. Ensuring access to a concentrated energy source with a reasonably high level of protein can stimulate the appetite and help to prevent this drop. Energy can be provided with a lead feed concentrate using a cereal grain such as wheat or barley at 2-3 kg per cow per day.

Prevent Metabolic Disease

The use of anionic salts to improve the cow's ability to mobilise calcium from her bones has been well publicised. Every farm has the ability to utilise this information.

Simple measures are: 100 grams of Epsom salts in the water supply of springer cows. This should be topped up each day. 100 grams of epsom salts and 100 grams of gypsum in the lead feed. These products are unpalatable. To improve palatability add sugar or salt to the lead feed. Use of proprietary lead feed mixes. Most of these have been formulated to provide anionic salts with other components to improve palatability. Addition of Biochlor. This is a protein rich by-product with anionic properties. The high protein and anionic component make this product very useful. The other major advantage is palatability. This stimulates greater acceptance by a large proportion of cows. Some cows will still reject Biochlor but acceptance can be 100% with the addition of molasses or sugar. Dietary Anion Cation Balance (DCAB) is a measure of the positive and negative ions in feed. This gives a good indication of the likelihood that a feed will cause metabolic problems if fed to a springer. Hay can be tested through the Timboon Veterinary Group for less than $50 per sample.

Adaptation of the Rumen

The transition from late dry cow ration to the milker's ration can play havoc on the rumen microbes. It takes two weeks for these bacteria and protozoa to adapt to a new diet. A transition ration designed to address this can reduce the time adaption takes to occur.
A concentrated lead feed will be a start. The use of additives to address rumen acidosis will also help.

Buffers such as bicarb are not advised due to the effect of the sodium in the bicarb. Sodium is a cation which acts in the opposite way to anions causing a reduction in the ability of the cow to mobilise calcium.

Rumen modifiers such as Eskalin will reduce the population of acid producing bacteria and enable a smooth transition to a high concentrate diet. The degree of adaptation required will depend on the amount of grain being fed during early lactation.

It should be remembered that the pasture the cows are consuming at this time has the potential to stimulate acid production in the rumen. The introduction of pasture may be the most disruptive aspect of the transition period. With a well formulated transition diet it would even be possible to graze springers on a significant amount of pasture to help the rumen to adapt.

The level of importance of these points will depend on the planned level of feeding in early lactation and the expected peak production levels. There is no point in having a high power transition diet if the early lactation diet is poor. If high peak production levels are the aim a well formulated transition diet will result in higher production, increases feed conversion efficiency and reduced animal health problems. Some of the products mentioned are quite expensive but the have to be weighed up with the results produced from their use.

Results that are commonly seen include:

Peak production levels 4 litres greater than with out the use of a transition ration.
The elimination of metabolic diseases such as milk fever and acetonaemia.
The elimination of abomasal disorders
Significantly reduced incidence of retained afterbirth.
Improved fertility.

Read the Labels

A recent seminar run by DNRE on control of insect pests on dairy farms a recurrent theme arose which applies to all chemicals used on farms.

Be they pesticides, herbicides or veterinary chemicals the message is the same.
Ignore the label instructions at your peril.

Open selling chemicals

Instances shown in this seminar revolved around pesticides.

Some of the pitfalls pointed out were:

Alteration in rates for different spraying techniques such as low versus high volume spraying.
Expected use of crop post treatment. Some chemicals have different withholding periods if they are to be applied to pasture to be grazed as opposed to pasture to be cut for hay.

It was apparent that the proper use of the product was not possible without fully reading and understanding the label. As the end user, the farmer is responsible for using the product in a manner for which it has been approved. The critical comments on a label are just as important as the rest and may have a bearing on the way the product is used.

If the product is used according to label recommendations there should not be a problem with residues in produce from the farm. If a problem does occur, being able to demonstrate correct usage will enable a sound defence. If there has been "off label" use of the product there is no defence and the penalties can be severe.

Use of an open selling product off label under the advice of an "expert" will also be difficult to defend, as there is no clear definition of an expert in these fields. So the message is if you're not sure don't do it.

Restricted Veterinary Chemicals

The drugs supplied by veterinarians come under similar strict controls.

Each product is registered for particular use in particular disease situations. Dose rates and withholding periods are set down by the controlling bodies based on scientific evidence which must be gained for every product prior to registration.

Use of products off label has the same consequences as with open selling products. On occasions veterinarians will prescribe use of a product off label. The responsibility for residue problems, if they arise, rests on the veterinarian as an officially recognised expert in the field. The producer advised on such use will be indemnified in this case. Only veterinarians are permitted to recommend off label use and only when they have supporting evidence that it is an appropriate therapy. There must also be no product available which can be used and is registered for this purpose.

There are certain veterinary chemicals that are not allowed for use in food producing animals. Use of these chemicals by veterinarians has been strongly discouraged. Apart from the regulatory requirements on these drugs there are certain ethical reasons to discourage vets from their use such as the chance of resistance development to an antibiotic use to treat certain diseases in humans.

Update on Calf Rearing

There have been many changes implemented in calf rearing systems on dairy farms in the last ten years. Some farmers have adopted a system similar to the Northern Hemisphere dairy farms where calves are reared individually in hutches whilst others have continued to produce excellent heifers using the more traditional group rearing system on predominantly milk.

Each farmer will have their own preference and it is often difficult to change old habits if they appear to be working well.

Do the heifers reach adequate mating size at 15 months so that they subsequently calve early in the new season at an acceptable size?
Is the current calf rearing system cost effective in both labour and capital infrastructure?

For many farmers with large herds, calf rearing may involve well over 100 calves annually. It can be a huge time commitment so they adopt simple systems.

Following is an outline of some of the features of calf rearing systems in these big herds.

Calves will only be saved for rearing over a six week period.
All calves are force fed colostrum within 12 hours of birth.
Calves are fed up to 3 litres of milk once daily. This may increase to 4 litres in a 4-6 week old large holstein calf.
A highly palatable 18% crude protein pellet is fed to calves from day 1. This does not need to be greater than 18%.
A coccidiostat such as bovitec or rumensin is added to the diet.
Good quality barley straw is supplied in small quantities above their heads. This avoids contamination. The straw limits intake of too much roughage, which would occur if hay were offered.
Bark chips, rice hulls or sawdust are used as bedding. Bedding is cleaned out between groups of calves.
Pellet intake is maximised since this will stimulate rumen function and efficiency of digestion by thickening the rumen papillae.
Calves are weaned at 5-6 weeks, eating 1-1 1/2 kg pellets.
Good clean water is available at all times.
Calves are reared in small groups to minimise competition.

Count Down Down Under

Reduce exposure to environmental mastitis bacteria

Cows are very susceptible to infection around calving because their natural defence mechanisms are low. New infections occur, and subclinical infections which have persisted through the dry period may flare into clinical cases. Induced cows are even more vulnerable to mastitis infections because their immune systems have reduced efficiency at that time. Around calving, the udder is often filled with milk for relatively long periods without the flushing effect of being milked. Bacteria may enter the end of the teat, particularly if high udder pressure opens the teat canals. They can then multiply and establish infections. High numbers of environmental mastitis bacteria may contaminate teats, especially if udders are wet and exposed to mud and manure. This can happen easily when cows and heifers are on the ground during calving. Because of the high incidence of mastitis in the first month after calving, special care in this period will pay off.

Calve on clean, dry pasture or on a clean, dry calving pad.

Pasture or pads for calving must have minimal manure contamination. If more than two pats of manure are present per square metre, it is not clean enough for calving cows. The calving area should be sheltered and well drained. Avoid pugging and mud. If water is visible on the surface or in your gumboot prints, it is not dry enough for calving cows.

It is important to check for abnormal milk and treat infections rapidly.

Be alert to the number of cases of mastitis occurring, especially in freshly calved heifers. This is an indicator of the state of the paddock.
If three or more cases have occurred in the last 50 calvings, you should move the springers to a new area, or renovate the pad.

Bring cows into the dairy as soon as possible to milk out and check - certainly within 24 hours of calving.
A new calf cannot suck all the milk from a fresh cow. Do not leave cows standing in the paddock dripping milk - bring them into the dairy, check udders, machine milk and disinfect teats (dip or spray).

Milk out completely - use milk fever control methods such as dietary control or calcium treatment (not incomplete milking) to prevent milk fever.

Take special care with induced cows.

Keep them in clean, dry paddocks after induction.
Machine milk them if they bag up tightly.
Don't let them drip milk in the paddock.
Watch udders carefully for signs of mastitis. Some cases can be rapid and severe with few changes or abnormalities (e.g. watery milk, clots or flecks) in the milk at first.

This article has been modified from the Countdown Downunder Farm Guidelines.
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