1999 August

Treatment of Non-cycling Cows

The veterinary examination and treatment of cows that have not been mated after one round of AI is a common and accepted procedure. These cows are referred to as No Visible Oestrus or NVO cows. In the last few years there have been a number of investigations into the most effective timing and treatment of NVO's. This work has been done in the major dairying regions of Victoria, including our area. It has been carried out on commercial dairy farms under normal industry conditions. The results are therefore very applicable to most of our commercial herds.

The National Dairy Herd Fertility project, now called "In Calf" has confirmed and reinforced the fact that later calving cows have substantially reduced fertility compared to their earlier calving herd mates. It is these later calving cows that make up this bulk of the group of NVO's. If we do nothing, many of these cows end up empty, or as late cows in the following year.

There is good evidence that early treatment of NVO cows results in:

Increased numbers in calf to AI.
Less empty cows.
Fewer cows to induce in the following year.

The timing of treatment appears to be important in getting the maximum benefit. There are two strategic times that treatment can be targeted.
Prior to Mating Start Date (MSD): This requires heat detection commencing about 30 days before MSD. An easy way to do this involves use of tail paint with twice weekly recording and topping up. If a different colour is used on cows that have cycled the NVO's can be readily identified.

After one "round" of AI: This allows all cows to have a chance to be detected on heat say 21-24 days after MSD or earlier in herds that have synchronised.

Treatment of cows prior to MSD will mean that approximately twice as many cows will be examined, however, this gives the true non-cyclers a chance to be mated twice in the first 30 days of mating. The trial results show that these early treated NVO's have fertility that is almost equal to their non treated naturally cycling herd mates.
The earlier that NVO's are identified, examined and treated, the better.

The standard treatment for true non-cycling or "anoestrus" cows involves the use of a CIDR and an injection of oestrogen. This results in a very high percentage of anoestrous cows showing heat after CIDR removal. Trial results have shown that some cows that fail to conceive do not come back on heat. This problem can be overcome using reinsertion of the used CIDRs (used but cleaned before reuse) and re-treatment with oestrogen. Re-treatment of anoestrous cows, is a low cost option that is worth considering.

Examining and treating NVO cows is a very worthwhile exercise. If you have any queries regarding the type of program appropriate for your herd, please contact us.

Coccidiosis

Coccidiosis is a disease seen commonly in calves and yearlings. In mild climates such as this, coccidia are present where-ever cattle are present.

Coccidia are microscopic organisms that invade and affect the gastrointestinal tract of young animals. It is the damage to the lining of the large intestine which causes the clinical symptoms we observe:

Diarrhoea usually blood tinged
Straining
Tail switching
Occasional death

Coccidiosis is commonly associated with environments which allow a build up of coccidial oocysts or "eggs" to occur, eg overcrowding of calves, housing in dirty wet conditions with poor drainage and lack of paddock spelling. These oocysts are ingested by the calves when they eat the pasture or lick infected calves. Infected calves shed oocysts into the environment via their faeces. Stresses such as heifers undergoing the stress of weaning, overcrowding and concurrent disease, can also predispose young animals to develop clinical disease. It usually takes 3 to 4 weeks from the ingestion of the coccidial spores to the time that clinical signs are seen.

The diagnosis of coccidiosis can usually be made from clinical signs, this can be confirmed by microscopic examination of the faeces.

Hygiene of calf rearing facilities is the most important factor in limiting the problems caused by coccidia. Preventing the calves from being showered with high levels of infective coccidial oocysts can be achieved by:

Hygienic calf sheds (slats, mesh or deep litter); well drained, clean, dry surfaces.
Low stocking rate in pens and in paddocks
Well drained calf paddocks
Rotating calf paddocks periodically
Ensuring that feed and water containers are off the ground
Regularly changing feeding areas in the paddocks
Isolation of affected calves

Affected calves should be treated immediately with sulfadimidine for three days, in severe cases broad-spectrum antibiotics such as Tribactril will be beneficial. Dehydration can be a problem in these calves, so adequate fluid therapy (either oral or intravenous) should be available if necessary.

On farms with persistent problems with coccidiosis, calves can be fed avoparcin and/or monensin (or other similar products) from birth to prevent infection. Immunity to coccidiosis will still develop while on monensin but clinical disease is prevented. This allows protection against coccidiosis when monensin is withdrawn.

Monensin is available in a number of commercial preparations which can be added to milk or be available in pellet form.

Maximising Milk Production in Early Spring

Favourable conditions in July have given us the opportunity to utilise more winter pasture than usual. On all but the lightest country, we normally anticipate pasture growth to exceed requirements sometime in early September. However, this year, it could well be 2 to 4 weeks earlier. Growth rates over 30kg per hectare have been measured already and with marginal losses due to pugging, there are many farms now being able to continue feeding 12-15kg of pasture per cow daily.<P>

To maximise pasture intake, cows need to be able to leave a post grazing residual of 1600-1800kg dry matter. Typically cows will have just started to give the clumps around dung patches a hair cut at this level. If cows have the opportunity to eat the 12-15kg we have available, they will obviously produce more milk. Many farmers will have been on a slow rotation (over 30 days) to ensure surviving a wet August. It is now feasible to speed this up to 20 days or less and offer cows more than they can consume. In the event of heavy rainfall this rotation can be slowed again.

The amount of concentrate feeding will be dependent upon expected and previous production level and the inherent ability of pasture growth on the farm. Nitrogen used in early spring will grow feed at well below $100 per tonne so unless this feed is not able to be utilised it will always be an option ahead of grain. If soil fertility is high and significant autumn fertiliser has been applied, it may well be feasible to apply only nitrogen as the spring fertiliser. As long as soil fertility levels are monitored, this will not cause long term detriment to soil fertility.

Urea at 100kg per hectare will boost pasture growth for 4-6 weeks by up to 20kg per hectare per day. Pasture Booster at 200kg per hectare will supply a similar nitrogen application with seven units of P and 26 units of K. The ideal time to apply these spring fertilisers is at the start of the spring growth which on most farms will be mid to late August.
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Remaining Positive

The general outlook for the dairy industry has overtones of gloom and pessimism. Those having this attitude are opting to join the queue of disenchanted farmers who will most likely leave the industry in the next few years. It is likely that the decline in dairy farm numbers will continue the trend that began 40 years ago with a temporary pause over recent years.

However, there will be a significant number of excellent dairy farmers who survive these tough times and maintain a profitable and enjoyable place in the dairy industry.<BR>

These farmers will have a number of common traits:

They will be efficient hard workers.
They will have continued to update their facilities.
Their dairy farms will be environmentally sustainable.
Their farms will be quality accredited.
They will predominantly be farms milking more than 200 cows.
Labour and contractors will be part of their work team.
They will have kept up with modern farming practices.
Their business management skills will be high.
They will grow and utilise a substantial amount of pasture.
They will have a positive attitude to dairy farming and they will enjoy milking cows.

Amongst these farmers will be young and old, high and low equity farms, well established and new farms, pure bred and cross bred herds, varying calving times, those that crop and those that do not. What they will have in common is the ability to run their dairy farming enterprise very well and be clear as to their farming and personal goals.

There are a plethora of courses, advisers, workshops, study programs and conferences that are available for farmers to assist them to achieve these goals. Government handouts and neighbours queuing up to buy the farm are no longer a likely event. Lets knuckle down and produce our way into the new millennium.

The Milk Price Outlook

The 10-15% drop in opening prices largely reflects the 10 year low in export market price for skim milk powder. Unfortunately because of our heavy dependence on the export market, we are vulnerable to such events and will continue to be in the long term. The other Western countries produce milk predominantly for domestic consumption.

The USA and European community are the major contributors to export markets along with Australia and New Zealand. Their surpluses sold on the export market only represent a small proportion of their total output. Their governments are prepared to subsidise this output. This has two effects on the export market. It sends incorrect market signals back to producers in those countries because they receive an inflated price for their export milk. Secondly, it increases supply of world trade in dairy products which reduces the price received on the export market. Australia and New Zealand must except this price without subsidies since our scale of production for export is too high to expect government subsidies.

Deregulation of the Australian milk market will have no impact on the world export price. For Victorian farmers, the inevitable drop in the price received by factories for whole milk will have a relatively small impact on the price received. If the price dropped to export price there would be a 7% drop. In favour of the milk price is the removal of the domestic market support levy on manufactured milk which is up to 20% of Victoria's milk. This will have the benefit of improving competition of Australian manufactured product sold domestically against imported products that do not pay the levy. Industry commentators suggest that these two deregulation impacts will oppose each other so that the final impact is minimal.

The deregulation package which is designed to keep a margin of 7-10 cents per litre on whole milk before is reaches the processor, has been put to the federal government. All states agree that deregulation is necessary. The states with the large share of liquid milk market will have the most to lose so are keen to see the package accepted. The government has looked favourably upon the proposed package. Given its wide industry support and non-inflationary nature it is predicted that it will be passed by parliament. If so, this will be a welcome relief to farmers who will have some space to breath whilst they decide whether or not to stay in the industry.
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Review of the use of Antibiotics in Food Producing Animals

At this point in time many of the countries in the developed world are in the process of, or have completed a review of the use of antibiotics in humans and animals, particularly the use of growth promotants. The European Union released its recommendations in June (PDF file). The Australian Review (called the JETACAR Report) is nearly complete and will be submitted to the Ministers for Health and Agriculture within the next few weeks. See the November newsletter for further information

The primary reasons for the reviews are to determine the scope and impact of bacterial resistance to antibiotics, and to devise methods of reducing the development and impact of antibiotic resistance. Rightly or wrongly, the use of antibiotics in food producing animals, and in particular the use of antimicrobial agents in feed has attracted considerable attention. There are sizeable sections of the community and medical professions who are now arguing against the use of certain therapeutic agents in animals. Some are going as far as to demand that if a drug or a class of drugs is used in human medicine they should not be used in animals. Products like avoparcin (Avotan) and virginiamycin (Eskalin) were approved long before they were important in human medicine and have been used for 30 years in animals, mainly to prevent lacticacidosis in grain fed ruminant and to prevent necrotic enteritis in chickens grown for meat.

This issue is a technical and moral minefield. There is little supporting evidence to suggest that bacterial resistance is developing unchecked in food animal populations, or that bacterial resistance is forming in animals and being transferred to humans. Nor is there any evidence to prove that this is not happening. The only solid and irrefutable data suggests that in environments where large amounts of antimicrobials are used, the likelihood that resistant bacteria develop will increase. This is true for human and animal populations.

The review released by the European Unions Scientific Steering Committee on Antimicrobial Resistance makes several clear recommendations being:

Tightening on the controls on the sale, supply and distribution of antimicrobial agents intended for use in human, animal or plant health systems. In some EU countries only Veterinarians or animal health technicians can administer injectable antibiotics.
Encourage the development of "best management practices" so that the need to control infective agents is reduced, the health and welfare of livestock is optimised and the need or demand for routine addition of in-feed medications is reduced. This includes the use of properly balanced rations.
Encourage an increased use of diagnostic procedures and discourage the use of antibiotics where a disease is likely to be self-limiting.
Actively encourage the phasing out of certain treatments.
Institution of improved recording and monitoring systems.

It is likely that the JETACAR Report will make similar recommendations.

What is the likely impact of the reviews on the way that cows are treated?

Firstly, there will probably be a greater requirement to prove that milk and meat products sold are free from chemical and bacterial contamination and that reasonable management practices have been employed in the creation of these products. The purchasers (international and domestic) of food products will not tolerate the presence of antibiotic residues. Luckily the Australian dairy industry is already instituting on-farm quality assurance programs and these will be the sort of evidence that markets are requiring.
The use of some drugs may become restricted. Certain drugs that have greater value to human health may be removed from use on animals, similarly drugs that are more valuable for use in animals may be withdrawn from use in humans. Already we are seeing the removal of certain drugs from the market place due to reduced effect or causing problems. For example, the injectable forms of streptomycin (Pen-Strep) are no longer permitted to be used in livestock because of residue problems. The use of products like Eskalin and Tylan in feeds have been discussed. The EU report and the 1997 WHO report consider that the use of these agents hold no immediate risk to public health, however this status will be constantly monitored and may be reviewed. Other in-feed medicants have been shown to rapidly cause bacterial resistance to develop. Six antibiotics have been banned from growth promotion in the EU including Tylsosin

What should be done?

In order to preserve the ability to treat bacterial infections in animals, action must be taken to reduce the overall use of antibiotics through the use of preventative measures and the sensible use of therapies. Simple actions such as examining sick or lame cows and determining the cause of their disease before treating them will significantly reduce the amount of antibiotics used. Diagnosing the condition permits the identification of the problem areas and the implementation of preventative measures, reducing the need to treat further cases. Thus reducing the cost of the problem in the short and long term.

Timboon Veterinary Group