New Zealand Sheep - Facial Eczema damaged liver

By Dr Clive Dalton

The fungus Pithoymyces chartarum is found in pastures mainly in the Northern parts of New Zealand, and in autumn after a summer dry period when a lot of dead litter has accumulated in the pasture base, rain and dew can provide ideal conditions for the fungus to produce spores in large numbers. But the spores can also be found in large numbers on new short fresh autumn grass.

The fungal spores, especially the freshly-grown ones produce a toxin called sporidesmin, which causes thickening of the bile duct and may even cause its complete blockage.

Sheep gall bladder punctured to show bile and healthy
bile duct entering the liver tissue

A damaged liver cannot get rid of waste products, and a breakdown product of chlorophyll accumulates in the tissues causing jaundice and sensitivity to sunlight.

Sunlight very quickly causes swelling and severe inflammation on exposed white skin parts of the body.

There can be some repair of the liver, but it depends very much on the level of damage. In a recovered liver you will see knew small lobes that have grown.

Sheep's liver cut through centre

The liver pictured above is from a 6-year-old ¾ Romney ewe with ¼ Finn. She spent 5 years of her life on a farm that is very prone to FE, so there’s little doubt that she will have experienced a toxin challenge and liver damage during those years. She has reared twins most years in her life and it’s amazing that she was able to do this.

In the picture at the knife point is a little motley yellowish tissue on the surface of the liver which shows toxin damage. A real badly damaged liver is like a lump of wood.

But note especially the nice new healthy liver lobe on the right of the picture, and the 3 new small ones at the top right, and how healthy the internal tissue is.

For the last two seasons, this old ewe has been treated regularly with a zinc-based nutritional supplement which has protected her from further liver damage by toxins, and helped to stimulate new healthy liver growth.

Internal signs of a dysfunctional liver
Often at post mortem of a ewe dying close to lambing, you'll find two dead almost mummified lambs insider her but great masses of fat in the body cavity which the liver has not been able to process to nurture the lambs.

Drench resistant worms in sheep – a farm with drench resistance

Sheep, farming, husbandry, disease, animal health, drench resistance, dealing with problem

By Dr Clive Dalton

What do you do to find out if your sheep have worms resistant to drench?

Acknowledgements
Thanks to Dr John Moffat, Schering-Plough Coopers for use of this case material.

The problem

• A family farming operation on a North Island hill country farm running 1200 ewes and 150 beef cows was concerned about the effectiveness of their sheep drenching programme, and suspected that maybe drench resistance had developed.
• This was because of poor growth rate, scouring and an unacceptably high death rate in their lambs (100 died between docking and weaning). They normally had to dag about a half of their ewes.
• Their suspicions were really alerted by a mean FEC of 800epg 10 days after drenching a mob of hoggets with ‘Closal’. Closal is a narrow-spectrum active which has roundworm-persistent activity against Haemonchus contortus but is also highly effective against liver fluke.
• No worms have shown drench resistance to it yet in New Zealand.
• Lambs were on a standard 7-drench programme of which two were given prior to weaning (10th September and 20th October), a weaning drench on 20th November followed by four drenches on 20th December, mid February, mid March and mid April.
  

Action taken

• The first step was to arrange for a ‘drench test’ to see what was happening, so 60 hoggets were used to carry out a Faecal Egg Count Reduction test (FECRT) starting in May 2004. The results are shown in the table.
• The percent reduction in pre and post-drench faecal egg counts overall and by different parasite species was revealed.
  

Key points from the table:

• Note the wide range in individual animal’s FEC within the groups. This is expected.
• A drench is considered effective if the egg count is reduced by 95% or more.
• So the Lev, BZ, Combo drenches were not effective. Indeed the egg count was higher in the post-drench than the pre-drench FEC for the BZ group. This can happen.
• The MLs were 100% effective.
• Culturing larvae is an essential part of the FECRT to see which species are killed by which drench family.

• Look for the 100% kill rates and clearly the Lev drench was killing three species, the BZ killing one and the Combo was still killing three species of worms.
• Trichostrongylus parasites were resistant to both BZ and Lev drench, and so have had a reproductive advantage on this farm.
• Not enough parasites had developed resistance to ML to be detected as yet, i.e. ML drench was still killing all species cultured.
  

Drenching Recommendations

1. Develop and monitor the farm drenching programme

• Review carefully the current programme.
• Future drench usage must be warranted based on sound knowledge.
• Monitoring of parasitism in the flock is needed to ensure the on-going control programme is working.
• Do another FECRT in autumn to check for Haemonchus resistance, in case it is a threat when a narrow spectrum active should be used,
  

2. Drench active options are limited.

• Never use single action BZ or Lev drenches or Combination BZ or Lev drenches.
• Never use BZ capsules.
  

3. Protect the efficacy of ML family:

• Use other long-acting drenches very sparingly.
• In general minimise ewe treatments.
• Do not use long-acting drenches in ewes.
• Use preferably combination ML drenches or ML products on their own.
• Combination examples should contain ML+Lev or ML+BZ+Lev.
• Don’t drench about 5% of the animals in the mob (the best ones).
• Drench to the heaviest animal in the mob and regularly check the drench gun.
• Check FEC routinely before and after drenching using a composite sample.
  

4. Maintain Border Security

• Ensure there is no spread of drench resistant parasites onto your property from other farms or from your farm to others.
• Quarantine drenching.
  

5. Other Recommendations:

• Reduce farm parasite burden.
• Make use of cattle in cross-grazing programmes.
• Carefully consider post-weaning lamb management.
• Ensure good nutrition.
  

Disclaimer This material is provided in good faith for information purposes only, and the author does not accept any liability to any person for actions taken as a result of the information or advice (or the use of such information or advice) provided in these pages.

Cattle farm husbandry - keeping a house cow

Cattle, farming, husbandry, keeping a house cow, mating, milking, health, breeds
By Dr Clive Dalton

Is it a good idea?
Keeping a house cow may seem like a great idea, but consider these points before you are persuaded:

• Right at the start, determine who is going to milk the cow and how many times a day in all weathers? Write their names on a roster and put it on the fridge for all to see. Negotiate the pocket money payment rate for milking only if the job is done to the correct standard. How much milk is in the bucket, its colour and what’s floating in it will be a good quality check!
• Do the potential milkers know how to hand milk? It’s got to be completed in about 6-7 minutes as you won’t get a “let-down” response after that time no matter how long and hard you pull.
  
• You can always use a small milking machine but remember it will be expensive and have to be cleaned daily and maintained.
• You can also run calves on the cow and shut them away for 8 hours for you to have a turn at getting some milk.
• Where you are going to get a decent cow that will enjoy being hand milked?
• A cow these days from a dairy farmer, or through a stock agent probably won’t have been hand milked and you may have some problems getting her used to it. The only time she will have had her teats pulled is when she’s been treated for mastitis when they were sore and she’ll remember!
• You can breed your own house cow by rearing a heifer calf which is then mated and calves on your property. This will give you a great opportunity to ensure she is quiet and easy to handle.
• A house cow must be super quiet to let anyone in the family milk her and not be panicked by noise, children or pets around her feet. Feeding her some grain or nuts during milking is a good idea to build a good cow-milker relationship. But remember when you want to stop the nuts, she may not agree with the idea and play up or keep her milk to herself!
• Buying a lactating cow lets you see if she is an easy milker – i.e. if it’s easy to get the milk from her. Some culls from dairy herds may be slow and tough milkers and you end up with wrist ache and lock jaw from clenching your teeth while squeezing.
• The main thing to make sure when buying is that a potential house cow has not been a recurring mastitis candidate.
• The surplus milk. After calving you will be flooded with milk so plan what you will do with it. Will you enjoy the extra work of making butter, yoghurt or cheese, or will you give that a miss and feed it to calves or a Christmas porker?
• Selling milk. Don’t plan to sell the milk to anyone or even give it away as it will not be pasteurised and you don’t want to have a run-in with the Health Department or the law.
• Which breed? A Holstein Friesian will give an average of 4,000 litres per lactation, a Jersey 2,900 litres and a Friesian x Jersey 3,600 litres. Can you find a money-making use for all this?
• Where are you going to milk the cow? Have you got a milking bail as part of a shed, or will you milk her in the paddock in all weathers?
• A cow produces milk for its calf so she’ll need to be mated to keep on having a decent lactation. But you can keep on milking some cows for a couple of years without a pregnancy and you’ll keep getting around 4-5 litres per day. Not all cows will do this and at these low levels it may not taste the best.
  
• Make sure the house cow complies with all the Tb regulations and that she has been vaccinated against Leptospirosis. And give her a decent name!
  

Disclaimer This material is provided in good faith for information purposes only, and the author does not accept any liability to any person for actions taken as a result of the information or advice (or the use of such information or advice) provided in these pages.

Sheep Farm Husbandry - Organic farming and Homeopathy

Sheep, farming, husbandry, organic sheep farming, homeopathy for sheep, health & welfare, quarantine

By Dr Clive Dalton

Increasing interest in organic farming
There is an increasing interest in organic farming around the world as consumers become more concerned about food safety and with the over-use of chemicals in farming. Farming using “organic principles” is seen by an increasing number of people as a solution to these concerns. Below are some general principles

General principles

• Organic farms need to be registered with an organic licensing authority to meet specific standards, and this will cost you an annual fee.
  
• Your farm will be audited at regular intervals to check if you are complying with the standards. New Zealand standards are set to comply with, and even exceed, overseas organic standards required by importing countries.
• It will generally take three years before you can become fully organic in New Zealand.
• The basis of organic farming is to have a healthy productive soil which then produces healthy pastures and crops, and then healthy livestock.
• Farming animals under an organic system requires an even higher standard of management than under a conventional system.
• The main difficulties (or challenges) will be issues of animal health as you cannot use antibiotics, conventional chemical drenches for internal and external parasites or vaccines, unless under special circumstances which will compromise your organic status.
• There are organic alternatives available to prevent and treat diseases, but if in the view of your veterinarian the animals are suffering, you must use conventional veterinary medicines with the implications of losing your organic status on those sheep for a period of time.
• If animals under a certified organic system receive a conventional animal heath treatment, then they must be quarantined for a specified meat-withholding period in a designated quarantine area.
• Homeopathy is approved for use in organic systems.
• You may have difficulty finding sources of organically grown supplementary feeds such as hay, silage or grain-based concentrates. These must have been grown on registered organic properties and inevitably these feeds will be more expensive.
• Conventional farms that have gone organic have initially had to reduce stocking rate, but after a few years production levels have returned to pre-organic levels with much lower costs, especially in animal health.
• You will have to spend time making organic treatments for your animals, but many can now be purchased from specialist suppliers.
• You should appreciate how organic farming differs from “biodynamic” farming, which embodies the principles of organics but takes them a stage further with many more commitments.
  

Perceptions about organic farming

In many conventional farming circles, organic farming has a poor image and its principles are viewed with great suspicion, mainly because of the lack of documented evidence in refereed scientific journals. Skepticism is increased when “biodynamic” farming principles and homeopathy are added into the picture.

Organic farmers are used to criticism from the establishment and are keen to point out to those contemplating going organic a few important rebuffs to their critics. They have to spend more time telling skeptics what organic farming is not, rather than what it is! Here are the points they make. Organic farming is NOT:

• Farming by neglect!
• Losing money from your enterprise.
• The road to bankruptcy.
• Letting your farm run down and look like a wilderness covered in weeds.
• Letting pastures and crops fail through low fertility and disease.
• Accepting poor animal performance through poor feeding and disease.
• Letting animals suffer, and breaking the law.
  

Successful organic farmers point out that to be a good organic farmer, you have to be an above-average conventional farmer. Farmers who struggle to make money from a conventional system will not adapt well to organic farming, hence they tend to blame the system for their failure rather than themselves.

The premium prices received for organic produce are certainly attractive, but then the skeptics say these won’t last. This has happened in Europe where there has been a massive interest in moving into organic farming, encouraged by farming subsidies.

What is quarantine?

• This is a designated area of a farm where animals are held until they are free from the effects of the treatment.
• The area must be well fenced and secure. An animal that has received conventional treatment and completed the quarantine period, can be returned to the organic area but lose its organic certification for a designated period.
• This period varies with the certification agency but is generally 12 months.
• Permanent identification and keeping accurate records are an essential part of the quarantine process.
  

More information on organic farming
Apart from the organic registration authorities, there are now an increasing number of organic farm consultants. Check the yellow pages of the telephone directory.

Homeopathy

• The Oxford dictionary defines homeopathy as “the treatment of diseases by drugs, usually in very minute doses that in a healthy person or animal would produce symptoms like those of the disease”.
  
• Homeopaths stress that it is a gentle, effective and scientifically based system of healing that encourages the defence mechanism of the body to heal itself. It is based on the principle of similars or “let like be cured by likes”.
• Traditional scientists are highly skeptical and are openly critical of homeopathy because they say it lacks research that shows statistically significant benefits. The hard thing for skeptics to accept is the principle that as the concentration of the cure (made from the disease organism or a plant) decreases, the curing power of it increases!
• Now an increasing number of veterinarians offer both conventional and homeopathic remedies for their clients’ animals. Another observation which may not be related, is the increasing number of veterinarians who are women. Remember veterinarians charge fees so they have to use things that get results for their clients.
• One of the main reasons why some traditional vets have changed their views and their practices, is that they are increasingly disappointed and concerned about how the current use of animal remedies (such as anthelmintics and antibiotics) is leading to farming that is not sustainable.
• So think about it. You can join those who rubbish homeopathy totally as a myth without satisfactory evidence to prove its worth, or be open minded and try it on your sheep and see if it works.

Here’s a question to ponder.
If homeopathy is nonsense, then why are an increasing number of hard-nosed commercial farmers who have tried it, paying their bills and re-ordering product? They don’t do that if they have been ripped off.

The real question is this - has the past 50 years of veterinary research costing billions of dollars failed to meet farmers’ current needs, and does someone with the resources need to urgently sort out new priorities in animal health and disease prevention, to help farmers who are under ever increasing economic pressure? At present nobody seems to be grabbing this opportunity.

Disclaimer
This material is provided in good faith for information purposes only, and the author does not accept any liability to any person for actions taken as a result of the information or advice (or the use of such information or advice) provided in these pages.