Preventive Health Strategies for Pasture Based Goat HerdsHolly Neaton DVM
Watertown, Minnesota

Grazing and parasite control

When it comes to controlling intestinal parasites in goats, Minnesota does have an advantage over warmer climates. Even the most diligent grazers need to pull their animals off grass and feed them hay for a period of time in the winters.  The freezing temperatures and rest gives us a chance to depopulate some worms. Many of the intestinal parasites of goats that reside in the world’s warm climates have become resistant to the anthelmintics that we have available to us. And there doesn’t seem to be any new drugs for us to fall back on in the near future.

We must use the anthelmintics we have – in the correct dosage, at the correct time and in the correct animals – to control one of the most difficult management problems we see in grazed animals – parasites.

 To start, we need to understand what we are dealing with:

• Haemonchus contortus – the most dangerous parasite is this blood-sucking nematode (stomach worm, barberpole worm). Her cousins, Ostertagia and Trichostrongylus, can be just as devastating. They are capable of drinking up to one cup of blood per day from a heavily infested goat. Signs of heavy infestation are weight loss, diarrhea, lethargy, pale mucous membranes, bottle jaw and death.
• Liver flukes – a parasite shared with deer and more commonly found in the northern parts of Minnesota. The intermediate host is a snail. This parasite damages the liver and can cause death. Prevention includes fencing off swampy areas and deer. This parasite cannot be seen in fecal exams.
• Tapeworms – intermediate host is a tiny mite that is ingested while grazing. Generally not thought to cause much damage but visibly displeasing.

Resistant worms have developed as dewormers do not kill 100% of the worms, even when dosed properly. The worms that are left behind are resistant. It is very important to know what worms you are purchasing when you buy goats, especially when they come from southern climates. Isolate your new purchases, run a fecal exam, deworm with a combination of several dewormers, run another fecal exam in 10-14 days. It should be negative prior to introducing the new goats to your pasture.

Most producers want easy answers – what dewormer should I use, how many cc’s, when should I give it to the goats? There are no easy answers, each farm needs its own strategy. There is some basic information that can be used by everyone.

• Most worms have a three week life cycle: The goat eats the larva on the grass; the larva grows to an adult in the goat’s stomach or intestines, sucking blood for energy; the adults lays eggs which pass out with the manure pellets and lay on the ground in the grass; the eggs hatch and larvae use moisture to crawl up the blades of grass where they will be eaten by the goat.
• Try to keep a “safe” pasture for spring turnout. Safe pastures are those that have not been grazed by goats for at least 3 months in the summer and 6 months in the winter. Safe pastures can be used for grazing other species (not sheep) or harvesting hay.
• The larvae cannot crawl up the grass more than around 4”.
• The eggs/larvae can live in the summer for 3 months and 6 months in the winter.
• The biggest hatch of eggs occurs after a rain that follows a drought.
• Cattle and horses graze at different levels and do not share parasites with goats. Sheep do. Pastures that have had cattle or horses grazing can be thought of as safe.
• Worms can hibernate in goats over winter, becoming dormant. They will wake up and multiply with a vengeance around kidding time.
• Overgrazed, overpopulated pastures contribute to heavy worm loads in goats.
• Intensive rotational grazing is not a way to control parasites – it may contribute to the problem if not included in the strategy for controlling parasites.
• We don’t have to deworm every goat every time. It is estimated that 20-30% of the goats carry 80% of the worms.
• Many adult goats have immunity to worms. Goats under one year of age are the most susceptible to damage and need the most attention.

Fecal Exams

It is important to monitor the success of your deworming program with fecal examinations. It is recommended to collect fresh pellets from 5-10% of your herd, mix them together to form a composite sample and have your veterinarian look for eggs. This is best done prior to deworming and again 10-14 days after. If there is no change in egg counts, evaluate your dewormer, dosage, timing, etc.

What dewormers are available to us that are effective?

The following are recommendations for use. Many will be used in goats in an off-label manner, using dosages higher than labeled. It is suggested to double the cattle meat withholding time for goats. Please work with your veterinarian to determine the best dewormer to use for your herd and what the proper withholding time should be.

• Abendazole (Valbazen) – PO (oral) 10 mg/kg or 5 ml/100#. Also effective against tapeworms and flukes. *Do not use during breeding or pregnancy.
• Doramectin (Dectomax) – SQ  .3mg/kg or 1 ml/75-100#. Similar to Ivomec, best saved for external parasites such as chorioptes mites.
• Fenbendazole (Panacur, Safegard) – PO 10 mg/kg or 5 ml/100#. Similar to albandazole though not effective against flukes.
• Ivermectin (Ivomec, generics) – 1 ml/75-100# sq for external parasites, 1 ml/22# PO for internal parasites.
• Levamisole (Levasol, Tramisol) – PO 8-12 mg/kg. The only dewormer mentioned that may cause overdose problems. *Suggested by some to cause problems during pregnancy.
• Morantel (Rumatel) – PO May be fed to lactating does with no milk withholding.
• Oxfendazole (Synanthic) – PO 10 mg/kg or 5 ml/100#. Similar to fenbendazole.

It is recommended to rotate dewormers annually.

When should I give the dewormer to my goats?

• Hold the goats off feed for 12-24 hours prior to deworming.
• Hold goats in a drylot for 72 hours after deworming, then move onto “safe” pasture.
• If you can’t put goats onto a safe pasture, deworm every 3 weeks until mid-July or so. Then monitor adults, keep deworming kids if on pasture.
• Deworm all goats in the winter when removed from pasture. Pregnant does should be dewormed around kidding time and again before entering the pasture. This time around kidding is when the worms are most susceptible. If you can remove most of the dormant worms, there will be fewer to bring out to the pasture with the goats in the spring.
• If you have a fluke problem, deworm with Valbazen in late fall and repeat in 4 weeks to kill the adult flukes missed the first time. *Be aware of the warning not to use Valbazen in early pregnancy.
• Deworm 10-14 days after a heavy rain, especially following a drought.
• For problem herds – repeat dose of white dewormers (albendazole, fenbendazole, oxfendazole) in 12 hours and ivermectins in 24 hours.

FAMACHA

FAMACHA was developed in South Africa where many of the intestinal parasites in the meat goats have become resistant to modern derwormers. This method only works for haemonchus control and basic training must occur before using so its limitations are known.  A card with pictures of varying degrees of pink color in the eyelids is used to grade the goats. This pink color – or lack of it – correlates to the degree of anemia caused by the blood sucking worms. Only the most anemic goats are dewormed.

The theory is that the pinker goats still may have worms, but they have learned to live with them in a form of resistance or immunity. These “immune” goats will shed their worms into the environment but they will be sensitive to the dewormers as they have not been overly exposed to them. The population of worms will eventually become sensitive to dewormers. Keeping records of the goats that do not need to be dewormed will help you in selecting replacements for your herd that may have genetic resistance to the worms.

Final Deworming Strategy Tips

• When you deworm, use dosages geared toward the heaviest animal. With the exception of levamisole, dewormers are very safe. Dosages are generally 1.5-2x the cattle dosage.
• Use dewormers orally if possible.
• Make sure the dose is given over the back of the tongue, not in the cheek pouch.
• Repeat dose in 12-24 hours.
• Move dewormed animals to “safe” pastures: pastures that have not been grazed by sheep or goats for 3 (summer) – 6 (winter) months.
• Rotate pastures with cattle or horses.
• Do not overgraze pastures. Worm larvae cannot crawl up grass more than 4” tall.
• Worm life cycles are around 3 weeks; deworm before the new batch of eggs are laid.
• Keep deer out of the pastures.
• Effectively deworm goats over the winter, especially around kidding time.
• Monitor your strategy with fecal exams.
• Animals that are not fed adequately are more prone to the effects of parasitism. Protein levels are especially important.
• Quarantine newly purchased animals and eliminate any worms purchased with them.

Vaccination Recommendations for Goats Herds

Pregnant does: Clostridium CD and Tetanus 2-4 weeks prior to kidding. Vaccinate for Chlamydia, campylobacter prior to breeding and mid gestation if necessary to prevent abortions.

Kids: Clostridium CDT at 4 and 8 weeks. Booster at 12 weeks if kids are on heavy concentrates or lush pastures. Some herds need to be vaccinated every 6 months.  Bucks: Vaccinate with Clostridium CDT annually with does.

Caseous lymphadenitis (Casebac or Caseous DT) bacterin may be useful in a program to eradicate CL from a herd. It can cause dramatic reactions from the goats so should be used with caution. Work with your veterinarian.  Rabies vaccine can be given by your veterinarian to valuable animals. Contagious ecthyma (soremouth) vaccine is a live virus that can be used to prevent outbreaks at inopportune times.

Tips for vaccinating goats:

• Give injections subcutaneously in upper necks. Behind elbows or over ribs unless specified IM.
• Expect some swelling, lameness and lethargy for a day or two after vaccinating. Some swellings may become permanent knots.
• Use clean, new needles. A whole box of 100 20 gg 1” needles is only around $10.
• Watch expiration dates on your vaccines and keep them refrigerated. Shake well.

Salt

• Goats prefer loose salt over blocks.
• Salt should be mixed at 4% of the diet for male goats to help prevent urinary calculi.
• Loose salt can be used as a carrier for coccidiostats and minerals.
• Use white, iodized salt to prevent goiters and breeding problems.
• Be careful of mineral formulated for sheep as it may not have enough copper and too much molybdenum.
• Be careful or mineral mixes with calcium and phosphorous included. Balance your complete diet to avoid imbalances and calculi problems.
• Keep your Ca:P ratio at least 2.5:1.