Pre Lamb Treatments for Ewes

There are not many times of the year that you can influence the production from your sheep flock. One notable time is pre-tupping through ram/ewe selection, and mineral and vaccine choices designed to maximise the conception rates. The other is pre-lambing.

This critical time when the ewe‟s natural immunity relaxes (Peri-parturiant relaxation) and her ability to cope with a parasite challenge is reduced. Choices you make then can have an influence on lamb weights at weaning and ewe weights prior to the next tupping period.

If we assume your feeding is as good as you can make it, ewe treatments pre -lamb come down to a choice of

1. vaccines

2. anthelmintic treatments
3. mineral supplements

Vaccines:

Clostridial Vaccines:

At around 30 cents a dose, clostridial vaccination is an inexpensive
insurance. You will be protecting the ewe during a period of susceptibility and the lamb via the ewes colostrum for around 8 weeks. The loss of only one lamb or ewe pays for a lot of protection at today’s pricing. 5 in 1 vaccine does not cover all clostridial cases so consider ULTRAVAC 6 in 1 for a little more protection. 6 in 1 vaccine includes Clostridium sordellii which caused ‘Sudden Death Syndrome’, more recently recognised in NZ.

Pre Lamb Ewe Treatments .. The options ..

• Change needles frequently. Administer under skin behind ear. Store vaccines at fridge temperature at all times.

Other vaccine options available include 5 in 1 vaccines with either or both B12 and Selenium. (see below)

Anthelmintic Treatments:

Oral liquid treatments are probably of very limited value unless your ewes are suffering from a high worm burden throughout the winter. This is unlikely if they are being well fed and being kept in good condition with no other concurrent disease e.g. Johnnes or liver fluke. If you are going to use an oral drench, then a dual or triple action product (Matrix or Switch) should be used.

No treatments (yarding of ewes) to ewes should be given in the last two weeks of gestation, due to the risk of stress related abortion, so the short action of an oral anthelmintic will miss that period of immune suppression or “pre-parturient rise‟ immediately prior to lambing, making them of no value to the lamb and of little value to the ewe.

Injectable anthelmintics may give a benefit as a pre-lamb ewe treatment but to be clear, they do not compare with drench capsule technology and they may pose a
risk to resistance development through the effect of their “tail‟ of
anthelmintic levels in the ewe below therapeutic levels.

Advertising tries to compare a Moxidectin LA (Exodus or
Cydectin) treatment with capsules and gives the impression that they are equally effective for 100 days. This is only true for one parasite, Ostertagia, which is not generally significant in sheep. More significant is the parasite Trichostrongylus against which Moxidectin is effective for a maximum of 42 days. All the rest, and some are very significant such as Nemotidirus, efficacy is for only 1 day! This is pretty much of no use at all, because the benefit will have passed long before lambing and the period of ewe immunity suppression.

In summary only Moxidectin LA will give some sustained benefit; all other injectables such as Eweguard and abamectin (Genesis) injectable will be of questionable benefit to ewe and lamb and can definitely NOT be compared to capsule technology. The main reason for this is the “constant contact‟ of the anthelmintic in the capsule, minimising the effect of the lowered immune response and energy diversion. What this means is the ewe can utilise every blade of grass into either milk production or body condition.

The advantage of injectable anthelmintics is a lower cost per head and ease of application. I addition the likes of Eweguard and Nilvax, they are combined with a 5 in 1 vaccine.

Anthelmintic or Drench Capsules vary in the active ingredient they carry, but all will last for 100 days at therapeutic levels.

If you have parasite resistance issues you need to be aware of your status and select a treatment that you are confident will work. If you are uncertain, then you are safer with a combination product. A premium capsule with combination anthelmintics is BIONIC and this will provide therapeutic levels against all 13 internal sheep parasites for 100 days.

To achieve a production gain (assuming your feeding levels are good) the requirement is to have an anthelmintic in the ewe at lambing time and for a reasonable period after lambing. In the face of a parasite challenge, the ewes energy will not be diverted to the challenge on its immune system, but will be put into maintaining its condition and milk production for lamb growth. The net result is a significant increase in lamb growth (supported by numerous trials) which is the real benefit of using capsules over other treatments and it is what sets them apart from all others.

Capsules provide many benefits:

1. Increased ewe milk production resulting in better lamb weights at weaning

   (between 4 and 8 kg)

2. Better ewe weights at weaning (average 5.8kg)
3. More lambs away at first draft
4. Increased wool production.
5. Ewes in better condition at mating (= more fertility)
6. Less dagging

Yes, they do cost more per head, but numerous trials over the years have shown that with good available feed, production gains as mentioned above will produce an economic return on the cost of the capsule.

In the interests of ‘refugia’ and on the basis of return on outlay, you might consider just treating the more susceptible ewe groups. This would include twins and triplets, hoggets (if mated) and 2-tooths.

Minerals.

• Vaccinations give you the opportunity to provide selenium and cobalt (B12) which will raise levels for 4 to 6 weeks.
• Oral anthelmintics will only provide very short term mineral supplementation, and injectable anthelmintics may contain selenium and cobalt (B12), also lasting 4 to 6 weeks.
• Drench capsules (BIONIC, EXTENDER SeCo) provide cobalt and selenium by slow release for 100 days.

Additional minerals can be of benefit for lamb survival and there is research to support this. Of note is LSD, originally developed by Vet, Pete Anderson of Blenheim.

The Vet Centre, Richmond & Motueka.

Gladstone Road, P.O.Box 3509, Richmond, Nelson.

Phone: 03 5445566 Fax: 03 5445561