Sheep vaccines

Androvax

This vaccine is designed to increase scanning percentages. This is done by briefly stopping ovulation from the ewes ovary when the effect wears off the ewe ovulates more mature eggs than before and this results in more multiples at scanning.

This product is not a golden bullet to fix poor management or poor condition scores at tupping. There is also some very specific timing that must be adhered to as vaccinations need to be given 6 weeks apart starting 12 weeks before the ram goes out.

Androvax can be very useful in certain circumstances, eg: consistently single bearing ewes, or to artificially ‘flush’ ewes when feed is unavailable. It is best used in younger ewes, as fertility increases with age and incorrect usage in older ewes can result in losses at lambing with too many sets of triplets and the increased risk of metabolic disease.

Toxovax

Toxoplasmosis is a common and widespread disease that occurs on sheep farms. It affects the reproductive performance of sheep and infection can have any of the following outcomes:

• Increased drys at scanning – most common in 2 tooth or hoggets
• The presence of mummified or dead lambs at scanning
• Abortion
• The birth of weak or stillborn lambs
• Increased wet/dry ewes at docking
  
  

Toxo is present on most farms due to the fact that it is spread by cats who contaminate the pasture by passing the parasite in their gaeces. The sheep then eats the contaminated feed and depending on the stage of pregnancy can have any one of the above outcomes. Once ewes have been affected with Toxo they are immune for life.

Vaccination is very effective and it only needs to be given once for lifetime immunity. We recommend vaccinating hoggets (if hogget mating) or 2 tooth ewes and this will provide protection for the rest of the animal’s life. The vaccination can be given at any time before mating so can be given over the summer period if that is easiest. It must be given at least 4 weeks prior to mating.

For the greatest efficacy, Toxovax needs to be given in the muscle. Unlike most other vaccines, Toxovax is a LIVE vaccine and therefore must be handled with care. In particular:

• Only mix when required and use the whole packet before stopping for a break
• Keep on ice or refrigerated when not in use
• Make sure it is used within a 7 –10 days of collecting
• Use new needles for Toxo, as any needles that have been in meths will kill the vaccine
  
  

Toxovax is made to order, so please ensure that your orders are made 4 weeks before you require the vaccine.

Campylobacter in ewes – causes of abortion and foetal loss

Campylobactera is one of the 2 most common causes of abortion and foetal loss in ewes, the other main player being toxoplasmosis. Campylobacter usually causes abortion in the last six weeks of pregnancy, but it can also be responsible for the birth of weak lambs. As a general rule, the ewes suffer no ill effects and retain their fertility for future years. Once exposed to Campy they also develop immunity to subsequent infections. A small percentage may develop a uterus infection and die, but this is uncommon. Infection is caused by C.fetus of which there are many strains present in New Zealand.

The bacteria may live in the intestine of sheep, these ewes are effective carriers. The infection may enter a flock by ingestion of contaminated food or water or by direct contact with aborted fetuses and their membranes. Birds that scavenge lambing paddocks, such as black gulls, may aid in carrying the bacteria from one farm to the next. In contrast to Toxoplasmosis, which tends to cause early pregnancy loss, Campylobacter results in abortion in the last third of pregnancy resulting in an increase in wet/dry ewes. Abortion is usually 7 -25 days after infection. Some ewes may carry their lambs to term resulting in the birth of dead or weak lambs. Abortion storms can occur in particular when ewes are grazing short grass at a high stocking rate.

Diagnosis is best made by post-mortem of dead lambs. However, this is not always practical on farms with little to no shepherding (the norm on hill country). A blood test is available to screen wet/dry ewes for Campylobacter antibodies. This needs to be carried out around the time of docking. The lab fees are paid for so the cost to the farmer is $50 plus mileage, making it a worthwhile exercise. Campylobacter infections can be prevented by vaccination with either CampyVax 4 or Campylovexin. The programme required 2 shots 4-6 weeks apart and is best started at least 4 weeks before mating. Ewes can be vaccinated with Campy at the same time Toxovax is given, just on opposite sides of the neck. Campyvax needs to be given under the skin, while Toxovax needs to go into the muscle. While the vaccine company recommends an annual booster with Campyvax most farmers find the 2 shot programme received as two tooths gives lifetime protection.

Scabby Mouth – poses a serious risk to lambs

Scabby Mouth is a serious disease, and once it is on a farm, it’s there for life. It poses a serious risk to lambs, every season. This highly contagious disease usually affects lambs during the key period of growth affecting your ability to finish lambs.. Lesions are painful and typically occur around the mouth and nostrils of young lambs making them reluctant to suckle or graze. Lambs can also be lame and are at greater risk of flystrike. In some cases infected lambs can transfer the virus to the udder of ewes, resulting in a risk of mastitis. The infection spreads rapidly and can affect up to 100% of the lamb mob. The virus enters the skin by damaged skin (e.g. from abrasions or continual wetting). Issues commonly occur with lambs grazing around scrub or in seasons where we have bad thistle growth. Scabby mouth spreads from lamb to lamb via direct contact or contaminated pasture. Infection from season to season is maintained on farm by carrier sheep. Vaccination is the only practical way to increase protection for your lambs. It should be an essential part of docking this, and every spring. Scabine® is New Zealand’s most widely recognised and used Scabby Mouth vaccine, developed and made here. It needs careful temperature control during storage, transport and use, so make sure it stays in the supplied chilly bag when out docking. Make sure every lamb has an ‘X’ scratched on the bare skin on the lamb’s inside thigh or foreleg. The scratch should be deep enough to let the vaccine ‘take’, but not so deep that bleeding will wash it away. It is important to check that the vaccine has ‘taken’ in vaccinated lambs. This is easily done by checking 10 – 20 lambs 7 – 10 days after vaccination. The ‘X’ should have developed into a raised, cross surrounded by a zone of inflammation. Vaccination is only required if disease has previously been confirmed on your farm. If you are not sure, or would like to discuss a vaccination programme for this spring, please contact us.

Salmonella – prevention is the key

One of the big factors that determine if your farm gets salmonella is the grass quality and quantity available to ewes. Years in which salmonella occurs tend to be years when there is good feed around, this is why we had many cases last year but few in the preceding years when we had a dry autumn. salmonella outbreaks can occur anytime from Dec – July. Most outbreaks in our area tend to occur in the Feb – May period when we are trying to flush our ewes prior to mating.

As many of you are aware salmonella outbreaks have terrible consequences and losses can go on and on if action is not taken promptly. Outbreaks can either occur as small trickling losses over a couple of weeks or sudden outbreaks. Once it is on your farm it tends to eventually spread to most mobs of ewes despite the best efforts to keep it confined to one area of the farm. While opening the gates and spreading the ewes out appears to be a cheaper option than vaccination it seldom works to control the disease and in the meantime wreaks havoc with your feed budget.

Vaccination is the only effective method currently available for protection and to control outbreaks once they occur. Many farmers who initially tried to stop the effects of last years outbreaks by opening the gates, ended up vaccinating in order to control losses.

Have you considered implementing a preventative vaccination programme?

A good preventative programme is to vaccinate all 2 tooths annually to maintain a level of immunity in the flock. It is recommended that they are vaccinated in December and January, 2 shots 4-6 weeks apart.