[SteveHants]

I was having my flock health check with my vet on Friday, so that I can go and get farm assured and he was asking me about whether I vaccinated my breeding ewes...


I said that I did, and he asked me when Id lambed and I told him the end of April, upon learning of this he said I'd better hurry and get the lambs in for their booster.


Booster? But I hadn't given them their first jab....


The vet explained to me that if Id vaccinated the ewes, then they would have gotten their first antibodies from their mothers and only one further jab was nescessary. Playing devil's advocate slightly at this point, I asked if this were the case, then why would he manufacturers tell you you needed to give the lambs two jabs the first time around?


"Well, they'd like to sell you more of the product"


Was the reply.


THANKYOU!


Id been thinking this for ages, but 'the voices' told me it was better to be safe than sorry and do what the manufacturers reccomend you did (why do I listen to other people, eh?).


Hopefully, I've just halved everybodys innoculation bill with this piece of information. 

[jaykay]

The lambs get passive immunity from their mothers, ie their mothers' antibodies, (proteins)  not the active memory cells which are able to launch a wave of their own antibodies if necessary.

The mother's antibodies have a limited life and the lamb can't make more of their own. A vaccination is needed to stimulate the production of their own cells, capable of making antibodies.

It may well be that one 'challenge' is sufficient to do this, in a large proportion of the population. The booster is to catch those who haven't produced a good enough immune response first time round.

Whilst I have no wish to line the pockets of the agricultural merchants, you tell me how I find out which lambs need a booster and which don't?

[SallyintNorth]

It used to be the case that Heptavac said lambs need two, while Covexin said lambs reared by fully vaccinated mothers need only a booster if vaccinated by, I think it was, 4 months old.

Now both seem to say lambs need two - presumeably for the reason jaykay gives.

[SteveHants]

This is interesting - the vet is a fairly young feller (40s, Id guess), Id hope he was basing his advice on the  most up to date peer-reviewed evidence.


It also kind of holds with what a friends wife who is an immunologist/virologist postdoc researcher told me once that boosters in general are considered to have a negligable effect (I'm assuming that she meant that in general the first vaccination nowadays was so effective that less than 0.05% of those innoculated required a booster), but she wasn't talking sheep.


I assume passive immunity would cause the lamb to make antibodies of its own if it was challenged by the bacteria whilst it was still in the period when it was assumed to be getting its immunity from its mother.


I'll ask the vet again - he seems particularly sensible and leads our surgeries ag practice (which is its main focus, somewhat unusually) and get back to you.

[kaz]

We have always given our lambs two injections as recommended by our vet who also recommended that the first one was given at the earliest date that they could have it to be sure of total protection. This vet is in his 50's.
Perhaps it's an age thing., but I'm sticking to what has always worked for me.

[jaykay]

assume passive immunity would cause the lamb to make antibodies of its own if it was challenged by the bacteria whilst it was still in the period when it was assumed to be getting its immunity from its mother.

No, passive immunity just means the mother has given it some antibodies, so it that bacteria came along, the antibodies would stick to it. The lamb can't make it's own antibodies. It needs active immunity, from its body's response to either the actual bacteria or a vaccine, before it can make its own.

I think what the vet is probably saying is that the first vaccine does sufficient job for a booster a few weeks later to be unnecessary in most lambs.

The advice used to be, for example, to vaccinate dogs every year. Then my vet said, actually they don't need a booster every year, the immunity doesn't subside that fast, it probably wiould do every 2 or 3 years. So the thinking seems to be heading that way.

[suziequeue]

Passive immunity is different from active immunity.


Yes - most lambs will probably get enough from one jab but the idea of two jabs is to get full coverage and herd immunity (where all the herd are covered because the majority are vaccinated and therefore spread of the infection is hampered). The problem is, because thou don;t know which ones are going to respond first time (you only know it's not 100%) - you have to cover all with boosters.


It's exactly the same in humans. Babies get three doses of Diphtheria, tetanus, pertussis, polio and Haemophilus influenzae type b, two doses of meningitis C, two doses of pneumococcus, two doses of measles, mumps and rubella etc etc. all in order to boost the system and make sure of full coverage.


"This is interesting - the vet is a fairly young feller (40s, Id guess), Id hope he was basing his advice on the  most up to date peer-reviewed evidence" (sorry - can't do quotes on Mac)

You are having a GIRAFFE!!!!! Touching faith

[kanisha]

It is also worth noting that maternal immunity interferes with active immune response and it is for this reason that vets will reccommend a series of vaccinations . as the maternal immunity wanes the youngster becomes vunerable to infection  hence provide protection by vaccination but if maternal immunity is high the vaccine will not be as effective leaving the lamb vunerable to infection later in life. One practice many years ago participated in a vaccine trial for parvo in an area with high parvo infection rates at the time ( corby) The pups as well as being vaccinatated were blood sampled to test for antibody response  It was interesting to see how variable the responses were to the vaccine and the worst a rotty pup of 20 weeks serially vaccinated and consistantly coming back as insuffucient antibodies died from parvo aged 20 weeks having never been  mixed socially with other dogs.
 I can tell you having watched dogs fall off the end of a needle as you are trying desperately to get fluids into them there is nothing that can persuade me that the cost of a vaccine is false economy, risk assessment is all.

[robert waddell]

the most of the flocks on here are small ones so if you handle the vaccine correctly it will do the two courses      what they are wanting is for you to chuck it after the first dose and buy a second bottle
 
nothing unusual in the vets main drive or income coming from a Solly based agg practise  personally I WOULD shy away from one dedicated to pets
 
jaykay the advice on dogs was given to me twenty years ago by our vet

[jaykay]

Passive immunity is different from active immunity.


Yes - most lambs will probably get enough from one jab but the idea of two jabs is to get full coverage and herd immunity (where all the herd are covered because the majority are vaccinated and therefore spread of the infection is hampered). The problem is, because thou don;t know which ones are going to respond first time (you only know it's not 100%) - you have to cover all with boosters.

Exactly 

It is also worth noting that maternal immunity interferes with active immune response and it is for this reason that vets will reccommend a series of vaccinations . as the maternal immunity wanes the youngster becomes vunerable to infection  hence provide protection by vaccination but if maternal immunity is high the vaccine will not be as effective leaving the lamb vunerable to infection later in life

which is another reason for the later booster, to pick up any lambs that had such high passive maternal immunity that the first vaccination didn't cause an active response (what happens is that the maternal antibodies attach to the vaccine, so the lamb's immune cells don't get chance to respond to it).

All in all, I think I'll stick with doing a second booster.

[suziequeue]

Same here.


I would never forgive myself if one of my flock suffered as a result of a vaccine preventable disease.

[SteveHants]

"This is interesting - the vet is a fairly young feller (40s, Id guess), Id hope he was basing his advice on the  most up to date peer-reviewed evidence" (sorry - can't do quotes on Mac)

You are having a GIRAFFE!!!!! Touching faith

Well, it was slightly tongue-in-cheek, but youd think that these guys go to conferences, look at papers etc - I mean its mildly risky to tell all your commercial farmers not to bother with a booster if they are going to have lambs die all over the place, isn't it?

[jaykay]

Commercial farmers make a cost/risk analysis. Cost of lost lambs versus cost of gathering them a second time....My neighbour doesn't vaccinate at all and accepts the losses. Personally I can't do that.

[SallyintNorth]

Commercial farmers make a cost/risk analysis. Cost of lost lambs versus cost of gathering them a second time....My neighbour doesn't vaccinate at all and accepts the losses. Personally I can't do that.

Always remembering that to a farmer, there can be losses (of life) arising from gathering - as the old saying goes, "A sheep's worst enemy is another sheep" - when you have a lot of stock, cramming them all together on the road and in the pens can cause problems you wouldn't have had had you not gathered.  So it is a balancing act.

Smallholders typically have far fewer numbers and are (generally) less highly stocked than farmers, so the losses arising from gathering, penning and treating should be minimal / negligent, hence a treatment would normally be the better choice.

[suziequeue]

Good point SitN