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July
Newsletter |
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Genotypes Scrapie is still in the
Veterinary Press as even at this stage more and more is found out about the
disease. Considering it was first reported in British sheep in1732 it is
about time we got to the bottom of it. Now that more and more animals have
been tested for their resistance to Scrapie it has been found that in a small
number of individuals have a complex genotype where more than two sets of
amino acids are present on the positions on the genes that can predispose to
Scrapie. So far of the forty seven thousand samples tested on the Official
Scheme some 0.08% have shown this abnormality and any that involve the least
desirable amino acids VRQ are not used for breeding. The genetic testing for
Scrapie has been done for ten years or more now and it is not clear why these
extra amino acids have not been noticed before. Clearly more research will be
done on the few animals that show this anomaly, but it is unlikely to have a
significant impact on the National Scrapie Plan, as the numbers of animals
affected are very small. Free Blood Testing We have been testing more flocks
recently in the official scheme. Most of the results have been favourable
with most animals tested in the two higher groups. It is surprising how much
progress you can make in just two years if you are able to use an ARR/ARR ram
on all of the ewes. Remember the National Scrapie Plan is not just for
Registered Pedigree Flocks. If you rear any Rams to sell, or intend to do so
in the future, you should be thinking about the genetic make up of your flock
so that you can concentrate on the animals that have a natural resistance to
Scrapie. The testing is free and so far we have not had any difficulties
administering the electronic bolus that identify the animals. Admittedly you
do have to agree to have castrated or culled any rams that are susceptible to
Scrapie, but there are likely to be few of these and it is not in your
long-term interest to retain them anyway. There is still time to have your
rams tested before the coming breeding season. If you would like to find out
more about the National Scrapie Plan take a look at their WebSite.We have more information at the surgery
or you can phone the advice line in Worcester on 0845 601 4858. Tuberculosis in Free Ranging Pigs Did you know that pigs can get
Tuberculosis as well as cattle? The only time we have ever had to test pigs
for this disease have been animals destined for export to America. They are
tested in a similar way to cattle. I understand that there is some concern
about Bovine Tuberculosis becoming established in the wild boar population of
Europe. For instance in one report of the fifty three free living wild boar
shot during one shooting season in Spain all of them showed lesions that were
caused by Bovine Tuberculosis. More than half of them had lesions in the
chest or abdomen and were likely to spread the disease. It is not clear what
the situation is in the cattle population in this part of Spain. The paper
was written more from the public health concerns that animals killed in this
way are not likely to come under the watchful eyes of a meat inspector. In
some areas of Britain there are of course increasing numbers of wild boar who
roam at will unaware of the complexities of movement licences and holding
numbers. Efforts from DEFRA are having little impact on the continuing spread
of Tuberculosis in the Cattle population and the chances are we may soon have
to deal with another host for the disease unless there is a radical change of
policy. The Energy Gap I get a regular newsletter from
the Dairy Health and Productivity Service at Edinburgh University because
sometimes I send them samples. They work with herds from all over the country
and admittedly they are most likely to get blood samples and feeding data
from herds that have either a production or a fertility problem. Although it
is difficult to generalise they have again sent out warnings that there is
not enough energy in the grass this summer to fulfil the needs of recently
calved cows. Last year 49% of the samples they tested in July had energy
problems sufficient to affect their fertility. When cows cannot eat enough to
satisfy their energy needs in early lactation they will loose weight and
their milk production will suffer. More significantly it is the way that it has
an impact on their fertility that is the most damaging. Cows will either not
show signs of being on heat or have silent heats. Some animals that have been
served will fail to retain the embryo, this is there way of self-preservation
responding to the metabolic changes that are going on in their bodies. Last
year in the herds that were surveyed cows were taking between forty and one
hundred days longer to get back in calf. On average this was at a cost of
£100 for each cow. Buffer Feeding The Dairy Health and
Productivity Service is interested in analysing blood samples and admittedly
a full metabolic profile on seventeen cows can be expensive if you have not
got a major problem. There is no reason why you could not target the samples
just to look at the energy levels of four to six cows that have calved in the
past ten to twenty days that might be all that we need to see if the feeding
is adequate. For summer calving herds for most cows to reach their full
potential and not pay a penalty with their production or fertility you will
need to use some system of buffer feeding throughout the summer months. The
best time to do this is before afternoon milking. It has been shown that
grass accumulates digestible sugars during the day and water is lost from the
leaves on summer days so it is at it's best in the evenings. If you buffer
feed in the afternoon you also get the benefit of the best grass available as
well. Maize silage has been shown to be the best buffer feed, but some farms
get consistently good results with first cut grass silage or whole crop
mixtures. If you can it is better to group the freshly calved cows together
and treat them as a separate group so that some of their concentrate ration
can be fed at the same time. There is more about this on the Dairy
Health and Productivity Service Website. Reminder Early lambing flocks need to
start thinking about their vaccination requirements for the coming year.
Enzovax and Toxovax are both live vaccines that need to be given at least one
month before the ewes go to the ram. Two of the flocks that vaccinated for
the first time last year got very good results. It is important to remember
to inject the replacement ewes to keep the infection out of your flock and
maintain the immunity of the rest of the flock. Extra Information. These Newsletters are also
published on our Web Site where there are links for you to find out more
information about some of the topics that are mentioned. This month there is
more about Scrapie and also about buffer feeding. I realise that not
everybody likes to use the Internet or knows someone to look up things for
them. There is no reason why you cannot use our computers to find specific
things that are of interest to you. Afternoons are the best time, but we can
help at any time when we are not too busy.
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