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P.O. BOX 231, BALCLUTHA
CUD
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“Cows Under Discussion” or “Something to Chew On”
BALCLUTHA CLINIC
Wilson Road - Phone (03) 418-1280
Fax (03) 418-1750
Merchandise Direct (03) 418-1281
[email protected]
MILTON CLINIC
Union Street - Phone (03) 417-8032
Fax (03) 417 8031
September 2012
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Clinic News: What a fantastic spring so far! It’s times like this that make me glad I took the right turn to
be a “large animal” vet rather than being stuck inside playing around with poodles. No offence intended to
our dedicated team of “companion animal” vets & nurses! Phil Skinner has joined us to help out as a
locum over the spring. Phil hails from Tuapeka (I think he might have been found on Skinner Road and
named after it) and has plenty of experience as a large animal vet both in New Zealand and overseas. Ali
Maw is also back for one day a week, while not lecturing at Telford. We will also have a few new faces
helping out with calf debudding & metrichecking, including Reuben Brown, Rebecca Herzig and Chloe
Dean.
The Twisted Uterus is literally one that has rotated over, inside the pregnant cow, sometimes a full 360
degrees. This is a problem because it means that the cervix and vagina are also twisted which narrows the birth
canal meaning that the calf cannot come out. It’s a bit like taking a jacket sleeve, twisting the cuff end around,
and then trying to put your arm through it.
A cow with a twisted uterus may be close to calving, or
some way off. She might look generally uncomfortable
and be getting up and down a lot, or she may be past that
stage and just be a down cow. She may look like she’s
calving and may actually have gone into labour but be
unable to push the calf out.
If you have a cow that is behaving like this, it is something
you may be able to diagnose yourself. You need to put a
clean rectal glove on your arm, put some clean lube on it,
clean the vulva, and put your hand and forearm into the
birth canal. The partial twists may be difficult to feel, but
when they’re twisted a lot you can feel the tissues of the birth canal all rotating one way, narrowing the space.
You may or may not be able to feel part of the calf. It’s important to be hygienic when doing this otherwise
you can start an infection. We have various methods for untwisting the uterus and then usually either deliver
the calf out the back end, or do a Caesarean. If it goes undetected though, the cow will deteriorate and
eventually die.
Calf Scours can be difficult to deal with at the best of times; when combined with all of the pressures of spring
and calving they can cause a lot of unwanted additional stress. Recently we have seen several outbreaks of
scours on dairy and bobby calf rearing units which have involved Salmonella. Outbreaks of Salmonella in calf
rearing units can be devastating and once in your calf sheds, unless you have strict hygiene and solid barriers
between calf pens, a high number of calves will become infected. 25-50% of affected calves may die, which
has the potential to really reduce your replacement numbers.
The affected animals have elevated temperatures, are depressed, dehydrated and present with a nasty, often
bloody, scour. Scour samples can be useful to confirm Salmonella (and other bugs). It may also be helpful to
allow us to “sacrifice” a very sick calf so we can take fresh samples of internal organs for the lab to look at
under the microscope. This should allow a definitive diagnosis.
Rehydration with regular 2lt feeds of high quality electrolyte is vital, as well as keeping affected calves warm,
dry and draught-free. Calf covers should be used. If Salmonella is suspected we may prescribe antibiotics,
both to treat affected calves and possibly to prevent infection in the others. Penicillin (Bovipen) is not a good
choice for scouring calves – be sure to speak to us about appropriate treatments. Metacam (an antiinflammatory) has been shown to speed up recovery in scouring calves. Salmonella is a zoonotic disease,
which means that humans can catch the disease. Care should therefore be taken with your own hygiene, and
young children should be kept well clear of the calf pens in a scours outbreak. If you are experiencing a similar
situation on your farm then we recommend you give us a call and we can come and check out your sheds and
management, as well as the calves, to help get to the bottom of the cause of the disease and the best way to
combat it.
Medicines for Calves A lot of information is presented at PAR (now called RVM = Restricted Veterinary
Medicines) Consults when we discuss appropriate treatment for a range of conditions affecting both adult cattle
and calves. Some farms now use these sessions to involve multiple staff members to promote consistent and
accurate administration of medicines. Other farms rely on information trickling through the ranks, much like
“Chinese Whispers”. Calf rearers often seem to be kept out of the loop altogether! Management and treatment
of common conditions like “navel ill” and calf scours needs to be discussed and documented. Antiinflammatories (e.g. Metacam) can be beneficial in some disease situations, as well as for painful procedures
such as debudding. Speak to a vet about coming out to have a chat to the calf rearers. We can also provide
laminated sheets suitable for the calf shed with different treatment options for the various conditions.
Abamectin Toxicity in Young Calves Again we have been called to farms this season where drenching of
young stock has resulted in dead calves. Drenching young calves should always be undertaken with caution.
Toxicity is a real issue, especially pre-weaning. The need to drench at all pre-weaning must be questioned.
Worm establishment and their gastrointestinal effects are much less in calves predominantly on a milk diet.
Providing clean pasture is the most important aspect to minimising parasites pre-weaning.
Drench should never ever be mixed with milk, or given at the calfeteria. Suckling stimulates the oesophageal
groove reflex which bypasses the rumen sending liquid straight into the abomasum (4th stomach), where it is
absorbed much more quickly creating a higher risk for toxicity.
Abamectin is present in several drenches (Matrix, Alliance, Outlaw etc) but has a small margin of safety –
especially in young stock. Deaths and nervous signs have been reported when given as little as 1.5x the
recommended dose. This applies to all forms of the drench; oral, pour-on and injectable. Drench young stock
with a combination drench that excludes abamectin (Arrest, Oxfen, Scanda etc.) then switch back to a triple as
soon as they are of age (see below). Incidentally, these alternatives contain levamisole which also has a low
margin of error in young stock, so always ensure when drenching young stock your weights for dosing are
correct.
Rules for drenching young stock:
• Never drench calves under 4mths or 120kg with drenches containing abamectin. Calves under this probably
don’t need drenching anyway.
• Never mix drench into milk or put it through a calfeteria.
• Don’t orally dose next to the calfeteria as the oesophageal groove will be stimulated. Take the calves to the
yards to drench.
• Never swap drench containers. If decanting to smaller containers always write on the container, or transfer
back to the original container when finished.
• Double check correct product is being used. Pour-ons given orally are lethal.
• Check drench gun is measuring accurately. This means using a measuring cylinder and squirting a dose in to
make sure the gun is giving the right amount.
• Weigh animals and split into groups if necessary. Whilst it is usually recommended to drench to the heaviest
in the mob this must not apply to young stock.
• Don’t drench the dog with abamectin. It is ineffective at killing worms – but effective at killing dogs.
Colostrum A number of farmers still aren’t separately collecting first colostrum from cows that have freshly
calved and giving this to the new born calves as their first feed. Pooled colostrum from the colostrum tank is
too dilute for new born calves. The ONLY way a calf has an effective immune system in the calf shed is the
quality of first colostrum it receives on day one of life. It is that simple, and that important.
Teat Lacerations and Other Wounds Teat lacerations often occur when cows stand on their teats in the
paddock. This can lead to difficulties with milking, mastitis and even the inability to get milk out of that
quarter. Due to the blood supply to the teat they can take a long time to heal. For the best results they need to
be seen as soon as possible, within six hours of the injury is ideal. This is because the longer the wound is left
the more tissue death there is around the wound as well as increasing the chance of introducing infection. As
the wound ages it shrinks and starts to try and heal by itself which can make it difficult to stitch back together.
So if you have a teat injury that looks like it needs vet attention give us a ring as soon as you see it. If we suture
the wound within 6-8 hours of it occurring we are able to do a much better job of fixing it compared to wounds
that are left for a day or two.
Wounds to other parts of the cow vary in their severity and whether or not they require veterinary attention.
Some superficial wounds may just require a good clean with disinfected water and some purple spray, while
others will require veterinary attention. Again, if these wounds are left for more than 6-8 hours they are more
difficult to close with stitches, and the likelihood of them remaining closed does reduce, so give us a ring as
soon as you spot them and we will be able to advise you on the best course of action.
BOS Splints and Down Cows Sid’s recent winter talk on “Down Cows
and Downer Cows” had over 100 farmers along to listen. If you have had a
cow stay “down” for more than 12 hours it becomes a “downer” cow.
Aftercare is an important part of getting a downer cow up, and if the cause is
nerve paralysis resulting in knuckling of the fetlock joint of a back leg a
BOS splint can be helpful. If you have never used one get us to show you
how to put one on first. NEVER use rope or strops, or anything other than
wide Elastoplast tape over the whole length of the splint to attach it to the
leg. Anything other than that will cut off the blood supply to the leg and
you may as well shoot the cow now. Hip lifters alone should never be used
for more than 15mins – we have seen examples of bruising round the hips
resulting in areas of dead tissue, abscesses and further leg damage that
prevent a cow getting better. We are looking at purchasing a “cow flotation bath” to help these cows.
Bulls for Mating It may seem a bit early to be thinking about bulls that are going to be put out after several
weeks of AI. However, in order to ensure that they are free of disease and up to date with vaccinations it’s
worth some early consideration. As a minimum bulls should be tested for Bovine Viral Diarrhoea (BVD)
antigen, to make sure that they are not persistently infected with this virus, and vaccinated so that they are not
going to become infected with it. If they have never been vaccinated they need two injections four weeks apart,
preferably at the farm of origin. The last injection must be at least three weeks before they are put out with the
cows, so they need the first injection two months before you’re planning to put them out. Previously
vaccinated bulls just need a single booster at least three weeks prior to mating.
While we’re looking forward to the bulls don’t forget to think about their numbers. Ideally, plan for a bull
rotation policy that allows half of the bulls to be resting while half are working. This will allow you to replace
bulls that become inactive or unhealthy e.g. lameness. For example, based on 1 bull/30 cows for mating, a 500
cow milking herd with 40-50% pregnancy rate at the start of bull mating would require 20 bulls to be available.
Give us a call if you would like some advice on bull numbers for this season.
Antibiotics for Mastitis It is generally considered that using injectable as well as intramammary antibiotics
will give slightly better cure rates than either one alone. If the cow is sick (dull, depressed) due to mastitis, then
you must do more than simply administer an intramammary tube. Only two injectable antibiotics achieve
sufficient concentration in the udder to be used as sole treatments for mastitis; these are penethamate (Mamyzin
or Penethaject) and tylosin (Tylo, Tylan or Tyloguard). Other injectable antibiotics can be used in conjunction
with a suitable intramammary – i.e. the intramammary will treat the source of the infection (the udder) while
the injectable will mop up any bacteria that have spread round the body through the bloodstream.
Theoretically, some antibiotics should not be used at the same time as others since they can counteract each
other. However, when using an intramammary and an injectable there is unlikely to be any significant
interaction. Where there are no culture results available we would prefer you to stick to the most appropriate
treatment(s) for the likely bacteria involved. Usually these will be Strep uberis for recently calved spring
(environmental) mastitis and Staph aureus for later season (contagious) mastitis.
Likely Bacteria
Intramammary
Strep uberis (spring)
Clavulox LC
Lactapen G
Lincocin Forte
Orbenin LA
Strep/Staph (mid season)
Staph aureus (later season)
Injectable
+
+
+
+
Bovipen
Bovipen
Tylo
Tylo
If the cow has port wine coloured fluid coming out of her teat(s) (“Black Mastitis”), Mastalone is a better
choice and should be used in combination with Engemycin injection (it’s a good idea to phone a vet if you have
a cow looking like this). Engemycin is not a product that is available on your annual prescription but, as with
any drug that you need for a particular case, it is available after discussing the case with a vet.
Anti-inflammatories (e.g. ketoprofen = Key or Ketofen) should also be used to help with the pain associated
with mastitis, and to aid recovery.
Withholding Periods (WHPs) for Milk & Meat apply to a single product used at the dose, number of
treatments and treatment interval as described on the label e.g. Clavulox LC – 1 tube every 12 hours for 3
treatments. These WHPs may need to be extended if we:
1.
2.
3.
4.
5.
Extend length of treatment (e.g. treat for 5 days instead of 3 days)
Increase amount per treatment (e.g. 30ml for 500kg cow instead of 20ml)
Increase treatment frequency (e.g. twice daily instead of once daily)
Reduce milking frequency (e.g. once a day instead of twice a day)
Administer more than one product at the same time (e.g. intramammary + injectable)
In general, you should add at least 24 hours to the longer Milk WHP when using combinations. This advice is
strictly “off label” and cannot be a guarantee against Inhibitory Substances in the milk. The official line for
unregistered combinations is Milk – 35 days; Meat – 91 days!!! Please speak to a vet if you would like further
clarification.
BVD Don’t forget to keep up your monitoring for this nasty little grumbler.
•
•
•
•
Test bulk milk sample for antibody levels once 90% of your cows are in the vat.
Blood test 15 yearling heifers to assess BVD status. A high result indicates likely presence of one or
more Persistently Infected animals; a low result is good news but means that these animals are at risk if
they came into contact with a P.I.
Now is the time to vaccinate your heifers (two shots four weeks apart).
Blood test & vaccinate bulls.
This Month’s Retail News –
• Eprinex Deal – Get 5ltr FREE! – Get 5ltr FREE when you purchase 3 x 5ltr Eprinex Pour-on. The
cheapest way to buy this proven performer. Nil Milk, Meat and Bobby withholding.
• Dectomax Injection & Pour-on – New Stoney Creek Clothing Packs with selected purchases. While
stocks last.
• Milligans Calf Milk Powder – $88.00 per bag or $4400 per tonne GST incl. Going fast.
• Merial Ancare Drenches – NEW Icebreaker deals. Buy selected Merial Ancare drenches and Pour-ons
and get a range of Icebreaker clothing from T-shirts to jackets. For a limited time.
• Shoof Specials – Remember that all Shoof products get the Clutha Vets Members discount on the RRP.
Rear of van, Dublin
Fetotomy gone horribly wrong