Animal Health The Key To Success With Fine Wool Lambs

The essence of successful fine wool lamb finishing is keeping the worms out, the feet sound and the guts right.

The gut microflora on fine wool lambs is more delicate than others.  Smaller lambs (less than 23kg) are at much higher risk of scouring issues.  There isn't the scope to debate the virtues of enzyme drenches or explain this complex here, suffice to say avoiding the scrubbers will reduce wastage.

Fine Wool Lamb Parasite Management

The way merino lambs camp and graze together with an immature immune system, means they can be more prone to internal parasitism.  A solid preventative drenching program from the start is vital.  Woe betide skipping or stretching out a drench in the autumn....

Many find a SeCo capsule or LA injection takes care of the autumn worm issues.  An exit drench of Zolvix or Startect is a prudent measure to ensure any resistant worms are not carted through the winter.

Clostridial vaccines (2 shots) are a no brainer.  These valuable animals (as pointed out above) are the highest risk because they're on your property longer, have several feed changes and are expected to grow fast in the spring after shearing.

Fine Wool Lamb Feet Soundness

Having a plan and set up for managing feet and starting with inspecting feet when they first arrive is advised.  You can't take chances with footrot.  If an infection is left to spread in mob it can really smash your margins and making running these animals a misery.  With planning and good management fine wool hoggets can do very well on improved pastures.  Because of the dry summer this year, there have been less footrot infected lambs at weaning, but the back end of autumn with dewy conditions footrot infection can take off in hoggets if not managed.

For more specific details about animal health and feet management for successful fine wool finishing contact the Veterinary Centre.

Where are the Ewes at?

March is crunch time for setting up sheep breeding units for next season's production.  We would all like to be lifting ewes up to optimum mating weight about now.

Talking to Simon Englebrecht, Dunback East Otago, last year was a very dry start to autumn, but he still managed to achieve very good ovulation rates during the dry conditions.  There was a lack of green quality grass then and it looks like we're heading into a similar scenario this year.  Simon fed sheep nuts leading up to tupping.  The supplement program not only allowed ewes to maintain and even put on weight over autumn, it enables blocks to be spelled.  "When it did rain we carried on feeding the nuts to allow pasture to recover."

If you don't have quality feed for ewes pre-tup or in the first cycle of mating a high energy supplement can be justified if it results in more lambs at weaning and ewes in better shape for winter.  To make the supplement investment even more targeted, feed out to only BCS 2 (light ewes) or 2 tooths.

When you are doing your pre-tup animal health it is of great value to weigh and measure the condition of the mob at 2 points.  Ovulation rate is significantly influenced by body weight and condition.  In the table below are some generic targets for capital stock.

For light ewes you cannot expect to put on more than 150g/day liveweight (50-100g/day is realistic).  Aim to have less than 10% in this category by mating.  Farmers who have realised it is the light ewe management where the biggest gains in production can be made will have dealt with them at weaning (culled or start feeding).

What do the top performing farmers do?  Well they are all different, but the consistent thing is they PLAN, EXECUTE AND MONITOR better than most.

The biggest drivers of a breeding unit is fecundity and lamb growth rates.  Hitting autumn targets, such as those listed above, is where it starts.

At the Veterinary Centre we thrive on seeing clients achieving.  We're all about planning animal performance and hitting targets.  Talk to us if you want to continue to be or become one of these "top operators'.

Beef Cattle Pregnancy Testing

Have you age pregnancy tested your beef herd?  There are many advantages to this over the standard wet/dry information.  This is where we estimate a calving date for each cow +/- 7 days.

The benefits of dating beef cattle pregnancies mean you can:

• Monitor cows closer at calving.  Especially with heifers and studs recording calves on the drop.
• Calculate a conception rate to each cycle and monitor the efficiency of cow cycling and bull activity.
• Winter later cows differently
• Sell 3rd cycle/late calving cows or can be the first to go if required.
• Identify bull sub-fertility.  Detected if there are different conception rates after bulls have been swapped.  Suspect bulls can be serviced, tested or culled.

If you have more dry cows than normal but have not aged pregnancy tested, you have missed a big opportunity to get to the cause of the problem.  Foetal aging is a key to diagnosing beef repro performance and vital to implementing change that ensures better results.

Fossil Creek Angus stud, founded by Neil & Rose Sanderson, aged pregnancy tested their herd with the Veterinary Centre for the first time last year.

"The data just saved so many issues for us at calving.  We were able to do regular drafts of cows due to calve and made calf recording so much easier....  There were real benefits with grazing management and we'll definitely do it again next year".

Recording of the aged data can be as simple as a spray dot on the back, some put a sheep tag in the ear of 3rd cycle cows, or we can record tag/EID with the pregnancy status data.  In order to get accurate data, foetal aging is best done 6-8 weeks post bull removal.

Feet Soundness in the Flock

It has been a while since I have mentioned feet, and it is amazing that a bit of moisture in December has seen flare-ups of scald within a matter of days.  It still looks dry but there have been opportunities for the dormant footrot bug to jump from its hiding place of chronically infected hooves to fresh scaldy ones.  Pre-weaning troughing is probably on the cards for some operations in order to halt further spread and enable a break in the cycle of infection prior to tipping ewes soon after weaning.

With respect to footrot control Never waste a good drought.  When it is dry and there is no active spread of footrot, this is the time to inspect feet and remove what pool of infection is there before the next wee autumn flare-up.

I do have several success stories of clients putting in the time AT THE RIGHT TIME, using a plan and Micotil system and have got rid of footrot recently.

Apply sustainable drench practices in dry conditions

There are 2 key aspects to long term sustainable and effective worm control in sheep:

• Using effective combination drench.
• Refugia (proportion left undrenched) and stock movements either side of drenching. Key questions every sheep farmer needs to answer if serious about parasite control:
• What drenches are effective on MY property?
• How do I maintain drench effectiveness into the future? December to January is the best opportunity to answer these main questions by doing a reduction test and/or doing an animal health plan for the year.

Australia leads us in many things but their drench resistance is something we do not want to emulate. There are a number of reasons why this is the case, but one of the main factors in Australia is the prolonged dry periods, which means a much higher proportion of the worm population is in the gut of sheep, not on the ground (as in wet, green grass situations). So when a worm population is exposed to a drench, resistant worms can rapidly become the more dominant gene pool. With a drier east coast predicted this summer, it is an opportunity to really think about work biology and some of the sustainable parasite management practices that the industry are advocating.

WE will be contacting farmers who have shown interest in completing a FECRT or making time to map out animal health events for the year.

New Product - Long Acting Drench Capsule For Cattle

A new beef drench capsule, called Alpheus, has been launched onto the market.  The product was designed to optimise growth rates of young dairy stock through their first autumn.  Trials on beef cattle properties have indicated there is definitely potential for enhanced productivity for beef farmers.

The capsule looks similar and uses the same technology that is in the long acting sheep versions i.e. the pre lamb Bionic and Extender SeCo capsules.  The differences are the length of action is longer @ 125 days, the active is abamectin alone (although there are one off priming doses of levamisole and oxfendazole given with each capsule) and there are no selenium or cobalt minerals included.  The capsule is made for cattle in the weight range of 150 to 300kg.

It is administered by applicator with the 2 priming tablets.  The with-holding period is 180 days for meat and milk.  Specific trials have indicated additional weight gains of up to an additional 10% of initial liveweight compared to a control of monthly oral drenching with a triple combination drench.

The main benefits are the potential to enhance growth rates during the autumn growth period and the convenience of 1 treatment through this high challenge period.  The risk to manage is selection pressure for resistant worms typical of long acting treatments, especially those that contain a single active.

Beef Cow Feeding Post Calving

The most important time to feed a beef cow is 2 to 4 months after calving.  This determines how fast her calf grows and how soon she gets back in calf.  Cows need to be gaining weight when they are with the bull to optimise cycling.  In a trial performed where the only difference between groups was high (20kgDM/day) versus low (8kgDM/day) the empty rates were 0% and 22% respectively.  In reality we want to be feeding somewhere around 12kgDM/day from calving to mating.  Any reduction in this and the cow will sacrifice her body weight first to maintain milk production.  With only 85 days for a cow to get back in calf to maintain a 365 day calving interval cows need to be cycling when the bull goes in.  Make sure selenium levels are adequate.  Yearlings and 2 year olds can benefit from a drench.

Feeding Ewes From Lambing To Weaning

Looking forward in the production cycle the best time to achieve 400g/day + growth rates in lambs is in the first month of life. This can be achieved through optimising lactating-ewe feeding.

Around North Otago I see some orgranised farmers poking freshly lambed ewes through onto green feed (Italian usually) which must be a pretty good way of achieving these top growth rates. If you're not one of these operations with green feed up your sleeve, matching the peak milking ability of ewes (2-3 weeks after lambing) with spring grass growth is key to getting good early lamb growth rates.

Managing Low Pasture Growth

August - September 2015 has had very low soil temperatures, so I think most sheep breeding operations are going to have less feed growing than expected. Before we commit to opening all the gates and seeing what happens at weaning, what levers can we pull in this slow-cold spring scenario?

• Apply nitrogen, especially to best paddocks, even consider applying gibberellic acid in addition. This works best in the colder shoulders of the grass growing cycle.
• Look at early weaning of lambs onto legume dominant feed (lucerne, new clover).
• Parasite control in ewes and lambs is more critical. If long-acting drench is not applied pre-lamb, a docking drench to younger and/or lighter ewes. Tape drench lambs pre-weaning.
• Bail out early. Sell terminal/older ewes all counted. This may also free up space to allow a paddock or two to be sprayed out for a summer crop (rape/turnips etc). This will be handy if it turns dry again....

I'm sure most of these issues will be pondered and debated around the tailing pens over the next few weeks. Will be interested to know what you've learned and decided.

Dave Roberston BVSc, BSc

dave@vet111.co.nz

Shearing in the Winter - Why do we do it?

Shearing is THE most stressful event on a sheep in their production cycle and wool is a great natural insulation against the cold so how do we justify the practice?

Lamb Survival - NZ field trials have shown twinning ewes that are shorn mid pregnancy (@ 50-100 days into pregnancy) will have 3% reduction in lamb losses compared with unshorn ewes.  The main driver of this increased lamb vigour is from having heavier lamb birth weights, with more fat reserves for heat production in the first critical hours after birth.

In order to get the positive benefits out of mid pregnancy shearing, there are some key management decisions that revolve around timing, feed and fat.

• Shear ewes between 14 and 7 weeks before due date.  Too close to lambing and heavily pregnant can suffer from metabolic diseases from the extra physical, nutritional and thermal stress that shearing can bring.  A storm after pre-lamb shearing can sap precious fat reserves in the developing lamb and udder, ultimately effecting lamb survival.  That's why they say a storm pre-lamb can have a bigger negative impact than one during lambing.
• Extra feed requirements.  Freshly shorn ewes need 10-30% more feed for at least 2 weeks to maintain themselves (and more the colder it is).  Most farmers now are pretty good at conserving sheltered paddocks of green feed or upping supplements post shearing.
• Body condition.  Ewe body fat is required to get positive lamb birth weight effect.  Shearing skinny ewes is unlikely to yield the lamb vigour effect, and may make their ride through the winter worse.

Nitrate Poisoning on Brassicas

Nitrates are found at high levels in all brassicas and if not managed correctly can end up with fatalities in grazing mobs.

Factors that increase nitrate levels in brassicas are:

• Frosty mornings
• Cold, cloudy days
• Excess or recent use of nitrate fertilizer
• Young, rapid growing phase of the crop (fewer than 90 days)
• Regrazing the crop after the leaves have been eaten (stems have higher level of nitrate)

Signs of nitrate poisoning include difficulty breathing, staggering or muscle tremors, weakness or collapse and brown gums.  In some cases sudden death occurs.

Strategies in preventing nitrate poisoning include:

• Feed hay/silage prior to feeding brassicas
• Feed in the afternoon
• Transition onto the brassica crop - 1 or 2 hours on crop to begin with
• Nitrate testing on crops before use (in-clinic testing or kits to take home are available)
• Long narrow break to allow stock to ingest similar quantities

Twisted Stomachs in Huntaways

GDV (Gastric Dilatation and Volvulus Syndrome)

Unfortunately, this is an extremely common cause of loss of working dogs, especially Huntaways.  Warning signs a dog is developing a twisted stomach are discomfort, panting, bloating, and reluctance to work or even walk around.

Dogs with a twisted stomach require emergency surgery to untwist the stomach and 'fix' it back in the correct location to prevent re-occurrence.  The faster you get a dog with a twisted gut to the vets, the more likely it can be saved!  The chance of survival reduces dramatically as hours pass.  The prognosis for younger dogs that survive a twisted gut is really good for getting back into work.

Reducing the Risk:

• Feed dogs smaller meals, twice daily.  Big meals and engorgements are risk factors.
• Avoid workings dogs too soon after feeding.  Morning feeding may not be practical if dogs are working early.
• Avoid stress during feeding - feed dogs separately.
• Do not use an elevated feed bowl.
• Avoid breeding from dogs with a first degree relative that has a history of the condition.
• For high risk huntaways, surgery to 'fix' the stomach in place can be considered as a preventative measure.  Contact the Veterinary Centre if you wish to discuss this option further.

Salmonella - Dougal McLachlan BVSc

The summer/autumn period has traditionally been the time when sporadic outbreaks of enteric Salmonella occur in sheep flocks. For those already experienced in this you will be aware how devastating it can be including the frustration associated with continual deaths as the diseases smolders on.

The dry period and feed stress may be the catalyst to predispose stock to future Salmonella outbreaks.

Affected sheep develop a watery scour, show lethargy and dehydration. Eventually deaths occur.

Treating Salmonella is frustrating. For prevention Salvexin B vaccine can be used in the face of an outbreak to break the course of the disease once a diagnosis is made. For those already using the vaccine do not forget your annual booster.

Another precautionary note! We did diagnose the dreaded Salmonella bradenburg abortion in the area this year and protection from this disease is only by preventative vaccination. Once the disease takes hold vaccination appears to be of little value. Sheep will require a sensitiser and booster vaccination prior to risk period, that being the third trimester.

FECRT (Faecal Egg Count Reduction Test)

You have now all heard the good reasons and benefits for getting some drench data on your farm. Now is the time to get a test done. I think we are going to get one good shot this year. Lambs at weaning usually have high egg counts and weaning is the most convenient time for you to hook out 100 un-drenched lambs for us to test at this time. In this years FECRT's we are adding Startect, a new "novel active", free of charge.

So if you have not heard from myself, Sarah Beaumont or your territory manager about getting started with a pre-count, please get in contact.

Dave Robertson BVSc BSc

Abortion Vaccines - Dave Robertson BVSc

The Veterinary Centre diagnosed a number of sheep abortion out breaks this year. The majority of cases tested positive for campylobacter with some toxoplasma. There is very little than can be done when a farm is in the middle of an abortion storm and losses of between 20% and 30% of a lamb crop is not uncommon. In some cases losses can be as high as 70%. Such losses are not just financially crippling but have a significant emotional toll as well.

Both diseases are present on most farms in Otago. A national survey of flocks showed 100% of farms have toxoplasma on farm and around 75% if farms have had exposure to campylobacter.

The risk of disease is highest in hoggets and two tooths, but we see many cases in mixed aged ewes as well, especially when bought-in lines are mixed.

In light of this vaccination is cheap insurance against a disaster.

Toxovax provides one shot for life. Ewes should be vaccinated prior to their first mating, as either hoggets or two tooths.

Abamectin Toxicity in young lambs

For most farmers the first drench of the new lambs will still be a few weeks away. However it is a good time to remind clients of the potential toxicity of abamectin to young stock.

Avoid using abamectin containing drenches (Matrix/Switch/Coopers Alliance) in the following scenarios.

• Pre weaned lambs
• Lambs less than 20kgs in weight.
• Dehydrated, weak or ill thrift young lambs

If drenching in any of these scenarios stick with Arrest or Scanda selenised as your best combination option. However as soon as lambs pass these milestones you can include the worm killing power of abamectin in your lamb drenching plan.

And a note on selenium toxicity.......

In young lambs it is important to stick to prescribed selenium dosage. In selenised or hi mineral products there will be 1 dose of selenium included in each dose of the drench or vaccine. It is not safe to double dose selenium to lambs such as giving a selenised B12 and a selenised oral drench. The risk of selenium poisoning is much greater than with older animals regardless of dose to weight ratio.

Scabby Mouth - Andrew Muir BVSc

As tailing approaches so does the most practical opportunity to vaccinate against scabby mouth. Outbreaks observed in the past 12 months confirm it is still present and extremely challenging and labour intensive to treat.

• Scabby mouth infects animals through breaks in the skin resulting in raised red lesions and scabs. Infections can occur anywhere on the body with the mouth, feet, udders and poll of rams being very common. Lamb infection results in significant effects on weight gains.
• Lambs are most susceptible over the first summer so tailing is the most practical time to vaccinate. Do not use the vaccine on farms that are free of the disease.
• The best place to give the vaccination is the inside of the back leg unless fly treatments are being used,  in which case the inside of the front leg should be used.
• The vaccine is given by scratching the skin to form a cross, but do not scratch so firmly as to draw blood. A blue dye is added to the vaccine so you can see where it has been applied.
• Check the vaccination area of 20 lambs 7-10 days after vaccination to ensure that it has taken. A take is a raised whitish line surrounded by an area of inflammation.
• Keep the vaccine in a fridge until it is used and only take enough for the day. During use keep it in a chilly bag out of direct sunlight.

Long Acting (LA) Ewe Anthelmintic Products

LA ewe products are commonly used pre-lambing, and have many advantages for both EWES and LAMBS,including;

•  Improved ewe condition – through increased feed efficiency and improved appetite.
•  More milk and less bodyweight lost during lactation.
• Less dags and improved lamb weights.
• Significant benefits for twin bearing 2-tooths.

The production benefits of LA ewe products must always be balanced with the risk of drench resistance –their use can increase selection for resistant worms on your property if not used strategically. Using best practice guidelines mitigates resistance pressure and extends the longevity of existing drench actives.

Best Practice Guidelines for SUSTAINABLE LA Product use:

• Use an effective product: The only way to know how effective a drench family is on your property is to perform a Faecal Egg Count Reduction Test (FECRT). This will allow sustainable product use which will also maximize production.
• Utilise Refugia: Utilising refugia involves not treating selected animals on a property to ensure a balance of susceptible larvae are present on the property. Pick up some ”refugia” tags to clearly identify undrenched animals for monitoring. Faecal Egg Counts: Check if capsules or LA injections are still working on your farm. Our veterinary policy is to test all farms we have supplied capsules or LA injection to, at our cost, around 60 days after administration. If eggs are detected use an exit drench or triple active at the end of the long acting treatment.
• Use a triple combination or novel active (Zolvix/Startect) drench on lambs at weaning.
•  Exit Drench with a novel drench or triple active at the end of the long acting treatment.

Products on the market

Combination Products:

• Bionic: A 100 day combination capsule with continued release of abamectin and albendazole, plus selenium and cobalt. Withholding time 126 days.
• Extender SeCo: A drench capsule which releases albendazole (white drench) for 100 days, plus selenium and cobalt. A priming dose of an effective combination drench must be given to the ewes when capsules are inserted. Withholding time is zero.
• Exodus LA, Cydectin LA: These products contain a long acting form of moxidectin. It is active against Ostertagia for 112 days and Trichs for 42 days after a single injection.
• Cydectin Injection (including Eweguard): A moxidectin injection that is active for 35 days against Ostertagia, and at least 7 days against Trich’s. It is best used 2– 4 weeks pre-lamb. Witholding time is 28 days
• Prolavax Ewe selenised is available available this season. This product combines B12, selenium and the standard clostridial 5 in 1. There are currently no stock shortages
  expected with this stock. Eweguard is also available in all versions with no shortages..

Copper

Copper is an essential trace element required for many functions directly related to the productivity of your stock. There are several reasons why animals become deficient in copper over winter and spring. These include;

• Copper absorption and availability are hindered by soil and plant factors (molybden, sulphur & Iron content)
• Animals may undergo gut lining changes caused by parasitism.
• Many crops that are fed in the winter such as kale are low in copper.
• Copper requirements increase during winter and spring due to the demands of pregnancy and lactation.

Testing Animals for Copper

To test copper in your stock blood samples will identify deficiency, however this will not quantify reserve copper levels. To determine reserve levels liver sampling of 6 animals is required. On farm biopsies are a good option. We also can organise samples to be taken from stock slaughtered through the works

Copper Options - The time to build your stock's copper reserve is now!

By supplementing copper now, your stock will be able to draw down on liver reserves during the approaching deficient period. Supplementation of pregnant animals will benefit the foetus via the placenta.

Contact one of our veterinarians to discuss supplement options and how copper deficiency may be affecting your production. 

Philip S. Hyndman BVSc

Novel Active Drench Families and Internal Parasites in Sheep

We have had a very busy drench testing season with some interesting numbers coming out of the properties tested. Efficacy to the three action families varies widely. Those with all three action families still effective are in a strong position for the future. Those with resistance have had to re-think how to manage the production impacts of paratism on the farm. One farmer commented that he could not imagine farming without this information now. It is not all doom and gloom when resistance is detected. It is an opportunity to re-think current practices and apply alternative parasite management strategies.

Novel active drench families- how can we use them in-light of the lessons learnt?

The current role for Zolvix and Startect is as either a quarantine drench to ensure problems are not imported or as an EXIT drench.

Many farmers are now understanding the benefit of giving an EXIT drench in the Autumn to lambs (or ewes that have had single actives in the spring). The concept is that after repeated exposure to a traditional drench type there is the chance that resistant worms may have accumulated in the gut. Cleaning these out (of replacement ewe lambs or winter trade lambs) prior to the winter with a novel active has good logic and will help maintain the effectiveness of the traditional drenches.

This April-May use a novel active drench (Startect or Zolvix) on remaining lambs before the winter.

Dave Robertson BVSc BSc

Quarantine Drenching of Beef Calves

Quarantine drenching of bought in lambs and ewes is now fairly common practice. With the ease of oral drenching the use of either Matrix (a triple drench) or a novel active helps avoid “buying in resistance”. Unfortunately this practice isn’t as wide spread with farmers who are buying in weaned calves for fattening. While triple combination oral drenches are available (and are the gold standard as a quarantine drench), calves are often of a size that makes it impractical to administer.

So what other options are there?

Firstly we have to consider that a quarantine drench must kill close to 100% of the worms in the calf, otherwise it isn’t achieving its purpose of protecting your property. Recent trial work looked at the use of single active ML pour-ons (such as Abamectin/ Ivermectin). The ML’s are mainly used for their efficacy against Ostertagia, the number one production limiting worm in cattle. In relieving news they still kill close to 100% of Osteragia. However their efficacy against Cooperia, a worm that is highly prevalent in calves (adult cattle acquire immunity to Cooperia at 12-18 months) is much poorer. To effectively kill Cooperia we require the addition of the drench Levamisole.

Therefore quarantine drench options must include both an ML drench component AND Levamisole to be effective. There are two options available:

• „ “Eclipse” (Abamectin + Levamisole) – a pour-on drench
• „ “Eclipse E” (Eprinomectin + Levamisole) – an injection

The injection may be the best option for beef farmers, especially if calves have long coats/mud that can interfere with the uptake of pour-on drenches. It is similar to Cydectin/Exodus that many sheep farmers are familiar with administering. Have a chat to one of our vets to work out the best quarantine drench option for your farming enterprise.