Category: FARM

GRASS STAGGERS

Stormy weather and lush pastures increase the risk of grass staggers, particularly in older lactating beef cows. Magnesium cannot be stored so a constant dietary supply is essential.

Magnesium levels vary considerably in soil and grass. High levels of potassium and ammonia from the application of fertilisers disrupt the ability of cattle to absorb magnesium from their diet. Lush pastures are low in fibre and increase the rate of passage of food through the rumen, reducing the time for absorption. Reduced intakes during periods of bad weather also reduce the overall intake of magnesium.

Affected cattle may show excitability, muscle twitching and aggression, progressing to recumbency, seizures and death. Due to the rapid progression of clinical signs most often cattle are found dead.

If found in the early stages, treatment consists of intravenous calcium spiked with 50ml magnesium. The remainder of the bottle of magnesium is given subcutaneously. Sedation may be required to control seizure activity. Treatment will maintain blood magnesium levels for 6-12 hours. Concentrates and palatable forage should be offered following treatment to avoid relapse.

Prevention options include supplementing all water supplies with magnesium chloride (250g/100 litres of water), feeding high mag rolls or magnesium boluses.

COBALT DEFICIENCY IN GROWING LAMBS

Last year we found multiple farms having poor growth rates in their lambs over the late summer months. Through investigation with forage analysis and blood sampling, we found many were deficient in cobalt; an essential trace element required for the formation of vitamin B12 by ruminal microorganisms. Vitamin B12 is important for the formation of energy from ruminal fermentation.

Cobalt deficiency (“pine”) may be seen in growing lambs put onto cobalt-deficient pastures after weaning.

Clinical signs include:

• Lethargy
• Pica
• Weakness
• Poor appetite and body condition, despite adequate diet
• Poor feed conversion efficiency and growth rate
• Pale mucous membranes
• Reduced wool quality

Diagnosis is based on clinical signs supported by low blood or liver B12 concentrations. Cobalt deficiency should be considered alongside parasitic gastroenteritis and coccidiosis in groups of lambs which are not thriving as expected as heavy parasite burdens interfere with the absorption of vitamin B12.

Cobalt can be supplemented via an oral drench, injection or slow-release bolus. Oral drenches are the cheapest and easiest way to supplement, however as cobalt is not stored in the liver, the benefits of oral drenches are questioned. The supplementation will last for 2-3 days which may not be sufficient enough, therefore will require many repeats throughout the season. SMARTSHOT®B12 is a long-acting injection which maintains adequate levels for 6 months, so avoids the need for repeated handling and drenching. 0.5ml for fattening lambs and 1ml for replacements may be given by subcutaneous or intramuscular injection in the neck from 3 weeks of age. Although slightly more expensive, boluses provide a much longer period of cover. They provide the nutrients on a slow-release basis at a consistent rate. One bolus could provide cover for the whole season!

Be aware though as many drenches & boluses come as a mixed mineral formulation, there is a risk for over-supplementation of some trace elements. With most, this won’t cause an issue as the excess minerals will pass through the gut and out the back end, however, be cautious with copper as too much can be toxic!!

ENVIRONMENTAL MASTITIS

Whilst the risk of environmental mastitis is present year-round, some farms see an increased incidence during periods of hot, humid weather. Warm, humid environments promote the survival and replication of mastitis-causing pathogens, particularly in bedding. Grazing herds may also experience an increase in environmental mastitis cases if grazing areas become poached or fly control is inadequate.

Environmental mastitis pathogens may be splashed onto udders in slurry or water, or transferred from contaminated bedding, hands, shared udder cloths and other equipment. Bedding, particularly if it is allowed to become damp whilst in storage or contaminated with slurry whilst in use, is a significant source of environmental pathogens.

Some pathogens have a particular affinity for certain bedding products, for example, Klebsiella lives happily in damp wood-based products, whilst Strep. uberis thrives in straw. Pseudomonas likes to live in water tanks, which is why only water direct from the mains should be used for parlour cleaning.

Rough or damaged teats can increase the likelihood of mastitis, as damaged skin is more likely to harbour bacteria and is difficult to clean and disinfect.

The severity of environmental mastitis varies from a mild elevation in SCC to full blown toxic “E. coli” mastitis with a down cow in toxic shock, and everything in between. Summer mastitis is caused by a group of bacteria found in the environment and transferred by flies. Therefore fly control is an important prevention strategy.

The incidence and cause of clinical and subclinical mastitis cases should be regularly monitored. We use the industry initiative QuarterPRO to promote and improve udder health on an individual farm basis. This includes data analysis, an on-farm assessment of potential risk factors and implementing a control plan tailored to your farm.

Speak to one of our vets on 01772 861300 for more info.

CLOSTRIDIAL DISEASE PROTECTION

Vaccinating ewes with Heptavac P Plus 4-6 weeks pre-lambing is the best way to protect them and their lambs against the 7 most common clostridial diseases: lamb dysentery, pulpy kidney, struck, tetanus, braxy, blackleg, black disease, and clostridial metritis.

Up to 12 weeks passive immunity against clostridial disease is expected in lambs who have received sufficient colostrum from fully vaccinated ewes. The vaccine also provides 4 weeks passive immunity against pasturellosis in lambs.

It is important to ensure that the nutritional status of ewes is optimal at the time of vaccination and that they are vaccinated at the correct time with respect to lambing. They should be gathered carefully to negate the chances of metabolic disease and abortion which may be brough on by stressful handling. Care should be taken when injecting to ensure that the vaccine is delivered into clean skin using clean needles. All breeding ewes not previously vaccinated with Heptavac P should receive 2 doses of 2ml, 4-6 weeks apart, with annual boosters thereafter. Boosters are ideally given 4-6 weeks pre-lambing to boost colostral levels of immunoglobulin.

Lambs can be vaccinated from 3 weeks of age with either Heptavac P Plus or Ovivac to provide ongoing protection against clostridial disease and pasturellosis. Lambs must receive a primary course of 2 doses, 4-6 weeks apart.

CATTLE LAMENESS: WHITE LINE DISEASE

White line disease is a non-infectious claw horn disease of cattle. The white line is the area of the sole of the hoof where the wall horn meets the sole horn. The horn along this junction is prone to damage, particularly from shearing (sideways) forces. Sole thinning as a result of increased wear can also cause the sole to flex more with resultant damage to the white line structure.

The feet may be subjected to shearing forces if cows have to turn tight corners, or change direction suddenly, for example if being herded forcefully or if trying to escape a bully cow.

If the white line becomes damaged it can become impacted with stones and debris. The resulting infection leads to the formation of an abscess and a sudden onset of lameness. Any cow exhibiting a sudden onset of lameness should have the affected foot lifted and examined at the earliest opportunity. The foot should be trimmed using the five-step Dutch method and the area where the white line has been damaged should be carefully explored until the abscess can drain. Anti-inflamatories should be administered and a block should be fitted to the healthy claw. Early treatment promotes faster resolution and minimises the impact the lameness will have on milk production and fertility.

Key areas to focus on to prevent white line disease include:

• Optimising cow flow and ensuring cows are handled quietly. Improving cow flow will reduce pushing, twisting and turning forces on feet. Ensure backing gates are used appropriately.
• Improving cow comfort to improve lying times – this includes cubicle design, lying surface, bedding provision and stocking density. Over stocking results in a greater likelihood of bullying interactions and greater competition for lying space. Cubicle buildings should provide at least 5% more cubicles than cows. Straw yards should provide 1m2 per 1,000 litres of milk, e.g. a 10,000l cow should have 10m2 lying space. The target is for cows to be lying for at least 12 hours per day.
• Reduce standing times. The longer cows stand on concrete the greater the risk of white line damage, sole ulcers, and other claw horn problems. Ideally cows should not stand for more than 1 hour at milking times.
• Improve flooring – repair areas of uneven concrete and use rubber matting in areas of high traffic and at tight turns such as exits from the parlour. Walking surfaces should be non-slip and as clean as possible.
• Manage cow tracks and gateways – avoid stones and manage muddy areas. Consider upgrading tracks with AstroTurf and sweep regularly. Tracks should never be used by machinery.
• Nutrition. Inclusion of biotin in the diet at 20mg/cow/day has been shown to reduce the incidence of WLD by as much as 50%. However, this is a long-term strategy and due to the time taken for new horn growth, improvements may take at least six months to be seen.

For more details on the five-step Dutch foot trimming method:
https://ahdb.org.uk/knowledge-library/trimming-cows-feet-the-five-step-dutch-method

BOVINE IRITIS – ‘SILAGE EYE’

Bovine iritis, also known as ‘silage eye’, appears as a bluish-white cloudiness in the eye, with a red angry rim at the junction of the sclera and cornea (where the white and black parts of the eye meet). Silage eye is extremely painful as demonstrated by excessive tearing and closing of the eyelids.

Treatment includes subconjunctival injection of antibiotic and steroid. Topical cloxacillin (Orbenin Ophthalmic ointment) can also be used in early cases.

The causal agent is the bacteria Listeria monocytogenes, which is widespread in the environment. Silage eye is most commonly associated with feeding big bale silage. Listeria are more likely to grow in big bales compared to clamp silage due to their lower density and higher DM content, which results in a slower rate of fermentation. Bales also have a high surface area to volume ratio, so more of the silage will be exposed to air if the wrap becomes damaged. Listeria thrive in the presence of air, even if the pH is low.

Affected silage may not always be visibly mouldy. The risk of Listeria surviving in big bale silage can be reduced by ensuring that air is excluded for the duration of storage and feeding big bales immediately upon opening.

Early diagnosis is key

The single most important factor affecting the success of calf pneumonia treatment is how early treatment is started. Treatment must be given as early as possible to minimise the degree of lung damage and reduce the risk of chronic pneumonia.

Detecting respiratory disease in the early stages requires careful observation. Calves may have a high temperature for up to 72hrs before they exhibit obvious clinical signs, such as an increased respiratory rate. Subtle signs to look out for include a slight delay in getting up to feed, a reduction in milk/feed intake, separation from the rest of the group, a clear nasal discharge, or a slightly depressed state.

Time to get the thermometer out

Any suspicion of a calf not being 100% should prompt a temperature check. Allocate some time daily to observe calf behaviour so that these subtle changes can be recognised.

If there has been a couple of cases of pneumonia in a group of calves, it is very wise to temperature check the whole group. It is impossible to tell which calf has a high temperature and who hasn’t without getting your thermometer out! Could you pick out someone who had a temperature increase of 0.1°C in a line of people without a thermometer?

Identifying the pathogen

Calf pneumonia can be caused by a range of pathogens including bacteria, viruses, and parasites. With regards to diagnostics there are two main options:

• Isolate the pathogen – nasopharyngeal swabs, transtracheal washes, post-mortem sampling, faecal sample (lungworm)
• Check if the animal has had an immune response against the pathogen – blood samples to check for exposure to pathogens

It is important to know what pathogens are causing pneumonia on your farm so that specific vaccinations can be selected, effective treatments can be utilised, and targeted management protocols can be put in place to prevent disease.

Dealing with an outbreak

Ideally sick calves should be isolated either on their own or as a group in a separate airspace away from healthy calves. Having a designated hospital pen will help to reduce the spread of disease to healthy calves. This allows for close monitoring of feed and water intake and assessment of response to treatment.

Although many causes of pneumonia are viral, secondary bacterial infection is almost inevitable and therefore all cases of pneumonia should be treated with antibiotics in combination with anti-inflammatories.

Anti-inflammatory will bring down high temperatures, reduce the degree of lung damage and inflammation and help feed intakes. The antibiotic that you choose may depend on which pathogens have been diagnosed on your farm, administration requirements and the duration of action.

Please get in touch if you would like to discuss your current pneumonia treatment protocols with us.

Early diagnosis is key

The single most important factor affecting the success of calf pneumonia treatment is how early treatment is started. Treatment must be given as early as possible to minimise the degree of lung damage and reduce the risk of chronic pneumonia.

Detecting respiratory disease in the early stages requires careful observation. Calves may have a high temperature for up to 72hrs before they exhibit obvious clinical signs, such as an increased respiratory rate. Subtle signs to look out for include a slight delay in getting up to feed, a reduction in milk/feed intake, separation from the rest of the group, a clear nasal discharge, or a slightly depressed state.

Time to get the thermometer out

Any suspicion of a calf not being 100% should prompt a temperature check. Allocate some time daily to observe calf behaviour so that these subtle changes can be recognised.

If there has been a couple of cases of pneumonia in a group of calves, it is very wise to temperature check the whole group. It is impossible to tell which calf has a high temperature and who hasn’t without getting your thermometer out! Could you pick out someone who had a temperature increase of 0.1°C in a line of people without a thermometer?

Identifying the pathogen

Calf pneumonia can be caused by a range of pathogens including bacteria, viruses, and parasites. With regards to diagnostics there are two main options:

• Isolate the pathogen – nasopharyngeal swabs, transtracheal washes, post-mortem sampling, faecal sample (lungworm)
• Check if the animal has had an immune response against the pathogen – blood samples to check for exposure to pathogens

It is important to know what pathogens are causing pneumonia on your farm so that specific vaccinations can be selected, effective treatments can be utilised, and targeted management protocols can be put in place to prevent disease.

Dealing with an outbreak

Ideally sick calves should be isolated either on their own or as a group in a separate airspace away from healthy calves. Having a designated hospital pen will help to reduce the spread of disease to healthy calves. This allows for close monitoring of feed and water intake and assessment of response to treatment.

Although many causes of pneumonia are viral, secondary bacterial infection is almost inevitable and therefore all cases of pneumonia should be treated with antibiotics in combination with anti-inflammatories.

Anti-inflammatory will bring down high temperatures, reduce the degree of lung damage and inflammation and help feed intakes. The antibiotic that you choose may depend on which pathogens have been diagnosed on your farm, administration requirements and the duration of action.

Please get in touch if you would like to discuss your current pneumonia treatment protocols with us.

Controlling lameness for a more productive flock

It is estimated that the UK flock contains over 3 million lame sheep. Staggeringly over 60% of the total amount of antibiotic used in flocks is used to treat lameness. Footrot and Contagious Ovine Digital Dermatitis (CODD) are two important highly infectious causes of lameness. Each flock should have a control strategy in place with the aim of reducing the number of new cases to improve flock welfare and efficiency. Control plans should centre on improving under-foot hygiene, culling chronic cases, improving biosecurity, ensuring prompt treatment, and using the footrot vaccine.

Footrot is the most common cause of lameness in sheep. Damaged interdigital skin, poor claw hygiene, and moist environmental conditions promote the spread and development of infection. Chronic cases can lead to overgrown and permanently misshapen hooves. Treatment has the best results when initiated early. Affected sheep should be isolated from the rest of the flock and treated with long-acting amoxicillin and Metacam.

CODD is caused by spirochaete bacteria (same family as digital dermatitis in cattle). CODD lesions start at the coronary band and progress down the hoof wall towards the toe. The hoof capsule eventually comes away to expose the sensitive underlying tissues. Affected sheep should be isolated and treated promptly.

Purchased sheep should be quarantined and have their feet examined carefully as around 30% of infected sheep show no signs of lameness. A randomised controlled trial found that a single dose of long-acting amoxicillin resulted in a 71% cure rate. Some cases may require a second treatment 3 days later. Tulathromycin (Draxxin) and tilmicosin (Micotil – vet-only) may be used in refractory cases.

Footrot bacteria have been isolated in 71% of CODD lesions and sheep with footrot are 3.8 times more likely to develop CODD. Therefore, controlling footrot is an important aspect of controlling CODD. In addition to significantly reducing the impact of footrot, the Footvax vaccine was found to reduce the number of CODD cases by 32%. Annual Footvax vaccination may provide sufficient control in most flocks. An additional booster may be given 4 weeks prior to risk periods (e.g. housing for lambing). The vaccine can also be used in the face of an outbreak.

Parasite management at housing time

At this time of year parasites take on a dormant state and “overwinter” within the stomach lining. It is important to remove this inhibited stage of the parasite because if left they can cause significant damage and disease when they emerge en masse in spring. Affected animals develop rapid clinical signs of weight loss, scour and dehydration, which may be fatal.

Parasites which survive over winter in the stomach lining will contribute to larval pasture burdens when they emerge the following spring.

1st and 2nd season grazed youngstock

This age group are most susceptible to gut and lung worms as cattle have not had time to develop a protective immune response until after their 2nd grazing season. Treat all youngstock at housing with a Group 3-ML (clear drench/injection/pour-on – ivermectin e.g. Enovex) that will remove all inhibited larvae. Avoid Group 1-BZ (white drenches – albendazole, fenbendazole) and Group 2-LV (yellow drenches – Levamisole) products are these will not remove all inhibited larval stages

The winter housing period will soon be upon us, which means that many of you will now be planning to treat your animals for gut parasites. Purchasing worm and fluke products can be a bit of a minefield, but this guide aims to help you choose the most appropriate product for your stock. The aim being to effectively remove parasites whilst minimising the likelihood of selection for resistance.

Purchased 1st lactation dairy/ 1st lactation beef cattle

The immune status of these animals is unknown with respect to lungworm. It is worth paying particular attention to this group of animals and treating them if they are coughing or under conditioned. Dairy cattle can be treated with an eprinomectin product (e.g. Eprizero -zero milk withdrawal). A Group 3-ML (e.g. Enovex) would be a good choice in beef cattle.

Adult dairy/beef cattle

Adult cattle should not require any treatment for gut worms as they will have built up protective immunity. However, it may be beneficial to perform faecal egg counts in any animals in poor condition so that they can be treated if necessary.

All age groups

Cattle (and sheep) are unable to develop a protective immune response to fluke infection. Therefore fluke control should encompass all ages of cattle. A bulk milk test can be used to monitor the infection level in milking herds and faecal tests can be used to test individual or small groups of animals.

In contrast to sheep, cattle typically only suffer from the chronic form of fluke infection. After a dry summer like we have just had, even if autumn is wet, cattle will only be harbouring immature flukes at the time of housing. Therefore, it is best to wait at least 10 weeks before treating with a product which targets adult fluke (e.g. Distocur). A nice job to look forward to at Christmas time!

Products containing Oxyclozanide (e.g. Distocur) or albendazole (e.g. Tramazole) may be used in milking herds (usually at dry-off) as they have a short milk withhold (Oxyclozanide = 108hrs and albendazole = 60hrs). Resistance to triclabendazole is becoming more widespread. Whenever possible we should avoid the use of triclabendazole products in cattle as this drug targets immature fluke which are more significant in sheep.

Combination products

Combination products are more costly as you are paying for the “convenience” of a 2-in-1 product. However, it is often the case that the two drugs which are combined should not ideally be given together at housing.

For example, if you used a product containing ivermectin and closantel at housing, you will remove all worms, but very few fluke as closantel will only kill fluke that were ingested over 7 weeks ago. Therefore, another fluke treatment would be needed later on. If you waited until the cattle had been housed for at least 7 weeks before dosing they will have carried their worm burden for an extra 7 weeks+. Adult cattle do not need treating with combination products as their worm burden will be low and does not require treatment. So overall, combination products are a more costly option and may increase the risk of resistance to these drugs.