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Flashcards in Bovine Deck (459)
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241

What is thimbling?

Horizontal fissure of the hoof wall. Poor horn production during a severe toxaemic condition such as coliform mastitis or metritis apears as a horizontal fissure in the hoof horn of all eight digits. As this defect in the wall grows down to about two thirds of its length three to four months later it weakens and may separate from the healthy horn proximally. The corium remains intact distal to the horizontal fracture holding the distal hoof horn attached at the toe. this fissure moves when weight is taken tensing the corium and causing pain and lameness. All four feet are affected.

242

How do white line abscesses occur?

White line abscesses arise following bacterial entry into the white line area, usually found in the lateral claw of the hind foot on the abaxial border close to the junction with the heel. the condition is more common in dairy cows that spend long periods standing / walking on poorly maintained surfaces and tracks. impaction with small stones/dirt - entry o fbacteria with multiplication forms an abscess which may extend and discharge at coronary band. Affected cattle often present with sudden severe lameness of the affected leg with only the toe touching the gorund.

243

What is interdigital skin hyperplasia?

Excess epidermal and hypodermal tissue occupying part of the interdigital space. Usualy appears as a protruberance of skin at the front of the interdigital space. Usually doesnt cause lameness unless it becomes so large taht excoriation leads to superficial infection.

244

What is slurry heel caused by?

affects almost all dairy cows during late winter months, new horn growth affects the weight bearing function of the hoof which predisposes to corium damage, sole ulcer and white line diease. Caused by prolonge exposure to slurry during the winter housing period. Dichelobacter nodosus infection has also been suggested.

245

How does slurry heel present?

Does not usually cause lameness alone. there is necrosis of the horn of the heel and heel sole area varying from small blackish pited areas of the horn up to black cracks penetrating deeply towards the corium of the heel sole area.

246

What is a sole ulcer?

A specific circumscribed lesion of the sole at the sole heel junction nearer to the axial than the abaxial wall affecting dairy cows. never seen in growing cattle and rarely in beef cows. The highest prevalence occurs during late winter after cattle have been housed for several months. Sole ulcer affects the lateral digits often involving both hind feet.

247

How do sole ulcers occur?

Pressure damage to the corium caused by compression at the posterior axial border of the pedal bone. build up of new horn consequent to chronic necrotic pododermatitis is an important factor.

248

What is the usual clinical preentation with a sole ulcer?

Sudden onset of severe lameness, may stand with the toe of the affected digit on the edge of the cubicle, may abduct the leg to weight bear on the unaffected medial claw, much new overgrown soft horn on the lateral claw containing the obvious sole haemorrhage.

249

How does septic pedal arthritis occur in cattle?

Following deep penetration of the distal interphalangeal joint by nails and other metal objects, or following extension from sole ulcer lesions in the lateral hind claw of dairy cows.

250

How does septic pedal arthritis present?

10/10 lame with marked muscle atrophy of the affected limb after 7-10 days. History of poor milk yield/body condition. marked swelling of drainage LN which may be five to ten times its normal size although the popliteal LN is difficult to palpate. The foot is hot, swollen and very painful. Marked swelling above the coronary band on the abaxial aspect extending to the bulb of the heel but discharging sinuses are uncommon except for neglected cases. The swelling above the coronary band on the abaxial aspect of the hoof wall extending around to the bulb of the heel is consistent with a diagnosis of septic pedal arthritis.

251

What is the treatment for a septic pedal arthritis?

Further antibiotic therapy is useless in cattle with infection of the distal interphalangeal joint. digit amputation under iv regional anaesthesia gives good results. use IV flunixin, then 25-30 mls lignocaine solution in a superficial vein after application of a tourniquet.

252

What is digital dermatitis in cattle?

Infectious contagious disease causing severe lameness in adult dairy cattle, the condition is uncommon in beef cows and growing cattle. Caused by a spirochaete.

253

How does digital dermatitis present clinically?

Lameness is variable. in severe cases the weight is borne at the toe leading to excessive growth at the heel bulbs. The early lesion is a distinct moist area of skin approx 2-5 cm in diameter above the cleft of the bulbs of the heel. there is erosion of superficial skin with a yellow green diptheritic membrane covering the lesion.

254

What is the treatment for digital dermatitis?

Remove all impacted faecal material overlying the lesion. thoroughly clean the lesion then apply topical oxytetracycline aerosol. repeat treatments are frequently necessary. Daily footbaths containing lincomycin or tylosin are frequently used to control herd outbreaks but ensure that cows dont drink these. formalin or copper sulphate footbaths appear to have no effect on transmission or development of this condition.

255

What is superfoul in cattle?

A peracute form of interdigital necrobacillosis. Very sudden onset lameness. Swelling and widening of the interdigital space with extensive tissue necrosis, can rapidly progress to involve the navicular bursa, flexor tendon sheath and distal interphalangeal joints. The foot is very swollen and cow 10/10 lame.

256

What is the treatment for superfoul?

Immediate action is very important. under IV regional anaesthesia, debride the interdigital lesion and pack with 2-4 500mg clindamycin tablets. apply bandage. treat with tylosin 20mls injected IM twice daily for atleast 3 days. Administer flunixin or ketoprofen.

257

What are antibiotic footbaths used for?

The treatment of acute raw digital dermatitis lesions. They are expensive, off license and so require a 7 day milk withold and can cause severe problems if drunk by cows. Bet to use to reduce acute active digital dermatitis infection or strategically through the winter every 4-6 weeks.

258

What are chemical disinfectant footbaths used for?

Used on a regular basis as a control measure to disinfect the cows feet to prevent new infections and the spread of infection within the herd. formalin must not be used on acute digital dermatitis lesions - very painful.

259

What is acetonaemia associated with?

It is a metabolic disease of high yielding milking cows associated with an inadequate supply of energy to sustain the high milk yields.

260

What is fatty liver syndrome?

This term is used to describe the mobilisation of fat that frequently occurs around calving and during the first month of lactation in high yielding dairy cows. This is thought to be a normal occurence in high yielding cattle. If greater than 20% fat is deposited in the liver it can interfere with liver function and result in exacerbation of energy problems and the development of acetonaemia.

261

What is carbohydrate converted into in the rumen?

VFAs such as acetate and butyrate which are ketogenic and propionate which is glycogenic.

262

What factors influence the occurrence of acetonaemia?

Inadequate energy content of the ration for high yielding dairy cows, inadequate intake of the diet, secondary acetonaemia due to inappetance following a primary disease eg. LDA, excessive intakes of ketogenic food eg silage with high levels of butyric acid, poor rumen function - includes sudden changes in diet or excessive levels of poor concentrate feeding.

263

What are the clinical signs of acetonaemia?

Usually occur sin the first month of calving but may occur at other times if the energy deficit is severe. wasting form is the most common form - cow loses body condition over a period of days or weeks, there is loss of appetite with refusal to eat concentrate feeds and a sudden drop in milk yield, the faeces are often dark and firm with a waxy appearance. A small number of cases of clinical ketosis will develop neurological signs due to a hypoglycaemic encephalopathy. Signs vary from the animal being jumpy to a frenzied delirium. There may be head pressing, circling, wandering, licking at any available object, salivation and depressed appetite.

264

How is a diagnosis of clinical acetonaemia made in cows?

History - usually high yielding cows, first month after calving.
Clinical biochemistry - low plasma glucose below 3mmol/l, but may be normal. mobilisation of body fat - elevated NEFA levels over 0.7mol/l indicate increased levels of fat mobilisation. Ketone bodies - Levels of B hydroxybutyrate in the serum/plasma - over 3mmoll.

265

How should cows with clinical acetonaemia be treated?

Use of 400ml 40% glucose intravenously. This only lasts for 2-4 hours. Oral administration of glucose precursors such as proplene glycol or glycerine twice daily by drench. Glucocorticoid hormone therapy stimulates gluconeogenesis reducing the levels of ketone bodies. vitamin b12 is essential for the metabolism of prorionate and some people drench cows with cobalt to promote vit b12 synthesis.

266

Which effects may NEB in early lactation have on milk?

Depression on milk protein - due to long term NEB. Increase in milk butterfat, due to increased levels of VFAs for butterfat synthesis.

267

What is fat cow syndrome and how does it occur?

This is the extreme manifestation of NEB and fat mobilisation in early lactation and occurs due to excessive body condition score in fat dry cows prior to calving (BCS >4 at calving) this results in a depressed DMI, and these cows thus enter a state of severe NEB in early lactation. Fat is then deposited in massive quantities in the liver leading to disruption of liver function.

268

How can acetonaemia be prevented in early lactation?

Correct dry cow management - should calve at condition score 2.5-3. Transitional cow management in the late dry period. Provision of a suitable ration to cows in late dry period/early lactation. Ensure that protein and energy in the diet is balanced, maximise dry matter intake in the late dry period/ early lactation, good nutritional management. ensure excellent cow comfort. regular monitoring of nutritional status. medication with sodium monensin to improve proprionate production in the rumen.

269

What is ovine pregnancy toxaemia? (twin lamb disease)

seen in last mont of gestation in ewes carrying two or more lambs, with a prolonged period of energy shortage - poor forage quality, inadequate concentrates, ewes in poor body condition score below 2. the rapid growth of the foetus in late pregnancy results in a marked increase in glucose requirements of the gravid uterus. Initially ewes are isolated from the flock, refuse to feed. neurological signs then progress due to development of hypoglycaemic encephalopathy. Progression to a profound depression and recumbency. High mortality rate.

270

How is diagnosis of ovine pregnancy toxaemia made?

frequently made on clinical signs and history. confirmation of diagnosis is by serum B-o butyrate levels over 3mmol./l. PM will reveal fatty infiltration of the liver.