Calculi in LA

Question 1

Comparing bovine and ovine patients:

Where is the most common site of uroliths?

What is the nature of the uroliths?

What animals are affected?

Answer 1

Question 2

List the major ddx of abdominal discomfort and straining in LA

Answer 2

GI tract – scouring, rectal/anal trauma, rectal/anal obstruction, constipation. UG tract – calving, cystitis, obstruction (trauma, neoplasia, urolithiasis).

Question 3

List the major abdominal organ systems associated with abdominal discomfort and distension

Answer 3

ruminal, abomasal, intestinal, uterine, hepatic/ascites, CHF, urinary

Question 4

List the major DD for ventral oedema

Answer 4

trauma/ haematoma, hypoproteinaemia, CHF, urethral rupture.

Question 5

List the additional clinical signs that would help you confirm the diagnosis?

Answer 5

Blood clots and crystals on preputial hairs, urethra may pulsate on palpation

Question 6

List 3 other diagnostic techniques you could use to confirm the diagnosis and prognosis of this patient

Answer 6

Abdominal ultrasonography, blood biochemistry, abdominal paracentesis if suspect bladder rupture.

Question 7

Briefly state what you would expect to find in each case

Answer 7

A)Enlarged kidneys/hydronephrosis, enlarged bladder, location of crystals, uroperitoneum. B) (azotaemia (raised blood urea and creatinine), hyperkalaemia (but variable). If renal failure/obstruction/bladder rupture, hyponatraemia, hypochloraemia, hyperphosphataemia. C) free urine (smell and specific gravity and creatinine content > serum creatinine).

Question 8

What are the major medical priorities in the (surgical) management of this condition (calculi in LA).

What are the limitations of medical treatment

Answer 8

• Medical tx alone is seldom sufficient, but is essential for successful surgery.
• *Diazepam is listed as best in a lot of articles but it is not included in the EU list of approved substances and its use is therefore illegal

Question 9

With this condition, what fluids, antibiotics, non-steroidals and sedation would you use?

Answer 9

Question 10

Complete the following table

Answer 10

Question 11

How can we prevent calculi in LA?

Answer 11

• No more than 0.6% P or Mg in ration. Keep the Ca:P ratio at least 2.0 to 2.5:1. Watch out for the following feeds (%P given): bran: 1.2%, Linseed cake, 0.8%, Skim milk powder 1.0%, Brewers grains 0.6%.
• Add calcium to restore the ratio (CaCo3 is 30% calcium w/w). NB too much calcium can lead to CaCO3 crystals in the urine (Lucerne hay).
• Add salt (up to 3-5% of DMI as NaCl) to increase diuresis.
• Use DCAD to acidify the diet eg CaCl2 1-2% DMI. But: very unpalatable.
• Monitor urine pH and aim to keep below 6.5.
• Delay castration (testosterone stimulates enlargement of the urethral diameter).
• Feed frequently rather than once or twice a day. Include roughage and reduce pelleting to increase rumination and salivation and so faecal excretion of phosphorous rather than urinary.