L14: Ketosis Of Dairy Cows (Risco)

Question 1

3 ketone bodies

Answer 1

BHBA
Acetoacetate
Acetone

Question 2

Energy balance =

Answer 2

(NE dmi - NE m - NE I) + NE bwt

Question 3

Peak milk yield occurs when

Answer 3

4 weeks PP

Question 4

Peak DMI occurs when?

Answer 4

8 weeks PP, and is about 3.5% of BW

Question 5

Why does cow go into negative energy balance PP?

Answer 5

Milk yield peaks before DMI peaks, so fat is mobilized to make up deficit

Question 6

Propionate is converted to what via the TCA cycle?

Answer 6

Oxaloacetate, then glucose

Question 7

Ketone body precursors

Answer 7

NEFAs from adipose tissue stores –> FFA –> acetate –> Acetyl CoA –> acetoacetyl CoA –> acetoacetate –> acetone and BHBA

-acetyl CoA should normally go into TCA cycle to make glucose, but if oxaloacetate is low, it instead goes to form ketone bodies**

Question 8

Ketosis occurs when:

Answer 8

• absorption/production of ketone bodies is greater than their use for energy source
• NEFAs are high
• ketone bodies are high
• blood glucose is low

Question 9

Most common ketone body used to diagnose SUBCLINICAL ketosis and concentration cutoffs***

Answer 9

BHBA

Lower threshold concentration of BHBA for SCK is 1.2 mmol/L, so SCK = 1.2-2.8 mmol/L***

Clinical signs develop when >3.0 mmol/L***

Question 10

Sequelae of SCK

Answer 10

• inappetance w/ wt. loss
• reduced fertility and milk production
• increased risk for LDA and herd removal
• immunosuppression (predisposing to metritis and mastitis)

Question 11

Clinical ketosis manifests as:

Answer 11

Acute onset of bizarre neuro signs:
-excessive grooming, licking
-head-pressing, ataxia, wandering, leaning
-apparent blindness
-hyperesthesia, bellowing, aggression
BHBA > 3.0 mmol/L

Question 12

Clinical/nervous ketosis Ddx

Answer 12

Hypermagnesemia
Rabies
Acute lead poisoning
Listeriosis

Question 13

Median time for resolution of SCK

Answer 13

5 days

Question 14

Average SCK incidence rate (in NY)

Answer 14

43%

Question 15

Incidence of SCK =

Answer 15

(# new cases of SCK during the risk period)/(# cows that completed the risk period)

• must measure BHBA conc. Twice
• approximately 2.2 x the prevalence
• better than prevalence at estimating the impact of SCK in a dairy herd*

Question 16

Prevalence of SCK =

Answer 16

The proportion of cows with BHBA concentration between 1.2-2.9 mmol/L at a given point in time (7-14 days PP)

• doesn’t require repeat measurements
• not as good as incidence at estimating impact over time

Question 17

Risk factors for ketosis

Answer 17

• age: older cows
• BCS 4 or higher
• BCS loss of >1 during first 60 DIM**
• lower DMI due to dz, temp change, inadequate housing, dietary factors

Question 18

Clin path of ketosis

Answer 18

• BHBA >1.2 mmol/L
• hypoglycemia (20-40 mg/dl)
• liver enzymes may be elevated w/ lipidosis
• mild electrolyte abn. If off feed
• stress leukogram
• increased NEFAs

Question 19

Dx of ketosis

Answer 19

• hepatic lipidosis at necropsy

- elevated ketone bodies in plasma, urine, and/or milk

Question 20

Which ketone bodies detected in urine?***

Answer 20

Acetoacetate

Acetone

Question 21

Most common ketone body found in urine

Answer 21

Acetoacetate

Question 22

Which ketone body can be detected in milk?***

Answer 22

BHBA

Question 23

Which ketone bodies detected in blood?***

Answer 23

BHBA
Acetone
Acetoacetate

Question 24

Which ketone body used to determine if ketosis is clinical?***

Answer 24

BHBA

Question 25

Precision Xtra blood test has highest sensitivity and specificity in detecting subclinical ketosis (better than Ketolac and Ketostix)

Answer 25

:)

Question 26

Treatment goals for ketosis

Answer 26

- restore normal DMI to resolve hypoglycemia, hyperketonemia and break the cycle that leads to excess ketogenesis - ID and tx underlying conditions

Question 27

Glucose precursors

Answer 27

``` IV dextrose (an isomer of glucose) -causes a transient increase in glucose (most lost in urine) Propylene glycol Propionate Glucocorticoids Insulin ```

Question 28

Oral propylene glycol as tx for hypoglycemia

Answer 28

- use 8-14 oz. drench SID-BID 3-5 days - rumen motility required for absorption - metabolized in liver to glucose - toxicity can --> appetite suppression, diarrhea

Question 29

Glucocorticoids as tx for hypoglycemia

Answer 29

- shifts glucose distribution and utilization by increasing blood glucose and decreasing milk production by less uptake - stims. Appetite - don't use in pregnant cows or cows w/ concurrent infectious dz - may not be good to use if hepatic lipidosis present (controversial) - may increase lipolysis and NEFAs - dexamethasone or isoflupredone acetate used - must administer dextrose in conjunction

Question 30

Caution with isoflupredone acetate for ketosis tx

Answer 30

May increase hypokalemia due to mineralocorticoid activity | -if used, only use once

Question 31

Rank txs for ketosis

Answer 31

Best: propylene glycol Ok: dextrose Worst: steroids

Question 32

Prevention of ketosis

Answer 32

- maximize DMI in transition cows - avoid over-conditioning late lactation cows - niacin fed in transition rations to decrease blood ketone lvls - propylene glycol administered prophylactically to high-risk animals - monensin increases production of propionate in the rumen (can decrease SCK in early lactation by 50% if given during late dry period) - monitor incidence of SCK 3-16 days PP - adequate bunk space

Question 33

Ketosis

Answer 33

Abnormally elevated concentrations of circulating ketone bodies - can be clinical or subclinical (most subclinical**) - during early lactation most common