Metabolic Diseases of the Cow Flashcards
What is the given definition of Metabolic Diseases in Cattle?
A manifestation of the cows inability to cope with metabolic demands of high production
What are the most commonly affected farm animals by Metabolic Disease?
- Dairy cattle
- Pregnant Ewes
What are the top 7 production diseases of cattle?
- Hypocalcemia
- Hypomagnesemia
- Ketosis
- Acidosis
- Mastitis
- Lameness
- Reproductive Disease
What are the top 4 Metabolic Diseases of Cattle?
- Hypocalcemia
- Hypomagnesemia
- Ketosis
- Acidosis
What are the effects of Hypocalcemia?
- Reduce immune cell function -> infections
- Reduced smooth muscle contraction -> teat sphincter wont close, leading to mastitis
- Retained fetal membranes -> metritis
- Infertility
- Reduced DMI -> leading to Neg Energy Balance -> ketosis
- Loss of BCS -> loss of fat pads in the foot -> lameness
- Drop in fertility and expression of estrus
What is the most common presentation of hypocalcemia in cattle?
Periparturient hypocalcemia
a.k.a Milk Fever
What are the normal ranges of Calcium, Phosphorus and Magnesium in the cow?
Ca = 2.1 - 2.5 mmol/L
P = 1 - 2.5 mmol/L
Mg = 0.65 - 1.3 mmol/L
What are the risk factors that predispose a dairy cow to Milk Fever?
- Age = 3rd + lactation
- Breed = Channel Island Breeds (Jersey + Guernsey)
- Overconditioning = High BCS cows eat less during the post-parturient period, intake less Calcium from diet and thus cant absorb from intestines
- Genetics = certain cows/ lines will have repeat offences
What are the main causes of Hypocalcemia in dairy cattle?
DIETARY!
- High Calcium in dry cow diet. Should be around 30g/cow/day. If above this then the mechanisms for bone resorption become relaxed
- Suboptimal Mg in dry cow diet = Lack of Mg reduces sensitivity to PTH and reduces secretion of PTH in response to hypoCa
- Excessive/ High DCAD Diet = Dietary Cation-Anion Difference (Na + K) - (Cl + S)
High DCAD causes alkalization, which reduces tissue sensitivity to PTH
What are the stages and associated clinical signs of Milk Fever in the dairy cow?
Stage 1: excitement phase (lasts 30mins - 2 hours)
restless, paddling, more vocal, inappetent
Stage 2: sternal recumbency (8 - 12 hours)
dull, depressed, swan neck, ‘calf sleeping posture’, low temperature, constipated, low RR, tachycardia (80 - 100bpm) but muffled heart sounds
Stage 3: lateral recumbency
comatose, death (usually due to the relaxation of the esophageal sphincters and inhalation of rumen contents causing asphyxiation/ drowning)
What factors can indicate Milk Fever in the dairy cow?
- History
- Clinical signs: recumbency within 24 - 48 hours post calving
- Response to treatment
What are the Differential Diagnosis for Milk Fever in cattle?
Excitation Phase can look like:
- Hypomagnesium tetany
- Nervous ketosis
- BSE (bovine spongiform encephalopathy)
Recumbent Phase can look like:
- Peracute toxemic mastitis
- Toxemic metritis/ peritonitis
- Uterine haemorrhage
What are the 3M’s of a dull, recumbent cow post calving?
Metritis
Mastitis
Milk Fever
Why is sub-clinical hypocalcemia an issue on a herd level ?
Cattle are hypocalcemic but arent showing clinical signs, but are at risk of:
- Suffering (animal welfare issue)
- Uterine inertia = take longer to calve down which increases calf mortality
- Retained placenta
- Displaced Abomasum
- Reduced Feed Intake = can lead to LDA and ketosis
- Mastitis
- Delayed ovulation post calving
What is the treatment of Milk Fever in dairy cattle?
- IV dose of 2g Ca/ 100kg of BW given slowly through a 14G needle and a flutter valve
e. g. 400mL of 40% Calcium borogluconate IV
Caution: will cause arrhythmia if given too quickly
How can you prevent Milk Fever?
- Adequate Mg in the Dry cow diet = 15-20g Mg/cow/day for the last month of pregnancy
- Silage low in K+
- <5% Calcium in dry cow diet
- optimal BCS pre-calving
- Avoid metabolic alkalosis = add acidic salts to the dry cow diet e.g. NH3Cl or CaCl
What diets or feeds can predispose a non-parturient cow (or even bull) to hypocalcemia?
- Lush pasture, causing diarrhea and electrolyte imbalance
- Sugar beet tops + carrots + potatoes
- Barley poisoning
- High grain diets
- Fusarium spp = estrogenic mycotoxicosis
What are the 3 main differences between cattle and sheep when it comes to hypocalcemia ?
Cattle:
- Occurs 24 - 48 hours post-calving
- High Ca demand in colostrum and milk
- Tx: ~400mls of 40% Calcium borogluconate
Sheep:
- Occurs 3-4 weeks before laming
- High Ca demand from calcification of fetal bones
- Tx: 50 - 80mls of 20% Calcium borogluconate
What is the definition of a Downer Cow?
Any cow which is down in sternal recumbency for more than 24 hours with NO EVIDENCE of a systemic disease, or clinically apparent structural injury, which would prevent it from rising
What are the 3 main causes of Downer Cow Syndrome?
1) Hypocalcemia
2) Calving paralysis = paralysis of the hind leg(s) due to constant pressure on the Obturator nerves as the calf passes through the pelvic canal
3) Spinal injury
What is the time frame for a cow being down where we begin to worry, and why?
6 - 12 hours
Muscle and nerve damage
- Pressure on the sciatic nerve caudal to the proximal femur
- Muscle tear and haemorrhage as the animal struggles to rise
- Renal damage associated with myoglobinuria
What is the general prognosis for a Downer Cow and how can it be measured?
- Most downer cows will rise within 4 days
- Cows down for 7+ days have a poor prognosis
- Can measure with biochemical indicators (CK and AST)
What kind of nursing care/ treatment is required for Downer Cows?
Outside: a small, sheltered paddock on flat dry ground
Inside: 0.5m of straw bedding cleaned daily
Important:
- Feed and give fresh water 2x a day
- 2x daily teat disinfection (higher risk of mastitis being on the ground)
- Move animal from side to side and assist in getting up
- NO antibiotics unless indicated with a wound or additional known/ suspected infection
- NSAID/ pain control = Ketoprofen 10% (low meat withdrawal time and zero milk)