AHAD Lecture 4
- Created by: Alyssa laird
- Created on: 14-05-24 12:44
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- AHAD - Lecture 4 (cows)
- Mastitis
- inflammatoion of mammary glands
- reduces milk prodoction, fertility and increases risk of early culling. this is costly
- more prevalent in the dairy industry
- appearance
- subclinical
- things seem normal but there is some inflammation of the udder which needs investigating
- need to test milk, this can either be done farmside or in a lab
- on the farm, california milk test is carried out. Milk is mixed with reagent, reaction will occur and turn gelatenous and lumpy if there is high SCC
- lab will test SCC count, and compare to threshold
- > 200,000 SCC is threshold for subclinical mastitis
- need to test milk, this can either be done farmside or in a lab
- things seem normal but there is some inflammation of the udder which needs investigating
- clinical
- external signs of mastitis that do not require further examining.
- milk: changes in colour, composition, output and somatic cell count (SCC) (1)
- further, does it smell, is it clotted, stringy, thick?
- udder: hard, hot, tender to touch, skin may redden (1,2)
- could be gangrenous caused by staphylococcus aureus (3)
- cow: changes in behavour (1,2,3,)
- decreased food intake, recumbent, collapsed, increased heart and respiratory rate
- milk: changes in colour, composition, output and somatic cell count (SCC) (1)
- 3 different gradings, 1 (mild), 2 (moderate), 3 (severe)
- external signs of mastitis that do not require further examining.
- subclinical
- aetiology
- contagious pathogens found on cows
- staphylococcus aureus
- streptococcus agalactiae
- streptococcus dysgalactiae
- found in natural flora on udder
- infected cows are primary reservoir so must be segregted and milked last
- 1-2
- 3 different gradings, 1 (mild), 2 (moderate), 3 (severe)
- 5 point plan to prevent this: 1) milking machine maintenance 2) post-milk teat disinfection 3) dry cow therapy 4) treat clinical cases 5) cull chronic cows
- contagious pathogens found on cows
- duration
- acute
- sudden and over a short duration, often clinical
- cows will be unwell and can even end in dealth
- chronic
- persists for a long duration, clinical or subclinical
- cows usually look well
- clinical signs are mild but can end in permanent udder damage
- acute
- udder defences
- anatomical defence - barrier for protection
- innate immune defence - immune response if bacteria entry occurs
- treated with antibiotics
- Metabolic diseases
- associated with high production systems
- hypomagnesaemia = grass staggers
- common in beef suckler cows, young growing grass has less magnesium so causes deficiencies
- neurological signs: twitching, abnormal behaviours, odd urination, seizures, or sudden death
- hypocalcaemia = milk fever
- jerseys and gurnseys are predisposed to this
- commin in high yielding or older cows
- weak and recumbent, weak neck muscles, called swan neck
- ketosis
- fat is mobilised into energy, often seen with cows who are lactating or in a NEG
- vague clinical sign, if not treated will lead to death, tho luckily we know they are susceptible during pregnancy / lactation so on the look out for signs
- measure ketones in blood, milk, urine to ensure correct diagnosis
- treated with propylene glycol orally
- prevent by optimising nutriton before and during lactation and do not feed buturic silage (often in poor quality silage)
- Lameness
- abnormal gate or posture that results from pain in the limbs
- though can also occur through neurological conditions which aren't painful
- results in: reduced milk yield, reduced fertility, vet costs, culling costs, treatment costs, labour costs
- 0-3 scoring system, looks at weight bearing, rhythm, fluid strides, back (flat or arched)
- most cases in hoof
- sole ulcers = non-infectious
- white line disease = non-infectious
- digital dermititis = infectious
- abnormal gate or posture that results from pain in the limbs
- Mastitis
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