Dairy cattle Flashcards
free stall
barn-loose housing systems
cows are able to move anywhere throughout the pen
includes resting areas
cleaner environment
fewer teat/udder injuries
tie stall
harder on milker, more walking/kneeling
can be harder on cows: decreased exercise; poor design can result in lameness, broken tails, swollen hocks, neck lesions, and decreased cleanliness
older buildings may have poor ventilation
dry lot
economical
cows are able to move freely, good ventilation
only for milder climates since cattle can be prone to heat stress during summer
what is important to allow with feeding when housing cattle?
allow free-grazing when weather allows
we can’t control exact forage nutrients, harder to manage individual cows and in extreme climates lead to cattle being housed indoors for part of the year
but pasture is more economical for feeding costs, more natural environment, and environmentally sustainable
dairy parlor
separate area in farm where cows are milked
rotary or carousel dairy parlor
arranged so that cows enter onto a turning platform that rotates slowly
grade A milk
fluid grade milk
milk produced under sufficiently sanitary conditions to qualify for fluid consumption
used in manufactured dairy products
grade B milk
used in cheese, butter, nonfat dairy milk
how long do dairy farms milk a cow for before culling?
the cow produces milk for about 5-6 years before being culled and used for beef
cow gestation
~280 days
what is important for cows to do in order to continue producing milk?
they need to give birth to 1 calf per year to continue producing milk
usually artificially inseminated within 3 months of giving birth
udder/teat anatomy
have 4 mammary teats
each teat in the udder has separate glands/ducts/quarters
mastitis
infection of mammary gland
doesn’t directly spread to the other ducts because of the separation it would have to spread down 1 quarter through the teat and duct and then up through another quarter
signs of calving
increased udder size (aka “bag-up”), tail head muscles slacken, will seek isolation
how long is labor?
3-8 hours if no complications
how much weight can a cow lose after giving birth?
~60 kg
40 kg calf, 20 kg fluids and tissue
dry period
part of the lactation cycle
nutrient intake is directed toward developing a fetus rather than milk (aka “drying up” or “dry cow”)
cow will rest and prepare for birth
when does lactation start?
toward the end of pregnancy
starts with prolactin and growth hormone
key for good milking
oxytocin: released in blood in response to contraction of udder’s muscle cells
milk available for removal from udder because of udder contractions
what is important to ensure oxytocin is released?
providing the cows with a clean, low stress environment
stress = adrenaline which inhibits oxytocin release
how to prepare a cow for milking
- if udder needs to be cleaned use a disinfectant to wash and dry udder/teats thoroughly
- once teats are visibly clean we apply a pre-dip halfway up teat ensuring a drop is observed hanging from teat end
- leave pre-dip on for amount of time specified by manufacturer (usually ~30 sec)
- remove pre-dip by drying teat and paying attention to cleaning/drying teat end
- “strip the teat”: milk 3 or 4 squirts of milk into a strip cup (container with a strainer that helps identify animals with abnormal milk)
types of pre-dips
can be sprayed or applied with a dip cup
sprays are more sanitary but dip cups are more effective
make sure to clean and disinfect dip cup after use
pre-dips
commercial preparations proven to be effective germicides
why do we remove the first few squirts of milk from each teat?
these squirts tend to contain the highest number of inflammatory cells if they’re present
when should you start milking after preparing the cow?
milking should begin 60-90 sec after pre-dip removal from teats
this has been shown to be optimal for oxytocin to cause milk letdown
machine milking vs hand milking
machine milking easier on hands but can result in overmilking and teat-end trauma if done improperly
ways machine milking can increase risk of mastitis: excessive vacuum pressure, leaving milk units on too long, not disinfecting units between animals, detaching unit with vacuum still present
post milking
teats should be dipped with another germicide (called post-dip) which decreases the risk of bacteria entering the teat opening until teat sphincter closes
post-dip is left on until next milking
in very cold weather leave post-dip on for 30 sec, then dry teats or they may get frostbitten
have fresh feed available to cows when they return to pen after milking
mastitis causing bacteria
streptococci (or similar gram-positive cocci), staphylococci, gram-negative rods (enteric coliforms)
most common: staph aureus, strep agalactiae, coliforms such as E. coli and mycoplasma
staph aureus
most common bacterial cause of mastitis
can produce toxins and abscesses
can resist phagocytes and immune response, some mutations have antibiotic resistance
staphylococci
cause of chronic infections
what is streptococci associated with?
associated with sub-clinical and acute infections
what is E. coli and staph aureus associated with?
acute gangrenous mastitis