Herd average milk production for Holstein cows in
US corn silage based systems is _______ lbs per day
At the peak of lactation cows may produce ______ lbs of milk per day
During milking up to a ______of milk/minute passes through each teat end.
The cow has _____ udder(s) and four quarters!
The _________ is the most important support structure
and supports and separates the two lateral halves of the udder
median suspensory ligament
There is no _________of the duct system between quarters
The front teats are usually a little _____than the rear teats
Teat skin condition, teat end condition and the
_______lining of the streak canal are important factors
in protection against new intra‐mammary infections.
With the exception of some ________infections, which may be seeded into mammary tissue by hematogenous spread,
all mastitis causing bacteria enter through the teat canal (streak canal).
The internal structures of the udder include the
__________consisting of grape‐like clusters of myo‐epithelial alveolar tissue
which express milk under the influence of oxytocin,
the ducts which lead from the secretory tissue,
and the cisterns, including the gland cistern, which opens into the teat cistern.
Milk available in the cisterns between milkings amounts to _____ mL in each quarter
Mammary tissue develops in the udder at an accelerated rate compared to the tissues of the rest of the body between about 3 months of age and puberty (9 ‐ 11 months).
This is known as the period of _______ growth.
Underfeeding in this period impairs udder development.
More importantly, overfeeding during this period can lead to the
deposition of excess fat in the udder and
reduce milk secretion capacity in adult life
Allometric growth period
___________is the predominant hormone governing synthesis of milk in cattle (vs. prolactin in non‐ ruminants)
Milk ejection (as opposed to milk synthesis) is under the influence of the pituitary hormone _______.
The delay between oxytocin secretion from the pituitary gland and
ejection of milk in the mammary gland
is between 60 and 90 seconds.
This is known as the _______ time
milk let‐ down time
_______secretion is triggered by stimulation of the mammary gland and teats, and also by other situational triggers, such as entering the milking parlor
The _______is the main barrier to infection entering the tissues of the udder
Polymorphonuclear leucocytes (known as ______cells) constitute the major cellular response to bacterial infection in the udder, but do not trigger immune memory.
Antibody levels in milk are much ________than those in plasma
Although there is an effective vaccine against _____mastitis,
no effective vaccines have been produced
against the other major mastitis pathogens including
environmental streptococci, Streptococcus agalactiae, Staphylococcus aureus and Mycoplasma bovis.
What 3 organisms can cause contagious mastitis?
Mastitis infections are transferred from
teat to teat by ______ (blow‐back of milk droplets into the teat end)
________mastitis is transmitted during the milking process as a result of contamination of milking equipment with milk containing mastitis bacteria
This used to be the most prevalent contagious mastitis organism. The Five Point Mastitis Control Program was introduced in the 1960’s to control this infection, primarily because of its negative impact on cheese yield.
Streptococcus agalactiae (contagious mastitis)
Streptococcus agalactiae infections
penetrate deeply into the mammary stroma
streptococcus agalactiae is commonly resistant to antibiotics
Recently there has been a resurgence of Streptococcus agalactiae infections because of the movement of infected cattle into _______ herds.
Once Streptococcus agalactiae was controlled
________became the most important cause of contagious mastitis.
Staph aureus causes subclinical and clinical mastitis.
Some strains cause an acute _______ mastitis which can result in sloughing of the affected quarter.