ASCI 250 - Exam 1 Study Guide

How long is the standard lactation period for a dairy cow?

305 days

The average dairy cow in the US produces how much milk per lactation?

23,000 lbs

Which of the following is NOT a primary reason for increased productivity in milk production starting around 1940 to 2000?

* enhanced record keeping - DHIA
* adoption of artificial insemination
* enhanced nutritional management - use of TMRs
* genomic testing

genomic testing

On average, how many times to a majority of larger dairies milk per day?

3x a day

which of the following breeds of dairy cattle provide the greatest % of fay and protein in milk?

jersey

T/F: the average Nebraska dairy has more cows and greater productivity (lbs milk/cow) than the national average.

true

relative to calving, when does peak milk production in the dairy cow occur?

\~ 2 months after calving

relative to peak milk production, when does dry matter intake peak?

DMI peaks \~ 45 days after peak milk

after “drawing a line” from hooks to thurl to pins, a flat, long “U” is present. What’s your estimated BCS?

4

what is considered the ideal body condition score of a dairy cow at calving?

3\.5

when is the most efficient time to replenish nutrient reserves (body condition) on the cow?

late lactation

which of the following analyses represents a “high quality” forage for lactating dairy cows?

20% CP, 30% ADF, 40% NDF (20-30-40 hay)

what is the maximum recommended amount of grain to incorporate into a lactating dairy cow diet?

50%

1 lb of fat added to the diet is equivalent to the energy value of how much corn?

3 lbs

what is the maximum % of fat that should be added to a lactating cow diet?

5%

what are the primary issues associated with too little fiber in the diet of a lactating dairy cow?

metabolic disorders and low milk fat

as a % of body weight, how much dry matter is a lactating dairy cow expected to consume?

4%

48 hours after calving, a cow is hypo calcemic, appears to be paralyzed, and is unable to rise. What is likely the issue?

milk fever

2 weeks post-calving, tapping the left side of a hunched up dairy cow reveals a “ping” sound. What is likely the issue?

displaced abomasum

which of the following is a characteristic of ketosis?

* low blood glucose levels
* high somatic cell counts
* low blood calcium

low blood glucose levels

in a free-stall barn, what percentage of cows should be able to eat at any one time?

75%

when is mastitis most likely to occur?

1st month post-partum

what does a “voluntary waiting period” of 60 days imply?

cows will not be rebred until at least 60 days after calving

the goal is to have what % of cows serviced within the 1st 21 days after the voluntary wait period?

90%

which of the following is NOT true regarding usage of estrus synchronization with timed breeding?

* more cows will be serviced
* conception rates will be lower
* pregnancy rates will be higher
* gestation length with be reduced

gestation lengths will be reduced

if detecting heat, which of the following is the primary sign that a cow is in estrus?

the cow will stand to be mounted

on what unit is dairy farm milk sold?

per cwt (hundred weight)

milk yield = 100 lbs

BF = 5%

P = 3%

BF Px = $1.50/lb

P Px = $3.50/lb

\
What is total milk value?

$18

what class milk is used for cheese manufacturing?

class 3

what is the national average culling rate within dairy herds?

30-35%

T/F: due to reduced competition, sexed semen produces a higher conception rate than conventional semen

false

T/F: sexed semen facilitates genetic progress, but simultaneously allows opportunity to use beef semen to enhance calf value

true

T/F: the difference in PTAs of two sires provides an estimate of expected difference in performance in their progeny

true

relative to predicted transmitting abilities, the reliability value provides an estimation of what?

accuracy

T/F: progeny testing is partially responsible for long generation intervals in dairy cattle, which slows genetic progress

true

T/F: genomic testing has doubled the rate of genetic progress, compared to progeny testing

true

T/F: due to expense, less than half of all dairy AI bulls are genomic tested today

false

what is the most popular type of parlor in the US?

herringbone

what type of parlor provides best usage of space as cows stand side-by-side, and allows for more employee safety?

parallel

in 2019, Nebraska had approximately how many licensed dairy operations?

140

with 58,000 cows averaging 24,293 lbs/milk/cow/year producing a total of 1.4 billion lbs of milk, what is Nebraska’s rank relative to dairy production in the US?

25th

through distribution of “milk marketing orders”, which of the following was NOT an objective of the 1937 Agricultural Marketing Agreement Act?

* enhance price stability for producers and consumers
* reduce disorderly marketing conditions and assure that a minimum milk price was paid to producers
* ensure adequate supply of milk for consumers
* facilitate expansion of the dairy industry

facilitate expansion of the dairy industry

when is it recommended that lost body condition associated with the freshening period be restored?

during late lactation

what is it called when a cow’s energy output in milk production exceeds her energy intake through feed consumption?

negative energy balance

what is the most costly health issue in the dairy industry?

mastitis

for the properly conditioned dry cow, how much grain should be fed?

limit grain to less than 0.5% of a cow’s body weight

which of the following is NOT considered a high-fat feedstuff that may be incorporated into a lactating dairy cow diet?

* soybeans
* sunflower seeds
* corn
* cottonseed

corn

what feed ingredient often makes up 40-50% of most lactating dairy cow rations?

corn silage

what may be used as an indicator of the presence and level of mastitis in the milk?

high somatic cell count

which metabolic disorder results from a metabolic drain on a cow’s glucose reserves?

ketosis

what is the key to preventing ketosis?

maximize dry matter intake post-freshening

when does milk production peak, relative to calving, for the dairy cow?

approximately 2.5 months after calving

approximately what percentage of the diet of the early dry cow should be forage?

80-90%

when the true stomach of a cow becomes filled with gas and relocates to a different part of the abdomen, this is known as what?

displaced abomasum

what is NOT a consequence associated with too much fiber the diet of a lactating dairy cow?

decreased milk fat

T/F: to minimize feeding costs and maximize milk yield, cows are commonly grouped based on production level or production groups to more adequately meet their nutrient requirements

true

today, nearly all milk is marketing through producer-owned cooperatives. what legislation, passed in 1922, allowed agricultural commodity producers to “act together in associations”?

capper volstead act

T/F: there are 10 recognized breeds of dairy cattle in the US

false

what process, developed in the 1800s, was mandated in 1917 due to food safety issues related to the consumption of raw milk?

pasteurization

given the guideline provided regarding intake as a percentage of body weight, how much dry matter would a 1500-lb, high producing, lactating dairy cow be expected to consume each day?

60 lbs

milk fever or parturient paresis is associated with a sudden drain of what due to milk production?

calcium

how is the BCS expected to change from calving until peak lactation for a dairy cow?

the cow will likely lose 0.5-0.75 BCS

what practice is used to treat a displaced abomasum with the greatest success rate?

surgery on the standing cow

what is a factor associated with milk that is directly related to inadequate levels of fiber in the diet of a lactating dairy cow?

low milk fat synthesis

to adequately “prime the mechanism” of a cow to extract calcium from the bones post-freshening to prevent milk fever, how should the cow be fed pre-calving?

feed low levels of calcium and minimize the feeding of legumes

what is the tell-tale sign for diagnosis of a displaced abomasum?

presence of a high pitched “ping” upon tapping the left side of the cow

what state ranks #1 in dairy production?

california

which state has seen a significant influx of dairy operations from California and now ranks as the #3 dairy producing state in the US?

idaho

for the properly conditioned dry cow, how much grain should be fed?

limit grain to less than 0.5% of a cows body weight

upon “drawing line” from the hooks to the hurl of the pins, what letter should appear for cows who have a BCS of 3.25 of greater?

“U” shape

what is the maximum amount of grain that should be incorporated into a lactating dairy cow diet to minimize the incidence of various metabolic disorders?

50%

to optimize space relative to facility cost and productivity, what percentage of the cows should be able to eat at one time to assure adequate feed consumption?

75%

which cows are most likely to benefit from addition of supplemental fat to the diet?

early lactation cows

what period of dairy cow production is considered a period of “rest” to facilitate mammary and rumen rehabilitation? a lower energy, high fiber diet is typically fed during this period.

dry period

what are symptoms of milk fever?

muscle tremors and paralysis (unable to rise or walk)

a common cure for milk fever is…

intravenous (IV) administration of calcium (calcium gluconate)

what is the primary advantage of incorporating ethanol co-products such as distillers grains into a lactating cow diet?

high protein, energy, & fiber, but no startch

what is the expected daily water consumption of a lactating dairy cow?

30-50 gallons/day

when is it recommended that lost body condition associated with the freshening period be restored?

during late lactation

what is the average calving interval for dairy cows?

13-14 months

what is the impact, if any, of continual high temperatures at the time of insemination on conception rates and embryonic development?

reduced conception rates and increased embryonic development issues

milk yield = 150 lbs

BF = 3.5%

P = 2.4%

BF Px = $1.45/lb

P Px = $3.05/lb

\
What is total milk value?

$18.59

what class of milk is associated with butter and powdered dry milk products?

class 4

how does the conception rate of sexed semen compare to the conception rate of conventional semen?

the conception rate is lower for sexed semen (40%) than conventional (56%)

onto which females in the dairy herd is it recommended that sexed semen be used?

the youngest females who should be genetically the best

when using sexed heifer semen, what percentage of the offspring are expected to be heifers?

90%

how is it suggested that the producers use the reliability value?

to assist in determination of bull usage intensity

T/F: sexed semen in combination with genomic testing has allowed dairy producers to produce an excess of heifers from the most genetically advanced females in the herd

true

the PTA in dairy cattle is synonymous with what genetic tool available for beef cattle?

EPDs

using an estrus synchronization plan instead of simple estrus detection and breeding will almost always result in what?

decreased conception rates

milk yield = 120 lbs

BF = 4.6%

P = 3.3%

BF Px = $1.64/lb

P Px = $3.04/lb

\
What is total milk value?

$21.09

what three generalized groups of traits are used in development of the Lifetime Net Merit Index?

production, health & fertility, and functionality

T/F: it is standard procedure to dry off all cows after 305 days in milk (DIM) regardless of the due date for their next calf

false

T/F: today, many dairy operations are breeding their middle and lower tier cows to beef semen to increase the value of non-replacement heifer calves

true

today (2021), approximately what percentage of dairy AI bulls are genomically tested?

\~80%

how has technology associated with genomics affected the rate of genetic progress since it became commercially available in 2009?

doubled the rate of genetic progress through reduced generation intervals and increased selection intensity and accuracy

what is the current world record for milk production during one lactation period?

\~78,000 lbs

how has the number of dairy operations in the US changed since 2000?

today, we have less than one-half the number of dairies that existed in 2000.

which dairy breed tends to produce the highest level of fat and protein in the milk, on average?

jersey

T/F: if a cow has a displaced abomasum and surgery is not an option, producers have had moderate success returning the DA to its normal position by turning the cow upside down (on its back) and rolling her back and forth

true