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Cow shouldn't stand in the holding pen more than ______ per day because...
1 hour; they are forced to stand on concrete and they are being kept away from the feed bunk (effectively decreasing intake)
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What is the average DMI of lactating holsteins, lactating jerseys, and dry holsteins?
- Lactating holstein: 50-55#/day (3.5-4% BW)
- Lactating Jersey: 40-42#/day
- Dry holstein: 2% BW
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What is the rule of thumb for milk production per pound of dry matter a cow eats?
~1.4-1.6# of milk per1# DMI
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What is the risk for feeding refusals to heifers?
the fat in a lactation diet is too high for non-lactating animals--> heifers get too fat--> post-partum metabolic disease (ketosis)
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Describe the importance of water intake in supporting milk production? How can we ensure adequate water intake?
- 20-40 gal per day; 14 drinking bouts per day
- ensure the tank fill rate is fast enough; if it's not, cows will get up to drink, the tank will be empty, and they will be bumped away by another cow before they get a chance to drink (fruitless drinking bouts)
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What are risk factors of rumen impaction? (2)
- dehydration
- poor quality forage
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Grass hay has more ________, while legumes (such as alfalfa) have more ________.
NDFs; lignen
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Why do we increase rapidly fermentable carbs in the close-up dry group?
causes elongation og rumen papilli over a few weeks (increased starch causes longer papilli because a higher surface area is required to absorb the increased VFAs that are formed)
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What do "normal" (or average) diets look like for lactating dairy cows? [breakdown nutrients]
- 16% protein
- 72% carbohydrate (split b/w structural and non-structural)
- 5% fat
- 7% ash
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Non-fiber carbohydrate = ________
- The mathematical equation to calculate this is...
- starch
- NFC = 100 - % protein - % ash - % fat - % NDF
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__________ (dietary component) are key in prevention of rumen acidosis; prevention of rumen acidosis includes... (3)
- Structural carbohydrates
- forage quality, particle length (tickle factor), and adequate mixing (to prevent sorting)
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Increased cases of rumen acidosis? What question should you ask yourself and why?
- How many cows are ruminating when you do a farm visit?
- reduce particle size
- increases surface area for bacteria in rumen to digest/ break down nutrients
- chewing increases saliva production which moistens food and buffers rumen
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________ is the highest concentrated VFA in the rumen; the other VFAs are...
Acetate; proprionate, butyrate
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________ in the saliva buffers the rumen; the more _________ in the diet, the more of this is produced to buffer the rumen.
Sodium bicarb; forages
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________ (dietary component) stimulates rumination.
Physically effective NDF [BUT if we have too much physically effective NDF, we will decrease intake]
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What are indicators of adequate rumen function (on a group level, not an individual cow basis)? (8)
- Milk Fat: holsteins >3.3%, Jerseys >3.8%
- Milk fat:protein ratio: >1:1
- Ruminating: >40% of the day
- DMI: >50#/ day
- Rumen pH: >6
- Fecal pH: >6.2
- Rumen acetate:proprionate ratio: >2.2
- Incidence of metabolic diseases
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What is a PMR and when is it used?
- partial mixed ration-used with robotic systems
- feed is mixed and fed at the bunk and the additional grain they need is given at the time of milking
- PMR is set at a lower # of milk than the cows are actually producing
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In a six row barn, do not stock over ________. In a four row barn, do not stock over ________. This discrepancy exists because...
100%; 115%; 2 additional rows in a 6 row barn without any additional bunk space--> cows will not get enough to eat
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What is the equation to calculate lead factor?
lead factor = (avg milk yield + 1.0STD)/ (avg milk yield)
[balance ration for milk yield above the mean for the group; 10#/ day for first lactation, 5#/day for second lactation to provide additional nutrient density for growth]
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What milk component problem is common in intensive grazing herds and why?
- low milk fat because less chewing and moist feed reduce saliva, low fiber in mature forages
- fix by adding high fiber byproduct feeds to grains
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Define "As Received"
- all values under this heading show the content of the nutrients with the moisture in the sample included
- because of the dilution of water, the values will be lower than the dry matter basis
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Define "Dry Basis"
- values in this column give the nutrient values with the water removed (dry matter)
- this allows comparisons to be made between forages; best indicators of nutrient value
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How is crude protein calculated?
from the determined nitrogen content and multiplying by a factor
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Define "Unavailable protein"
- forage report only shows this if there is heat damage
- this value is an indication of heat damage reducing the protein digestibilty
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What is "available protein"?
difference b/w crude protein and unavailable protein
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Define "soluble protein".
protein which is rapidly degraded to ammonia in the rumen; used by the rumen bacteria when their growth is high
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Define "acid detergent fiber" (ADF).
- refers to the cell wall portions of the forage that are made up of cellulose and lignen
- these values relate to the ability of an animal to digest the forage
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As ADF increases, ...
the ability to digest/ digestability of the forage/ TDN decreases.
TDN= total digestible nutrients
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Define "neutral detergent factor" (NDF).
- the total cell wall which is comprised of the ADF fracture (cellulose and lignen) PLUS hemicellulose
- these values reflect the amount of forage to animal can consume
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As NDF percent increases, ...
dry matter intake generally decreases
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Define "relative feed value" (RFV). How is it used?
- an index that combines the important nutritional factors of intake and digestibility
- allows for comparisons of legume, grass, and legume/ grass forages
- NOT used for ration balancing
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Define "relative feed quality" (RFQ). How is it used?
- calculated by estimating the digestibility of the forage dry matter and by determining how much the cow can eat based on its filling capacity; used fiber digestibility to estimate intake and TDN (energy)
- used to more accurately predict animals' performance
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Define "ash".
represents the mineral content of the feed or forage
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Define "lignen".
the prime factor influencing the digestibility of plant cell wall material
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As lignen increases,...
digestibility, intake, and animal performance decrease
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As the percent of lignen increases,...
percent ADF and NDF increase
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