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)
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
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
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)
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)
What are risk factors of rumen impaction? (2)
- poor quality forage
Grass hay has more ________, while legumes (such as alfalfa) have more ________.
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)
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
Non-fiber carbohydrate = ________
- The mathematical equation to calculate this is...
- NFC = 100 - % protein - % ash - % fat - % NDF
__________ (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)
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
________ is the highest concentrated VFA in the rumen; the other VFAs are...
Acetate; proprionate, butyrate
________ in the saliva buffers the rumen; the more _________ in the diet, the more of this is produced to buffer the rumen.
Sodium bicarb; forages
________ (dietary component) stimulates rumination.
Physically effective NDF [BUT if we have too much physically effective NDF, we will decrease intake]
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
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
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
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]
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
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
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
How is crude protein calculated?
from the determined nitrogen content and multiplying by a factor
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
What is "available protein"?
difference b/w crude protein and unavailable protein
Define "soluble protein".
protein which is rapidly degraded to ammonia in the rumen; used by the rumen bacteria when their growth is high
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
As ADF increases, ...
the ability to digest/ digestability of the forage/ TDN decreases.
TDN= total digestible nutrients
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
As NDF percent increases, ...
dry matter intake generally decreases
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
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
represents the mineral content of the feed or forage
the prime factor influencing the digestibility of plant cell wall material
As lignen increases,...
digestibility, intake, and animal performance decrease
As the percent of lignen increases,...
percent ADF and NDF increase