Final Exam Flashcards
What are at least 2 biological advantages that the ruminant gastrointestinal tract provides compared to the non-ruminant digestive system
VFA production
Digest more materials than a nonruminant can- can use stuff monogastrics cannot
Provide at least 4 defining characteristics of ruminant animals
split hooves
herbivores
different teeth- no upper incisors
have a rumen/ pre-gastric stomach
What are the 5 sacs of the rumen and what biological advantage do they provide compared to if the rumen was a single continuous compartment
Ventral
Ventral blind
dorsal
dorsal blind
cranial
these sacs allow for better digestion as they increase the time food is caught in the rumen
What are 2 factors that influence digestion of feed in ruminants
rate of passage
rate of fermentation
What are 2 examples of fermentation end products that are not directly useful to ruminant animals
methane
carbon dioxide
Ruminant species have different grazing strategies and differences in grazing strategies often related to body size. Why?
The smaller the animal is, the smaller their rumen will be. This means they will have to eat certain foods that can be digested quicker since there is less room for it to hang out
What are the 3 different grazing strategies utlilized by ruminant species and describe how they differ from each other
Browse- leaves and berries- goat
Grazing- less picky- eating the grass and forage- cattle
Intermediate- eat a bit of both, leaves, berries, grass, etc.- sheep
List 3 short-chain fatty acids produced in the rumen that account for almost all organic acids produced from ruminal fermentation. Which short-chain fatty acid is typically found in the greatest amount
Butyrate
propionate
Acetate- found in the greatest amount
What nutrients can be metabolized from food to provide energy to ruminants
proteins
lipids
carbohydrates
What is the standard unit of energy used in the United States in reference to dietary energy concentrations in cattle diets
Mcal- because cows require so many more calories it is easier to use this larger unit
What fraction of energy in a food represents the heat of combustion
gross energy
What energy losses describe the difference in metabolizable energy and the heat of combustion
fecal
gaseous
urinary
What form of energy loss represents the difference between net energy and metabolizable energy
heat losses
Illustrate the partial efficiency of energy use from fasting (no food intake) to ad libitum for a rapidly growing beef steer. Identify there maintenance energy requirements are met
Graph 1 on Notability document
Explain why energy is of increasing importance for growth in cattle after the typical age for weaning
After weaning their main energy source is through fats/lipids given to them in feed. This is important for growth/performance
How are energy values derived in most feed libraries
TDN
What do measures of TDN reflect
energy
How can TDN be calculated if one knows the digestible nutrients in a feed
digestible carbohydrates+ digestible protein+ digestible fats times 2.25=TDN
What is the inherent flaw in calculations of TDN
It assumes that carbs and protein are equal
What is an example of an inaccuracy that results from the flaw in calculations of TDN
TDN being more than 100%
If TDN is flawed, then why is it still commonly used in reference to feed ingredients for ruminants
It is easy to use
can do it in a lab with calculations and no animals
How is energy related to predictions of dry matter intake
Energy drives dry matter intake
Empty body weight gain (EWG) can be predicted using the below model equation. In this model equation what is EQEBW and what does it reflect
Equivalent empty body weight
shows physiological maturity
what dietary components contributes the most to determining predictions of body weight gains in cattle be specific
retained energy
How are energy requirements for lactation determined in ruminants
all of their energy should go into milk so you can measure the components of the milk to determine them
Name and describe the 3 forms of starch discussed in class
Amylose- plant starch
Amylopectin- plant starch
Glycogen- animal starch
What are 3 functions of carbohydrates
Provide energy
building blocks for other stuff
heat production
What is the main difference in the chemical structure between starch and cellulose
Their linkage alpha vs. beta
animals cannot break down beta linkages
What are examples of two heteropolysaccharides
pectin
hemicellulose
What fiber fraction is included in measurement of NDF but not ADF
hemicellulose
What produces VFAs
What are 3 common VFAs
Microbes
Butyrate, acetate, propionate
Describe the differences in VFA production between a stocker calf and a calf in a feed lot
stockers use a forage based system meaning there is more acetate created while feedlots use a grain based system meaning more propionate
What are 2 benefits to increasing propionate production
increased production for the animal
decrease in methane production
Describe how/why VFA production relates to methane
Methane is the byproduct of the fermentation that is used to create VFA
H+ into CH4
What is the primary impact of grain processing on starch digestion in ruminants
processing allows a higher starch digestion because it breaks the undigestible barrier. This allows the starch to be used
What are ionophores
antibiotics that change the ion gradient of microbes by messing with the channels
Describe at least 3 impacts ionophores have when fed to cattle
increased propionate production
decreased meal size
increased efficiency of ruminal fermentation
What are at least 4 possible symptoms of lactic acidosis in catle
death
lower activity
abscessed liver
laminitis
Rank the following in order from the most rapidly digestible to the slowest ruminally fermented carbohydrate; cellulose, neutral detergent fiber, water soluble carbohydrates, and starch
Water soluble carbs
starch
neutral detergent fiber
cellulose
explain why protein is an essential nutrient
the protein is broken down into amino acids that are then used to build the proteins that are needed by the body
what is a limiting amino acid
the AA that when it is lacking will limit protein synthesis
is hydrolysis of starch by enzymes or transport of glucose form the small intestine most limiting to small intestinal starch digestion in ruminants
hydrolysis of starch by enzymes
Name 2 separate strategies used to improve the amino acid profile of diets fed to ruminants
protein complementation
synthetic amino acids
How does net protein differ from metabolizable protein
Net protein is the protein/ amino acids that are actually used by the body for protein synthesis
Metabolizable protein is the protein/ amino acids available for protein synthesis
The extent of ruminal digestion is determined by two competing processes (Kd and Kp) What do Kd and Kp stand for
Kd= rate of digestion
Kp= rate of passage
Write out the extent of digestion equation that was on slide 3 of the 3/13/23 lecture
extent of digestion= rate of digestion over rate of digestion + passage rate
Give an example where feed processing would lead to a greater Kp but likely reduce the extent of digestion
grinding down feed particles would lead to greater rate of passage but reduce extent of digestion
increasing feed intake
If I limited feed intake to 55% of ad libitum, what impacts did it have on passage rate (either solid or liquid) and what impact did it have on dry matter digestion
with less intake the rate of passage was slower, allowing for a greater dry matter digestion
what is the primary route of excretion of waste products from nitrogen metabolism
urine
what are two different forms of digestion that occur in the gastric phase of postruminal digestion
chemical
enzymatic
What segment of the large intestine accounts for the majority of postgastric fermentation
cecum
why is meal duration important to consider when managing ruminants
a fast rate of consumption can lead to acidosis
(HOT)
what is the difference between chemo static and physical fill mechanism for regulation of intake in ruminants
physical fill- size of the stomach
cheomostatic- reaching the caloric intake needed
What 2 fraction of crude protein contribute to metabolizable protein
RUP and MCP
Is microbial crude protein estimated to more or less efficient when cattle are fed diets with greater than 3.9% fat
more efficient
What is the goal of protein and carbohydrate synchrony
to maximize microbial efficiency/ fermentation efficiency
Why do diets that provide synchronous amounts of ruminally degradable protein and fermentable carbohydrates often fail to provide real benefits
the animal does nitrogen recycling
Why is metabolizable protein not usually the most limiting nutrient for production in cattle
metabolizable protein is made up of almost always present microbial crude protein and metabolizable protein includes what amino acids are available, rather than actually used by the tissue
MCP is produced in excess of the requirements of the animal
What role does the liver play in nitrogen use by ruminants
Converts ammonia into urea which is then given to the salivary glands, the kidney, or recycled back to the rumen where it can be used to make skeletal protein (beef)
Illustrate ruminal fermentation of protein. clearly identify the different fractions of protein on the chart
Graph 2 on Notability document
What are 3 factors that can influence rate of protein disappearance in the rumen
composition of the feed
forage: concentrate ratio
types of microbes in the rumen protozoa vs bacteria
How much metabolizable protein is provided from ruminally degradable protein
RUP+RDP=MP
so it is that fraction that RUP does not provide to MP
Which hormone is most commonly associated with long-term signaling of satiety when intake is regulated by chemostatic mechanisms
Leptin
Generally anabolic implants do what to daily dry matter intake in cattle
increase it
Concentration of what is the primary factor that controls daily dry matter intake in cattle when intake is limited by chemostatic mechanisms
Net Energy for Maintenance
Generally, cattle require about how many gallons of water per hundred pounds of body weight
1
Measures of what are most useful when evaluating water quality for cattle
Total dissolved solutes
Why does the caloric requirement for gain increase with increasing body weight in ruminants
because fat makes up an increasing percentage of gain as ruminants mature
When is feed conversion to body weight gain most efficient in cattle
When they are less mature, because fat makes up a lesser proportion of body weight gain
Generally energy and protein requirements are based on
composition of gain
Efficiency of dietary energy is use is most efficient when
fat makes up the greatest proportion of gain
