EXAM 3

Question 1

What is a least cost ration?

Answer 1

a diet that meets the animal’s needs at the cheapest price
- must consider: cost of feed, transportation costs, processing costs (if processing is performed), and labor involved in feeding the diet to the animal

Question 2

Why is there no perfect ration?

Answer 2

producers formulate diets for groups of animals (ie. lactating sows) by finding the groups’ average needs
- some animals may have higher or lower nutrient requirements, and eat more or less of the ration, respectively

Question 3

What is the NRC, and why is it so important?

Answer 3

a. non-profit, non-government organization, puts together a committee of nutritionists who specialize in a particular species
b. National Research Council publishes nutrient requirements and content of feeds every 7 to 10 years (for different breeds, ages, weights, and productions)

Question 4

What are the 4 different energy units?

Answer 4

1. TDN (total digestible energy): - sum of the digestible fiber, protein, lipid, and carb components of a feedstuff/diet (US used to use this unit)
   - doesn’t consider diet related energy loss in urine, methane, and heat
   - not suitable for ruminants because of microbial fermentation
2. DE: - amount of energy in the feed- amount of energy lost in the feces
   - used for horse diets because they have small dietary energy loss from methane
3. ME: - used by pigs and poultry because they lose most dietary energy through urine and methane
4. NE: - most commonly used for ruminants
   - used to measure energy available for both maintenance (NEm) and production (RE) requirements

Question 5

What are the different protein requirements for ruminants and non-ruminants?

Answer 5

ruminants: - utilize degradable intake protein (DIP), undegradable intake protein (UIP)
- protein requirements met through the protein that reaches the abomasum and SI
- more difficult to formulate ration because hard to predict or directly measure how much protein within a feed will be degraded and how much will bypass microbial fermentation

Question 6

What is basal metabolism, and what 5 factors influence it?

Answer 6

a. amount of heat produced by the body (the metabolic rate) in a post-absorptive state with minimal physical activity as well as thermal and psychological stress (aka minimum amount of energy required to maintain vital functions in an animal when at rest)
b. 1. body size: larger the animal, the greater its maintenance energy requirement
2. species
3. age: younger the animal, the greater its maintenance energy (on top of growing)
4. previous level of nutrition: animals consistently fed a low energy diet have a reduced maintenance requirement (same applies for animals that are fasted) (body’s protection mechanism)
5. climate: animals in cold climates have an increased basal heat production, and increased basal metabolism (body needs additional heat to maintain internal temp.)

Question 7

How are muscular work and temperature regulation related to maintenance?

Answer 7

muscular work: - energy expended is directly related to the intensity and duration of the work
- (ex.) heart beating, diaphragm contractions, maintaining muscle tone
temperature regulation: - when temp. drops, body must expend energy to maintain its body temp.
- lower critical temp. depends on level of feed intake, body size, and tissue and coat insulation

Question 8

Definition of reproduction, indicators of optimal reproduction, and objective of good feeding program.

Answer 8

a. the process by which animals (and plants) give rise to offspring, that consists of a sexual or asexual process and the subsequent growth of the parental gametes and differentiation into a new individual
b. - easy conception
- low rate of fetal and neonatal death
- normal parturition
- maximum litter size
- adequate lactation
- optimal rate of growth of healthy offspring
c. -optimize health and body condition of the dam throughout the various periods
- optimize reproductive performance
- optimize offspring health and development through the weaning period

Question 9

What’s the average for different animals to reach puberty, and what can affect when it is reached?

Answer 9

a. - cow: 7 to 8 months
- mare: 10 to 12 months
- ewe: 9 months
- sow: 5 to 7 months
- queen: 6 months
- bitch: 6 months
b. body size can affect when puberty hits (well-fed animals grow faster, and reach puberty sooner)

Question 10

How do you assess an animal for breeding (both younger and mature animals)?

Answer 10

both (young and mature): - in good health and up to date on vaccines
- ideal body weight
mature: - nutrition

Question 11

What is flushing, and when and how is it used?

Answer 11

a. it’s a technique used on SOME production animals
b. it’s practiced on breeds or industries where litters are more desirable (not cattle or finn sheep/animals that produce litters), like dorset sheep (usually produce singlets)
c. it increases the nutrients arriving to the ovary, which convinces the ovary that the animal is in good nutritional status
- not used on females with good BCS (why)

Question 12

What the ways to access pregnany?

Answer 12

1. abdominal and uterine palpitations
2. ultrasound
3. radiographs (involves calcification of fetus, and is done after ultrasound)

Question 13

What are the different gestation lengths of animals?

Answer 13

• cow – 9 months
• sheep (Ewe) and goats (Doe) – 145 to 150 days (5 months)
• pig (Sow) – 3 months, 3 weeks, 3 days!! (114 – 115 days)
• horse (Mare) – 11 months
• cat (Queen) and dog (Bitch) – 63 to 65 days (2 months)

Question 14

What are the general nutrient requirements during the three trimesters of pregnancy?

Answer 14

1st and 2nd trimesters: pregnant animal is often fed at or slightly above a maintenance diet
3rd trimester: requirements increase rapidly because fetal growth increases rapidly, and mammary gland is growing

Question 15

What are the differences in maternal and fetal body weight between the species?

Answer 15

guinea pigs: 40% maternal: fetal BW (reason they are so large at birth at can be weaned immediately)
sheep: 13.3% maternal: fetal BW (shorter gestation period than a cow, and generally produce lambs)
cow: 7.5% maternal: fetal BW (typically produces singlet)
sow: 6% maternal: fetal BW (large litter of small piglets that grow rapidly the first few weeks after birth)
humans: 5.8% maternal: fetal BW (very long period of paternal care preparing the baby to function on its own)
higher ratio % means more energy mom is putting into baby

Question 16

What are the key nutritional factors during pregnancy?

Answer 16

1. water
2. energy
3. protein quantity and quality
4. calcium and phosphorous

Question 17

What are specific nutrient requirements for ruminants and non ruminants?

Answer 17

In well fed ruminants and non ruminants, almost all fetal energy and nitrogen requirements are met by placental transport of glucose and AAs

Question 18

How does the heat increment (HI) play a role during pregnancy?

Answer 18

• the 3 main sources are: fetal metabolism, uterine and placental metabolism, and non-uterine tissues (liver, GI tract, and kidneys)
• as pregnancy goes on, more energy heat is lost as heat each day

Question 19

What are the effects of a malnourished animal during pregnancy?

Answer 19

• can negatively impact fetal growth (degree depends on specie, severity and duration of underfeeding, and body condition at the onset of underfeeding)
• has greatest impact on placenta during early pregnancy (why)
  if adequate fat reserves, dam will decrease her glucose utilization to spare it for the fetus, and use FAs, and rarely protein, to meet her own energy needs

Question 20

How are lactose, fat, and protein synthesized?

Answer 20

lactose (glucose-galactose disaccharide): blood glucose enters the milk secretory cell and some of
it is used to synthesize galactose; forms lactose
- milk yield is directly related to the rate of mammary lactose synthesis (lactose is osmotic regulator of milk)
- increase in lactose production = increase in total amount of milk produced
fat: FAs that compose these
triglycerides are either produced from
blood acetate and 3-β-hydroxybutyrate
directly within the milk secretory cell or
enter the mammary secretory cell as
pre-formed long-chain fatty acids from
plasma lipoproteins
- glycerol 3-phosphate required for
fatty acid esterification is synthesized from glucose within the milk secretory cell
protein: albumins and immunoglobulins pass from blood to mammary gland to synthesize whey fraction of protein
- mammary gland takes up AAs, and secrete majority of it into milk
- a lot of transamination occurs in the mammary gland

Question 21

What are the nutritional requirements during each stage of the cow’s lactation cycle?

Answer 21

early: focus is to meet the cow’s energy needs, while her appetite is declining and energy need is increasing (negative energy balance)
- energy needs are met from body stores (this makes up for the energy consumed in the diet not being enough for milk production, alone)
- increasing grain in the diet reduces gut fill and provides more energy
mid/late: fed a ration that matches her production potential
- cow is pregnant, so high energy need
dry period (3rd trimester): fed high energy diet to prevent mobilization of lipids and support the growth of the fetus
- this period allows mammary glands to rest
- goal is to maintain cow’s BCS from 3.5-4
as cow ages, nutrient requirement increases because she’s gaining weight

Question 22

What are the feeding guidelines for a calf and heifer?

Answer 22

calf: fed mostly milk until weaned at 5-8 weeks
- functionally a non-ruminant, so easily digestible carbs, lipids, and proteins should be fed
- forage and grain are offered when the calf is a few weeks old (rumen rapidly develops)
amount of forage and grain fed depends on quality and age of calf
heifer: should be fed a diet consisting of forage, additional concentrates, and protein for growth
- at first calving, should be good body size and condition, high feed intake, and delivery of nutrients to mammary glands

Question 23

What are some metabolic diseases, and what are the type of diets/ways to prevent metabolic diseases?

Answer 23

a. ketosis (decreased blood glucose), milk fever (decreased calcium), and high blood urea nitrogen
b. - provide diet during dry period that is already rationed for early lactation
- diet that contains adequate amounts and lengths of fiber
- early lactation diet with a rumen buffer to maintain proper pH

Question 24

What condition can occur if blood glucose drops too low?

Answer 24

ketosis:
- ketones can appear in the blood, urine, milk, and breath
- ketone production occurs as the cow tries to mobilize and utilize body fat through the TCA cycle
treatments: infusion of glucose and/or propionate into the blood; avoid BCS over 4.0; formulate ration that maximizes available propionate and carbon entering the TCA cycle

Question 25

What is milk fever and when does this typically occur?

Answer 25

a. low blood calcium
b. occurs within a few days of calving
- at calving, the requirement for calcium increases, since onset of lactation causes large drain of extracellular calcium
- can occur in dairy cows (most common in older cows, and Jersey cows over Holsteins’)
treatment/prevention: feeding forage that contain low quantities of calcium, or a diet having a negative dietary electrolyte balance; calcium injections (subQ or IM) to help maintain blood calcium levels until her body is able to come back into balance

Question 26

What is milk fat depression?

Answer 26

occurs when cows are fed a low energy diet or if the roughage: concentrate ratio is out of balance (ration with more than 60% starchy concentrates)

Question 27

What are the benefits of Somatotropin (bST) and how does it work?

Answer 27

a. increases milk production by 10-15%, when given to a lactating cow
b. it’s a nutrient partitioning agent
- causes more of the nutrients being eaten to be used for production and
less to be used for adipose tissue deposition
- cows receiving bST increase their feed intake to meet the increased demands of the mammary gland (if not properly fed, she will not respond)
cows receiving bST produce the same quality of milk as cows who are not

Question 28

What is meant by the term growth? What happens during this time period?

Answer 28

a. a very broad term that encompasses many phases of life; it is a continuous and dynamic process
b. - process of development which includes a gradual increase in size
- stage of development to reach one’s full size
- development from a simpler to more complex organism

Question 29

What is colostrum and why is it so important?

Answer 29

a. aka “first milk” thin milky secretion from the nipples that precedes and follows true lactation
b. rich in antibodies, minerals, total solids (about 25%), as well as high concentrations of protein and fat
studies have shown that if not received, newborn may experience a “failure to thrive”

Question 30

What is unique about the digestive tract of a newborn? What characteristic is especially unique to ruminant neonates?

Answer 30

a. - lactase activity is high (lactose is the predominant carbohydrate in milk)
- little pepsin activity in the stomach (protein digestion is low; also helps to prevent the breakdown of the immunoglobulins ( colostrum contains trypsin inhibitor that also does this))
- animals are born with spaces between the intestinal epithelium cells that allow the large immunoglobulin protein molecules to cross through the epithelium and enter the blood (space closes around 35 hours after birth)
b. - esophageal groove: brings milk from the esophagus directly into the abomasum bypassing the rumen
- forms when animal is suckling (suckling sets off a series of nerve transmissions that stimulates a section of tissue to form a channel for the milk to pass through the rumen; when animal is not suckling, muscles relax, and the groove disappears)

Question 31

What are some important management processes for the newborn? When will milk replacer be used?

Answer 31

a. - removing fetal membranes
- drying the animals
- cutting the umbilical cord
- make sure the newborn has received its’ colostrum and the new mom is safe and warm
- piglets receive iron shots to prevent anemia (mom’s colostrum doesn’t have iron)
- ruminants receive vitamin A shots, and may also receive a dose of vitamins E, D and iron
b. when a newborn cannot be raised by its dam

Question 32

What is the weaning process, and the importance of creep feeds?

Answer 32

a. process of gradually introducing a mammal infant to what will be its adult diet and withdrawing the supply of its mother’s milk
b. supplementing the diet of young livestock by offering feed to animals who are still nursing
- prepares the animal’s digestive tract for weaning
- initiates and promotes gut and digestive enzyme development; enables the animal to digest nutrients from food sources other than milk
- encourages feed intake (smooths transition at weaning
- very palatabel, and high in energy; should only be accessible to growing animals and away from the dam

Question 33

What is the definition of postnatal growth?

Answer 33

processes that occur after birth:
- progressive net accretion of nutrients and metabolites
- begins at conception (fetus doesn’t grow properly, then it won’t grow properly after birth)
- continues as long as nutrient intake exceeds requirement for maintenance of existing tissues

Question 34

What is allometric growth?

Answer 34

occurs in an animal when different parts grow at different times and at different rates
first bone -> muscle -> fat

Question 35

What is body composition, and different methods of measurement?

Answer 35

a. - varies in species, stage of growth, nutritional history, and genetic bases (also, organ systems, pregnancy and presence of abnormalities)
b. direct: - whole body dissection (organs and tissues are removed and weighed, or dissect out the carcass, and seperate the muscle and bone)
- chemical composition of the animal (analyzing the amount of water, protein, fat and ash; must grind carcass into homogenous mixture to perform proximate analysis)
indirect: - most common and uses live animals
- ultrasound
- back-fat probe (incision made in the skin to measure fat depth w/ ruler; more often in pigs, then cattle/sheep)
- live weight (very common)
- visual assessment and subjective evaluation (very common)
- radioactive isotope of potassium (amount of K in body is directly related to amount of lean tissue)

Question 36

What are the parameters for the 4 factors that influence body composition?

Answer 36

1. age: BW increases w/ age
   - young animals grow more efficiently than older ones (lower feed: gain)
   - young animals tend to be high in protein while older animals are higher in fat
2. genotype: - determines mature body size, and physiological maturity and body composition at any BW
3. sex: - sex steroids affect body composition
   - at the same BW, males tend to be
   leaner than females (castrated males tend to fall between males and females)
4. nutrition: - lower feed: gain means more protein is being. deposited, and the animal is more efficient
   - extra energy gets deposited as fat

Question 37

What are the general trends of the beef cattle industry?

Answer 37

decline in the amount of beef cattle, but increase in beef production

Question 38

What is the structure of the beef industry?

Answer 38

• known as a “diffuse” (produces heavier animals at the lowest cost)
• has more phases than any other livestock animal:
  cow-calf (calf sold at weaning)
  stocker/yearling (area where lighter calves that need to gain weight are housed)
  feedlot/finishing (fed to market weight, then sold)
  packing plant (slaughterhouse)

Question 39

What are the general guidelines for feeding the cow at different life stages?

Answer 39

1. postpartum: period of greatest nutritional demand (when voluntary feed intake is highest)
   - adequate fresh forage ad lib
   - if necessary, a grain supplement for additional energy
   - mineral supplement to grazing cattle
   - if not fed to meet her nutritional demands, she will fail/be delayed in rebreeding and lose weight
2. lactating (1st trimester): begins AFTER calving and ends when calf is weaned
   - nutritional/energy requirements are still high, but decrease from postpartum (fetal growth is limited)
   - time of peaked lactation (usually lose weight)
3. gestation (2nd trimester): nutritional requirements are lowest because lactation has stopped
   - 1st calf is weaned, pregnant with 2nd (development still slow)
   - cow feed intake is lowest, but still best to increase BW and BCS
4. pre-calving (3rd trimester): must calve with a BCS of 3-4 to have healthy calf and rebreed quickly
   - energy and protein needs increase compared to gestation (preparing for lactation)
   - late in this period, feed intake decreases because calf is taking up space normally occupied by the rumen

Question 40

What are the general guidelines for feeding the calf at different life stages?

Answer 40

1. lactating calf: stays with mom and lactates for 6-7 months on cow-calf operation
   - grazes on pasture (may be provided creep feed)
2. weaned calf: after weaning, placed in feedlot
   - heifers reach grade at a lighter body weight than steers
   - fed a high grain diet to gain weight ASAP

Question 41

What are the general guidelines for feeding the bull?

Answer 41

mature bulls: need good quality pasture, and about 15% more than a mature cow
younger bulls: need increased grain and CP to have BCS of breeding bull
- BCS should be a 6 at the time of breeding season

Question 42

Why does bloat occur? What are the clinical signs? What is/are the treatment(s)?

Answer 42

a. occurs when cattle can’t belch/release gases produced by rumen microbes
- pressure on diaphragm and lungs, which reduces/cuts off O2 supply and suffocates the cattle
- problems for animals on high grain diet
b. - swell rapidly on the left side (may die within an hour)
- signs of discomfort (kicking side, stomping feet)
c. - veterinarian can administer poloxalene through a stomach tube (helps breakdown stable foam, and animal belches)
- feed coarsely chopped roughage as 10-15% of the ration in finishing diet
- bloat needle/trocar puncture the left side of the rumen wall to relieve pressure (extreme cases; last resort)
most common digestive disorder in beef cattle, often in feedlot cattle (frothy bloat)

Question 43

Why does acidosis occur? What are the clinical signs? What is/are the treatment(s)?

Answer 43

a. associated with a shift from a forage-based diet to a high concentrate-based
diet/excessive consumption of fermentable carbs.
b. - rumen stasis (slowing/stopping of gut movement)
- diarrhea (soft, gray, and foamy)
- dehydration
- appear weak, anorexic and uncoordinated
- subacute acidosis (pH less than 5.6) leads to variable feed intake and decreased performance
- acute acidosis (pH less than 5.2) can result in heart and lung failure and death
c. - keep at least 10% roughage in final diet (forages and cottonseed hulls)
- combination of grains or dry drain w/ high moisture grain
- processing grains less thoroughly
- feeding ionophores (Monensin and Lasalocid), especially to claves starting on high concentrate diets

Question 44

Why does grass tetany occur? What are the clinical signs? What is/are the treatment(s)?

Answer 44

a. when magnesium and calcium levels in forages are too low to meet the requirements of cattle, and no supplementation
- most commonly affects lactating cattle (when magnesium and calcium requirements are highest), particularly the highest-producing animals in the herd
b. - nervousness
- muscle twitching
- staggering during walking
- may go down on its side, experience muscle spasms/convulsions, and death if not treated
c. - slow IV of calcium borogluconate solution with 5% magnesium hypophosphate
- calcium, phosphorus, magnesium and potassium gel solution should be given orally
- treat magnesium deficient pasture with dolomitic lime
early treatment is important; collapsed cattle that have been down more than 12 to 24 hours will seldom
recover