Feeding cattle

Question 1

Beef cow calf cycle is

Answer 1

Calve in winter/spring
At pasture over summer
Wean calf in fall
Bout 200 to 300 kg
Over winter cow
Preserved feed/pasture
Heifer
Until had third calf

Question 2

What is the reproductive cycle of a cow

Answer 2

First calf at 22-24 months of age
Breed heifers at 12-15 months
% in estrus directly related to weight
53-65% of mature body weight
Adult cows
% coming into estrus related to nutrition
Remain in herd until 10+
Usually pregnancy check in fall
Sell open cows (~43% of cull cows pregnant at time of culling)

Question 3

What is the BCS you should go for in a breeding cow

Answer 3

Aim for good to moderate condition (5-6)
Each score = 34-45 kg
Generally takes ~2 months to gain 1 point

Question 4

How does the digestive system work for bovids

Answer 4

Efficient digesters
Microbial fermentation
More tolerant of poor-quality diets
No dietary source of essential amino acids
No dietary source of essential fatty acids

Question 5

What deos the water consumption of bovids do

Answer 5

Consumption affected by many factors
Temperature
Body weight
Lactation status
Not all needs need to be met by drinking water
Feeds contain water
Metabolism releases water

Question 6

What are the nergy needs of cattel

Answer 6

For the most part, adult beef cattle can meet energy needs from good-quality roughages
Shortage can occur:
Overstocked pastures
Inadequate feed allowances
Poor-quality forages
Drought
Heat increment
Heat released during digestion
Contributes to maintenance of body temperatures in winter

Question 7

Carbs and cattle

Answer 7

Ruminal microbes convert plant carbohydrates (cellulose, starch) to volatile fatty acids
Acetate (cellulose)
Butyrate
Propionate (starches)
VFAs provide 60-80% of a cow’s energy
Maintaining a healthy microbial flora is essential

Question 8

Fibre and cattel

Answer 8

Supports rumen health
Maintains rumen distention
Stimulates motility, cud chewing, salivary flow
Delivers less dietary energy
Balance fibre and non-fibre carbohydrates to optimize energy intake and rumen health

Question 9

Protein and cattle

Answer 9

Have overall nitrogen requirement
No amino acids are essential in the diet
Sulfur requirement (sulfur-containing amino acids)
Protein or Non-protein nitrogen
Ammonia and urea
Ruminal microbes can synthesize amino acids using
Non-protein nitrogen source
Carbohydrate source
Dietary energy
Generally need at least two-thirds of nitrogen as dietary protein
Energy is limiting factor

Question 10

How do cattle get their minerals

Answer 10

Direct add to feed
Mineral blocks
Typically contain Ca and P source
Copper, iodine and selenium
Free choice blocks should contain 25% salt-why?

Question 11

Rhughage for ruminants is

Answer 11

Cattle are ruminants
Require roughage for rumen health
An inexpensive and widely available feed
Maintenance requirement
1.5% of body weight as roughage DM
More if poor quality
Typically at least 60% of diet DM is roughage

Question 12

Why do you allow for food wastage with cattle and how much

Answer 12

Allowance for wastage
Extra 10 to 30%
Some of this is unpalatable feed
Some is pure wastage
Feed trampled when fed loose
Reduce by using bale feeders
Chopping forage and feeding from a bunk

Question 13

Dry matter intake is impacted by

Answer 13

Feed Composition
Neutral detergent fibre content
Quality of feeds
Maturity of forage
Nutrient availability
Cow Physiology
Age
Body size
Physiological state
BCS
Lactation/Production level
Management
Feed bunk management
Grouping strategies
Heat abatement strategies
Maintenance of body temperature
Maximal dry matter intake is about 2-3% of body weight

Question 14

Energy neds of cattle

Answer 14

In general, fresh, actively growing forages are typically capable of meeting or exceeding the needs of beef cattle
Mature or dormant forages may or may not meet the requirements… need to consider the energy needs and the nutritional phase

Question 15

What happens in spring for cattle and what do you feed

Answer 15

Calving, lactation and early pregnancy
Cow calf pairs graze pasture
May move to community pasture
Pasture may not be adequate
Too cold early in year/drought
Supplement cows
Good hay
Grain?

Question 16

What happens in summer for cows and what do you feed

Answer 16

Lactation and pregnancy
At pasture
Roam with bull(s)
Typically on community pasture
Pasture rotation is best
Parasite control
Fertilize for optimal growth
Allows grass a recovery period

Question 17

What happens in fall and waht do you feed for cows

Answer 17

Calves are weaned
Mid gestation, lactation stops at weaning
Period of lowest nutritional requirements for cows
Weaning
Typically wean at end of summer/in fall when grass no longer growing
Gradual weaning using a nose ring to stop sucking is best.
Wean about a week later when nursing has stopped.
Calf then
Backgrounded
Sent to feedlot

Question 18

What happens in fall and how do you feed cows

Answer 18

Cows may graze:
Forage left on grain fields after harvest
Straw plus missed grain
Damaged crops
Grass undersown in barley field
Maize fields
Pasture–particularly in warm wet falls

Question 19

What happens in fall and how do you feed cows

Answer 19

Preserved feeds
Hay
Silage
Greenfeed
Straw/chaff (<80% of diet) + grain
Mature cows have greater body reserves and lower nutrient requirements than heifers
Can generally be over-wintered on rations of poor quality
Should maintain weight fall to fall
Calve at BCS 5.5-6
Over-conditioning causes excess fat deposition in udder and lower milk production
Increases risk of dystocia

Question 20

How does feeding change by breeding stage

Answer 20

Two months pre-calving
70-80% of fetal growth
At late-stage gestation or lactation
20-45% higher energy requirements
40-80% higher protein requirements

Question 21

What are common pasture probelms for cows

Answer 21

Variable quality
Not always growing
Damage from over grazing
Shortage of pasture
Move to new pasture, crop residue, preserved feed
Poor cattle prices
No incentive to sell, but can’t afford to feed
Drought
Not enough to feed
Welfare cases
Sell cows, don’t let them starve
Producers often don’t want to lose genetics

Question 22

Acute bovine pulmonary emphysema and edema is and caused by

Answer 22

ABPEE, aka “Fog fever”
Sudden onset respiratory distress, minimal coughing
Course ends after a few days (fatally, or with dramatic improvement)
Typically in the fall, 5-10 days after change to lush, green pasture
Rapidly growing pastures
L-tryptophan
Converted by ruminal microbes
3-methylindole
3-methylindole absorbed into blood stream
Pneumotoxicity
Uncommon disease
Introduce to lush pasture slowly

Question 23

BCS is done when and what is ideal in cattle

Answer 23

Perform in fall when pregnancy checking
Check that enough feed available for winter
Feed to reach or maintain a BCS of 6 or 7
To move a 500 kg cow from score 2 to 6 in 100 days
Requires nutrients for maintenance, fetal growth, gain in body condition
The colder it get the more difficult it is to improve condition.

Question 24

What are common winter feeding problems for cows

Answer 24

Cold
Increases nutrient requirements
Rely on heat produced in rumen to maintain body temperature
Particularly in thin cows
Feed 0.5 kg extra grain for every 5C drop:
If below -20C and drop is sudden
Poor quality feed
Insufficient feed

Question 25

What are common winter feed problems in the winter for cows

Answer 25

Moldy feeds
Reduced nutritional quality
Risk of abortions and other reproductive problems
Moldy sweet clover
Sweet clover high in courmarin
Converted by moulds to dicoumarol
Interferes with metabolism of Vitamin K
Bleeding problems, death

Question 26

What are the limitations for feeding NPN in cattle

Answer 26

Ruminal microbes can synthesize amino acids using
Non-protein nitrogen source
Carbohydrate source
Dietary energy
Need at least two-thirds of nitrogen as dietary protein
Energy is limiting factor
High producing animals
Lactating dairy cows, feedlot calves
Require all/most of dietary nitrogen as protein
Microbial synthesis of amino acids from urea requires too much energy
Beef cows in mid gestation
Can be fed urea

Question 27

What is hypocalcemia and what causes it in cattle

Answer 27

Usually seen in late pregnancy/early lactation
Early or rapidly rising lactation
Dairy cows after parturition
Going off feed also predisposes
Affects all types of muscles
Weakness and recumbency
Increased demand for calcium overcomes the ability to maintain homeostasis
Body stores (bone) are adequate
Low plasma ionized Ca++
Calcium removal exceeds replacement from diet and bone
Mobilization from bone cannot keep up
Avoid high calcium concentrations in prepartum ration
High calcium rations prepartum down-regulate the regulatory system
`

Question 28

How can you stop hypocalcemia from happening in cattle

Answer 28

Anionic diets
DCAB (dietary cation-anion balanced feeding system)
DCAB promotes acidic condition, which promotes calcium mobilization
Magnesium
Important in PTH secretion and activity and activation of vitamin D
Low magnesium diet inhibits PTH secretion and prevents activation of Vitamin D

Question 29

How do you feed a cow in clinic

Answer 29

Basal Diet?
Typically hay
How much?
Maintenance, 1.5% of body weight
1200lb mature cow
18lbs feed

Question 30

How do you feed cattle

Answer 30

“Creep feeding”
Grain mixture or high- quality forage accessible only by calves
High-fibre
Corn gluten, dry distiller’s grain, soyhulls
Salt-vitamin-mineral mix
Commercial 14-16% protein creep feed

Question 31

How do you feed weaning to breeding replacement heifers

Answer 31

Must be fed separately
Weigh about 53-65% of mature weight at breeding
Usually breed one cycle (21 days) before cows
13-14 months of age
Better observation at calving
Short calving period
Need to gain about 0.5 kg /day from weaning to breeding

Question 32

What are some possible winter diets for replacement heifers

Answer 32

Grass hay (75%), and grain (25%)
Corn silage (96%), protein supplement (4%)
Alfalfa / grass hay mixture
Feed ad lib (2.5% of body weight plus wastage)

Question 33

How do you feed a replacement heifer from breeding to calving

Answer 33

Summer-at pasture
Next winter
Still require separate feeding
Require more feed than adults as still growing

Question 34

How do you feed a breeder bull

Answer 34

Growing bull calves require balanced ration
Yearling bulls fed extremely high energy diets prone to disease and reduced longevity
Deficiency of carotene, phosphorus, energy and protein can reduce fertility
Ensure present in adequate amounts in ration 6-8 weeks prior to breeding

Question 35

How do you finish calves in feedlot

Answer 35

Enter feedlot
Immediately following weaning
After backgrounding (yearlings)
Less disease
Purchased from a variety of sources
Shipped long distances
Comingled
High risk of (respiratory) disease
Especially at entry into feedlot

Question 36

What is backgrounding for cattle

Answer 36

Growing, feeding and managing steers and heifers from weaning until they enter the feedlot
Feed is typically forage-based
Some grain may be fed
Control weight gain
Gain enough muscle and bone before laying down fat covering and marbling

Question 37

What are the approaches to purchasing a cow

Answer 37

Buy “preconditioned” calves
Adapted to partial grain diet
Dewormed
Vaccinated
May be favored by small feedlots
Buy poorer calves
Less expensive
Favored by feedlots with good treatment protocols
Concerns about policing of preconditioning

Question 38

What is compenstory growth

Answer 38

Growth initially restricted by a low energy (roughage) diet
Poorer body condition
Placed on a high energy diet
Eat more, grow faster, less energy used for maintenance compared to better conditioned animals
Attain normal mature size
Favored by buyers

Question 39

What is the diet for backgrounding cattle

Answer 39

FED AD. LIB
First two weeks-good quality hay.
Then switch to higher energy diets
Transition Diet
Growing-finishing diet
Contain 30% or less roughage
Contain grain and often a protein supplement.

Question 40

What is ruminal acidosis and what causes it

Answer 40

↑ Rapidly fermentable carbohydrates
Accumulation of VFA
↓ Ruminal pH
Grain overload
- Ruminal pH < 5
- Lactic acidosis and acidemia
- CV collapse, shock, death
Subacute Ruminal acidosis
- Ruminal pH 5.6-5.2; repeated occurrence
- Indigestion, decreased feed intake
- Bacterial leakage into the portal circulation can result in liver abscesses
Slow transition to allow ruminal mucosa time to adjust
Longer forage particles

Question 41

What is bloat and what causes it

Answer 41

Frothy bloat
Production of insoluble slime by rumen bacteria when fed high-carbohydrate diets
Particularly if feed is too finely ground
Fermented gas entrapment by the fine particle size
Most common in cattle on grain diet for 1-2 months
Increase in level of grain feeding?
Slime-producing rumen bacteria proliferate to large enough numbers

Question 42

Fat and finishers and cattle

Answer 42

Possibly added fat at up to 4% of DM
Excess fat levels may be unpalatable and affect rumen microbes
Sources–rendering, vegetable oil, kitchen grease
Advantages
Increased caloric density
Less dust loss

Question 43

What are conditioners used for in cow feed

Answer 43

Reduce dust loss (blown away) in dry feed
Reduce sorting
Selective eating of more palatable feeds
Improve palatability
Usually used on dry (90% DM) diets
Beet molasses
Cane molasses
Tempering feed with water

Question 44

What are buffers in cattle feed

Answer 44

Sodium Bicarbonate
About 0.75% of diet DM
Protects against ruminal acidosis
Improves feed intake

Question 45

What are inophores

Answer 45

Antibiotics that are not medically important.
Not used therapeutically or in non-ruminants
Lasalocid (Bovatec)
Monensin (Rumensin)
Used in feed

Question 46

What are inophores used for

Answer 46

Especially effective against G+ve
Alter ruminal microbial population
Increase propionate
Decrease methane
Reduce amino acid degradation

Question 47

What are the benefits of inophores

Answer 47

Routinely added to feedlot diets
Improved feed efficiency as less methane wastage
2.5-25% inc feed efficiency
3% dec dry matter intake
2.5% inc average daily gain
Less ruminal acidosis
Off feed, mild bloat, +/- diarrhea, low rumen pH
More meals, eat more evenly
Less bloat
Coccidiostats

Question 48

What are the steps to formulating a ration for cattle

Answer 48

Determine nutrient requirements, feed intake and desired weight gain for each class of cattle
Feed-test “on-farm” feeds to determine nutrient levels
Determine required “off-farm” feedstuffs (protein supplements, minerals, feed additives, vitamins…)
Formulate rations
Implement the nutritional program and monitor the performance of the cattle
Adjust rations according to weather conditions and animal performance
Designing a diet is complex! It should be done by a veterinary PhD nutritionist
If there is concern about the diet, have the feed analyzed