Feeding cattle Flashcards
Beef cow calf cycle is
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
What is the reproductive cycle of a cow
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)
What is the BCS you should go for in a breeding cow
Aim for good to moderate condition (5-6)
Each score = 34-45 kg
Generally takes ~2 months to gain 1 point
How does the digestive system work for bovids
Efficient digesters
Microbial fermentation
More tolerant of poor-quality diets
No dietary source of essential amino acids
No dietary source of essential fatty acids
What deos the water consumption of bovids do
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
What are the nergy needs of cattel
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
Carbs and cattle
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
Fibre and cattel
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
Protein and cattle
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
How do cattle get their minerals
Direct add to feed
Mineral blocks
Typically contain Ca and P source
Copper, iodine and selenium
Free choice blocks should contain 25% salt-why?
Rhughage for ruminants is
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
Why do you allow for food wastage with cattle and how much
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
Dry matter intake is impacted by
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
Energy neds of cattle
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
What happens in spring for cattle and what do you feed
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?
What happens in summer for cows and what do you feed
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
What happens in fall and waht do you feed for cows
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
What happens in fall and how do you feed cows
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
What happens in fall and how do you feed cows
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
How does feeding change by breeding stage
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
What are common pasture probelms for cows
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
Acute bovine pulmonary emphysema and edema is and caused by
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
BCS is done when and what is ideal in cattle
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.
What are common winter feeding problems for cows
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
What are common winter feed problems in the winter for cows
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
What are the limitations for feeding NPN in cattle
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
What is hypocalcemia and what causes it in cattle
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
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How can you stop hypocalcemia from happening in cattle
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
How do you feed a cow in clinic
Basal Diet?
Typically hay
How much?
Maintenance, 1.5% of body weight
1200lb mature cow
18lbs feed
How do you feed cattle
“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
How do you feed weaning to breeding replacement heifers
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
What are some possible winter diets for replacement heifers
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)
How do you feed a replacement heifer from breeding to calving
Summer-at pasture
Next winter
Still require separate feeding
Require more feed than adults as still growing
How do you feed a breeder bull
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
How do you finish calves in feedlot
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
What is backgrounding for cattle
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
What are the approaches to purchasing a cow
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
What is compenstory growth
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
What is the diet for backgrounding cattle
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.
What is ruminal acidosis and what causes it
↑ 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
What is bloat and what causes it
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
Fat and finishers and cattle
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
What are conditioners used for in cow feed
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
What are buffers in cattle feed
Sodium Bicarbonate
About 0.75% of diet DM
Protects against ruminal acidosis
Improves feed intake
What are inophores
Antibiotics that are not medically important.
Not used therapeutically or in non-ruminants
Lasalocid (Bovatec)
Monensin (Rumensin)
Used in feed
What are inophores used for
Especially effective against G+ve
Alter ruminal microbial population
Increase propionate
Decrease methane
Reduce amino acid degradation
What are the benefits of inophores
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
What are the steps to formulating a ration for cattle
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
