EXAM III Horses & Diary Cattle
150 Cards in this Set
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Texas Horse industy
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1,066,800 horses
288,000 households
$4.2 billion
$11.2 billion/year to TX economy
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Cost of horse ownership
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Around $1,486-$3,060/ year
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Challenges of equine nutrition
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Size and breed differences
Feed forage and grain separately
Owners feed by volume and not weight
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Right side of digestive tract of horse
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Large intestine, Cecum; sounds like a whooshing sound every 20 seconds
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Left side of digestive tract of horse
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Stomach and small intestine; Constant gurgling sound
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Equine digestive system
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Hindgut ~ 60% GI tract
Low capacity and activity in foregut
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Horse VFAs
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do not contribute to diet, may need to supplement protein
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Equine diet
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balance is important; cannot just supplement calories, must keep nutrients balanced
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Equine supplements
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Not regulated by government, don't necessarily enforce labels
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Forages
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minimum 0.75% recommend 1% mature can comsume 2-3%
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Don't feed to horses
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sorghum, sudan, kleingrass
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Possible grass problems
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Fescue (endophyte fungus), alfalfa (cantharidin blister beetles), Sweet clover (dicoumarin), Millet (alkaloids), Dallisgrass (dallisgrass toxicity - easy to see and treat)
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Pull mares off fescue
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90 days before they foal or late term abortion/retained placenta/ poor lactation can occur
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Concentrate feeds
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used for supplementing; work, growth, pregnancy, lactation
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Length of time for feed to reach end of SI
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90 minutes
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If fed too large of concentrate meal
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starch can reach LI and rapid fermentation can occur causing acidosis of cecum
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Omega 6
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pro inflammatory - working horse joints
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Omega 3
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anti inflammatory - poor palatability
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Founder - laminitis
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microbe that digest roughages die and release endotoxins which change blood flow and damage tissues
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As fiber increases
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DE decreases
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As fat increases
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DE increases
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Mature idle horses should survive on
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forage only - 2% BW/ day
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Weanlings can't use forage as well
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they require concentrate. And they're often underfed at this efficient age and overfed later on.
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Protein quality of a horse's diet is
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critical.
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First limiting AA for horses
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Lysine
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Urea can be tolerated by horses
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but MCP not absorbed successfully
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Best source of EAA for horses
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SBM
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Nutrition:calorie ratio requirement for weanlings not met by
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oats and alfalfa alone
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Minimum needed Ca:P ratio for equine diet
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1:1
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Recommended Ca:P ratio for equine diet
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1.5:1
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Many common feed ingredients have
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inverted Ca:P ratios
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Electrolytes supplemented to performance horses
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Na, Cl, K
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Mirominerals important during growth and reproduction
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Cu, Zn, Mn
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Microminerals important for disease resistance
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Cu, Zn, Se
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Thiamin
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usually synthesized in adequate amounts in the hind-gut of horses, but some hard working horses need supplementation
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Long term biotin supplementation
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may improve hoof integrity in 1/3 or more of horses
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Body condition score
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1-9; used to access energy status
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Recommended BCS at foaling
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6
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Open or maiden mare should enter breeding season at BCS
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5-7
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Feed maiden or open mare
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for maitenance
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For pregnant mare
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feed maintenance for first two trimesters then increase concentrate for 3rd trimester; must have balanced diet for protein and minerals
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Early lactating mares
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increase in energy, protein, and Ca requirements; increase concentrate of ration slowly at foaling
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Milk production in mares
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Highest between 2-3 months post foaling; around 38 lb/day
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Late lactation
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does not support all nutrient needs for foal
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Creep rations
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should be high quality and have a higher nutrient:calorie ratio than mare's diet; weanlings have low forage consumption
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Working horses
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increased energy requirements proportional to work.
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Horses in training undergo
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bone remodeling
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Bones weakest at
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50-60 days of training
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Light work
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25% increase from maintenance; seldom worked to exhaustion; same CP:DE ratio
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Moderate work
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50% increase from maintenance; work frequently performed; same CP:DE ratio
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Intense work
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100% increase from maintenance; same CP:DE ratio
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Most horses consume
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2-2.5% BW daily
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Recommend free access to
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trace mineralized salt block
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Recommend
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feed by weight, not volume
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Ionophores are
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toxic to horses
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Ration changes for horses
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gradual; over 1 week to avoid digestion disturbances; 3 weeks to adapt to any dietary changes (supplements)
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For individual feeding
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avoid feeding on the ground; keep troughs clean; attempt to slow aggressive eaters
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Group feeding
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adequate space if single trough used; better to feed 50 feet apart; discourage aggressive eating with obstacles and spreading grain over large area
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Feeding time and frequency
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feed regularly at same time each day; if grain >0.5% BW feed at least 2X per day with even time interval.
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Limit grain intake of horses to
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0.5 lb feed/ 100lb body weight per feeding
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Milk cow operations since 1994
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have been decreasing overall
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Milk cow numbers since 1994
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has increased
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Number of cows/operation is
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increasing
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Milk output overtime
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has increased
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Cows becoming more productive due to
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genetics and technology
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Percentage of diary cows in Texas
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is increasing
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Cheese plants
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caused negative environmental impact and had to be shut down, initial drop in dairy numbers in Texas but eventually it began increasing again
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NE values of feed affected by
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chemical composition of ingredients and physiological function of the animal
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As fiber increases HI
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increases and NE decreases
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As fat increases HI
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decreases and NE increases
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Heat increment
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highest for fiber, intermediate for starch, lowest for fat
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NE will be lower for
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growth than for lactation
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HI will be higher for
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growth than for lactation
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NE for maintenance is similar to
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lactation
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NE accounts for
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Gross energy, digestible energy, and metabolizable energy
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To meet nutrition demands for high-producing dairy cow
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Increase DMI and increase nutrient density of diet
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To meet huge energy needs for dairy cow we rely on
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natural increase in appetite and making more nutrient rich diet
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Phase I : Early lactation
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0 -10 weeks; peak milk production occurs within 3-6 weeks
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Phase II: Mid lactation
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10-24 weeks; Milk yields begins to decrease. Peak DMI occurs within 11-13 weeks.
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Phase III: Late lactation
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>24 weeks; Milk yield continues to decrease. Cows regain body tissue reserves.
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Phase IV: Dry period
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5-8 weeks; Dry period. Late pregnancy (rapid fetal growth).
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Phase V: Transition period
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2-3 weeks; Dry period. Late pregnancy. Prepare for lactation.
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Phase I
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negative energy balance; appetite lags. Break down of muscle and fat
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Phase II
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neutral energy balance; adequate AA and energy
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Phase III
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positive energy balance; deposits fat lost in last phase
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Phase I physiological priorities
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1. Lactation 2. Reproduction 3. Growth 4. Maintenance
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Phase II physiological priorities
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1. Reproduction 2. Lactation 3. Growth 4. Maintenance
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Phase III physiological priorities
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1. Reproduction 2. Growth 3. Maintenance 4. Lactation
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Bovine somatotropin (growth hormone) shouldn't be given
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in phase I since lactation increases demands already
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Goal of feeding diary cattle
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Provide high energy diets to allow cows to achieve their genetic potential to produce milk
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Dilemma with feeding dairy cattle
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Feeding high grain diets for more milk, but too much dietary starch may damage rumen papillae (Parakeratosis) and depressed milk fat due to inadequate intake of dietary fiber.
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Parakeratosis
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rumen papillae damage
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Challenge of feeding dairy cattle
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Feed diets with sufficient energy to support maximal milk production while maintaining adequate dietary fiber levels to avoid rumen damage and milk fat depression.
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Fiber is important because
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if milk protein quality is poor, producers face discounts
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More fiber in dairy diet means
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more rumination, adds saliva and increases rumen pH. This favors fiber loving microbes which produces more acetate.
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Acetate gets higher with roughage and is a precursor for
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milk fat
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Propionate gets higher and lowers rumen pH causing
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lower milk fat
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Rules of thumb for lactating dairy cows
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1. formulate diet with min forage:concentrate ration of 40:60
2. Formulate diet which contain min 17% crude fiber or 21% ADF
3. Feed minimum of 1 to 1.5% of body fat body weight as a forage
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Why do rules of thumb not always apply?
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Form of roughage is VERY important
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Effective fiber increases with
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particle size, amount of fiber, proportion of lignin
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Roughage value index
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measured as minutes chewing per unit of feed DM
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Method used to measure effective fiber
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Penn state particle size separator
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Recommended amount of large particle size (> 0.75 in)
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10-15%
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As particle size increases
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pH increases, acetate increases, milk fat increases
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Other nutritional factors that affect milk composition
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1. Type of grain
2. Grain processing
3. Dietary buffers
4. Dietary fats
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Type of grain
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faster starch fermentation lower milk fat. Wheat> barley> corn~Sorghum (wheat fastest fermentation)
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Grain processing
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the more processing, the faster fermentation
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Dietary buffers
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adding dietary buffers to the diet will increase rumen pH and help minimize milk fat depression
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Dietary fats
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adding dietary fats to the dairy diet may decrease milk protein
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Add buffers to
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maintain pH of rumen; 0.75-1.5% elevates rumen pH
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When adding fat to a dairy cows diet
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allows more energy while avoiding excess starch or low fiber. can be added at 5% (for an 8% total) without affecting DMI or digestibility.
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Which cows benefit most from fat-added diets?
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first 2-5 months of lactation
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Cows fed fat-added diets
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typically produce 4-6 lbs more milk per day
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Heat stressed cows
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eat less and produce less milk. Feeding fat decreases heat increment.
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Feeding fat added diets
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reduces the incidence of ketosis and enhances reproductive performance.
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Unprocessed fat
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has an effect on microbial fermentation of fiber
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To avoid microbial fermentation of fat we feed
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bypass fat.
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Usually feed dairy cows a blend of all three sources of fat:
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plant and oil seed sources, unprocessed fat sources, and processed fat sources.
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Unprocessed fat sources in rumen
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LCFA --> saturated LCFA (biohydrogenation)
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Traditional feeding system for dairy cattle
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Fed forage and grain separately
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Steps to traditional feeding
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Determine nutrient requirement (easy)
Estimate forage DMI (difficult in grazing cattle)
Estimate forage nutritional quality (difficult)
Challenging to formulate concentrate mix to supply nutrient beyond what the forage provides
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Total mixed ration system for feeding dairy cattle
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Forages and concentrates mixed together
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Steps to TMR feeding systems
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Determine nutrient requirements (easy)
Estimate forage DMI (easy because cows not grazing)
Estimate forage nutritional quality (easier for harvested forages)
Formulate TMR (easy compared to formulating supplements)
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Advantages of using TMR feeding system
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Cows not permitted to eat their favorite forage
Cows are forced to eat the correct balance of forage and concentrate feeds
Many small meals eaten throughout the day which help maintain stable pH in rumen
Easier to feed cows in various production groups
Reduce social dominance
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Advantages of traditional feeding system
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Harvesting and chopping for TMR is expensive
Cost of grazing forages is cheaper
The cost of feeding equipment for traditional system is less expensive
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Body condition scores for dairy cattle
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1-5
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Target BCS for calving, Drying-off
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3.5
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Goals during early lactation
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Maximize intake ( every 1lb increase in DMI leads to 2.5 lb milk increase during early lactation)
Minimize body tissue loss
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Feeding recommendation for early lactation
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Use high quality forages
Use palatable feeds
Ensure adequate fiber levels
Add fat to the diet
Use all natural protein supplements (no urea/NPN)
Consider use of high quality bypass protein/ UIP sources
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When using UIP
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ensure high quality to get increase in milk production
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Goals for mid lactation
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Maintain high milk production
Begin to regain condition lost in phase 1
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Feeding recommendations for mid lactation
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Use palatable feeds with high energy density
Use high quality forages
Ensure adequate fiber (min 20% ADF)
Use all natural protein supplements (no NPN)
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Goals during late lactation
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Restore body condition
Limit overconditioning
Target BCS 3.5
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Feeding recommendations for late lactation
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Use lower cost feeds when possible to meet cows nutritional feeds when possible to meet cows nutritional needs
Consider use of NPN to meet portion of protein needs
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Replacing fat during late lactation is more or less efficient than during the dry period?
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More efficient - dry cows don't convert feed to tissue as efficiently
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Goals of the dry period
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Optimize fetal growth, prepare cow for next lactation, minimize length of dry period (must have min of 60 days), feed cows to achieve BSC of 3.5 at calving
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Feeding recommendations during dry period
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Separate dry cows from lactating cattle, feed higher roughage (lower energy) based diet, avoid high-grain diets to prevent abomasal displacement, avoid feeding excessive Ca levels to prevent milk fever
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Goals of the transition period
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Acclimate the rumen microbes to the diet that will be fed during early lactation, proper acclimation will allow cows to be switched to a high-grain diet with minimal digestive upsets
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Feeding recommendations during the transition period
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Feed 0.5-1.0% of BW as grain to prevent acidosis, continue to limit intake of Ca to prevent milk fever, feed negative cation-anion balanced diet, feed high levels of Vitamin A and E to prevent mastitis
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80% of cases of milk fever occur within
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48 hours of calving
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Milk fever rarely occurs in cows during their
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first lactation
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Milk fever symptoms
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Hypocalcemia, inactive GIT, "downer cows", uncoordinated walking, more susceptible to mastitis, ketosis, dystocia, displaced abomasum, uterine prolapse
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Cows are often fed high Ca diets before calving
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when cows are fed excess Ca, the mechanisms to absorb Ca from the GIT and mobilize ca reserves from the bone are down regulated. Right after calving, the cow's high demand for Ca is not met resulting in hypoglycemia.
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Can feed low Ca diet to
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activate mechanisms for intestinal absorption and bone mobilization of Ca, this is the traditional method for preventing milk fever
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Feed negative dietary cation- anion balance (DCAB)
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diet during the dry period, which activates mechanisms to absorb more Ca from gut and mobilize more Ca from bone
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Recommended DCAB is
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-10 to -15 meq/100 g diet DM
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If a ration is positive, we must add
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more salts to make ration more negative
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Ketosis usually occurs
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within 60 days of calving
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Ketosis occurs when
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appetite decreases, milk production decreases, and the cow can develop ketosis
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Prevention of ketosis
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#1 ia Avoid excess BCS at calving, feed glucose precursors, feed niacin
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Exam 1 Flashcards