Cattle and Sheep Nutrition

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• Cattle and Sheep Nutrition

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Digestion

• Cattle and sheep
• Natural diets primarily plant material.
• High in fiber (plant cell walls)
• Animals uniquely adapted to extract energy from
  fiber
• Complex stomachs
• Rumination

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Ruminant Digestive System
Ruminant GIT have unique characteristics. Note
the 4 stomach chambers
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Mouth

• Mastication Ruminants initially swallow food
  without much mastication. Later, food is
  regurgitated and masticated (rumination)
• Rumination reduces particle size of fiber and
  exposes sugars to microbial fermentation.

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Mouth

• Saliva
• Aids bolus formation
• Moistens feed
• 160 to 180 liters when a cow chews 6 to 8 hours
  per day, but less than 30 to 50 liters if
  rumination is not stimulated (too much
  concentrate in the diet).
• No amylase
• Buffers in the saliva (bicarbonate and
  phosphates) neutralize the acids produced by
  microbial fermentation to maintain a neutral
  acidity which favors fiber digestion and
  microbial growth in the rumen.

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Esophagus

• Tube from mouth to reticulorumen
• Functions
• Transports bolus via muscular contractions
• Downward and upward (rumination)

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Complex Stomach
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Reticulum

• Honeycomb surface
• Capture and retain dense particles
• Only particles that are small (lt 1-2 mm) and
  dense (gt 1.2 g/ml) move to the omasum.

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Rumen

• Largest compartment 100 to 120 kg of digesting
  material.
• Fiber particles remain 20 to 48 hours (bacterial
  fiber fermentation is slow)
• Extensive microbial fermentation
• Bacteria, protozoa, and fungi
• Population is diet and intake dependent
• Lined with papillae
• Increases surface area and absorption

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Rumen

• Microbial fermentation produces
• 1) volatile fatty acids (VFA) end-products of
  the fermentation of cellulose and other sugars
• 2) a microbial mass rich in a high quality
  protein.
• VFAs are absorbed through the rumen wall.
• Used as the major energy source and for the
  synthesis of milk fat (triglycerides) and milk
  sugar (lactose).
• Through belching about 1000 liters of gases per
  day.

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Omasum

• Membranous leaves in lumen
• Sieve large particles regulates food passage to
  abomasum
• Absorption of water, sodium, phosphorusand
  residual VFA.

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Abomasum

• Glandular stomach
• Largest compartment prior to rumen development
• Secretion of strong acids and digestive enzymes.
• Digestion of feed fractions not fermented in the
  rumen (some proteins and lipids).
• Digestion of bacterial proteins produced in the
  rumen (0.5 to 2.5 kg per day).

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Unique characteristics of ruminants

• Young ruminants have no functional rumen they
  have reticular or esophageal groove
• Milk directly from esophagus to omasum
• Rumen development
• Stimulated by volatile fatty acids (VFA)
• Lambs 8 weeks
• Calves 6 to 9 months
• Rumination
• Regurgitation and remastication
• Eructation
• Emission of fermentation gases

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Rumen fermentation

• Advantages
• Efficient utilization of fibrous feedstuffs
• Rumen microbes metabolize Hemicellulose and
  cellulose to VFA (acetate, propionate, butyrate).
  VFAs are used for energy.
• Efficient utilization of lower quality protein
  and NPN
• Conversion to higher quality microbial protein
  digested in the abomasum
• Production of water-soluble vitamins and vitamin
  K

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Rumen fermentation

• Disadvantages
• Reduced utilization efficiency with higher
  quality feeds
• Reduced yield from digestible energy sources
• High converted to lower quality protein

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Small Intestine

• Secretion of digestive enzymes by the small
  intestine, the liver and the pancreas.
• Enzymatic digestion of carbohydrates, proteins
  and lipids.
• Absorption of some water, minerals and products
  of digestion glucose, amino acids and fatty
  acids.

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Large Intestine

• Cecum (fermentation) and large intestine
• A usually small microbial population ferments the
  unabsorbed products of digestion.
• Absorption of water and feces formation.

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Practical Implications

• Ruminants can use a greater variety of food
  sources than non-ruminant animals.
• The microbes living within the reticulo-rumen
  allow ruminants to convert fibrous feed (forages,
  crop residues and industrial by-products) and
  non-protein nitrogen (ammonia, urea) into highly
  nutritious and palatable food for humans (milk,
  meat).
• Fibrous feed is necessary for the health of the
  cow because it maintains rumination and saliva
  production which are necessary for
• the proper function of the rumen and
• to obtain the desired bacterial population within
  the rumen.

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Practical Implications

• A cow can eat forages (low energy feed) and
  concentrates (high energy feed).
• Large additions of concentrates to a ration
  should be gradual (over a period of 4 to 5 days)
  to allow the population of bacteria in the rumen
  to adapt to the new diet.
• The feces of ruminants are rich in organic matter
  (undigested microbial debris) and inorganic
  matter (Nitrogen, Phosphorus and Potassium) that
  are excellent fertilizers.

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Feeding Sheep

• Supplying the nutrient needs is the largest
  single production cost in all types of sheep
  operations.
• Goal is to maximize efficiency of converting feed
  into meat, wool, and milk.

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Nutrient Requirements

• Water
• Daily consumption in ewes 0.72 gal in winter to
  2.2. gal in summer.
• Water intake increases with the increased intake
  of DM, protein, or minerals, the temperature
  above 70F, and the stage of production such as
  during the late gestation and lactation.
• Sheep can get water from feed, snow dew,
  oxidation of feed/metabolic water, as well as
  drinking water - Thus, depending on the
  situation, can get by without drinking water!

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Nutrient Requirements

• Energy
• Inadequate energy limits performance of sheep
  more than any other nutritional deficiency,
  especially during the late gestation and
  lactation.
• Deficiency - Results in reduced growth,
  fertility, wool quantity quality, etc.
• Generally can satisfy the needs with good quality
  pasture, hay, or silage, but may need supplement
  (e.g., grains) immediately before after
  lambing, conditioning for breeding, and finishing
  lambs.

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Nutrient Requirements

• Protein
• The amount of protein is more critical than
  quality, i.e., microbial protein is often
  adequate.
• Green pastures provide adequate protein, but if
  mature or dry may need additional protein.
• Bypass protein might be beneficial
• Can use non-protein nitrogen in some instances.

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Nutrient Requirements

• Minerals vitamins
• In practice, the true "dietary" requirements vary
  considerably depending on the amount and nature
  of minerals.
• Most requirements can be met with under normal
  grazing and feeding habits, but trace mineral
  salt is usually fed free choice, and often
  contain Na, Cl, I, Co, Fe, Mn, and Zn.

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Nutrient Requirements

• Although sheep need all the fat-soluble vitamins,
  normally, the forage feed supply all the
  vitamins in adequate amounts. Exceptions
• Vitamin A (grazing on dry or winter pasture for
  an extended period time)
• vitamin D (under confinement)
• The B vitamins are synthesized in the rumen,
  there is no need for supplementation.
  

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Feeding Ewes

• Ewes are the backbone of the sheep enterprise
• Raise lambs produce wool.
• Their nutritional status during the all stages of
  production is critical for optimum production
• During pregnancy - Determines the number of lambs
  born alive, lamb birth weight and survivability.
• During lactation - Critical for milk production.

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Feeding Ewes

• Optimum feeding systems vary based on the system
• intense feeding of confined sheep
• supplementation of flocks on range forage.
• How a ewe should be fed? - Monitor changes
  inbody weight during lactation.
• Should lose about 5 to7 during lactation
• recover this during the post weaning period
• gain weight appropriately during gestation.
• Nutritional needs differ depending on the
  size,body conditions, and levels of production
• may be useful to divide the flock into groups of
  ewes with similar needs?

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Feeding Ewes - Flushing

• Flushing Increase feed intake of ewes prior to
  and during mating to increase ovulation rate and
  thus lambing rate.
• Start about 2 wk before breeding until 2-3 wk
  into the breeding season.
• Turn ewes onto a lush, high-quality pasture just
  prior to breeding, or
• Supplement ¼ to ½ lb of grain or pellets/day.
• Mature ewes respond better than yearlings or fat
  ewes
• Expected increase in the lambing rate 10 to 20.

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Feeding Ewes - Gestation

• Many lamb deaths shortly after birth are due to
  poor nutrition during gestation
• With mature (3 to 8 years) ewe
• Feed to maintain "normal" weightfrom weaning
  until about 15 wk ofpregnancy.
• Pasture and other "field feeds,"
• Harvested feed hay, haylage, corn or sorghum
  silage.

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Feeding Ewes - Gestation

• Last 6 wk of gestation
• About 70 of fetal growth during this phase
  critical period!
• Poor nutrition Lighter lambs at birth, uneven
  birth wt in twin triplets, reduced wool
  follicle development, lower energy reserves of
  newborns, etc.
• Birth wt is a major factor affecting lamb
  mortality.
• Need 50 or 75 more feed if bearing a single
  twin lambs, respectively.
• Nutrition during this phase influences milk
  production after parturition.

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Feeding Ewes - Lactation

• A. Nutrient needs - Usually 2 to 3 times
  maintenance.
• B. Ewes with twin lambs produce 20 to 40 more
  milk than those with singles, thus have higher
  nutrient requirements.
• C. Milk production
• a) Peaks 2 to 3 wks after lambing and then
  declines
• b) Ewes produce 3 to 6 lb milk daily.
• c) Milk is the total source of nutrients for
  lambs during the first mo. and a significant
  proportion for the first 2 mo.
• D. Wean lambs at 8 wk - More efficient to feed
  the lamb directly than to feed the ewe to feed
  the lamb beyond 8 to 10 wk.

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Feeding Ewes - Lactation

• Not necessary to feed the ewe very much for a day
  or so after lambing - Important to have plenty
  of fresh water
• By day 3, feed (as-fed basis)
• 2½ - 3 lb each of hay and ground ear corn,
• 4 - 5½ lb hay plus 1 to 1½ lb shelled corn,
• 8 to 10 lb corn silage plus ¾ to 1½ lb shelled
  corn ½ lb soybean meal, or
• 10 lb alfalfa haylage plus 1½ lb shelled corn.

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Feeding Ewes - Lactation

• Daily feed intakes can be increased by feeding
  frequently
• If the ewe is nursing one lamb, feed once a day,
• if she is nursing two lambs, twice a day, etc.
• Splitting the amount fed per day reduces the
  potential for acidosis when more concentrates are
  fed.

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Feeding Lambs

• Born with a nonfunctional rumen - need dietary
  sources of nutrients such as milk and milk
  replacer.
• Make sure that a lamb nurses within 1 hr or its
  chance of survival is limited
• most lambs nurse within 30 min after birth.
• Give access to dry feed immediately, some degree
  of rumen functionality appears within 2 wk or so.
• With continued consumption of dry feed, milk is
  no longer essential for good growth by 45 to 60 d
  of age.

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Feeding Lambs Creep Feed

• Advantages
• Increased weight gains, especially in twins
  triplets - Up to 0.25 lb /d more
• Can be marketed at younger age - 1 to 2 mo
  earlier
• Moving lambs to the drylot earlier allows more
  ewes on available pasture.
• Start as soon as possible - set up when lambs are
  7 to 10 d of age on the location where they
  spend most of their time.
• Commercially prepared complete creep feeds
• Cracked, shelled corn, bran, rolled oats,
  molasses, soybean meal, and high quality, leafy
  alfalfa hay PLUS a complete supplement top
  dressed on the corn to provide added CP, Ca,
  vitamin E, Se, antibiotic, etc.

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Feeding Dairy cattle
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Feeding Dairy Calves

• Commercially, calves need to be separated from
  mother as soon as possible
• Health and vigor of calves at birth depend on the
  nutrition of the cow during the last 60 days of
  gestation - about 70 of birth wt of the calf
  during that time.
• Newborn calves have all the necessary organs of a
  ruminant digestive system, but their processes
  are similar to non ruminants.
• The rumen is not populated with the typical
  microbes until close to 60 d of age, thus
  necessary to provide milk/milk replacer in the
  beginning.

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Feeding Dairy Calves

• Newborn calves have all the necessary organs of a
  ruminant digestive system, but their processes
  are similar to non ruminants.
• The rumen is not populated with the typical
  microbes until close to 60 d of age, thus
  necessary to provide milk/milk replacer in the
  beginning.
• Calf may be left with dam for 24 hr to get
  colostrum
• Then placed in a milk or milk replacer feeding
  program

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Feeding Dairy Calves

• Feed milk replacer for about 3 weeks
• At about 1 week of age offer a starter ration
• High energy high protein low fiber grain
  mixes
• Based on corn Soy bean meal
• Supplemented with minerals and antibiotics

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Feeding Dairy Calves
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Feeding Dairy Calves

• Milk Feeding Programs
• Liberal milk system
• Veal calves
• Herd replacements
• Limited milk system
• Conventional
• Feed milk, milk replacer, or stored colostrum at
  8 to 10 of body wt until they start consuming 2
  to 3 lb starter/day, at which time "milk feeding"
  can be decreased no milk by 4 to 7 wk of age.
• Start feeding hay at 1 wk of age

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Feeding Dairy Calves

• Milk Feeding Programs
• Limited milk system
• Early Weaning
• Off milk entirely by 1 mo of age - Requires good
  management practices and early adjustment to
  starter feeding.
• Suggested milk feeding program 4-6, 5-7, and 3-4
  lb milk/d for 0-3, 4-24, and 25-31 d of age
• At the time of weaning, in addition to milk,
  should be consuming "dry feed" at the rate of
  1.5 of BW.

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Feeding Dairy Calves

• Give hay at 5 10 days of age
• Limit Silage offerings before 3 months of age
  because of moisture content

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Feeding Heifers 4 to 12 months

• If heifers are properly introduced to solid feeds
  before weaning, the growing ration can be changed
  gradually so that they reach puberty at 15 mo of
  age.
• Rumen capacity - Not sufficient for the animal to
  satisfy the energy need from forages alone, thus
  feeding some grain is necessary until 1 yr of
  age.
• Summer - Pasture, hay and grain mix (3-7 lb/d
  depending on body size and forage quality
• Winter - Hay, silage and grain mix (3 -7 lb/d
  depending on body size and forage quality.
• The same forage and grain mix used for the
  milking herd can be used for heifers.

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Feeding Heifers 12 months to calving

• Sufficient rumen capacity to meet their nutrient
  needs from good quality forages.
• Should be gaining 1.5 to 1.8 1b per day.
• Feed grain mix only when/if forages are poor or
  limited in amount.
• Summer - Use pasture and (or) hay, and feed 2 to
  8 lb of grain mix if necessary depending on the
  body size.
• Winter - Hay and silage, and feed 2 to 8 lb of
  grain mix if necessary depending on body size.
• Free-choice minerals (Ca, P, salt, and trace
  minerals if feeding poor forages).

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Feeding Heifers 12 months to calving

• To breed at 15 mo, heifers should weigh 550
  (Jerseys) to 800 lb (Holstein and Brown Swiss)
• Should gain about 1.75 lb/day from birth
• Growing heifers use available nutrients in an
  irreversible order 1) Daily maintenance, 2)
  growth, and 3) ovulation and conception.
• Avoid over-conditioning to avoid impairment of
  the reproductive efficiency, and also reduced
  milk production because of fatty deposits in the
  udder.
• Management techniques for early conception
• "Flushing" - Increase the intake of all the
  nutrients to heifers with appropriate age.
• "Bypass protein" - Use during the first breeding
  period

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Feeding Heifers bred heifers

• Breeding to 60 days before the expected calving
  date
• Aim for growth, avoid excess fat deposition,
  especially in the udder.
• Last 60 days of gestation
• Start feeding a grain mix and increase gradually
  to adapt heifers to high grain intake needed for
  lactation after calving. By doing so
• Can adjust the rumen population to increase
  microbes that ferment the specific feeds in the
  "lactation" ration.
• Can increase nutrient intake to increase body
  reserves necessary to support early lactation . .
  . plus own growth.
• Can provide for the increased demand for
  nutrients because of the rapidly developing fetus.

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Feeding for Milk Production

• Systems used in the US depend on geographic area
  and availability of feedstuffs
• Pasture system - "Traditional" system is
  continuing in areas of sparse human population.
• Drylot systems with minimum roughage and higher
  quantities of less bulky feeds such as
  concentrates - Being used in areas surrounding
  some of the larger cities.

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Feeding for Milk Production

• Dairy cows consume a lot of feed/nutrients to
  achieve today's expected milk production
• Feed represents about 50 of the total production
  costs.
• The feeding program can determine the
  productivity of lactating dairy cows
  profitability
• About 75 of the differences in milk production
  between cows is determined by environmental
  factors, with feed making up the largest portion.
• At peak production, may require 3 to 10 times as
  much as protein energy vs late gestation, but
  the cow's appetite usually lags behind her
  nutritional needs.

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Feeding for Milk Production

• The lactation and Gestation Cycle

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Feeding for Milk Production

• The lactation and Gestation Cycle
• Milk production increases rapidly and reaches
  peak 6-8 wk after calving.
• Feed intake lags behind production, i.e., maximum
  DM intake does not reach until 12 to 15 wk
  after calving.
• Body reserves - Make up differences in the need
  supply by mobilizing body stores.
• Often loose 90 to 135 kg of body wt

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Forages

• The cow cannot consume enough forage to meet her
  nutrient needs during lactation
• Allowed to consume all the forage at their will,
  then may not have enough room left to consume
  necessary grains to meet the energy needs of high
  milk production
• Limit forage intake to 1.75 to 2.0 of boy wt
• Increase forage intake by feeding several
  times/day and providing a variety of forages

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Concentrates

• Mixture of grains, mill feeds, protein
  supplements and minerals

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Concentrates

• The kind of mixture to feed varies with the kind
  of forage fed (e.g., a high-protein mix will be
  needed with a low-protein forage), availability,
  and cost.
• The amount of concentrate fed depends on
• Amount of forage consumed
• Amount of milk produced
• Composition of the milk produced

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Concentrates

• Limit the concentrates to a maximum of 60 of the
  diet
• Higher levels of concentrate affect VFA profile
  and milk fat content

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Phase Feeding Program

• Feeding periods/phases can be divided into four
  or five
• Phase 1 First 10 wk of lactation. Peak milk
  production - body stores are used to make up
  deficits in the nutrient intake.
• Phase 2 10 to 20 wk or so of lactation. Maximum
  DM intake, and the intake is in balance with the
  needs
• Phase 3 The intake exceed the needs. The period
  to restore body reserves for the next lactation.
• Phases 4 5 - Dry period, and can be considered
  as only one phase
• Phase 4 - Most of the dry period, and replete
  body reserves regenerate secretory tissues for
  the next lactation.
• Phase 5 - The last 1 to 3 wk of prepartum. Start
  increasing grain intake to prepare the rumen for
  the increased nutritional demands

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Phase Feeding Program

• Peak milk production (Phase 1)
• 1) Bring cows into peak milk production as soon
  as possible after calving
• Feeding slightly more grain than recommended
  until there is no increase in production then
  adjusting the amount of grain accordingly.
• 2) Milk production increases rapidly, peaking at
  6 to 8 wk after calving.
• 3) The most critical period for a dairy cow is
  from parturition until peak milk production
• a) Objective for this phase is to increase feed
  intake as rapidly as possible!
• b) Increase grain intake 1 to 2 lb per day after
  calving to meet the energy needs.
• c) Avoid excessive grain (gt 65 total DM) and
  maintain 17 to 19 acid detergent fiber in diet
  to reduce rumen disorders.

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Phase Feeding Program

• Peak milk production (Phase 1)
• 3) The most critical period for a dairy cow is
  from parturition until peak milk production
• d) Extra dietary protein permits more efficient
  use of body fat for milk production because cows
  are usually losing body weight.
• e) Feed more ruminally undegradable protein
  source (i.e., bypass protein) for high-producing
  cows in early lactation.
• Limit urea to 0.2 to 0.4 lb/day - urea is
  utilized less efficiently when total ration
  protein level is high.
• Increasing the energy density of the ration may
  help cows meet the energy requirement - Feed 1 to
  1.5 lb of added fat per day may increase energy
  intake while maintaining adequate fiber intake.
• Buffers such as Na bicarbonate alone or in
  combination with Mg oxide may be beneficial
  during the early lactation - Aid in maintaining
  ruminal pH, which minimizes acidosis, reduce
  digestive upsets, and result in increased DM
  intake.

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Phase Feeding Program

• Peak dry matter intake (Phase 2)
• 1) To maintain peak milk production, should
  achieve maximum DM intake as early in lactation
  as possible - 12 to 14 wk
• 2) With maximum DM intake
• a) Can minimize the negative nutrient balance
  experienced during the early lactation.
• b) A conception rate is greater for ones in
  positive energy balance
• 3) Maximum DM intake will likely to reach 3.5 to
  4 of body wt for most cows
• a) Grain intake may reach 2½ of cow's body wt,
  and forage intake (DM) should be at least 1-1¼
  of cow's body wt to maintain rumen function and
  milk-fat test.
• b) Should feed forages and grain several times
  daily.
• c) High-producing cows (i.e., gt 70 lb 4 FCM)
  should be fed only natural protein and not urea

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Phase Feeding Program

• Mid to late lactation (Phase 3)
• 1) Easiest phase to manage? - Milk production is
  declining and the nutrient intake exceeds the
  needs. Also, the cow is pregnant at this phase.
• 2) Keep in mind that young cows are still growing
  - i.e., Nutrient requirements for growth are 20
  of the maintenance requirements for 2-yr-olds and
  10 maintenance for 3-yr-olds.
• 3) Match grain intake to milk production
• 4) NPN is well utilized, use urea (0.4 to 0.5
  lb/cow/day) to reduce feed costs.
• 5) Feed extra nutrients, if needed, to replace
  any body tissue lost during the early lactation -
  Cows are more efficient in replacing body tissue
  while lactating than during the dry period, but
  avoid over-conditioning.

61
Phase Feeding Program

• Dry period bred heifers (Phases 4 5)
• 1) Cows need a short dry period as rest to
  prepare for the next lactation - The optimum dry
  period would be 6 to 8 wk!
• a) Shorter that 40 d? - Not enough time for udder
  regeneration, thus may reduce the
  production rate.
• b) Longer than 60 d? - Do not increase the
  production, and may result in excess body
• condition calving difficulties.
• 2) Bred heifers
• a) Nutrient needs are slightly higher vs dry cows
  of similar size - Still growing!
• b) Good-quality hay can provide all the nutrient
  needs during the early gestation.
• c) Need some grains along with forages during the
  last 3 to 4 mo of gestation to support growth
  provide nutrients for fetus.
• d) As with dry cows, should be in good condition
  but not too fat at calving.
• 3) Quality of forage may not be as critical
  during the dry period, but cows need sufficient
  feed to support both the unborn calf and to meet
  body reserves not replaced in the previous period.

62
Phase Feeding Program

• Dry period bred heifers (Phases 4 5)
• 4) Nutrient needs can be met with only forages
  and no grain, but may be fed up to 4 to 6 lb of
  grain per day (0.5 of body wt) depending on the
  condition.
• 5) "Fat cow syndrome" - Feeding high levels of
  corn silage or grains may cause excess fat
  deposits in the liver region
• a) "Fat cow syndrome" - Characterized by high
  blood lipids fatty livers.
• b) May result in calving difficulties, displaced
  abomasum, ketosis, and other.
• c) Less likely to have problems with hay and (or)
  haylage vs corn silage.
• 6) About 2 wk before calving, increase grain
  feeding so cows are consuming 12 to 16 lb
  grain/day at calving (1 of body weight).
• a) Helps cows get accustomed to high grain intake
  needed after calving, and can reduce the
  occurrence of ketosis during lactation.
• b) Best to increase the amount of grains
  gradually, which may minimize the chance for milk
  fever