BEEF COW NUTRITION

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					                                   BEEF COW NUTRITION
                                      Steven C. Loerch

Profitability of the commercial beef herd depends on:
1. The pounds of calf, stocker or fat cattle sold.
2. The price received for cattle sold.
3. The percent of calves weaned.
4. The cost of maintaining the cow for a year.

                                DEMANDS ON THE BEEF C0W

1. Maintain her own body.
2. Come into heat promptly after calving (estrous cycle is 21 days in cattle).
3. Conceive early in the breeding season < 82 d post-calving.
4. Nourish the fetus.
5. Deliver a live calf without difficulty.
6. Nurse the calf adequately for approximately 7 months.

  CONSIDERATIONS WHEN PLANNING A COW OR HEIFER NUTRITION PROGRAM

1. Stage of production (pregnant vs open) or (lactating vs dry).
2. Condition of the female (too thin, proper or too fat).
3. Age of the cow or heifer.
4. Animal size or weight.
5. Environmental conditions such as temperature, rainfall or humidity.
6. Geographical area nutrient deficiencies or toxicities.

                     MAJOR NUTRITIONAL NEEDS OF BEEF CATTLE

1. Water
2. Energy
3. Protein
4. Calcium
5. Phosphorus
6. Salt
7. Trace minerals (Se, Cu, Mg)
8. Vitamin A (D comes from sunlight, E comes from forages)
  "The most important nutrient is the one that is missing"!

      GENERAL PERFORMANCE GUIDELINES THAT CATTLE SHOULD ACHIEVE
                                                                           1200 # cow
1. Calf birth weight should be 7.5% of the cow's weight.                        90 lb
2. Calf weaning weight (205 days) should be 50% of the cow's weight.           600 lb
3. Heifers should be 65% of their mature weight at puberty.                    780 lb
4. Heifers should be 75% of their mature weight when they are bred for the
   first time. This should be at approximately 14 to 15 months of age.              (1.4 lb/d)
5. Heifers should be 85% of their mature weight when they calve for the first time. 1020 lb
   This should occur at 23 to 24 months of age.

               THERE ARE 4 PHYSIOLOGICAL STAGES OF PRODUCTION

Stage 1. The first 82 days post-partum. During this time, the cow must be re-bred.
Stage 2. Days 83 - 205 post-partum. At the end of this stage, the calf is weaned.
Stage 3. Days 206 to 315 post-partum. The nutritional requirements of the cow are the lowest at
         this time.
Stage 4. Days 316 to 365 post-partum. This is the time immediately pre-calving. Nutritional
         requirements are increasing at this time due to the increasing size of the fetus.

NRC Requirements for an 1100 lb. beef cow with 15 lbs. of milk production per day are as follows
    in the 4 stages of production.
                                            STAGE
                               1          2               3              4__
Nem, Mcal/d                  15.6        11.9             8.1           10.3
PROTEIN, lb/d                  2.7        2.1             1.4             1.6
CALCIUM, g/d                 33.0        27.0           17.0            25.0
PHOSPHORUS, g/d              25.0        22.0           17.0            20.0
VITAMIN A, Iu/d
(thousands)                  39.0        36.0           25.0            26.0

STAGE 1: (82 days post-calving)
    The cow has four basic functions to perform in this stage:
    1.Lactation
    2.Undergo uterine involution
    3.Ovulate
    4.Conceive

-Highest nutritional requirements because lactation and re-breeding are occurring at the same time.
-Cows spend most of this time on pasture, however, in northern climates harvested feeds are being
   fed to a majority of the cows during the early part of the stage.
-Cost of feeds is the most important at this stage because of the high animal requirements.
Dietary Energy level and Protein level as well as Cow Body Condition all Determine the length of
   time required for the animal to start having estrous cycles after giving birth. This postpartum
   period of reproductive inactivity is known as the postpartum interval (PPI) or POSTPARTUM
   ANESTRUS.

POSTPARTUM ANESTRUS in beef cattle averages 60 days. However, periods of up to 100 days
are commonly seen. The length of anestrus is of economical importance because a strict schedule
needs to be maintained for breeding. If a cow misses one estrous cycle, but breeds on the next one,
her calf will be 21 days younger when marketed. For one animal, this can mean 50 to 60 fewer
pounds of calf marketed during the fall. Additionally, if the cow calved at the end of the calving
season, she may not breed at all during the breeding season and, therefore, will be culled from the
herd.
STAGE 2: (83 - 205 days post-partum)
       "Usually summer and early fall in northern climates"
       The cow has 3 basic functions to perform during this stage:
       1. Lactation
       2. Maintain the pregnancy
       3. Put weight back on that she lost during the previous winter

-Utilize pasture to maximize the use of animal harvested forage. "It is always cheaper to have the
     animal harvest its own feed."
-If grazeable forage becomes inadequate, there are 3 alternatives:
        1. Feed concentrates to the cows
        2. Early wean the calves
        3. Creep Feed the calves

CREEP FEEDS:
     1. Must be fed so that access is limited to the calves only.
            a. Creep Feeders
            b. Limited access areas
     2. Should provide adequate Energy and Protein to the calves.
     3. Should not contain Urea, as some calves will limit their intake.
     4. Limiting excess intake with salt has been used, but it may defeat the purpose.

Problems with creep feeding:
       1. Extra management needed
       2. Extra cost for feed and feeders

When should creep feeding be used:
      1. When you are selling feeder calves and milk production is limiting their gain.
      2. When you are being paid a premium for selling bunk ready calves.
         (This is extremely rare)

When should creep feeding NOT be used:
      1. When you are retaining ownership of the feeder calves, and the timing of gain is of little
         importance economically.
      2. Cost of creep exceeds value of additional gain.

STAGE 3: (206 - 315 days post-partum). Normally October to January in this part of the country.
    The cow has 2 basic functions to perform during this period:
    1. Maintain herself
    2. Maintain the pregnancy

      "MAKE OR BREAK PERIOD"
- Maximize the use of cow harvested forage
- Utilize fall regrowth or crop residues
- Feed poorest quality hay
        (First cutting or round bales not stored inside or wrapped)
STAGE 4: (316 - 365 days post-partum)
        IMMEDIATELY PRE-CALVING

       The cow has 3 basic functions to perform:
       1. Provide nourishment to allow for the majority of fetal growth to occur during this stage.
         "The fetus grows approximately .9 lbs/day during the last Trimester"
       2. Prepare for Parturition
       3. Prepare for Lactation

Restricting Nutrient intake to the Cow during Stage 4 can cause:
        -Reduced calf birth weight and survival percentage
        -Dystocia (Calving Difficulty)
            6% of all cattle deaths are a result of dystocia
        -Reduced immune system function of the calf
            This has been shown to reduce survivability to weaning by 20%.
        -Increased the Post Partum Interval
        -Reduced Conception Rate (percent that get pregnant) during the following breeding season.
        -Reduced Milk Production
        -Reduced calf weaning weight

BODY CONDITION AT CALVING AFFECTS % IN ESTROUS POST-CALVING

BODY CONDITION             % IN HEAT AT 60 DAYS                       % IN HEAT AT 90 DAYS
THIN                                       46                                    66
MODERATE                                   61                                    92
GOOD                                       91                                   100
source: Whitman, Colorado State University

Does cold weather effect nutrient requirements?
Temp.        Mcal             lbs. Hay               lbs. Crude Protein
40 F.           8                16                          1.2
 0 F.          10                21                          1.2

FOR A PREGNANT COW, for every 1 degree F. drop in temperature, there is a 1% increase in
calories required.

HEIFER MANAGEMENT:
1. Feed separately from mature cows during first and second winters, since they are still growing.
2. Feed them to gain 1 to 1.5 lbs/day during their first winter, when they are not pregnant (open).
3. Feed them to gain .5 to 1.0 lbs/day during their second winter, when they are pregnant.
                               ADDITIONAL CONSIDERATIONS

1. Body condition does not reflect protein status of the animal. However, if energy is not being
   met, protein will be used for energy through gluconeogenesis, and it is safe to assume that
   protein is deficient also.
2. Recurrent diseases such as IBR, BRSV or other infectious diseases in vaccinated yearling
   replacements are a sign of inadequate protein intake. This is because a protein deficient animal
   cannot mount an effective immune response.(REMEMBER--ANTIBODIES ARE PROTEINS).
3. Since first calf heifers are still growing, their protein requirements are higher than that of adult
   cows. They should therefore be fed separately.
4. LOW CRITICAL TEMPERATURE is that temperature at which the cow starts to use energy to
   stay warm. It ranges from 5 to 49 degrees Fahrenheit (F). FREEZING RAINS AND WIND
   ARE MORE DEBILITATING THAN COLDER, DRY WEATHER.
5. Temperatures below 24-40 degrees F. can increase feed intake 3-8%.
6. Temperatures below 0 degrees F can boost feed intake up to 25%.
7. When feed intake is increased, feed quality should be increased too. Feeding more of a poorly
   digestible forage will cause an accumulation of relatively indigestible feed components in the
   rumen due to too little energy for the bacteria to efficiently digest the feed. This will lead to a
   decrease in energy intake to the animal. In order to adequately supplement cattle in winter
   weather, it is necessary to use a high quality hay such as alfalfa, or feed a concentrate in addition
   to the normal hay.
8. The critical temperature for a young calf is approximately 50 degrees F. higher than for its dam.
   This is because the calf does not yet have a rumen microbial fermentation to help supply heat.
   Therefore, wind breaks or bedded areas are greatly beneficial to the calves. (Have you ever seen a
   young calf inside a round bale feeder after the bale has been mostly consumed?--It is trying to
   keep warm)

                                           SUMMARY
1. Maximize use of cow harvested feeds
2. Utilize crop residues during stage 3
3. Use a short breeding season and breed heifers 1-2 cycles before cows so that their PPI does not
   increase the length of the calving period.
4. Group heifers separately from cows
5. Feed the worst hay from weaning to January
6. Feed the best hay during and immediately after calving
7. Provide Trace Minerals and Salt year round (Se and Mg too)
8. Provide A,D and E shot 1-2 months prior to calving
9. Provide Bo-Se to calf (shot)

                            HAY STORAGE CONSIDERATIONS
1. Once a forage is harvested, nothing you do will increase its nutritive value above what it was
   fresh. This includes adding preservatives or ensiling the forage. Fermentation requires
   carbohydrates. This is a loss of energy.
2. Storing dry hay indoors results in dry matter losses of 1-7%.
3. Storing twine-tied round bales on sod results in approximately a 20% loss in dry matter due to
   spoilage.
4. Storing twine-tied round bales on crushed rock results in less moisture damage, and reduces dry
   matter losses due to spoilage to around 5%.
              Source: Hay and Forage Grower, January 1992.

                   NUTRITIONALLY RELATED DISORDERS OF COWS

PARTURIENT PARESIS (MILK FEVER, HYPOCALCEMIA)
Signs: Lack of muscular contractions, depressed appearance, cow lies on her side, cold
         extremities.
Occurs: After parturition
Prevention:
       1. Feed a relatively low level of Ca during late gestation and increase the level near
           parturition.
       2. Give high levels of vitamin D for a few days prior to parturition.

DISPLACED ABOMASUM
Signs: Cow goes off feed, appears uncomfortable.
Occurs: After parturition when there is excess space internally.
Prevention: A high fiber diet that gives more bulk in the rumen may help.

RETAINED PLACENTA
Signs: The placenta has not come out 24 hours after parturition.
Occurs: Approximately 7% of cattle have retained placentas. However, in Se deficient areas, such
         as Ohio, 20% of cattle suffer from this.
Nutrients involved:
Vitamin A: Not a problem on green pastures. Can give an A,D and E shot prior to calving.
Selenium: Recommend injection of 50 mg. Se approximately 2 months prior to calving.
Vitamin E: Taken care of with an A,D and E shot prior to calving.
Calcium:     This becomes a problem if it is not in sufficient quantities due to poor muscle
             contractions. Follow the same guidelines used to prevent milk fever.

KETOSIS
Metabolic disorder associated with carbohydrate metabolism.
Occurs: When cows are in a negative energy balance and therefore, is mobilizing body fat
          stores. A buildup of acetyl CoA yields KETONE BODIES (acetone, beta-hydroxy
          butyrate and acetoacetate).
Signs: Decreased feed intake, acetone on breath and in milk, occurs during the first 2-3 weeks of
          lactation and steadily gets worse.
Treatments:
       1      I.V. glucose or Ca gluconate (short term relief)
       2.     Propylene glycol as a drench
       3.     Increase propionate production in the rumen by feeding a higher concentrate diet.

FAT COW SYNDROME
It is a metabolic disorder associated with recently calved cows that are in a negative energy balance.
It only occurs if the cow is fat, and is much more prevalent in dairy cows than in beef.
Occurs: When fat is deposited in the liver.
DEATH usually occurs within 7 to 10 days.
GRASS TETANY
     -Hypomagnesia in grazing cattle and sheep
     -Low blood and cerebro-spinal fluid (CSF) Mg levels
     -Low CSF Mg levels thought to be related to convulsions

       Supplement with magnesium oxide (Magox) on pasture
             60 g/d for cattle
             10 g/d for sheep

                           BODY CONDITION SCORING SYSTEM

SCORE                                DESCRIPTION______________________________________

1. Severely emaciated. Ribs and bones visible. Animal physically weak. No external fat
   present by sight or touch.
2. Emaciated. As in 1, but not weak.
3. Very thin. Palpable or visible fat on ribs or brisket. Individual muscles in the hind quarter
   easily visible and spinous processes very apparent.
4. Thin. Ribs and pin bones are easily visible and fat is not apparent by palpation on ribs or pin
   bones. Individual muscles in the hindquarter are apparent.
5. Moderate. Ribs are less apparent than in 4 and have less than .5 cm (.2 inch) of fat on them.
    Last 2-3 ribs can be easily felt. No fat in the brisket. At least 1 cm (.4 inch) of fat can be
   palpated on pin bones. Individual muscles in hind quarter are not apparent.
6. Good. Smooth appearance throughout. Some fat deposition in brisket. Individual ribs are
   not visible. About 1 cm (.4 inch) of fat on the pin bones and on the last 2-3 ribs.
7. Very good. Brisket is full, tailhead and pin bones have protruding deposits of fat on them.
   Back appears square due to fat. Indentation over spinal cord due to fat on each side.
   Between 1 to 2 cm (.4 to .8 inch) of fat on last 2-3 ribs.
8. Obese. Back is very square. Brisket is distended with fat. Large protruding deposits of fat
   on tailhead and pin bones. Neck is thick. Between 3-4 cm (1.2 to 1.6 inches) of fat on last 2-
   3 ribs. Large indentation over spinal cord.
9. Very obese. Description of 8 taken to greater extremes.

Source: Wagner, J.J., J.K.S. Lubsy and J.W. Oltjen. 1988. Carcass composition in mature Hereford
cows: Estimation and effect on daily metabolizable energy requirement during winter. Journal of
Animal Science. 66:603.

				
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