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An Sci 4384, Reproductive Management

Animal Science 4384

Reproductive Management Plan

Management Information

Management of the herd begins on the first day of calving season!!

  1. General Information
    1. Herd size (at the start of the breeding season) must include between 375 and 400 breeding females (heifers & cows) each year.
      1. Only nonpregnant replacement heifers may be purchased.
      2. Purchase of pregnant animals is not permitted.
    2. Assume bull fertility and reproductive diseases are not a problem.
    3. Annual cow cost is $120 ($0.34 per head per day; does not include feed: see table 1 below).
    4. Annual heifer cost is $100 ($0.27 per head per day; does not include feed: see table 1 below).
    5. Annual bull cost is $500 ($1.40 per head per day; includes feed).
    6. Use Table 1 to calculate the feed costs for heifers and cows for the yearly economic summary.

      Table 1: Feed costs for cows and heifer throughout a production cycle.

    7. Maintenance 0.25 0.5 0.75 1 1.25 1.5 1.75 2
      Animal Class Period Feed option $/day lb / day lb / day lb / day lb / day lb / day lb / day lb / day lb / day
      Heifer Weaning to end of fiscal year Pasture - - - $0.36 $0.39 $0.44 $0.49 $0.54 $0.59
      Hay and Concentrate - - - $0.87 $0.91 $0.97 $1.01 $1.05 $1.09
      Start of fiscal year to breeding Pasture - - - $0.36 $0.39 $0.44 $0.49 $0.54 $0.59
      Hay and Concentrate - - - $0.87 $0.91 $0.97 $1.01 $1.05 $1.09
      Breeding to preg check Pasture - - $0.57 $0.63 $0.69 $0.76 $0.88 - -
      Hay and Concentrate - - $1.29 $1.36 $1.43 $1.48 $1.52 - -
      Preg check to calving Pasture - - $0.57 $0.63 $0.69 $0.76 $0.88 - -
      Hay and Concentrate - - $1.29 $1.36 $1.43 $1.48 $1.52 - -
      Cow Calving to Breeding Pasture $0.87 $0.92 $0.96 $1.01 $1.06 - - - -
      Hay and Concentrate $1.87 $1.92 $1.98 $2.02 $2.07 - - - -
      Breeding to weaning Pasture $0.69 $0.72 $0.77 $0.81 $0.86 - - - -
      Hay and Concentrate $1.65 $1.71 $1.74 $1.77 $1.83 - - - -
      Weaning to calving Pasture $0.61 $0.63 $0.66 $0.69 $0.75 $0.80 $0.84 $0.90 $0.96
      Hay and Concentrate $1.58 $1.66 $1.71 $1.77 $1.84 $1.88 $1.95 $2.01 $2.07
      Open and dry Pasture $0.51 $0.54 $0.57 $0.60 $0.64 $0.71 $0.77 $0.82 $0.88
      Hay and Concentrate $1.09 $1.19 $1.28 $1.37 $1.45 $1.49 $1.54 $1.59 $1.63

    8. An increase of 80 lbs. is needed to increase a single body condition score (i.e., 4 to 5).
    9. Calves are currently weaned 225 days after first calf is born.
    10. Gestation length = 287 days.
    11. Calf birth weight: 1st calf heifers = 75 lbs.
      Cows = 80 lbs.
    12. Average daily gain from birth to weaning:

      Heifer calves born to 1st calf heifers = 1.6 lbs./head/day
      Bulls born to 1st calf heifers = 1.8 lbs./head/day
      Heifers born to cows = 2.0 lbs./head/day
      Bulls born to cows = 2.2 lbs./head/day

    13. There are 15 bulls available for breeding.
      1. Annual bull cost is $511 ($1.40 per head per day; see I, section E).
      2. Price for new bulls = $4000
      3. Selling price for bulls = $2430
      4. Bull to cow ratio :
        • 1 bull/40 head nonsynchronized
        • 1 bull/20 head synchronized
        • 1 bull/30 open females following AI (i.e. cleanup bull)
  2. Replacement Heifers
    1. Percentage of heifers cycling at different ages and weights (see Heifer Target Weight Information or instructor for information)
    2. Conception rate = 65% per service.
    3. Calf loss from birth to weaning = 8%.

      0 to 72 hr = 6%
      72 hr to weaning = 2%

    4. Estrous synchronization for replacement heifers. (see attachment, Beef Heifer Protocols, pdf)
      1. Assumptions for the following protocols
        • Only cycling heifers will respond to Prostaglandin F2α (PG).
        • If the protocol includes a CIDR the percentage in heat will be 10% greater than the predicted target weight percentage.
        • If the protocol includes MGA the percentage in heat will be 5% greater than the predicted target weight percentage.
        • See individual protocols (below) for cost and conception rates (heat detection) or pregnancy rates (TAI).
      2. Heat Detection
        • 1 Shot Prostaglandin F2α (PG) - Conception rate = 60%;
        • CIDR-PG - Conception rate = 65%;
        • MGA-PG - Conception rate = 55%;
      3. Heat Detection & Timed AI (TAI)
        • Select Synch + CIDR &TAI - Pregnancy rate = 65%;
        • MGA-PG &TAI - Pregnancy rate = 60%;
      4. Fixed-Time AI (TAI)
        • CO-Synch + CIDR - Pregnancy rate = 55%;
        • MGA-PG - Pregnancy rate = 50%;
        • CIDR Select - Pregnancy rate = 60%;
    5. Artificial Insemination

      Assume the cost of breeding AI is $20 per service. If you synchronize estrus then decrease the AI cost to $17

      per service. Assume weaning weights of calves from AI will be increased 30 lbs.

  3. Cows
    1. For the effect of cow body condition and days postpartum see table below.

      EFFECT OF COW BODY CONDITION ON PERCENTAGE OF COWS CYCLING

      Days Postpartum
      Cow Condition 30 40 50 60 70 80 90 100 110
      Thin 3 19 34 46 55 62 66 71 77%
      Moderate 7 21 45 61 79 88 92 95 100%
      Good 13 31 42 91 96 98 100 100 100%
    2. Change in cow body condition score (i.e., 4 to 5) equals an 80 lb change in cow body weight
    3. Calf loss from birth to weaning = 5%.
    4. Conception rate cows bred by natural service.
      Days
      postpartum
      Conception rate
      at breeding
      0-31 45
      31-60 55
      >60 65
    5. Estrous synchronization of beef cows. (see attached, Beef cow protocols, pdf)
      1. Assumptions for the following protocols
        • Cows in thin body condition will not respond (show estrus).
        • Assume 60% of anestrous postpartum cows (> 30 days postpartum) will respond.
        • Assume 95% of the nonpregnant, nonlactating cows will respond
        • See individual protocols (below) for cost and conception rates (heat detection) or pregnancy rates (TAI).
      2. Heat Detection:
        • Select Synch – Conception rate = 60%;
        • Select Synch + CIDR - Conception rate = 65%;
      3. Heat Detection & Timed AI (TAI)
        • Select Synch & TAI – Pregnancy rate = 60%;
        • Select Synch + CIDR & TAI - Conception rate = 60%;
      4. Fixed-Time AI (TAI)
        • CO-Synch + CIDR – Pregnancy rate = 62%;
    6. Artificial Insemination

      Assume the cost of breeding AI is $20 per service. If you synchronize estrus then decrease the AI cost to $17 per service. Assume weaning weights of calves born from AI will be increased 40 lbs