Calving Season and Weaning Management

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Calving Season and Weaning Management

• Calving time
• Spring-reasons
• 1. Grasses and forages have their highest
• nutritive value in the spring, and therefore most
• animals in the wild have their young in the
  spring
• 2. Weather more conducive to survival of calves
• 3. Minimum housing needs
• 4. More economical to feed dry in winter
• 5. Tradition in U.S.

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Calving Season and Weaning Management

• Calving time
• Fall-reasons
• 1. Calves weaned in spring when feeder
• prices are generally more favorable
• 2. More steady supply of feeders if also
• calving in the spring
• Regardless of calving season chosen, one should
  strive to calve within a 40 to 60 period-
  reasons
• 1. More uniform calf crop resulting

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Calving Season and Weaning Management

• Creep feeding
• Advantages
• 1. Increases weaning weights by about 50 lb.
• 2. Eases the stress on 2, 3 and 4 year old cows
• 3. Eases the stress on drought-shortened and
  over populated pasture
• 4. Lowers the stress on calves at weaning and
  makes adaptation to feedlot diets easier
• 5. Fall born calves maintained in drylot
  substitute creep feed for lack of pasture
• 6. Prepares calves for early weaning program

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Calving Season and Weaning Management

• Creep feeding
• Disadvantages
• 1. Calves may lose some condition if going into
• backgrounding program following weaning
• 2. Requires extra labor, equipment, feed and
• management
• 3. Not easily adapted to large pastures or range
• conditions

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Calving Season and Weaning Management

• Creep feeds
• Can start as early as about 6 weeks of age
• Many producers start at 3-4 mo. of age (
• July 1 when grass is short) 10-11 salt of
• total creep DM will limit intake to about 2.5 lb.
• daily DM intake
• Consideration
• 1.
• 2.
• 3.

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Calving Season and Weaning Management

• Creep feed examples
• All oats may or may not be processed
• Cracked corn 62.5 lb
• Oats 37.5 lb
• a.
• b.
• c.
• d.

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Calving Season and Weaning Management

• Implanting
• May improve weaning weight
• If implant at birth, may need to reimplant 70
• to 100 days later to get full benefit of 50 lb.
• weight increase

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Calving Season and Weaning Management

• Implanting
• Concerns
• 1. Steer and heifer calves implanted during
  nursing period, may not respond as well to
  implants during feeding period research
  contradictory on this

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Calving Season and Weaning Management

• Implanting
• Concerns
• 2. Reproduction
• a. Bulls implanted as calves suffer at least 50
• reduction in testicular size and similar
  reduction in
• futility
• b. Recent research by Montana and Kansas
• workers has shown no detrimental effects on
  fertility
• 1.) Previous research has shown lowered
• conception rates and incidences of fertility
• c. Conclusion do not implant nursing calves
  that
• are potential breeding stock

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Calving Season and Weaning Management

• Early weaning
• Considered to be any weaning age younger
• than 6 to 7 months
• Situations promoting early weaning
• 2 and 3 yr. old cows
• Cows with twins
• Drought conditions or insufficient pasture
• Fall calving
• to accelerate rebreeding in late calving cows

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Calving Season and Weaning Management

• Early weaning
• ISU study
• Crossbred cows 42 day. breeding season
• Spring calving late March through early May
• Fall calving late August through early October

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Postpartum Estrus Distribution
Postpartum interval to estrus (days) Calving Time Weaning Age Fall 45 Spring 45 Spring 200
21 4.5 1.1 .5
42 42.0 14.3 14.1
63 42.5 62.9 31.4
84 9.3 17.4 29.4
84 .5 3.2 17.3
No heat 1.2 1.1 7.3
Total 100.0 100.0 100.0
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Effect of Season and Age of Calf at Weaning on
Reproductive Performance of Cows
Calving Time Weaning Age Fall 45 Spring 45 Spring 200
In heat and bred during breeding season () 97.5 98.9 88.6
First service conception () 66.0 69.1 65.7
Services per conception 1.57 1.48 1.54
Pregnancy rate of those bred () 80.5 84.0 79.6
Pregnancy rate of total () 78.5 83.2 70.2
Avg. da. of breeding season conception occurred 16 15 17
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Death Loss of Calves through 365 Days of Age
Calving Time Weaning Age Fall 45 Spring 45 and 200 Spring 45 and 200
Age at Time of Death (Days)
Dead at birth 4.4 6.9
0 45 1.8 8.0
46 90 2.0 .4
91 200 5.3 1.1
201 365 .5 .2
Total 14.0 16.6
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Effect of Season and Weaning on Calf Performance
Calving Time Weaning Age Fall 45 Spring 45 and 200 Spring 45 and 200
Wt., 45 da. 155 153 151
Wt., 90 da. 222 210 238
Wt., 200 da. 468 447 468

Wt./ da. of age 2.34 2.24 2.34