EQUATION OF REPRODUCTION

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CHAPTER 1
EQUATION OF REPRODUCTION
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FOUR FACTORS

• A of Herd Detected in Heat
• B Inseminator Efficiency in
• C Herds Fertility Level in
• D Semen Fertility Level in

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PREGNANCIES

• Product of Four Factors
• A x B x C x D pregnancy
• Total Can NOT be Larger Than the Smallest
  Percentage

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FACTOR A

• Recovery Interval Since Calving
• Percent Heat Occurrence
• Percent Cows in Heat that are Detected
• Nutritional Adequacy Before and After Calving

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FACTOR B

• Inseminators Competency
• Proper and Hygienic Handling of Semen
• Placing Semen on Target

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FACTOR C

• Freedom From Disease
• Herd Management Efficiency
• Length of Postpartum Waiting Period
• Postpartum Metabolic Disease
• Change in Body Condition Score

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FACTOR D

• Capability of Bulls to Produce Quality Semen
• Competency of Laboratory Processing Procedures
• Frozen Semen Handling

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Summary

• 4 Variable Independent Factors Determine
  Calving

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Question 1

• What is the equation of reproduction?
• What factors make up the equation?

A x B x C x D Pregnancy
A Herd members detected in heat and inseminated
() B Inseminator efficiency () C Fertility
level of the herd () D Semen fertility level
()
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Question 2

• A really poor inseminator with an efficiency of
  only 60 was working in a herd with very high
  fertility. In fact the percentages of herd
  fertility, cows detected in heat and inseminated,
  and semen fertility were all in the 90s.
  Without needing to know the exact figures for
  these factors you can tell that the percentage of
  pregnancies resulting from A.I. during this time
  will not exceed a certain upper limit.
• What is it?

60
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Question 3

• The fertility level in herd X was 90, but
  because of poor heat observation techniques, only
  65 of the cows were detected in standing heat
  and inseminated. The bull semen had a fertility
  rating of 90. Inseminator efficiency was 90.
• What is the percentage of pregnancies resulting
  from A.I. during this time period?

65 x 90 x 90 x 90 47.39