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Reproductive Management of Dairy Cattle
Important Records for Reproductive Management
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1st breeding – anytime after VWP
Later breedings Conception Voluntary waiting period Cycle from one calving until the next calving Calving Gestation The Reproductive Cycle
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Voluntary Waiting Period – (VWP)
- Determined by herd owner. - Fixed period following calving before attempting to breed cow. - Often the same for all cows in the herd although some have a longer VWP for 1st lactation animals. - Usually between 40 and 70 days
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Option Interval or Voluntary Waiting Period
Two factors seem to play a role in the cow’s calving interval. - High producers tend to have silent heat more often than low producers. - Dairy farmers may give high producers a longer wait period before being bred back.
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Option Interval or Voluntary Waiting Period
This may vary depending upon individual cow’s production. - High producing cows – Bred at first estrus 60 day postpartum – 13 month calving interval may be optimal. - Medium/Low producing cows – Breed at first estrus 40 days postpartum – 12 month calving interval may be optimal.
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Dairy cattle reproductive cycle
Voluntary waiting period Breed after this date Calves
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Days to first service Number of days between calving and when the animal is bred for the first time. Calculated on a herd basis – not for an individual animal. Animal may or may not conceive to this breeding/service.
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Dairy reproductive terms – linear display
Days to 1st service Bred for 1st time Calves
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Days Open Number of days between calving and conception.
Calculated on a herd basis – not for an individual animal.
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Days open & Days to first service - linear display
Days to 1st service Bred for 1st time and conceives Calves
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Days open + Days to first service - linear display
Days to 1st service Bred again and conceives Bred for 1st time Calves
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Dairy reproductive terms – linear display
Days open Days to 1st service Bred again (3rd service) and conceives Bred again - 2nd service Bred for 1st time - 1st service Calves
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Gestation period Number of days that a cow is pregnant.
Number of days from conception to birth of the fetus. Average gestation: 279 days-there are breed differences
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Calving Interval Period from one calving until the next.
Measured in months. Calculated on a herd basis – not for an individual animal. Days open Gestation period Calving interval
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Dairy reproductive terms – linear display
Calving interval Calves again Calves
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Measures of Reproductive Efficiency
Days to first service Days open Calving interval Services per conception Conception rate Heat detection rate Pregnancy rate
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Services per conception
S/C = Total number of services (breedings) Total number of pregnant cows Calculated on a herd basis – not for an individual animal. Inverse of conception rate.
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Conception Rate Total number of pregnant cows
CR = Total number of pregnant cows Total number of services (breedings) Calculated on a herd basis – not for an individual animal. Inverse of services per conception.
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Heat detection rate Also known as service rate.
Percentage of eligible cows detected in heat during a 21-day period.
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Calculated in two ways:
Pregnancy Rate Calculated in two ways: PR = Total number of cows pregnant Total number of opportunities to get cows pregnant PR = Conception Rate x Service Rate
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