Download Beef - Breeding, Genetic, and Reproductive Management

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Livestock Management CDE
Beef: Breeding, Genetic, & Reproductive Mgmt
B. A. Reiling
January 19, 2017
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Breeding/Genetics – Objectives
 Students should understand ...
 Dominance vs. Recessiveness
 Phenotype = Genotype + Environment
 Relative heritability of traits
 Use of Performance Data & Genetic Evaluations
• Actual Data & Ratios
• EPDs
• Selection Indexes
 Benefits of Crossbreeding Programs
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Breeding/Genetics – What to Expect
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Punnet Square:
 Dominance vs. Recessiveness
 Homozygous, Heterozygous
 Punnett Square: Black vs. Red, Polled vs. Horns
2 phenotypes
3 genotypes
 BB * bb =
 Bb * Bb =
Bb * bb =
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b
B
B
BB
Bb
b
bB
bb
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Codominance
Phenotype = Genotype + Environment
 So how do we get a “ROAN” Shorthorn?
 Example – Shorthorn Cattle
 Selection is based upon phenotype
 R = Red; W = White
 RW = Roan
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 Phenotype is not only the “looks”
 But also, what we measure.
• Birth Weights
• Weaning Weights
• Yearling Weights
• Average Daily Gain
• Pregnancy Rate
• Etc.
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Phenotype = Genotype + Environment
 Environmental Effects
 1) Random
 2) Known  Adjusted Performance Records
•
205-day Adjusted Weaning Weight
-
1) ADG = (current weight – birth weight) / Days of Age.
2) (ADG * 205 days) + birth weight
3) Adjust for sex of calf & age of dam
2
3
4
5-10
11+
Male
+60
+40
+20
---
+20
Female
+54
+36
+18
---
+18
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Relative Heritability of Traits
General Traits
Avg Heritability
Reproduction
LOW (<20%)
Growth Performance
Moderate (20-40%)
Mature Size
Carcass Traits
HIGH (>40%)
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Use of Data & Genetic Evaluations
Use of Data & Genetic Evaluations
 Actual Data
 EPDs
 Phenotype = Genotype + Environment
 For growth traits, heritability = 30%
 Minimal value for estimation of genetic merit
 Best tool for genetic improvement
 Comparative Value
 Expressed as + or – Values
• Theoretical
 Trait Ratios
 = (Ind Perf / Avg Group Perf) * 100
 Provides relative ranking among contemporaries
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average = 0
 Expressed in units of measure
• For
the trait
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Use of Data & Genetic Evaluations
Use of Data & Genetic Evaluations
 Comparing EPDs
 EPDs are NOT additive
 Sire A = +90 Yearling Wt EPD
 Sire B = +65 Yearling Wt EPD
 Difference = 35 lbs
 If the current average carcass weight = 800 lbs
 Calves of Sire A should weigh 35 lbs heavier (on
average) at one year of age than those of Sire
B, when bred to the same cows and raised
under the same environmental conditions.
 After 4 years, how much more carcass weight?
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•
•
•
•
Year
Year
Year
Year
1:
2:
3:
4:
• Compare
Sire
Sire
Sire
Sire
CW
CW
CW
CW
EPD
EPD
EPD
EPD
=
=
=
=
+20
+30
+10
+15
75 pounds!
875 lb CW!
the differences = 15 lbs added CW
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Use of Data & Genetic Evaluations
Benefits of Crossbreeding
 True / False –
 Breed Complementation
 A bull with a negative marbling score EPD is
guaranteed to decrease the % of choice cattle
in your herd.
 Selection Indexes
 Profitability Indexes
 Facilitate Multiple Trait Selection
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 Matching the strengths & weaknesses of different breeds
• Angus * Hereford = Black
• Angus * Charolais
 Heterosis (hybrid vigor)
  in productivity of crossbred progeny
that is greater than expected based upon parent’s
average performance
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The Heterosis Advantage
Weaning weights
Dam (Breed A) =
Sire (Breed B) =
Average =
460 lbs
540 lbs
500 lbs expected
Crossbred AB =
530 lbs
Heterosis advantage 30 lbs
CRITICAL for REPRODUCTIVE Traits
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Use of Data & Genetic Evaluations
 What might your students have to do?
 Answer some basic “test” questions
 Keep/Cull with data & questions
 Sire Summary Quiz
 Resources
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NebGuide: EPD Basics & Definitions
NebGuide: Economic Indexes for Beef Sire Selection
Beef EPD Definitions (Reiling)
Sample Sire Summary Quizzes with Keys (Reiling)
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Objectives – Reproduction
 Students should ...
 Identify basic reproductive organs/structures
•
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Bovine Female Reproductive Anatomy
Ovary
of the cow (female reproductive tract)
Uterine Body
Estrous Synchronization & Artificial Insemination
Breeding Soundness Examinations
Process of Calving & Providing Calving Assistance
Cervix
 Identify & describe purpose of basic reproductive equipment
 Know Beef reproductive numbers
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Uterine Horns
(calf will develop
in one of the horns)
 Describe the importance of scrotal circumference
 Discuss/outline/demonstrate reproductive mgmt practices
•
•
•
Baldy
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Bovine Female Reproductive Anatomy
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Bovine Female Reproductive Anatomy
Corpus Luteum
Ovary
Follicle
Oviduct (Fallopian Tube)
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Oviduct (Fallopian Tube)
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Bovine Female Reproductive Anatomy
Basic Reproductive Hormones
 Ovarian Structures
 Follicle Stimulating Hormone (FSH)
 Follicles
•
•
Grows in response to FSH
Secretes Estrogen
 Corpus Luteum
•
•
Secretes progesterone
Maintain pregnancy
 Causes the follicles to grow
 Application – superovulation & embryo transfer
 Estrogen
 Secreted by the follicles
 Estrous behavior
 Luteinizing Hormone (LH)
 Causes ovulation of egg from the follicle
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Basic Reproductive Hormones
Male Reproductive Management
 Progesterone
 Breeding Soundness Examination
 Secreted by corpus luteum (CL)
 Maintains the pregnancy
• Keeps
“heat” from recurring
 Application = Estrous synchronization
 Prostaglandin
 Secreted by uterus, due to atrophy of egg
 Regresses CL; restarts the cycle
 Application = Estrous synchronization
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 4 components
• 1)
• 2)
External Body Evaluation
External Reproductive Organ Evaluation
• 3)
• 4)
Internal Reproductive Tract Evaluation
Semen Evaluation
- Scrotal
Circumference
- Motility, Morphology
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Possible Skill Activities (Hands-on)
Possible Skill Activities (Hands-on)
 Artificial Insemination
 Calving Assistance
 Demonstrate proper loading of an AI pipette.
 Demonstrate proper obstetrical chain application
• https://www.youtube.com/watch?v=KKlM0YZ_83A
• https://www.youtube.com/watch?v=9aIcnLBXdL0
 Demonstrate proper AI technique (on tracts)
 Scrotal Circumference
 Demonstrate proper measurement of SC
• https://www.youtube.com/watch?v=U8PhqLZtrZk
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Reproductive Equipment (20)
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AI gun/pipette
AI sheath
Artificial Vagina
Bulb Syringe
Cane
CIDR
CIDR applicator
Cito cutter
Electroejaculation Probe
Goblet
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Heat Detection Patch
Hemacytometer
Obstetrical Chains
Pelvimeter, Rice
Pelvimeter, Krautman
Scrotal Tape
Semen Collection Device
Semen Straw
Warm Water Thaw
Beef Reproduction
By the Numbers ...
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Age of Puberty:
Estrous cycle length:
Duration of Estrus:
Time of Ovulation:
Gestation Length:
1st estrus post-calving
8-15 months
21 days
18 hours
12-14 hrs AFTER estrus
285 days
(PPI): 30-60 days
 Ultrasound Endocavity Probe
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Reproductive Management Resources
 Ext Circular: Synchronizing Estrus in Beef Cattle
 NebGuide: Assisting the Beef Cow at Calving Time
 Bull Management & Nutrition
 From the Range Beef Cow Symposium, 2009
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Questions
&
Discussion
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Thank You
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Extension is a Division of the Institute of Agriculture
and Natural Resources at the University of
Nebraska–Lincoln cooperating with the Counties and
the United States Department of Agriculture.
The Youth Development program abides with the
nondiscrimination policies of the University of
Nebraska–Lincoln and the United States Department
of Agriculture.
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