Bovine Breeding Management Flashcards
Puberty is generally seen when the heifer reaches _______% of adult body weight
50-60
What genotyical factors can influence puberty?
Inbreed — later onset
Cross breed- sooner onset
Bos Taurus earlier than bos indicus
Heifers from bulls large scrotal circumference
What is the most important factor in onset of puberty?
Body weight
Eg beef reach puberty at 9-12months and larger dairy cows tend to reach puberty at 10-15months
How long does have bovine spend in each phase of the estrous cycle?
Estrus — day 0
Metestrus — day 1 to 4
Diestrus —day 5 to 18
Proestrus — day 19 to behavioral estrus
What is the most definitive signs of estrus in the cow?
What other signs might be present?
Standing to me mounted
Increased restlessness Decreased rumination Decreased appetite Decreased milk production Bellowing
Clear vaginal mucus/discharge
What occurs in metestrus in the bovine estrous cycle?
Final follicular maturation
Ovulation
Formation of early CL —> progesterone
Bleeding off 1-3days after estrus
What occurs during diestrus ?
Period of CL dominance through luteolysis
What changes do you see in hormone levels during proestrus?
Decreased P4
Increased E2
How does breeding differ between beef and diary herds?
Beef -most are bred by bulls and have tight calving intervals
Dairy - most are bred by AI and have early round calving
Dairy cows are bred at _______ months
14-15months
When do dairy cows calve?
22-24months
What is the voluntary waiting period?
Time period after calving in which cow will not be bred
Usually 45-65days
What is the purpose of the dry period?
Allows mammary involution before heifer goes through caving
How long is the lactation period vs the dry off period?
Lactation 305 days
Dry period 60days
Software can help identify what for dairy herd managment?
Open cows and okay to breed Not to breed Fresh Bred and waiting preg check Pregnancy Dry Sold or died
What type of graph can be used to determine if you have proper estrus detection?
Q-sum graph
How can you enhance estrus detection in a diary herd?
Proper cow ID
Separate into and observe small groups for heat
Ensure proper nutrition
Provide good footing
Maintain/assess accurate records
Train/assign heat detect to one person
Use estrus synchronization program s
Use estrus detection aids
What are the estrus detection aids available?
Tail-head pressure monitors (Kamar, lottery tickets, tail paint, chalk, heatwatch)
Estrus detector animals (chin bull markers, homer/teaser bulls/androgenized heifer/steer)
Pedometer year
Vaginal fluid electrical resistance decreases during estrus
What is a usual breeding period for a beef herd?/
21days
What cardinal signs would you be looking for if you were detecting pregnancy in cows that were in a breeding pen for 3 months and removed form the pen 2 months ago?
Signs of pregnancy between 3-5months
Fetal membrane slip
Placentomes
Fetus
Anminotic vesicle would be too large to palpate
What is a reasonable target for conception rates on the first cycle of the breeding period?
60% on first cycle.
Should have less than 10% open after 3 breeding cycles
What is control vs synchronization of the estrous cycle?
Control = to hasten or delay onset of estrus
Synchronization = coordinated control of estrous in multiple animals
What are advances of estrus synchronization?
Reduce the window of time when AI is appropriate
Reduce time spent in estrous detection
Enhance estrus detection due to anticipation/ increased display
Allow scheduling of breeding/inseminations
What three products are used for manipulation of estrus synchronization?
Prostaglandin (lutalyse)
Progesterone (
GnRH (cystolrelin)
What does lutalyse do?
Causes regression of CL
Estrus is displayed in 2-5days (only works during metestrus/diestrus )
What are the most common methods of using lutalyse?
One shot —> observe cows for 7 days for signs of heat
- if you observe in heat, breed
- if you dont observe heat, give progesterone and they should move up to proestrus
Two hot —> give every cow a shot on day 0, wait 11 days and give a second shot qwauyaq
How does MGA synchronize estrus?
Suppresses estrous (progesterone)
Lengthens luteal phase
How is CIDR used ?
IUD
Recommended for 7 day time frame
Follicle stimulation
Initiate estrous in non-cycling females
What are the advantages to CIDR?
By giving GnRJ we are inducing synchronous emergence of a follicular wave
Ovsynch — no heat detection required
All cows undergo timed insemination
