Cattle Flashcards
What are some features of a highly fertile beef herd?
- Calving pattern length 8wks in cows, 6 wks in heifers)
- 70% females calve in first cycle
- Calving rate >95%
- Heiffers calve down as 2 yo
- Heiffer dystocia rate <5%
What are 7 habits for effective heifer and cow management?
- Calving pattern
- Heifer critical mating weights
- Heifer weaning
- Heifer nutrition
- Parasite control
- Reproductive diseases
- Selection of heifers for joining
At what % bodyweight should we aim to start joining beef heifers? At what age to beef calves wean?
60-65%
100 days from when the last calf was born (min) to 6 months (max). As a rule of thumb: calves can be weaned when cow CS falls to 2-2.5
Why are younger beef herds better?
- Cow value declines after 6-7 years
- Bodyweight peaks at 7-8 years
- Weaning weights of calves decline in older cows
- Older cows are more likely to die (cancers, grass tetany)
- more flexibility to cull for genetic gain
When should preg testing be done in a beef herd?
Depends on joining period length:
Short joining period- heifers at 6-8 weeks after joining finishes, cows at weaning
Longer- 16 weeks (10c piece cotyledons) of gestation. if more than 8 week joining period, preg test 8 weeks later
What are uncompensible defects relative to sperm? How can their effects be avoided?
“toxic sperm”= sperm that still work but don’t work well. they can fertilise an egg but the fertilised egg will often die
Know the hix of the bull, own it for 70d before joining, don’t use sick injured bulls for at least 70d
What is the bull:cow ration for dairy and beef cattle?
Dairy 1:30
Beef 1:50
What should beef bulls be vaccinated against?
5 in 1 leptospirosis vibriosis pestivirus others... (depends)
What things might affect pregnancy rates in Australian beef herds?
- Heifer weights
- Callving patterns
- Fertility of bulls
- Bull:cow ratio
- Nutrition
- Venereal diseases
What is the definition of a fertile bull? How about a subfertile bull?
One that can impregnate by natural service at least 60% and 90% of 50 normal cycling disease free cows within 3 and 9 weeks respectively
Sub: Can achieve pregnancies by natural service but not at the rate of fertile bulls and can produce viable semen but cannot achieve pregnancies by natural service
A full veterinary bull breeding soundness exam includes…?
- Identification
- Hx
- General physical exam
- Examination of testes and scrotal sizing
- crush side semen evaluation
- Serving ability testing
- Semen morphology testing
If the testicles of a bull were either soft or firm would this be okay?
No, should check sperm morphology
Preputial prolapse is most common in which breeds?
Bos indicus
What age group of bulls is most prone to prepuce stenosis? What about papillomas?
2-4 yo (this is a high risk condition)
1-2 years old
What things are involved in a general physical exam of a bull?
- Identify the bull
- CS
- Check the eyes
- Sheath structure
- Examine the hooves
- Examine leg structure and conformation
- Examine gait
- Reproductive organs
What do you check in a crush side semen evaluation?
What criteria allow a pass/tick?
- Gross motility/ mass activity (waves)- undiluted, 40x, no cover slip
- Individual motility (high power, diluted semen)
Criteria: no blood/urine, no pus/flocculent material, 200 sperm per 100x field, 60% progressively motile sperm for a tick (30-59% for a pass)
What might affect a bull’s serving ability?
- Haematomas, persistent frenulum, preputial trauma etc may affect erection
- corkscrew penis, dorsal analgesia, pain etc may affect intromission
- Neural pathology or pain may prevent ejaculation
How do you assess semen morphology?
8 drops semen in bufferd formol saline. Should have 70% normal sperm for AI
What is Countdown Downunder?
Program funded by dairy Aust. with an aim to increase farm profitability and improve milk quality
What changes occur to the milk of a cow with mastitis?
- Decreased lactose -> influx of sodium and chloride ions
- Decreased casein (and increased albumin and globulin)
- Increased plasmin (decomposes casein)
- Increased lipase (degrades milk fats)
Payments to milk producers are affected by what milk quality factors?
BMCC
Total plate counts
Bactoscan
Thermoduric count
What is the rosette of Furstenburg?
Internal opening of the teat canal which contains lymphocytes and plasma cells
What are some general risk factors for mastitis?
- Age and parity
- Stage of lactation
- Teat conformation/ condition
- Production
- Selenium and Vit E status
- Previous mastitis
What are some management risk factors for mastitis?
- Environment (cleanliness of laneways etc)
- Milking practices
- Seasonal conditions