FAC3-5: Suckler, Cow, and Bull Management Flashcards
What is the target cow:bull ratio during breeding?
1: 50
1: 20 for young bull
What is the target length of time for a mating period?
9 weeks
What is the target percentage of cow/heifers in calf at PD?
at least 95%
What is the target calving period?
9-12 weeks
What is the target for how many calves are still alive at one week old?
≥98%
What is the target number of calves alive at weaning?
≥98%
What is the target age of sale for bull beef, steers, and heifers?
12 months bull beef
18 months steers and heifers
How does one assess the genetic merit of a bull?
Estimated breeding values (EBVs)
What are the main characteristics of EBV testing?
- Breed specific
- Presented as an average for the breed
- Reliant on phenotypic data collected from recorded pedigree herds
- Calculated using BLUP (Best Linear Unbiased Prediction)
- Variable accuracy
REMEMBER: a bull only makes up half of a calf’s genetics.
How do you control for infectious diseases when bringing in a bull?
- Isolate for 28 days and observe for signs of infectious disease
- Screen for:
- BVD
- Johne’s
- IBR
- Leptospirosis
- Treat for liver fluke
- Only by virgin bulls
When does one conduct a Bull Breeding Soundness Exam (BBSEs)?
- Prior/after sale
- 6-8 weeks before breeding season - spermatogenesis takes two months
- When a problem is suspected
What are the different levels of a BBSE?
Level 1 - Physical Exam
Level 2 - Physical Exam + Semen Evaluation
Level 3 - Physical Exam + Semen Evaluation + Libido/Serving Capacity
At what temperature do you handle semen (and its collection equipment)? Why?
37C to prevent cold shocking
What are you looking at when you assess semen quality?
- Volume and density (watery, milky, creamy)
- Gross motility (scale 1-5)
- A minimum of 60% should be progressively motile
- Morphology
- Minimum of 70% should be normal
What is the difference between primary and secondary semen morphological abnormalities? Which is more serious?
Primary: occurring during early spermatogenesis - more serious
Secondary: occurring during epididymal transit
How does one assess libido/servicing capacity of a bull?
you need to observe the bull mating females to ensure good libido and normal intromission
Is a single BBSE enough to determine a diagnosis/cull stasis of a bull?
No. A bull should never be culled on the basis of a single evaluation and a re-test 60 days later should always be offered.
Why is careful management of nutrition important throughout a cow’s productive cycle?
It is essential to maximise fertility and productivity.
Both over- and under-conditioned cows are more likely to experience dystocia and decreased neonatal calf survival.
Sufficient energy and protein is essential for adequate colostrum milk production
What are the most common causes of perinatal/neonatal mortality?
- Dystocia
- Failure of passive transfer from inadequate colostrum intake
- Early infection due to a dirty calving environment and failure of passive transfer
- Congenital anomalies
What are the common causes of dystocia? What is their common denominator?
- Poor choice of bull badly matched to cow breed and confirmation
- Undergrown heifers
- High twinning rate
- Over-conditioned cows
- Under-conditions cows
- Metabolic problems
THEY ARE ALL MANAGEMENT ISSUES
How do you measure the failure of passive transfer in calves?
GGT, serum total protein, zinc sulphate turbidity test
At what age do you start feeding the suckled calf?
At 4 months old, half its requirement should be met by grass, silage, or creep feed rather than milk.
Creep feeding can be introduced at any time after calving but should be fed for at least three weeks before weaning to reduce stress and to minimise a drop in performance at weaning.
When should the calf be weaned?
Once calves are around 200 days old, 75% of its nutrient requirement should be from feeds other than milk
Are finishing rations good on rumen health? Why?
How do you combat this?
Finishing rations contain less forage and more supplements than growing rations. This leads to increased rumen acidity and can be challenging to animal health (bloat, CCN, abomasal ulceration, nutritional diarrhoea)
Finishing rations should be introduced gradually and forage amounts slowly reduced over a period of a week
What is the grading system for carcase classification? What does it judge?
EUROP (E=best)
Judges:
Conformation (E=best)
Fat (1-5)
Sex category (A = young bull; B = bull; C = steer; D= cow; E = heifer)
What are the five management areas in which suckler herd health and welfare management can be influenced?
Bull choice and management
Nutritional management of cows
Perinatal calf management
Youngstock management
Heifer management
What do you look for in the ideal bull purchase?
Safe to handle
In good health
Terminal Sire traits
Maternal trais
When conducting a BBSE, what do you look at in the physical exam?
Feet and leg conformation
BCS
Eyes
Nose
General health
Scrotum
When conducting a BBSE, what do you look for when examining the scrotum?
Scrotal circumference - directly related to sperm output
Palpate testes and prepuce
Disease
- Orchitis
- Epididymitis
- Seminal vesiculitis
When conducting a BBSE, what are some morphological issues with sperm that you could come across?
Proximal droplets: either immature sperm (or bull) or insult to sperm during development
Bent tails: thought to happen in the epididymis or due to cold weather or stressors
Pyriform Head: pear-shaped head making less able to join with oocyte - heat stress or hormonal disturbance
Detached head: often a rusty load or due to testicular abnormalities or inflammation of the epididymis or seminal vesicles
Vacuoles: Sperm less able to join with oocyte - heat stress or hormonal distrubance
Why should you monitor BCS in cows re:breeding?
Fat cows = dystocia
Thin cows = extended anoestrus and cant get back into calf
What are the benefits of artificial insemination and synchro in beef herds? Any down-sides?
Benefits
- Can help drive a compact calving period
- Can allow new and more varied genetics to be bought-in
- Can help manage infectious abortion
Down-sides
- Lots of handlings
- Expensive
- Animals only respond to synchro if they are in good BCS and have recovered will from calving
What is the difference in parasite burden in spring born v autumn born calves?
Spring born
- Take on worms slowly through the season
- May arrest over winter
- At risk of re-emergence in spring
Autumn
- At turn out eating lots
- At risk of parasitic gastroenteritis
