Nutri Girls Test Flashcards
Growth rate for heifers
0.7kg/d
% MLW for puberty
35-45%
How many days and what weight do we wean at?
240d around 200kg
weigh at weaning and compare with target critical mating weight and see who will make it
What is critical mating weight?
The average weight a group of heifers would achieve 85% conception from a 45d mating
60-65% MLW
British breeds = 280-320kg, bos indicus 300-320kg
What age do we want heifers calving by?
2 years (join at 15 months)
Conception rate for 42 days (2 cycles)
96% (we lose 30% of these and come back to 65% pregnant)
3 cycle joining period calving rate
95 in 63 days
How many cows should be pregnant on first cycle?
65%
First date for ultrasounding heifers
22-35d after joining
Pregnancy nutrition MJME
8.5-9.5MJME/kg DM
may need to increase to 10 in last 2 months gestation
Birth to weaning LW gain
1kg/d
Lactating MJME
more than 10.5MJME
Reasons for dystocia
- Foetal malpresentation (should be anterior)
- Foetal size
- Maternal pelvis conformation
- Uterine inertia - lack of contractions
- Insufficient dilatation of cervix and uterine torson
risk factors for dystocia
Breed
Age - primiparous heifers highest risk
Nutrition - under or over (more fat in pelvic area, smaller pelvic inlet or under nutritioned heifer wont have enough energy to deliver calf
Genetics -> live birth weight and calving ease are inherited
Methods of investigation for dystocia
- Clinical exam (palpation of birth canal and calf position)
- Ultrasound for size and position
- Labour monitoring for strength and frequency of contractions (intervene if struggling for more than 2 hours)
Prevention and control strategies for dystocia
Selective breeding -> lower birth weight calves
Nutrition
Regular monitoring -> detect pregnancy abnormalities throughout
Assist calf early
Bulls -> good ebvs
Cull cows with dystocia previously
Purpose and Process of reproductive tract scoring
Purpose -> to determine if the repro tract is able to carry a pregnancy, done at puberty and cyclicity development
45-60d prior to breeding >50% of heifers should be a score 4-5
Process -> Assesses uterine horns and ovaries by measurements (diameter, length, height, width) and any follicles or tone
Process of pelvimetry
Measurement of pelvic dimensions to assess the risk of potential obstruction
Describe heterosis in heifers
The production advantage from crossing breeds
Offspring have better production values than their parents
BVDV AGID Test process
Agar gel Immunodiffusion assay
Used to measure seroprevalence + detect recent infection (especially within last 9 months)
Test will detect antibody (Ab) from at least several years before Ab reaction measured and quantified:
negative = susceptible animal
1 or 2 (weekly positive/positive) = exposure to BVDV less likely to have happened within the last 12 months
≥3 (strongly or very strongly positive) = recent infection, usually in the last 3-9 months
Samples from pregnant females that yield this result indicate the female may be carrying a PI foetus
What age do heifers begin cycling?
9-15 months
Puberty is at 35-45% MLW
Gestation length of cows
280d
Calving to first heat interval length
55d
How many MJ does it take to grow 1kg?
35MJ ME
Bacterial causes of abortion
Leptospirosis (hardjo) - spirochete aquatic and zoonotic
Campylobacter
Brucellosis
Trueperella pyogenes
Mycoplasma
Ureaplasma
Viral causes of abortion
BVDV
Fungal causes of abortion
Mycotic placentitis (caused by aspergillus, coccidiosis, cryptococcus)
Parasitic causes of abortion
Neosporosis (protozoan)
3 Venereal diseases in cattle
Campylobacter fetus venerealis (vibrio)
Tritrichomonas foetus
Bovine Viral Diarrhoea Virus
Campylobacter description (type of pathogen)
Motile, gram negative flagellated bacteria
Campylobacter clinical signs
Early embryonic death and sometimes abortion between 4-8 months
Vaginal and cervical erythema
Irregular oestrus cycles
Temporary infertility lasting 3-5 months followed by recovery
Bulls are asymptomatic - organism found in penis and prepuce
Campylobacter diagnosis
ELISA test on vaginal mucous in 15-20 suspects
Smegma from bull culture
Vaginal culture immediately after abortion
Bacteriology on aborted fetus
Tritrichomonas pathogen description
Single celled flagellated protozoan with undulating membrane
Tritrichomonas clinical signs
Early embryonic death (50-100d) and infertility
Vulvovaginitis and cervicitis 4-9d -> discharge 5 days after joining
Pyometra in 10% of cases
Pregnant cows can be carriers
Infection carried on bulls penis and prepuce
Diagnosis of tritrichomonas
Swabs from male and female repro tract
Preputial culture of older bulls
Culture from pyometra
Control of campylobacter
Vibrovax -> 2 injections 4-6 weeks apart with 2nd 1 month before joining
Do bulls and sometimes heifers
Have a clean and dirty herd and use AI if needed
Females self cure with immune repsonse
Control of tritrichomonas
No vaccine or antibiotic
Clean and dirty (cull) herd
Keep bull herd young
BVDV Cytopathic vs non-cytopathic
Cytopathic -> mucosal disease, becomes cytopathic from non-cytopathic version in PI calves and leads to death within a couple years - causes erosion to epithelial and endothelial tissue
Non-cytopathic -> Acute and causes PI calves, no damage to cells but still causes disease
When does BVDV cause abortion?
3-5 months after acute stages in dam
Clinical signs of BVDV
Pyrexia, lethargy, leukopaenia, oculonasal discharge, oral lesions and ulcers, diarrhoea, decreased milk production
Immunosuppression
Can infect bulls in puberty and cause BVDV in semen later in life
Isolates in repro tract and causes failure to conceive, mummification or maceration
PI animal description and when do they become PI calves in a pregnancy?
Antigen positive
Antibody negative
Become PI calves on day 30-90d pregnancy
Infected after 125d = born immune and seropositive (not PI)
How to determine a PI calf
Test antigen in group then test a few weeks later for antibodies -> those that do not have them are PI calves
Vaccination boosters that should be given prior to calving
Clostridial (7in1)
Leptospirosis (leptoshield)
3 Reproductive associated vaccines
Campylobacter (Vibrovax)
Lepto (zoonosis)
BVDV/pestivirus
What is an EBV?
The difference between an individual animals genetics and the genetic baseline (historic genetic level of the population).
Each EBV is reported in units the measurement is taken (weight is in kg)
How much of the EBV difference will be passed onto progeny?
half -> the other half comes from the dam
3 AGID test advantages
Can detect antibodies 2 weeks post infection, max reaction 5-12 weeks after
High sensitivity and specificity
Quick
Tritrichomonas sampling Mediums
Mucous IgA used for diagnosis in female
- Transport media = 20ml phosphate buffered saline stored i universal container
- Store this at 4 degrees prior to use but warm to 18-37 degrees prior to sample collection - Enrichment medium = 5ml reddish fluid
3.
Campylobacter sampling mediums
- Transport media = 20ml phosphate buffered saline
- kept at 4 degrees and warmed to 18-37 degrres prior to collection - Enrichment medium = 5ml black fluid
Preputial sample - wet method
- Clip preputial hair prior
- 20ml phosophate buffered saline drawn from sample container into 20ml syringe and attached to 60ml infusette
- Be adjacentt o shoulder of bull to prevent being kicked
- Insert infusette through opening of sheath to preputial fornix
- Infuse PBS as pipette moved back and forth in 15cm stroked until all volume is infused while opening of sheath held closed between fingers and thumb
- Draw back plunger to draw back as much volume as possible while pippette moved back
- Put recovered sample back into universal container
Preputial sample - dry method
- Tricamper device plastic rod 50cm tod - top of rod has 7cm undulating plastic to collect preputial lining sample
- put into prepuce and work back and forth within prepuce for 20 seconds
- Tip flushed with phosphate buffered saline into universal container and tip removed into container
- place lid on container and mix/shake well
- 3ml syringe with 18g needle withdraws 1ml of sample to put into campylobacter transport medium (black fluid) and mix gently
- 0.5ml then placed into tritrich transport medium (red fluid) and gently mix
- Small drop of recovered sample put on slide with coverslip and looked at with condenser down under 400x magnification
Semen for venereal sample process
- 1ml semen into campylobacter enriched transport medium (black top)
- 0.5ml semen into tritrich enriched medium (yellow top, white circle)
not as reliable as preputial samples
Collection of cervical mucous process
swab on end of insemination pipette for anterior vaginal sample through speculum to reduce contamination from caudal tract
Or, guarded culture device used in equine
Swab into phosphate buffered saline in 5ml container (stored at 4 degrees until prior to use), swab cut and submerged into container with lid on and gently mixed
sample placed in submission satchel, air expelled and sealed, lab form in separate pocket
Put in container with gel packs less than 4 degrees but not frozen
The purpose of using Estimated Breeding Values when selecting replacement bulls.
Allows producers to select sires that meet their specific breeding and production goals
Choices can be guided through genetic data to increase probabilty of offpsring aligning with breeding goals
Eg. selecting low birth weight calves for a heifer
List three factors that may contribute to dystocia due to feto-maternal disproportion in heifers.
For each cause, briefly describe one management intervention that will assist in preventing that particular problem.
- Low yearling weight -> supply with adequate nutrition to grow 0.7kg/d
- Bull EBV -> select low birth weight calves
- Inadequate BCS (above or below 3) -> Ensure heifers remain at BCS 3 and no lower as this can cause dystocia due to insufficient energy or uterine intertia
2 factors leading to fewer conceptions in the first 2 cycles and more in the 3rd and 4th
Cows not cycling when bull goes in
Bull copulation issues -> lameness, infertility
Describe the important epidemiological features of ‘Vibriosis’ in cattle, and explain how these factors contribute to creating a spread out conception pattern
Carried on the prepuce and infects naive cows at service, causes early embryonic death and transient infertility for 3-5 months or irregular oestrus cycles (increased inter-oestrus interval) resulting in increased pattern
Younger bulls can be transiently infected whereas older bulls are permanently infected
Briefly justify both positive and negative points of the following statement: ‘It is appropriate to use induction agents to advance the timing of parturition in late pregnant heifers’.
Positive: Know that the cow will calve in 48 hours, ease of management
Negative:
Increases chance of foetal mortality
Increase anoestrus interval in the dam
Difficult to know true conception date (2 weeks) so may not have a viable calf
Only change weight by 1-2 kg
Lower fertility in subsequent breeding systems, stillbirths
Risk of retained placenta and metritis
Succinctly, explain how you would advise a manager to assess and manage puberty and nutritional status in replacement heifers in order to optimise their breeding potential in a beef breeding herd. Ensure to include selection prior to breeding for the replacements, and the critical principles and processes involved in having viable calves born from those replacement heifers.
Managing puberty and nutrition -> Puberty occurs at 35-45% MLW and about 9-15 months of age in heifers with an aim to get pregnant at 15 months and calve at 2 years of age. The critical mating weight must be met (60-65% MLW) at which 85% heifers will conceive in 45d mating) for success. this relies on adequate nutrition where growth from weaning to mating should be 0.7kg a day minimum and a bcs of 3 reached at joining. Heifers should then be 85% MLW at parturition, reached by 0.5kg/d growth from joining.
1kg liveweight gain requires 35MJME.
Heifers require 60MJ/d plus 5MJ/d every month from 6 months gestation.
A heifer above BCS 4/5 will have a lower chance of conception and if she calves in this condion dystocia is likely. Likewise, if she is too skinny and in a NEB, she may not have the energy to deliver to calf and suffer hypocalcaemia and uterine intertia at calving.
Select based on growth in year following weaning not on weight at weaning which depends on age.
Repro tract scoring target prior to breeding season
Assess 45-60d prior to onset of the breeding season to ensure >50% of heifers have a RTS of 4-5
= 30+mm uterine horn diameter with >10mm follicles and good tone with CL present
What should PD data be analysed in light of in beef herds?
Data analysed with:
- Heifer retention rates
- Age groups in the cow herd
- Nutrition
- Patterns of foetal age
Info gained from PD
Spread of calving
Pattern of calving
Number pregnant
Indication of herd fertility
4 reasons for spread out calving
- Pattern from last year
- Nutrition
- Bull power
- Venereal disease
How to reducing spread of calving
Cull late calvers
Reduce joining period
To keep herd numbers up in the meantime:
- Purchase PC cows
- Buy in steers
- Increase replacement heifers kept
How to decrease the anoestrus interval
Nutrition meets demands
Supplement if needed
Feed P during lactation if deficient
Early weaning
Optimal BCS at CALVING
Restrictive suckling if needed`
Why is a spread calving bad?
Becuase calf growing at 1kg a day born 4 months earlier will be 100kg heavier if weaners are sold at the same time
