Reproductive Failure Flashcards
What kind of questions would you ask the farmer if there was a concern about reproductive failure in the beef herd?
Examples of some questions:
- How many bulls were used?
- Where have the bulls been sourced?
- Any pre-joining tests done on the bulls?
- Any pre-purchase tests done on the Hereford heifers?
- Any pre-joining tests done on the Angus cows?
- Vaccination history?
- Any other treatments administered?
- Any concurrent diseases observed?
- Nutrition – what type of pastures are present?
- Any supplementary feeding?
- Any abortions observed?
What is the acceptible abortion rate in a beef herd?
3-5%
When do most losses occur in cattle?
Before 80 days
What are some differentials to consider in a situation where a farmer is noticing reproductive failure?
- Failure to conceive: Infertility, inadequate bull poer, poor AI practices, nutrition/meg energy balance, poor transition, BVDV, vibriosis, trichomoniasis
- Early losses: BVDV, camplylobacter fetus spp., trichomoniasis, leptosporosis, iatrogenic.
- Abortions (mid or late): neosporosis, lepto, listeriosis, salmenellosis, brucellosis, mycotic, sporadic bacterial infections, BVDV, IBR, ureaplasma, nitrate toxicities, theileria, babesia, anaplasma, or iatrogenic
What is the acceptible abortion rate in a dairy herds?
5-12%
In terms of bull power in breeding beef herds, how many bulls are needed?
- Unsynchronised beef herds - 1 bull per 50 cows plus 1 spare
- Synchronised beef herds - 1 bull per 25 cows plus 1 spare
What are the 5 parts of the bull breeding soundness exam?
- Physical exam
- Scrotal circumference
- semen motility
- sperm morphology
- serving capacity
In a BBSE exam, what are the 3 categories for assessment and what do they mean?
- Tick: low risk for reproductive failure
- Fail: High risk for reproductive failure
- Qualified: Does not meet all ACV standards, but is still conidered suitable as part of a bull team, but not suitable for single sire mating or as an AI sire.
If a bull has a corkscrew penis on electroejaclation, does this make him useless?
No, some bulls will corksscrew when electroejaculated but not during paddock mating.
What would a score of 3 or >3 mean on serological testing to detect BVDV antibodies?
This would mean the animal has high levels of antibody and therefore has had recent exposure to BVDV (within the last 6-9 months)
How is BVDV transmitted?
- Transmission is via close contact: PIs shed virus from all body secretions (saliva, tears, nasal discharges, milk, urine, semen and faeces)
What happens if non-pregnant cattle get BVDV?
- In non-pregnant cattle BVDV causes mild illness before an immune-response clears the virus
What happens if a foetus is infected before 4 months?
- Either aborts or becomes a persistently infected carrier
What happens if a bull gets infected?
- A transiently-infected bull will not become a PI, but can develop a persistent testicular infection
Does the stage of gestation affect how BVDV manifests? Explain what you would expect to see on days: 0-45, <125, 100-150 and 125-285
Yes an no, as abortion can occur at any stage
- 0 – 45 days: Decreased conception rates and embryonic death
- < 125 days: PI calf (BVDV antigen positive, antibody negative)
- 100 – 150 days: Congenital defects
- 125 – 285 days: Immune response to virus (ag negative, ab positive)
What would you expect to see in a PI calve?
- Poor performers
- May have congenital defects (hydranencephaly, cerebellar hypoplasia)
- Are a source of BVDV (a source of future reproductive failure)
- Develop mucosal disease and die (often around 12-18 months of age)
How might BVDV affect the herd?
- Less cows will calve this year
- A proportion of the calves born will be PIs
- The calving pattern will be spread out this year (implications for the fertility of the herd next year)
How would you manage PIs in a beef herd?
- Test any new bulls for BVDV prior to purchace
- Vaccinate the herd with Pestigard before joining an immunologically naive herd
- Cull PIs (calves and cows)
What is the main source of vibriosis (Campylobacter fetus ssp venerealis) infection?
Bulls - venereal pathogen
In terms of reproduction, what does vibriosis do?
- Infection prevents implantation of the embryo or causes loss of the developing embryo, resulting in significant reproductive wastage.
- Cows return to oestrus with prolonged and irregular cycles
- Abortions occasionally occur around 6 months gestation – although sporadic Campylobacter-associated abotions are more likely to be caused by Campylobacter fetus ssp fetus or Campylobacter jejuni (NOT vibriosis)
How is vibriosis diagnosed?
- Diagnosis by PCR of preputial wash from the bulls or culture of preputial wash from the bulls (sample in CETM) or IgA ELISA of vaginal mucus from infected cows
- Culture is gold standard
What is the most effective method to prevent vibriosis?
Vaccinate the bulls annually
For trichomoniasis, where is infection maintained?
Infection is maintaineed in the folds of the prepuce
How might a cow get trichoniasis? What clinical signs would you expect to see?
- It is a venereal pathogen
- Organisms transferred to the cow’s vagina migrate to the uterus and cause infection. Recently infected cows have a sticky vaginal discharge of up to 2 months. Infertility in the cow can last up to 5 months
Should bulls with trichomoniasis be culled?
Yes
How is trichomoniasis diagnosed?
Diagnosis by culture or PCR
What stage of gestation would you expect abortion if the cow has lepto?
Commonly assoicated with mid to late term abortion, can also be a source of increased infertility in carrier cows.
Which leptospira serovar is most likely to be a source of infertility?
- Leptospira borgpetersenii serovar hardjo, type hardjo-bovis
How is leptospirosis diagnosed?
- MAT - Microscopic agglutination test
- PCR
- FAT
How can lepto be prevented in cattle?
prevention by vaccination of the herd annually with a 7 in 1
