Approach to Sub/Infertility in Dairy & Beef Cows Flashcards
what is the logical approach to infertility
- Breed type: Are we dealing with beef vs. dairy cows?
- Age: are we dealing with cow or heifer?
- When do fertility problems occur?
what are the issues that beef vs dairy cows commonly get that affects fertility
High yielding dairy cow:
- Cystic ovarian disease
- Persistent vaginal discharge/endometritis
- Metabolic diseases
Beef cow:
- Venereal disease causing pregnancy losses
how does age affect fertility
Puberty?
Freemartin?
Infectious causes of pregnancy losses
when do fertility problems occur
Estrous cyclicity before service: (submission rate problems)
- Affecting heat expression
- Detection
- Mating
Pregnancy after service: (conception P/AI problems)
- Leading to inability to establish or maintain a pregnancy
what could underlying causes of a cow that has not expressed estrus and has not ovulated (4)
1. True anovulatory anestrus postpartum:
- Prolonged postpartum or prepubertal
- Can be nutritional anestrus (negative energy balance post partum)
- Calving to service interval simply too short
- Haven’t had time to resume ovulation
2. Just ovulated first time and can’t yet detect CL
- Early forming CL difficult to see
- Can take 2-3 d to see them
3. Cystic ovarian disease
4. Developmental abnormalities in heifers
if a cow has not expressed estrus but has ovulated what could be going on, CL detected on ultrasoumd, high progesterone measured in milk or blood (6)
1. Estrous detection efficiency
- Was it missed by staff?
2. First ovulation post partum -pubertal
- 2-3 hour duration in high yielding dairy cows
3. Calf presence in cow calf cow
- Suppresses estrus behaviour
4. Stressors inhibit behaviour
- Environment, flooring etc
5. Luteinization of a DF after GnRH
6. Persistent CL
- Endometritis/pyometra!
- Need to scan uterine horn
if a cow is expressing estrus and ovulating what could be going on, CL detected on ultrasound, high progesterone measured in milk or blood (3)
- Estrous detection accuracy
- 1st and 2nd post partum - pubertal ovulation
- Simply a short luteal phase, or after PGF2a
if a cow is expressing irregular and not a 21d interval of estrus and not ovulating what could be going on
cystic ovarian disease
where do pregnancy failures occur (4)
- fertilzation failure
- failure in maternal recognition of pregnancy
- Late embryonic loss
- Fetal loss
what % of pregnancy failures occur at fertilization
0-10%
~40% occur with heat stress
what % of pregnancy failures occur at failure in maternal recognition of pregnancy
10-43%
why does failure at maternal recognition of pregnancy occur
Trophoblast protein by the blastocyst that will suppress PGF2alpha
Correlation between the amount of protein and the length of the embryo
- Depending on the number of cells, higher or lower amounts produced
- Need a certain amount to get maternal recognition
what % of pregnancy failures occur at late embryonic loss
3-4%
how does late embryonic loss occur
After maternal recognition has occurred but before fetal development at 6 weeks
Most often after day 24
After PD at 4.5-6% weeks
- Should be <10% of pregnancy losses to calving, ca. 3-4% from 6 weeks to 3 months
what % of pregnancy loss occurs due to fetal loss
5%
After PD at 4.5-6% weeks, should be <10% of pregnancy losses to calving, 3-4% from 6 weeks to 3 months
what is the timeline of infectious causes of bovine abortion
