Dairy Herd Fertility Parameters

What is Submission rate?

how effectively we put semen in cows

What is conception rate?

how effectively semen + egg = calf

What is Pregnancy rate or 21d PR?

combining submission rate and conception rate

How do you calculate submission rate?

number of animals served/ number of animals eligible to be served * 100

**only in 21 day window**

Which animals are eligible in measuring submission rate?

passed the voluntary wait period (50-60 days) meaning they have complete uterine involution and return to cyclicity and are not yet pregnant and are being used for breeding in any 21 day window

If a farmer has 8 eligible cows out of 12 and serves 5 after 21 days and 2 of 5 become pregnant what is the submission rate?

5/8 = 62.5%

How is conception rate calculated?

number of animals pregnant/ number of animals served * 100

If a farmer has 8 eligible cows out of 12 and serves 5 after 21 days and 2 of 5 become pregnant what is the conception rate?

2/5 = 40%

How do you calculate pregnancy rate (21d PR)?

number of pregnancies observed/number of eligible cows * 100

**in any 21 day window**

If a farmer has 8 eligible cows out of 12 and serves 5 after 21 days and 2 of 5 become pregnant what is the pregnancy rate?

2/8 = 25%

What is a calving interval?

described overall fertility (all year) - historical, some limitations

What is calving - first service?

heat detection evaluation - some limitations

What is calving to conception interval?

only cows that conceived - some limitations

What are some ways of measuring fertility performance?

calving interval, calving - first service, calving to conception interval

What is the correlation between PR and peak yeild?

higher PR = higher peak yield

What does this graph represent?

good fertility

What does this graph represent?

average fertility

What is the target and range commonly seen for submission rate in a seasonal beef herd?

>90% and 50-95%

What is the target and range commonly seen for conception rate in a seasonal beef herd?

60% and 30-60%

What is the target and range commonly seen for pregnancy rate in a seasonal beef herd?

45% and 20-45%

What is the target and range commonly seen for submission rate in a seasonal (extensive) dairy herd?

>90% and 50-90%

What is the target and range commonly seen for conception rate in a seasonal (extensive) dairy herd?

50% and 25-55%

What is the target and range commonly seen for pregnancy rate in a seasonal (extensive) dairy herd?

40% and 15-40%

What is the target and range commonly seen for submission rate in a year round (intensive) dairy herd?

>70% and 40-70%

What is the target and range commonly seen for conception rate in a year round (intensive) dairy herd?

40% and 15-50%

What is the target and range commonly seen for pregnancy rate in a year round (intensive) dairy herd?

25% and 10-25%

What factors limit fertility performance? (9)

heat detection, lameness, transition cow disease, nutrition, infectious disease, semen management, genetics, mastitis, heat stress

What factors limit fertility performance specifically in the submission rate?

heat detection efficiency (sensitivity)

What factors limit fertility performance specifically in the pregnancy rate?

transition disease, nutrition, genetics, lameness, mastitis, heat stress

What factors limit fertility performance specifically in the conception rate?

semen quality, semen management, heat detection accuracy (specificity), infectious disease

How does estrus expression effect milk yeild?

increased duration of estrus = increased milk production

What is the sensitivity of heat detection?

% cows served that were actually on heat

What is the specificity of heat detection?

% cows not served that were not on heat

What does a low sensitivity mean in heat detection?

false negative = animals missed!

How do you know if your heat detection is poorly sensitive?

pregnancy diagnosis (PD) negative, low submission rate (SR)

What does a low specificity mean in heat detection?

false positive = animals served when not on heat

How do you know if your heat detection has poor specificity?

poor heat detection (HD), low conception rate (CR)

What is interservice interval?

Time between one service and another, should be ~ 21 days

When has the interservice interval had a good sensitivity and specificity?

18-24 days in cycle

When has interservice interval had a low specificity?

2-17 and 25-35 days in cycle

When does interservice interval have a low sensitivity?

36-48 and >48 days in cycle

How do you improve heat detection to improve fertility?

combination of visual observation, heat detection aids, hormones/synch, sensor technologies

How does lameness limit fertility performance?

lame cows spend more time lying down

reduction of estrus intensity → altered estrus behavior → lower conception rates

When does breeding typically occur?

50 days post calving

What transition cow diseases can affect fertility? (7)

milk fever, dystocia, twins, metritis, ketosis, retained fetal membranes, left displaced abomasum

How do you calculate incidence of transition cow diseases?

number of clinical disease (one specifically) / number of calvings

What parts of nutrition affect fertility? (5)

negative energy balance, macro-minerals, protein excess, trace elements and vitamins

How does a negative energy balance in the transition period affect fertility?

mobilizing excess body fat → high plasma non esterified fatty acid (NEFA) and high plasma ketone bodies (K)

How does a change in BCS (from dry off to 30 DIM) affect fertility?

increased loss in BCS = decreased fertility (SR and CR) and increased transition cow diseases

How does milk fever/hypocalcemia at calving affect fertility?

Lower SR and CR due to poor appetite → loss of condition → negative energy balance → +?- retained fetal membranes or immunosuppression

How does acidosis and high plasma urea affect fertility?

Lower CR due to high dietary crude protein (measurable in blood, urine, and milk) → changes in uterine environment → affects embryos quality and viability

What vitamins affect fertility?

E and A

What trace elements affect fertility?

Iodine, Copper, Selenium, Cobalt, Zinc and Manganese

How does vitamin E, copper and selenium affect fertility?

have anti-oxidant effect

Idk how to make a question on this so look at it

ok!

How does BVD lower conception rates?

Embryonic loss and Immunosuppression - leads to susceptibility to diseases

How does BVD lower submission rates?

immunosuppression - leads to susceptibility to diseases

How does BVD lower replacement rates (birth to first calinvg)?

increased calve diseases

How can management of semen affect fertility?

handling, AI technique and breeding policy (sexed semen)

How does sexed semen affect ferility?

lower CR? easier calving, genetic gains, increased herd size, bull calf issue

As of 2025 how many farmers use sexed semen?

76.5%

What is UK PLI (profitable lifetime index)?

indicates the additional profit that a daughter of a high __ bull is expected to earn over her lifetime compared wit ha daughter sired by an average bull with a __ of 0.

What factors affect UK PLI?

this one

What factors affect USA TPI (total performance index)?

this one

Why should we can about genomics?

provide young bulls with higher reliability proofs compared with pedigrees index proofs

higher reliability genomic proof compared with traditional pedigree index calculation for female youngstock

give you greater confidence in selecting youngstock from which to breed next replacement heifers

allow you to serve the genetically superior animals with sexed semen and put the rest to beef to increase calf value

What is PTA (predicted transmitting ability)?

average genetic value for a certain trait that an animal transmits to its offspring

How does PTA (predicted transmitting ability) affect fertility?

poor heritability (3-4%) but cannot be ignored

How does mastitis affect fertility?

lower SR and CR → inflammation, temperature and pain

What would you expect a cow with mastitis in the first 70 days in milk to have for SR, CR, and PR?

50%, 35% and 17.5%

What would you expect a cow with NO mastitis in the first 70 days in milk to have for SR, CR, and PR?

57%, 40% and 23%

How does heat stress affect fertility?

decreases

How do you monitor performance (minimally) in a herd fertility scenario?

calvings, AIs/services, PDs, Abortions, Do not breed cows, animals leaving herd (sold, dead), animals arriving (purchased)

How do you monitor performance (extras) in a herd fertility scenario?

lameness, mastitis, reason for animal leaving herd, clinical disease (PP), Per service - technician, bull selection, heat detection method, routine visit (frequency) - scanning, postpartum check, BCS

What can you use to help keep track of data for monitoring performance?

CIS/NMR, other farm softwarm, homemade (excel sheets)

What should you be keeping track of at routine visits regarding scanning?

pregnancy diagnosis (set the limit), secondary PDs, not detected on estrus, 30 DIM with PP problem

What should you be keeping track of at routine visits regarding postpartum check?

all cows within 1-2 weeks, problems with cows (RFM, M, K, LDA, others)

What should you be keeping track of at routine visits regarding BCS?

education - at calving, 30 DIM, 60 DIM, secondary PD, dry off, close up

How do you implement control over performance?

routine visit and herd health discussion