Assessment of fertility

What causes financial loss

• Cows longer in dry period

• Unnecessary culling

• Cost of replacement

• Fewer calves per year

• Increasing semen costs

• Increasing labour costs

What events are measured

• Breeding events - who, when, how often

• Pregnancy events - diagnosis, losses

• Birth events

• Rearing and selling events

What is recorded on cattle farms

• Calving dates

• Culls

• Abortions

• Service dates using AI

What primary indices affect loses

• Calving interval

• Reproductive culling

• Failure to conceive

• Serves per conception

• Abortion

• Heifers age at first calving

What secondary indicies affect losses

• Abortions

• Heat detection

• Overall pregnancy rate

• 1st service pregnant rate

• Calving to 1st service

How does timing of 1st service effect losses

• Too early can decreases infertility

• Too late prolongs the calving interval

How is the 1st service pregnancy rate calculated

Number of 1st services resulting in pregnancy / total number of 1st services

How is submission rate calculated

Number of cows presented for service / number of cows eligible for service

What is the non-return rate

• Often used by A services

• Relies on co being seen to return to oestrus

What is the ideal inter-service interval

18-24 days which is the normal cycle length in a cow

How do you calculate the weaning percentage

Calves weaned / cows to bull

How is herd efficiency calculated

Total 200 day old weaned calves weights / total cows weight

What is the aims and benefits of a compact calving period

• Homogeneous group at sale

• Favorable environment

• Management procedures

• Disease control

• Strategic nutrition

• Heifer selection

• Cow reproductive fitness

• Calving supervision and work efficiency

What needs to be monitored to ensure optimal reproductive performance 

• Ovulation rates

• Conception rates

• Early embryonic and foetal loss

• Abortion

• Peri-parturient problems

What is the lambing percentage

• Lumber of lambs reared per 100 ewes to ram

• Allows comparison between farms and breed

• Includes non-fertility reasons

What are useful paramteters in pig breeding herds

• Weaning to service internal

• Farrowing rate

• Litter size

• Pre-weaning mortality

• Age at first service

• Culling rate

What are useful parameters in laying hens

• Habitability

• Mortality rates

• Feed conversion ratio

• Egg weight and quality

• Age at sexual maturity

How is male fertility assessed

• Matings per week

• Percent pregnant of served

• Females pregnant in 1 oestrus cycle

What is the fertility index

• Effect of bull on fertility of daughters

• Based of predicted transmission ability

• Desirable positive value

• Scale of -15 to +15

What are the targets for 365 day calving interval

What are the targets for secondary indices

What are the targets of beef herds

What are the targets of pig breeding herds