assesment of fertility

number of offspring in a given time

per 100 dams - casualties, disease, prgnancy loss

per yr - seasonality, market demands

whats counted - born, live births, weaned, sold(no., kg), gender

financial loss example - daairy cow infertility

less milk per yr - cows longer in low yield or dry period

unnecessary culling - cost of replacement, decrease other culling options

fewer calves per yr

increase semen costs

increase labour costs 

e.g £50-100/cow profit

what is measurable

breeding events - who, when, how often ( natural mating vs AI)

pregnancy events - diagnosis, losses, service date

birth events

rearing/selling events

cattle farms - satutory obligation

calving dates

culls

abortions

service dates if using AI

combined with PD = fertility indices can be calculated early

monitoring repro performance

data - collect for a purpose

targets = first thing to do - appropriate and agreed, areas of weakness, improvements seen, warning of underperformance

cow repro cycle eg

VWP - 6 weeks for cows

monitoring - primary indices

= factors affecting losses

calving interval

repro culling - failure to conceive

serves per conception - semen usage

abortion

heifers - age at 1st calving

secondary indices

= directly affect primary indices but can be monitored constantly/ earlier

calving to 1st service

1st service prgnancy rate

overall pregnancy rate

heat detection

abortions/ embryo loss

monitor monthly 

timing of 1st service

importance = too early - decreases fertility, too late = prolonged calving interval

calving to 1st service interval = doesn’t include cows not served, average cancels ot cows served early or late 

1st service pregnancy rate

importanc e waste of semen, influences calving interval

no. of services resulting in pregnancy/ total no. of 1st services 

Submission rate

= same as heat detection rate

= number of cows presentted for service/ number of cows eligible for service 

over a set period of time eg 21 days

pregnancy rate - alternative terms

conception rate

preg rate

conception rate 

non return rate - relies on cow being seen to return to oestrus 

100-day in-calf rate 

heat detection

HDR = heat detection rate

HDA = heat detection accuracy 

inter-service interval

ideal - 18-24 days = normal length of cycle in cow

36-48 is normal as a multiple oestrus cycle length

poor HDA = large no. of cows at incorrect interval, other causes = embryonic death 

beef herds

weaning % = claves weaned/ cows to bull

herd efficiency = total 200-day-old weaned calves weights/ total cows weight 

aim: compact calving period of 9-10 weeks

homogenous group at sale

favourable environment

managment procedures

disease control

strategic nutrition

heifer selection

cow repro fitness

calving supervision/ work efficiency 

monitoring performance

% pregnant 21 days, % pregnant 63 days, median calving date

overall PR

calving rate

weaning rate

ewe

optimal repro performance -

ovulation rates

conception rates

early embryonic/ foetal rates 

abortion

peri-parturient problems 

definitions/ targets

lambin percentage = no. lambs reared per 100 ewes to ram

allows comparison between farms/breeds

incl. non-fertility reasons e.g. neonatal probs 

production ewes

deaths← =total ewes minus → barren ewes 

encourage basic records

no. ewes to ram/tup

no. ewes lost during prgnancy

no. barren ewes 

pig breeding herds fertility parameters 

litter size

weaning numbers 

weight at weaning

born alive/ litter

neonatal mortality

reared/sow/yr

meat sold/sow/yr

avg weaning age

reared/litter 

sow measures 

weaning to service

repeat matings

empty days

abortions

NIP>80d

sow mortality and culling

parity at culling

gilts - age at 1st service

% mated during 1st cycle

80%

good indicator for matching - season, environment, breed and nutrition 

companion animals

individual

selection fertility = low priority

high value → preservance sire ability

sire ability

natural service - females pregnant in 1x oestus cycle, mating per week, percent pregnant of served

AI - imprecise, non-return rate plus herd/cow factors

fertility index 

effect of bull on fertility of daughters

based on PTA

desirable = +ve value

scale -15 to +15

1 point  difference of ½ day in calving interval

using best FI bulls = <7 days shorter CI

targets for 365 day calving interval

targets inter-service interval

targets for secondary indices 

beef herd/ seasonal dairy herd targets 

pig breeding herd targets