dairy cattle production

friesian

jersey

ayrshire

factors influencing income

• milk yield- bonus and penalty payments, contract

• fixed costs and variable costs- buildings, feed purchase, vet bills

• efficiency- lifespan, calving interval, endemic diseases

what is a dry cow

milk production has stopped due to calving

usually lasts 6-9 weeks

synchronisation

bringing a large number of cows into oestrus at the same time using hormones

production cycle

• needs to be pregnant by day 85 post calving

• pregnancy 280 days

• target calving interval 365 days

• target lactation 305 days

• dry period 60 days

• VWP 45-56 days

types of milking parlour

• herringbone

• rotary

• robot

• rapid exit

groups

• milking (fresh cows, fresh heifers, main herd, cull cows)

• colostrum group

• sick, mastitsis/AB group

• dry cow (far off, close up grou)

• heifers (milk fed, weaned, breeding, pre calving, milking)

calving pen/ paddock

• should be close to the dairy staff house

• close to milking parlour

• prone to being poached

• should not have barbed wire or electric fencing

non return rate

proportion of inseminated cows which are not re inseminated after a set period of time

in calf rate

• proportion of cows intended for re breeding that are in calf 6 weeks or 100 days after the start date of the breeding season

open period

• time from calving to re conception

• length depends on voluntary waiting period and breeding period

• target mean of 12 weeks

• 7-17 week range

reasons for culling

empty, lame, udder health

cost of poor reproductive performance

• milk production decrease as more milk per lactation but more time in late lactation or dry

• calving interval increase- fewer replacements available, slow genetic progress

• culling increase

• low conception rates so semen costs increase

• vet bills increase

• long dry periods- over fat cows

phases of fertility management

oestrus cycle

• 21 days

• sexual activity starts at puberty

• Coincides with presence of mature Gaafian follicle

• lasts from 6-30 hrs

• ovulation 6-14 hrs later

• ovum can be fertilised within 8-12 hrs of ovulation-Spermatozoa can fertilise for 24-48 hours in female genital system

• cow should be inseminated in second half of oestrus

• 11th day after fertilisation embryo signals its presence by secreting trophoblastin. The cyclic corpus luteum becomes corpus luteum of pregnancy and remains to end of pregnancy

advantages of AI

• higher genetic merit bulls

• easier to transport semen internationally

• less inbreeding in herd

• less risk of STDs

• cheaper and safer than buying in high genetic merit bull

• can select

• sexed semen available

when should you inseminate?

• 2-15 hours after standing

• 6-18 hrs after bulling behaviour

• observe in morning inseminate in afternoon

heat detectors

• tail paint which rubs off when the cow is mounted

• heat mount detectors which are applied to back or tail head

• pedometers often worn on the leg

• electronic detection systems

behavioural signs of heat

• standing

• bellowing

• attempt to ride

• moist, swollen vulva

• clear mucus

• stands to be ridden

• frequent bellowing

• nervous, excitable

• riding

• attempt to mount

• smells others

• clear mucus

fertility interventions- synchronisation

• intravaginal progesterone delivery device

• prostaglandin injection to stimulate luteolysis (degredation of the corpus luteum)

• GnRH injection to stimulate ovulation

fertility interventions- embryo transfer

• increases number of offspring a genetically important cow can have

• usually done with superovulation and non surgical recovery of eggs and embryos frozen and transferred to a recipient later.

• specialised service