repro Flashcards
manipulation of estrus cycle
seasonality based (short day breeders)-> highest price before easter (labour, time management)
in season-> sync females
out-> force cycle
transitional period-> advance start
in season sync
prostaglandin-> regresses CL-> starts estrus
needs Cl (must be in season)
two dose program- give one inj to short cycle and repeat in 11d to get sheep that didnt respond-> tight lambing group
progesterone implant-> keeps diestrus going until removed-> decrease triggers estrus
leave for 10-18d-> heat 24-48h after removal
MGA- cost effective for lg groups, feed pellets. heat 36-48h after last
out of season breeding
lamb out of season, efficient use of labour
only 70% conceive out of season
genetic selection
out of season sync
use progesterone 7-9d to develop follicles, PMSG to cause ovulation
manipulation of day length-> keep barn dark (long days 12wks-> short day 12wks), rams need to be exposed too
transitional period
sync w progesterone
start cycling within 6wks of the season, keep males away and use teaser ram
traditional breeding program
fall breeding, spring lambing
better fertility, good feed
low prices, more parasites
modified breeding programs
out of season: spring/summer breeding for fall lambs (certain breeds)
more expensive, more labour
advanced breeding programs
accelerated lambing-> birth every 7-8m, extreme management (3 lambings in 2 years)
5 in 3 years-> cornell star (needs heavy genetic component)
pregnancy diagnosis
remove open ewes, sort into feeding groups
U/S dx-> Cl dependent till day 60, can dx at 45d
BSE
health, hx
BCS 3.5
scrotal measurement and palpation
examine pp
semen collection
repro technology
AI- import frozen semen
maintain biosecurity, genetics-> laprascopic or cervical
50-70%
embryo transfer- increase elite female genetics, import frozen embryos, use less valuable ewes 40-75%
