Pig reproduction and infertility 1+2 Flashcards
What is the pigs/sow/year target?
22-26, perhaps 28 is target (Depends on type of unit); consists of number of litters/year (aim for 2-2-2.4, some farms will do 2.6), litter size (12-14) and pre-weaning mortality (<10%).
When do gilts reach puberty?
6-8 months old, need to achieve a minimum weight of 120 kg
When do you first mate a gilt?
2nd or 3rd oestrous (if you wait for a later litter, you tend to have a slightly larger litter size, 3rd is optimal)
How long is the lactation?
28 days (legal requirement, if you can fulfil certain criteria, you can wean earlier, perhaps 3 weeks).
What is the WOI?
3-5 days later. WOI = weaning to oestrous interval
When are sows culled?
Culled = after 6 litters (some companies beginning to say their sows can last 8 litters)
What is the MRP sign in pigs?
Oestradiol from the piglet
When does a gilt/sow ovulate?
Ovulates 2/3 of the way through oestrous (48-72 hours).
How do you induced farrowing?
Prostaglandin and oxytocin, work out farm gestation length (2-3 days before expected farrowing, not before otherwise you induce abortion and have dead piglets)
Define stillbirth
some farmers say anything that dies in first 24 hours is stillbirths when it is actually a neonatal death – bear this in mind when investigating farm records. Vet definition tends to be an animal that is not born alive/never lived outside the sow. Ask for definitions of farm’s measurements.
What is a mummified foetus?
don’t macerate because it is a sterile environment, leathery – water absorbed around them, there can be an infectious cause for this, ok to have the odd one of these but no more
What do regular and irregular returns to oestrous suggest?
regular – an indicator of fertilisation problem such as boar problem
irregular - management problem such as incorrect AI timing OR early embryonic loss
What is an average cull rate?
40% sows/year
What proportion of abortions have an infectious origin?
30-40%
What is suggested by mummified foetuses/stillbirths/ weak pigs of all one size?
there has been a single insult to the uterine environment (stress, fever)
What is suggested by mummified foetuses/stillbirths/ weak pigs of differing sizes?
consider this prolonged damage to foetuses. Think infectious causes – commonly viral – parvo, PRRS and CSF etc. (e.g. virus that infects the foetuses but doesn’t give the sow a fever)
List common (4) and uncommon (3) infectious causes of abortion.
o Commonly: parvovirus, PRRS, leptospirosis, erysipelas
o Uncommon but severe: Aujeszky’s, ASF, CSF
List the marker stages of gestation
o < 35 days of gestation – most absorbed
o 35-40 days – ossification begins
o Foetus dying > 35 days – mummified foetuses through to stillborn piglets (aborted at any stage)
o 70 days foetus immunocompetent, look for evidence of an infectious cause
o Full term at 112-116 days
List non-infectious causes of abortion
o Husbandry and management – stockman, hygiene, policies (age structure of the herd)
o Environment – season, heat stress.
o Genetics – parental/ progeny
o Nutrition - micronutrient deficiencies (Vit E and A)
o Toxic agents - misuse of hormonal drugs, chemicals (teratogens in hemlock), mycotoxins (i.e. Zearalenone)
Define SMEDI. Cause?
Stillbirth mummification, embryonic death infertility
Majority of these are caused by porcine parvovirus, (porcine enteroviruses are less frequently implicated)
Classical signs of SMEDI
Full term litter consisting of small mummified foetuses, full grown stillborn, live weakly piglets, ***RARELY CAUSES ABORTION
Transmission - SMEDI - 2
oronasal and venereal
Treatment - SMEDI
none
Control - SMEDI
vaccination is available and widely practised. Vaccinate 8 weeks before service on first occasion and 2 weeks before for subsequent boosters. It is actually a good thing to have a few cases (but not too many) of mummified foetuses on a farm because it shows the virus is still circulating and that the vaccine is working. Manufacturers say you need to vaccinate before serving, but you don’t need to do this.
