Note
Studied by 25 peopleRepro dz pigs
Reproductive disease:
Fertility
Definitions | § Farrowing rate: % of sows served that go onto farrow – target = 88% § Farrowing index: number of litters a sow has a year – target = 2.35 |
Lactation cycle length | § 26 days |
Gestation length | § 3m, 3w, 3d |
To synchronise oestrus | § Oral progesterone for 18d § Once stopped ® oestrus in 5d |
Diet | § Increase diet last 3w of gestation § Entry to farrowing accommodation – decrease diet (prevent udder engorgement/oedema) § First 10d lactation – increase diet gradually (determines quality of next litter) |
How to optimise fertilisation | § Good oestrus detection § Serve at correct time § Don’t move between day 5-35 § Correct nutrition |
Factors affecting ovulation | § Nutrition § General health § Good feed intake in lactation § Manage sows so come into oestrus during early fertile period |
Areas of reproductive failure | § Anoestrus § Ovulation and oocyte production - see decreased litter size, decreased farrowing rate § Fertilisation – see variable litter size, irregular return to service § Implantation – decr |
Post-weaning management
Boar and pig contact | § From day 1 post-weaning – needed for LH pulses o 2x daily, short intensive periods Stop day before serve or wont stand on gestation |
Wean to service interval | § Sow = 6d, serve 24h after onset of standing oestrus § Gilt = 5d, serve 12h after onset of standing oestrus |
Day length | § 16h light § 200 lux |
Insemination | § Minimum 2 insemination § 12h intervals in gilts § 24h intervals in sows |
Movement | § Don’t move between 5-35d post insemination (interferes with implantation) |
Signs of reproductive failure
Irregular return to service | § Issue with fertilisation § Issue with implantation |
Decreased litter size | § Issue with ovulation and oocyte production § Issue with fertilisation § Issue with implantation |
Decreased farrowing rate | § Issue with ovulation and oocyte production |
Non-infectious causes of reproductive failure
Autumn infertility | § Pig originally seasonal spring breeder (doesent want to farrow in winter – so wont get pregnant end of summer/early autumn) § Usually gilts and young sows affected § Clinical signs: not cycling, increased returns to oestrus, abortions § Causes: o Short days, e.g. dark autumn o Variation in day-night temperature § Management o Prepare for it: increase feed level, increase boar contact o If inside can manipulate daylight length (16h a day ideal) |
Summer infertility | § Causes: o Heat stress o Sunburn – releases PGF2a ® poor reproductive performance § Management o Wallows – dig holes and provide water source to allow access to mud (protects against sun) |
Viral causes of reproductive failure
PRRS | § Porcine respiratory and reproductive syndrome § Clinical signs: abortion + respiratory signs § 3 disease statuses o Negative – good biosecurity, all ab -ve on serology o Positive, stable – sows ab +ve on serology but not actively shedding virus, piglets weaned -ve, achieved through vaccination o Positive, unstable – sows ab +ve and shedding virus, piglets weaned +ve, restabilisation hard to achieve § Control: o Vaccination o Replacement programme (buy in PRRS -ve, breed >6w post-infection/vaccination o Monitor +ve herds (PCR of oral fluids, blood, tissues (foetal thymus, spleen, lungs)) § Restabilisation: blanket vaccination of all animals, 2x doses 28d apart § Eradication: cull all sows, maintain closed herd with repeated blanket vaccination (but eradication = naïve herd – not good) |
Swine influenza virus | § Clinical signs: respiratory disease ® pyrexia ® abortion, weak/inappetent piglets § Diagnosis: nasal swab, serology § Control: biosecurity |
SMEDI | § Stillbirth, mummification, embryonic death, infertility (not abortion) § Causes: o Porcine parvovirus – infection related to gestation § <35d = return to service § 35-70d = piglet death and mummification § >70d = weak piglets/still birth o PCV-2 o Teschoviurs o Encephalomyocarditis virus § Diagnosis: foetal serology, PCR § Treatment: vaccination |
Aujezsky’s disease | § Clinical signs: abortion, neurological signs in piglets § Cause: herpes virus § NOTIFIABLE – contact APHA |
Bacterial causes of reproductive failure
Brucella suis | § Causes infertility, weak piglets, abortion § Diagnosis: serology § NOTIFIABLE – contact APHA |
Leptospirosis | § Clinical signs: abortion, stillbirths, vaginal discharge § Diagnosis: serology of sow or foetal tissue § Treatment: tetracyclines – oxytetracycline § Control: vaccination, improve service hygiene, AI |
Erysipelas | § Clinical signs: abortion, mummified foetus, return to oestrus § Diagnosis: red diamond shaped lesions § Treatment: penicillin § Control: vaccination |
Approach to abortion
History | § How do they farrow? § What is the farrowing rate? Service rate? – poor fertility = brucella § How many abortions? § How are the piglets that are born alive? – neurological signs = Aujezky’s § Any abnormal foetuses? – mummification = Erysipelas § Dams otherwise well or systemically ill? – unwell = infectious cause § Any other clinical signs? – red skin lesions = erysipelas, vaginal discharge = leptospirosis, respiratory signs = swine influenza, PRRS § Vaccination protocol? § Still eating? – not eating = infectious causes § What time of year is it? – autumn infertility |
Investigation | § Full clinical exam of dam +/- piglets – pyrexic = infectious cause § Nasal swab – swine influenza § Serology of sow +/- foetal tissue – swine influenza, leptospirosis, Brucella |
Treatment | § Amoxicillin – erysipelas § Tetracyclines – leptospirosis |
Prevention and control | § Vaccinate against PRRS, Leptospirosis and Erysipelas § Good hygiene at service/AI – leptospirosis § Improve biosecurity – swine influenza |
Causes | § PRRS § Swine influenza virus (SIV) § Aujezky’s disease § Leptospirosis – NOTIFIABLE § Erysipelas – zoonotic § Brucella suis – NOTIFIABLE § Non-infectious – autumn infertility |