Breeding management Flashcards
Puberty in the female
From around 5 months
Gilts: 150-180days of age, at approx 90-100kg
Not fully fertile in first cycles
Factors affecting age at puberty
genotype
nutrition – energy, protein content and quality (especially lysine)
boar contact
stress – transport, mixing
seasonal factors ?
Length of oestrus cycle
21 days (19-23)
Average duration of oestrus
60hrs
Average numbers of piglets born
14
Length of gestation
116 days (113-119)
Seasonal trends
More fertile in late autumn
Commercial lactation length
3-5 weeks - rapid cessation after weaning
WHen does first oestrus after weaning occur?
4-6 days
Weaning to service interval
5.5 days
After which parity does performance drop significantly
6
Most productive parities
3, 4, 5
Maiden gilt
An unserved female
about 100kg at first service
In-pig gilt
From successful service to farrowing
Sow
From birth of her first litter onwards
Sow herd
Sows plus in-pig gilts
Youngest a gilt is usually served
210 days (optimum is 220-240)
Minimum weight a gilt should be served
130kg
Best feed for gilts
Gilt specific ration with higher levels of protein, calcium, and phosphorus
Breeding age of gilts
From 7 months
Annual herd replacement rate
50-55%
Farrowing index
Litters per sow per year
Empty days
time from farrowing to successful conception
Non-productive days
time from weaning to successful conception (Min = 5days)
Weaning-to-conception interval
affected by the interval from weaning to service, and subsequent conception
ideally 5 days, but each ‘return’ will add approx 21 days.
Farrowing interval
lactation 27 days
wean-service 5 days
gestation ~116 days (common average)
theoretical minimum = 147 d (21wks)
~52/21 = 2.47 litters /sow/year
Parity profile
The breakdown of ages within a herd
When do boars reach puberty?
8-9 months, but sexual activity starts earlier
When do boars approach ‘workable fertility’
10-11 months
How long does spermatogenesis take
about 7 weeks (so can be infertile 6-7 weeks after illness)
Boar:sow ratios
1:20 on indoor units
1:15 on outdoor units
Pheremones of a boar
5 alpha-androsterone
Volume of semen production
150-250ml
Transport heat
Gilts come on heat 3-7 days after delivery
How can you artificially establish and maintain luteal phase
Synthetic oral progesterone (Altrenogest - Regumate)
Why are prostaglandin regimes not successful in the pig?
CL is refractory to the effects except for a very short period
Oestrus cycle
Oestrus: about 60hrs
Dioestrus (luteal phase): approx. 12 days
Prooestrus: 5 days
Signs of oestrus
Oedema and redness of vulva
Seeking out boar
Mounting behaviour between females
Standing reflex to back pressure
Vocalisation
Restlessness
Drop in appetite
Length of copulation
5-15 minutes
Stimulation of oestrus
Boar exposure - intermeittent more effective
How long are ova and sperm viable for?
Ova: 8-10hrs
Sperm: 36-48hrs
So optimum timing for mating is 8-10 hrs before ovulation
When to serve
Server every 24 hours during standing oestrus
Pregnancy
blastocyst stage persists for six days,
elongation and dispersal takes place during day nine to twelve,
attachment to the endometrium commences approximately 13-15 days after oestrus, and is usually completed by day 21
Target of pigs born alive per sow per year
Over 31
Target for pigs born alive per litter
15 or more
Target for litters per sow per year
2.4
Conception failure
Too many returns to service
Litter scatter
a poor Litter Scatter is small litters upsetting the system
(classically this has been more than 15% of litters of 8 piglets or fewer; however, in modern production systems litters of 10 or fewer from 15% of sows would be considered to be poor performance – or 10% with 8 or fewer),
Specific infectious causes of infertility
Absent from the UK and notifiable
· Aujeszky’s disease
· Classical swine fever (CSF)
· Brucella suis (not notifiable)
Present in the UK
· Porcine parvovirus (PPV)
· SMEDI viruses other than PPV
· Porcine Reproductive & Respiratory Syndrome (PRRS)
· Porcine Circovirus type 2 (PCV2) -some evidence
· Swine Erysipelas (SE)
· Leptospirosis
· Chlamydophila (?)
· Trueperella abortisuis
· Mycotic abortion
· Swine influenza (SIV) due to the effects of the fever.
Non-specific infectious causes of infertility
· Vaginitis/cervicitis/endometritis - often post farrowing and chronic;
Orchitis etc.
Any systemic infection producing a high fever (>40°C)
Abortion associated with non-specific metritis
Lameness – especially in the boar, but also the sow or gilt that cannot stand for service
Non-infectious causes of infertility
Incorrect nutrition
‘Physiologically sub-optimal management’ = “Stress”
Heat stress, cold stress
Sunburn and photosensitisation
Seasonal infertility
Behavioural stresses – bullying and fighting
Mycotoxicosis
Quality of service – natural & AI (sperm transport, stimulation of oxytocin release, etc.)
Human factors – natural & AI
Herd (sows and boars) age, and parity profile
Lameness in boar or sow inhibiting service
Reasons for failure to concieve
Not even served
Gilt anoestrus (rare possible <3%)
Sow post-weaning anoestrus
Farrowing rate
those which actually farrow
Losses will include resorptions, (long returns), abortions, culling, deaths of sows etc.
Regular returns
based on 3wk integers – (19-23d)
Irregular returns
other intervals - <19s, 24-37d, 47-56d, >68d,
after that it becomes blurred, the assumption is that conception had occurred.
Late returns
> 11wks post service up to farrowing – previously assumed by staff to be pregnant, important to know if they were confirmed in pig, and by whom?
Possible treatments for poor conception and fertilitsation
Injectable synthetic peptide analogues of GrRH
Buserelin (Porceptal), Peforelin (Maprelin): Given after weaning, to increase stimulation to increase FSH/LH (Buserelin) or FSH (for Peforelin)
Synchronisation (gilts)
- Altrenogest (Regumate, MSD), given orally for 18days, oestrus 5-7 days later
Ovarian stimulation (gilts)
- PG600 (MSD) Gonadotrophins (FSH/LH)
Causes of foetal death
Stress
PPV
(Other) SMEDI virus infection
Aujeszky’s disease (Notifiable) - not currently in UK
CSF (Notifiable)
PRRS
PCV2 ?
Litter size – absolute numbers – placental space
Parvo and enteroviruses spread slowly through the litter (get more and more mummified), CSF spreads very quickly
Specific infectious causes of abortion
PRRS
Erysipelas (SE)
Mycotic abortion
Leptospirosis
Trueperella abortisuis
PCV2 ?
Aujeszky’s disease
Non-specific infectious causes of abortion
Bacterial metritis/placentitis
Any febrile infection
Toxaemia - endotoxins etc
Non-infectious causes of abortion
Sunburn
Heat stress
Photosensitisation
Toxaemia, - poisons, mycotoxins, physiological,
Mummification
Dead some time before birth
Stillbirth
Dead within a few days before or during parturition
Causes of piglets not surviving to birth
PPV (mummified and still born)
PRRS (mummified, stillborn, weak)
Oxygen - placental separation, or trapped cord.
Birth weight
Birth order
Litter size
Premature/dysmature
Causes of dystocia
Primary uterine inertia
Secondary uterine inertia
Foetal dystocia
Others
Primary uterine inertia
Not common
Over fat sow
Over distension of uterus
□ overfull
□ hydrops foetus(es)
Lack of exercise
Hypocalcaemia (??)
Other illnesses - fevers etc (flu, PRRS)
Endocrine malfunction
□ Posterior pituitary
□ Lack of luteolysis
Secondary uterine inertia
More common
Heat
Exhaustion
Dehydration
Hypocalcaemia?
Intercurrent disease
Prolonged foetal dystocia
Often leads to retention of foetal membranes
Often leads to failure to involute resulting in metritis
Dead putrefying foetuses
Foetal dystocia
Actually not common
Log jams
Oversized foetuses (often few piglets = big piglets), so rare in big litters
Abnormals - splits, hydrocephalus, hydrops, etc
Dead and gassy
Malpresentations - rare, “T boned” and usually oversized
Other causes of dystocia
Uterine rupture - usually operator induced
Uterine twists
Narrow pelvis - Genetic, poor growth, immature, historical accidents
Pelvic - cervical/vaginal/vulval damage - usually operator induced
?overdose of oxytocin (dose too big, rather than too frequent)
Treatment of dystocia
Oxytocin - Always use, but don’t overdose!
□ 2-4 iu (0.2 -0.4ml) during farrowing
□ 6-10 iu (0.6-1.0ml) after (?) farrowing and next day
Antibiotics- Cover for infection
□ LA penicillin, or daily penicillin if badly damaged
Anti-inflammatories- especially if bruising/damage/swelling
□ Corticosteroids - are indicated
□ Dexamethasone (avoid ‘steroidaphobia’), very effective.
Pain relief- NSAID’s
□ Ketofen, Finadyne, Metacam. (Some farms use routinely, particularly in gilts)
Prostaglandins- To induce - must know due date
□ To expel remnants, only effective if used 24-48hrs post farrowing
Calcium- Some claim benefit
Pessaries- ?? if uterine inertia; ? may be cosmetic?, usually antiseptic
C-section
Possible and pigs heal well
Usually for unresponsive inertia or pelvic blockage
GA – Ketamidor (the only licenced product) (Ketamine) 0.15 – 0.2mg/kg
After sedation with Stresnil (Azaperone) 1 – 2mg/kg
Flank incision either side
Can be big mechanical difficulties finding and manipulating the other half of uterus on far side
Or euthanase (by gun or humane killer, not pentobarbitone!) Then open midline and open uterus in situ and remove piglets; 3 mins allowed. Very good piglet survival rate
Rectal prolapses
Annoying but often not affecting parturition
Sedate, Ring block with local, replace, purse string suture (with tape)
Vaginal prolapse
Pre and rarely post farrowing
Sedate, lateral block with local, replace, ‘in-out’ cross-band suture. (with tape)
Uterine prolapse
Can sometimes be replaced (not a ‘5 minute job’).
Surgically remove (heroic!) - possible but don’t ever try it
Euthanasia
Cover whilst piglets take colostrum or collected manually
Often get ruptured ovarian arteries
Cervical prolapse
Push back in and use a purse string suture
Do not suture through sensitive tissue, do it through the surrounding skin
Replacement is relatively successful
MMA (mastitis metritis agalactia)
A management disease
‘Farrowing fever’ but often not pyrexic
Constipation (is this the underlying physiological cause, or an effect?)
Mastitis
Metritis
Agalactia
Endotoxaemia? And/or ketosis?
Treatment of MMA
Corticosteroids (dexamethazone)
Oxytocin 5iu (repeated as necessary)
Antibiotics - broad spectrum: Trimethroprim/sulphonamide, or Pen/Strep, or Oxytetracycline
Pain relief: NSAID’s - Ketofen, Finadyne, Metacam. (for anti-inflammatory role) Not if given corticosteroids
Physical comfort of sow
Supplementary feed to piglets – very important
Control, - target the management factors that pre-empt it
