99. Mating behaviour and symptoms of heat in swine, including differences of gilts and sows

Question 1

Mating behaviour of gilts and sows?

Answer 1

Mating Behaviour

• Behaviour in pigs is sexually dimorphic (difference in form between individuals of different sex in the same

species) as early as 1 month old

• Mounting of pen mates is observed more frequently for males than for females
• This mounting reaches its highest frequency during the 2nd month of life and then declines to a low

frequency in prepubertal pigs

• During the prepubertal period (3-5 months of age), boars will not only mount oestrus females, but they are

also receptive to mounts by older, mature boards

• If males are castrated during neonatal development (first 2 months) and treated acutely with oestrogen

during adulthood, they display sexual behaviour that is characteristic to females

o Show a selective preference to remain near boards in a choice test, are receptive to mounts by

mature boars and have a short latency to receptivity after contact with a mature boar

• Males castrated at 6 months old or later, or males castrated neonatally and treated chronically with

oestrogen or testosterone during the prepubertal period display significantly less female behaviour after

acute oestrogen treatment that do males castrated neonatally

• Behavioural changes occur in the female several days before the onset of oestrus; she becomes nervous and

moves about at the slightest disturbance, while is di-oestrus pen mates continue to rest

• When kept indoors, females will use any opportunity to move out of a pen
• When pro-oestrus females are tested with boars at regular intervals, they often leave their sleeping quarters

to await the arrival of the males as the regular time of testing approaches

• Movement in an open field are more frequent
• Spontaneous activity increases to about twice the normal level during oestrus
• Di-oestrus females show frequent genital control, nose the flanks of the oestrus pen mates, and attempt to

mount

• At this time and during oestrus, the sow utters characteristic sounds, a soft and rhythmic grunt

Question 2

Heat detection?

Answer 2

Heat detection

• Head-to-head contact
• Sniffing and nosing
• Mounting attempts
• Standing reaction

o Copulation

Question 3

Vulva heat symptoms?

Answer 3

Question 4

Standing reflex?

Answer 4

Standing reflex

• Some females in oestrus will exhibit the standing reflex without any direct physical stimulation when a boar

passes nearly

• The ears may spring into an erect position in some breeds and females often arch their back slightly and

brace their legs through isometric muscle contractions as if preparing to be mounted

• ~10 min, 45 to 60
• Minute later try again
• Back check even after synch

Question 5

Differences of Gilts vs. sows?

Answer 5

Differences of Gilts vs Sows

• Gilts usually display signs of oestrus in a similar sequence but vulva reddening and swelling, and mucous

discharge may be noticeable earlier and last longer than in sows

• The vulva swells (1) and reddens significantly in gilts (2, center gilt) but only the interior tends to redden in

sows

• Clear, sticky mucous collects on the vulva of a gilt (4) and sow (5)
• Testing the stickiness of the mucous by “thumb checking” (6)
• A sow coming into or out of oestrus mounts and rides and pen mate, whereas crated sows attempt to bite or

climb towards a neighbour