Problem Solving - Gilt Management

The gilt determines the base performance of a breeding herd. She needs to be initially selected for high reproductive performance (particularly litter size or, even better, litter weaning weight). Wherever possible, she should also be selected from a sow (not gilt) litter that had at least 12 piglets in it at birth with few male piglets. Even better if she is also selected on the basis of a high birth weight & is raised in a suckled litter of less than 8 piglets. Lastly, the way she is raised & her management from around 20-23 weeks of age up to first mating largely determine her lifetime value in the breeding herd.

Focus Areas

A 50% annual replacement rate equates to an average herd life of 2 years for breeding females or approximately 2 years x 2.4 litters/sow/year = 4.8 litters/female. Allowing for sow deaths & early culling due to structural & reproductive failures, together with an imposed culling on age of 6-8 parities, it is unlikely that a figure of less than 45-50% is realistically achievable.

Causes	Solutions
Poor gilt performance	Check puberty stimulation procedure Check heat detection procedure Ensure dietary Ca (0.95%) & P (0.7%) are adequate Ensure sub-fertile gilts are culled by 30 weeks of age
Poor sow performance	Check heat detection procedure Check semen quality Ensure AI technique is good Check pregnancy diagnosis procedure Use simple fertility culling procedure (2 par. <15 pigs & >15d weaning-to-oestrus

Cycling by 30 weeks - Target: 85-90%

Rationale
Cause & Solutions

There is good evidence that the last 10% of gilts that begin cycling in response to boar stimulation will be sub-fertile & thus reduce all aspects of herd performance if they are allowed to join the breeding herd. Thus, the start of puberty stimulation should be timed to result in only 90% of gilts being cyclic at 30 weeks of age – this may mean starting at anything between gilt ages of 25 to 28 weeks of age depending on the individual herd.

At 30 weeks of age it is recommended that the 10% of non-cycling gilts be culled while the remaining 90% of gilts are bred at their next (second) heat over the following 4 weeks (weeks 30-34).

Causes	Solutions
Poor puberty stimulation	Check puberty stimulation procedure
Seasonal problems	Increase frequency / duration of boar contact Give boar contact in cooler times of day If necessary use PG600
Poor housing	Provide at least 1.8-2.0m²/gilt House in groups of 3-50 gilts House away from boars Ensure adequate light (300 lux +) Ensure good ventilation
Poor feeding	Provide at least 35MJ of DE/d in a diet containing 0.72% lysine
Incorrect puberty diagnosis	Only define puberty by a standing heat
No stimulation after puberty	Ensure boar contact for 5 min. twice weekly with a regularly mating boar

Mean age at puberty (weeks) - Target: 28-29 weeks

Rationale
Cause & Solutions

The overall aim here is to have 90% of gilts cycling at 30 weeks of age so that they can be bred at second heat at 30-34 weeks of age. To achieve this the puberty stimulation with boars should begin at anything between gilt ages of 25 to 28 weeks of age depending on the individual herd.

Causes	Solutions
Poor puberty stimulation	Check puberty stimulation procedure
Poor heat detection	Check heat detection procedure
Seasonal problems	Increase frequency / duration of boar contact Give boar contact in cooler times of day If necessary use PG600
Poor housing	Provide at least 1.8-2.0m²/gilt House in groups of 3-50 gilts House away from boars Ensure adequate light (300 lux +) Ensure good ventilation
Poor feeding	Provide at least 35MJ of DE/d in a diet containing 0.72% lysine

Mean weight at mating (kg) - Target: 145-155kg

Rationale
Cause & Solutions

A gilt of 150kg liveweight at first breeding will be in good condition but not overweight. If she is significantly lighter she is likely to have sub-optimal early reproductive performance. If she is heavier (e.g. 160-190kg) at 32 weeks of age her growth rate will have been excessive & is likely to lead to an imbalance between her muscle content & her skeletal structure such that early culling as a result of locomotor & other structural problems will increase rapidly.

Even if this is not the case a 180kg gilt at first breeding will have an ongoing higher maintenance feed requirement than will a 150kg gilt.

Causes	Solutions
Overfeeding before puberty	If growth rate is too high restrict feed by up to 20% in period 20/23 weeks to start of boar stimulation
Delaying mating to 3rd heat	Mate at 2nd heat
Seasonal problems	Increase frequency / duration of boar contact Give boar contact in cooler times of day If necessary use PG600
Poor housing	Provide at least 1.8-2.0m²/gilt House in groups of 3-50 gilts House away from boars Ensure adequate light (300 lux +) Ensure good ventilation
Poor feeding	Provide at least 35MJ of DE/d in a diet containing 0.72% lysine

Mean mating age (weeks) - Target: 31-33 weeks

Rationale
Cause & Solutions

Once the timing of the start of puberty stimulation using boar contact has been worked out for the individual herd, & the 10% of sub-fertile gilts has been culled at 30 weeks of age, the 90% of gilts remaining should be cycling & thus ready for breeding at their second heats over the next 3-4 weeks (i.e. at 30-34 weeks of age).

Research shows that while breeding at first (pubertal) heat reduces gilt farrowing rate & litter size, breeding at third or later heat does not improve these measures above what is achieved with second heat breeding.

Causes	Solutions
Poor puberty stimulation	Check puberty stimulation procedure
Poor heat detection	Check heat detection procedure
Seasonal problems	Increase frequency / duration of boar contact Give boar contact in cooler times of day If necessary use PG600
Poor housing	Provide at least 1.8-2.0m²/gilt House in groups of 3-50 gilts House away from boars Ensure adequate light (300 lux +) Ensure good ventilation
Poor feeding	Provide at least 35MJ of DE/d in a diet containing 0.72% lysine

Standard Operating Procedures

Standard Operating Procedures (SOPs) are the day-to- day instructions for running the breeding herd. The information given here provides the essential points that must be covered in SOPs in the key areas of management of the breeding herd.

Gilt puberty stimulation

Start boar contact when gilts are 25-28 weeks of age such that 90% of gilts have reached puberty by 30 weeks of age
Ensure gilts are not crowded – house with at least 1.8-2.0m²/gilt
Use a stimulus boar that is at least 10 months of age & performing regular matings (at least once every 2 weeks)
Expose gilts to the boar in groups of no more than 12. If group size is larger use pairs or groups of boars at a ratio of one boar to 12-15 gilts
Ensure contact with the boar is full (i.e. in the same pen NOT just fenceline contact)
Give daily boar contact for 15-20 minutes/day Alternatively, if more stimulation is required (e.g. in Summer & early Autumn) give 10 minutes of contact twice daily
If all the above points are being followed & gilt response is still poor assume the boar is a low stimulus value boar & replace him

Heat detection

Vulval reddening & swelling are insufficient to define a female is on heat – only a true standing heat is definitive
Ensure females are housed at least 1m away from a boar. This may need to increase, depending on airflows within the building
If using group housing ensure a space allowance of at least 2.0-2.4m²/female
If females are stall-housed, restrain stimulus boar to no more than 4-5 stalls whilst performing heat checks
Conduct heat detection when females are in head-to-head contact with a mature boar who is 10 months of age or older & performing regular matings (at least once every 2 weeks)
When conducting heat detection assume a female is not sufficiently on heat to breed if she does not show a good standing heat within 20 seconds of checking her using the above method

Use of PG600

Do not use PG600 to induce heat & ovulation in either gilts or sows until you have investigated why females are not coming on heat in response to boar stimulation
Gilts

Do not use PG600 to induce cyclicity in the last 10% of gilts to reach puberty in response to boar contact. These are sub-fertile females & should be culled
In gilts response to PG600 will improve with both age & liveweight
On average expect 70% of treated gilts to show heat 5-6 days (usual range 4-7 days) after treatment although response can be unpredictable
If gilts are left to cycle before breeding expect about 30% to revert to a prepubertal state
It is recommended that PG600-treated gilts are bred at the induced heat. Reproductive performance to this breeding can be variable but is normally equivalent to breeding at a natural heat

Sows

PG600 can be given to sows at weaning or one day later to partially overcome variation in time taken to return to heat after weaning, particularly in Summer/early Autumn or in Parity 1 sows
Expect sows to show heat by about day 7 after weaning & to have normal fertility if bred at the induced heat
Do not use PG600 to treat sows failing to show heat within 7 days after weaning as their response to treatment & fertility to subsequent breeding is likely to be poor

Use of Regumate

The dose of Regumate required is 15mg/female. Exceeding this dose level is expensive while under-dosing can reduce efficacy & cause ovarian cysts
Gilts

Regumate does not, at least in theory, work on prepubertal gilts
In cycling gilts it can effectively synchronise the timing of heats
Individually feed Regumate to cycling gilts for a minimum of 12-14 days. Mix it into a small amount of feed & give to the gilt before she receives her daily feed allowance
If gilts are group-housed they should be ‘drenched' with Regumate in a highly palatable solution
Expect gilts to show heat 5-6 days (range 4-7 days) after Regumate withdrawal & to have normal fertility at that heat

Sows

Regumate can be used in herds that see a significant drop in second litter performance
These sows weaning their first litter can be placed on Regumate for a minimum of 3-6 days (preferably 10-12 days) to allow recovery & improvement of nutritional status before breeding
Expect sows to show heat 5-6 days (range 4-7 days) after Regumate withdrawal & to have normal fertility at that heat

Feeding Lactating Sows

Step up feed intake as quickly as possible for your genotype from farrowing to reach a peak intake at 5-10 days post-farrowing
Maximum intake daily at peak should be at least 90 MJ of DE/day, 55g of lysine, 40g. calcium & 18g av. phosphorus
Consider feeding higher specification diets (both higher protein & higher energy content) to parity 1 & 2 sows in lactation
Target a body weight loss in lactation of less than 8%

Cross-fostering piglets

Do not cross-foster until all piglets in a litter have had a chance to suckle – at least 6 hours after farrowing & preferably 12-24 hours
If necessary use shift suckling (shut the heavier piglets in a litter that have a full belly away from the sow for 1-2 hours to allow smaller less vigorous piglets to access colostrum)
Try to equalise suckling litter size across a batch of farrowed sows recognising variables such as sow parity, body condition & number of functional & accessible teats
Wherever possible foster out of a litter the heavier, stronger, more vigorous & healthy piglets that clearly have full bellies
If a second round of cross-fostering is needed 4-7 days later try to move weaker piglets onto nurse sows that were about to be weaned & culled

Natural mating

Perform heat detection each morning & ensure female is solidly on heat before allowing boar into the pen
If a good standing heat is not obtained after 20-30 seconds of boar courtship remove the sow & re-test her 12 hours later
For sows on heat 1-5 days after weaning give first mating in the afternoon of first detection & again at 24 hour intervals while she remains in good standing heat (N.B. don't force standing heats in sows that are going off heat – see vulval discharge problems - & don't give more than 3 matings).
For gilts, sows on heat 6+ days after weaning, & sows returning to service after breeding give first mating in the morning at first detection & again at 24 hour intervals while she remains in good standing heat (N.B. don't force standing heats in sows that are going off heat & don't give more than 3 matings).
Use a fertile boar – keep records & cull on poor farrowing rate or low litter size
Don't overuse boars – for boars of 8—10 months allow 2 matings/week rising to 4/week at 10-12 months & then 6/week thereafter. N.B. These 6 matings may occur over a period as short as 3 days.
Cull boars at a maximum of 2.5-3 years of age
Provide good mating conditions – pen of at least 3 x 3m² with a non-slip floor, vertical (not horizontal bars) & no protrusions
Size match the boar to the sow as much as possible
Wherever possible use a designated mating pen rather than the boar's home pen
Supervise all matings & assist the boar to gain access to the sow's hind quarters & subsequent intromission (N.B. don't handle the boar's prepuce)
Only count a mating if it lasts for longer than 2.5-3 minutes. Shorter matings should be repeated 1-2 hours later

Artificial insemination

Farrowing induction

Only follow this strategy if you plan to have staff present during the farrowing – see attended farrowing strategy
Know the average pregnancy length for your herd & don't treat any gilt or sow more than 2 days earlier than this
Treat with any commercially available prostaglandin, although you may wish to give preference to one that contains a synthetic rather than natural prostaglandin
This treatment is normally given as a single injection of the prostaglandin at a dose level which is recommended on the bottle. Such treatment usually results in approximately 80% of sows farrowing the next day during working hours. You may wish to discuss with your veterinarian splitting this single prostaglandin dose into two half doses, these being given on the morning & afternoon before you wish the sow to farrow. Commercial experience suggests this method of use usually results in approximately 95% of sows farrowing the next day during working hours.

Attended farrowing

If the interval between piglet births exceeds 20 minutes manually stimulate the vagina to release oxytocin
If this doesn't result in a birth within 10 minutes conduct an internal examination
If a piglet is blocking birth manually deliver it, if no piglet is blocking treat the sow with oxytocin
After birth free newborn piglets from foetal membranes
Clear mucus from the piglet's mouth & throat to prevent suffocation
Attempt to resuscitate apparently dead piglets
Assist all piglets to reach the udder & suckle
Remove piglets from a nervous sow during farrowing & keep them warm