1. science
2. biology
3. breeding

Maximizing productivity- 30 pigs/sow/year
Niels J. Kjeldsen,
Department Manager, Ph.D., MSc. Anim.Sci
Danish pig Research Centre.
Danish Agriculture & Food Council
This paper provides an analysis of how Danish pig producers manage to produce 30 pigs/sow/year.
The paper also includes a description of Danish Pig Research Centre’s activities in relation to the
production of pigs in Denmark and ofthe Danish breeding system, DanAvl. Furthermore, management
routines in gilt and sow production on Danish pig farms as well asfeeding and management of nursing
sows will be summarised.
Danish Pig Research Centre
Danish Pig Research Centre is an integrated partof the Danish Agriculture and Food Council(DAFC)
and employs around155 persons. The role and activities of Pig Research Centre are laid down by the
Sector Boardconsistingof 12 elected pig producers.
Pig Research Centre’s activities are funded by a range of sources. An essential source of income is
thefinancial support of trials undertakenby Pig Research Centre. Many projectsare financially
supported by the Ministryof Food, Agriculture and Fisheries of Denmarkand the European Agricultural
Fundfor Rural Development. Pig Research Centre organizes and managesthe DanAvl breeding
programme andcharges fees on sales of genetics.Widespreadsales of genetic material have
increased the funds available to PigResearch Centre.
In order to strengthen sales and marketingprogrammes, DanAvl recently implementeda new offensive
strategy. The aim is toposition DanAvl among the two or threemajor players in the global market
forbreeding stock.
Pig Research Centre’s strategy for2014-2018 includes the following mainareas of activity:
• Competitiveness
• Environment
• Animal welfare
• Animal health and food safety
• Knowledge transfer
• Policy and reputation.
Structural development in Denmark
In 2012, there were a total of 4,181 pig farms in Denmark, which is around 10% fewer than in 2011.
The size of fully integrated farms averaged 436 sows/year. The average size of farms with sows only
was 661 sows/year, and they accounted for around 43% of all sows kept in Denmark in 2012.
Approximately 47% of all pig farms operated exclusively in finisher production in 2012, delivering, on
average, around 5,800 finished pigs for slaughter. Farms with finishers only accounted for around 60%
of all finishers produced in 2012.
Production
During 2012, the number of sows in Denmark averaged around 1.03 million, which 2% below the level
recorded in 2011. This fall is attributed partly to poor production economy and partly to the
requirement for group-housing of sows. The sow population in Denmark in 2012 was at its lowest level
since 2001. 29 million pigs were produced in Denmark in 2012, which is a small drop of
around 1.2% compared with 2011.
The number of pigs slaughtered in Denmarkfell by 6.7% to 19 million in 2012.
Export of pigs (30 kg)
The export of live pigs is increasing as thesow population is remaining largely stable.Records show an
annual increase in the number of pigs weaned per sow/yearof 0.5-0.8%, butthe number of finished
pigs slaughtered inDenmark continues to decline.
Germany remains the main destination forexport of Danish pigs at 30 kg, accounting for ashare of 68%
in 2012.
The export of 30 kg pigs to Poland rose dramatically in 2012, rising from 1.4 million in 2011 to 2.1
million head.
Trends in pig production in Denmark, 1990-2012
Productivity
Today, Danish sow farmers produce averagely 30 pigs/sow/year. However, this average covers large
variations as the top 25% sow farmers produce 32.5 pigs/sow/year. Genetic progress results in an
annual increase of around 0.3 piglet per litter/year. The result is an average of approx. 15.4 liveborn
piglets/litter and approx. 13.1 weaned pigs/litter. Piglet mortality averages 13.7%, but records show
that the top 25% pig producers actually have far lower mortality rates, which is mainly attributed totheir
management routines. Besides large litter size, high farrowing rates – that average 87% in Denmark –
are also essential to productivity. Farrowing rates of 90 are seen among the top 25% farms.
In Denmark, pigs are weaned at around 26-27 days of age at a weaning weight of approx. 7 kg.
Production control reports show that weaners (7-30 kg) have a daily gain of around 450 g, increasing
to around 480 g among the top 25% farms. In the weight interval 30-106 kg live weight, finishers have
a daily gain of approx. 900 g; feed consumption of 2.67 kg feed per kg gain; and a lean meat
percentage of 60.2. Once more, the top 25% pig producers manage far lower mortality and far better
daily gain and feed consumption.
Average and top 25% results on sow farms:
Efficiency - sows
Weaned pigs per year per sow*
Liveborn pigs per litter
Weaned pigs per litter
Weight at weaning, kg
Mortality during lactating, %
Farrowing rate, %
Top 25%
32.5
16.1
14.2
6.7
11.5
89.8
Av. 2013
30.2
15.4
13.3
7.0
13.7
86.6
Av. 2012
29.6
15.1
13.1
7.0
13.7
87.0
Average and top 25% resultson weaner farms:
Efficiency – weaners (7-30 kg)
Feed conversion ratio, kg per kg gain
Post-weaning mortality, %
Top 25%
1.62
2.5
Av.2013
1.77
2.9
Average daily gain 7-30 kg, g
476
448
Top 25%
985
2.50
83.4
109
60.3
2.9
Av. 2013
917
2.67
82.7
108
60.2
3.5
Average and top 25% results on finisher farms:
Efficiency – finisher (30-106 kg)
Daily gain, g
Feed conversion ratio, kg per kg weight gained
Average slaughter weight hot, kg
Average live weight, kg
Average lean meat. %
Dead and culled, %
DanAvl – a world-class breeding system
In Denmark, breeding work in the pig industry is managed by Pig Research Centre through DanAvl.
The Danish breeding system for pigs, DanAvl, is world-class. More than 100 years of dedicated
selection and breeding on the pigs gives the best meat quality and best production economy. This has
given the Danish pig producers a giant lead ahead of our international competitors. Selection methods
today are based on comprehensive recordings and research in few selected pig herds and
subsequent analysis of this data in which both advanced theory and computer power are necessary.
DanAvl is the joint trademark in the Danish pig breeding system. Pig Research Centre is in charge of
prioritizing and co-ordinating tasks in this system, and the work is thus organized for pig producers by
pig producers. A very important part of this work takes place in the breeding and multiplication herds
under DanAvl.
DanAvl Structure
The number of breeding and multiplication herds affiliated with DanAvl has decreased over the last
years. In 1980, there were 250 breeders with 8,500 sows and 150 multiplication herds with the same
number of sows. Today, records show 30 breeders with approx. 16,000 sows and 176 multiplication
herds with approx. 52,000 sows (excluding breeding herds with multiplication).
These herds are owned by private breeders who have a contract with Pig Research Centre
concerning breeding and multiplication work.
Danishcommercial pigs originate fromthree-way crossbredswhere the hybrid mother is hybrid between
DanAvl Large White and DanAvl Landrace andDurocis used as boar. For females, the breeding
objectives puts great emphasis on feed consumption, and litter size measured as live piglets on day 5
(LP5).
Feed consumption
The genetic weighting of feed conversion constitutes 42%, while litter size (LP5) constitute 47%. Less
weighting is put on production traits such as gain and longevity among female pigs. For Duroc as sire,
weighting is primarily on production traits such as gain (20%); lean meat percentage (17%); and feed
conversion (55%).As a result, Danish finishers are second to none in terms of feed conversion, and
are extremely efficient economically as well as environmentally.
Management of sows
Most Danish sow producers buy gilts from multiplication herds to be as close as possible to the
genetic progress. Some sow farmers produce their own maternal animals using purchased semen and
thereby lack slightly behind the genetic progress seen in nucleus herds. They do this from a
biosecurity point of view, as there will always be a risk of transmission of disease when purchasing live
pigs. Around 90-95% of all inseminations in Denmark are made with semen purchased from Danish AI
stations, which are part of the Danish DanAvl system. This is a guarantee that the semen is of the
highest quality.All pig producers have equal access to genetic material, and the large differences seen
between farms are therefore attributed to differences in management routines and handling of the pigs.
A central area is management of the future sows in the herd. Gilts are not finishers, ie full utilisation of
their genetic potential for growth is not recommended as this will make them too heavy and increase
their feed requirements as sows. Taking future reproduction and longevity into account, optimum gain
in the period 30-130 kg is 700 g a day. Results from numerous trials have demonstrated that the
optimum age for inseminating gilts is when they are approx. 8 months and that they should be
inseminated in their second heat. Provided they are fed correctly, gilts should weigh 130-150 kg at the
optimum time of insemination. Owing to the excellent genetic potential for growth, it may be difficult to
feed gilts ad libitum as this would lead to a daily gain of up to 1,000 g, which will make the gilts too
heavy.
Flushing is easily planned if the gilts’ first heat is recorded. Flushing involves feeding the gilts one
extra kg feed for a period of two weeks before their second heat – this ensures high ovulation rates
and a high litter size.
Feeding the modern sow
High production efficiency and high milk producing capacity in modern three-way crossbredsrequires
attention to nutrient content and composition of the diets used. Danish Pig Research Centrelays down
the nutrient requirement for all pigs in Denmark. This is done in cooperation with Danish universities
and is based on studies of international literature and trial activities at Danish Pig Research Centre’s
experimental farm or on commercial farms in cooperation with the pig producers.
The vast part of the Danish feedstuff production is made up of co-operative feedstuff mills that largely
comply withthe nutrient recommendations. Therefore pig feed in Denmark is fairly uniform and based
on the same nutrient content regardless of which feedstuff supplier a pig farmer chooses. More than
half of all Danish pigs are fed feed mixed on-farm based on own production of grain and purchased
ingredients such as soybean meal and mineral diets. However, because of the nutrient
recommendations these pigs receive largely the same nutrient content through their feed as those fed
purchased feed.
Most Danish sows are fed two different diets: one during gestation and another during lactation that is
particularly rich in energy and nutrients. It is crucial to manage the amount of feed given to each sow –
during gestation as well as lactation. Around half of all Danish sows are fed liquid feed, which
facilitates recording of the exact amount fed from each valve and thereby information can be compiled
on the amount fed to each individual sow.
Feed prices are currently high in Denmark, and it is therefore essential that sows be fed as
appropriately as possible to prevent unnecessary weight loss and thereby additional costs for feed for
regaining this weight. On average, sows increase their weight by approx. 20 kg in each cycle, but this
varies greatly.. Weight loss during lactation is seen to vary from 10 to 60 kg wherefore it is important
that the sows are fed according to the correct feed curves in the farrowing unit. A high weight loss
during lactation will have a negative impact on the size of the subsequent litter, and research has
shown that it takes approx. 4 kg feed to increase sow weight by 1 kg. Consequently, an effort should
be made to avoid unnecessary weight loss during lactation. Management of body condition is an
important tool in this, as thin sows have an increased risk of developing shoulder lesions in the
farrowing unit. In Denmark, this means destruction of the sow. In addition, thin sows will have
decreased performance in the subsequent parity. Fat sows have an increased risk of dying in the
farrowing unit, and large variations in sow weight lead to a high feed consumption. Several methods
are available for assessment of sows’ body condition during gestation: Pig Research Centre
recommends palpating the sows and assessing body condition at insemination, 30 days into gestation,
70 days into gestation and at farrowing, and then use this information to determine the feed dose for
each sow.
Body condition score.
Various scanning equipment is also available for assessing body condition, but the actual value of
such equipment varies greatly. Correct assessment of body condition is actually possible
throughscanning combined with palpation.
Gestation
The aim is for gestating sows to be in medium body condition. When this has been achieved, they
must be fed 3.0 feed units for the first four weeks followed by 2.5 feed units from day 30 to 84, and
finally 3.5 feed units until two days before farrowing. There are many systems for feeding of sows, but
electronic sow feeding is the best method for ensuring individual feeding. With electronic sow feeding,
the feed curves for all sows are programmed in the feeding system, and as all sows are ear tagged,
the amount of feed released once a sow enters the feeding station will match the dose that was
programmed for that particular sow. Other, cheaper, methods are also available such as group feeding,
but that makes it difficult to keep sows in uniform body condition. In systems such as this there may be
a great deal of competition for the feed and this requires attention to sows that are not thriving or that
lose too much weight in this particular period.
Feeding of lactating sows
Feeding of lactating sows must promote a highmilk producing capacityand keep loss of body condition
to a minimum.
The first week after farrowing is crucial, and there is a risk of giving the sows too much to eatwhereby
they may stop eating or fail to reach a suitable feed intake subsequently. It is therefore important that
the troughs are empty 30 minutes after feeding – it is recommended for the staff to monitor feeding of
each sow minimum once a day to check this. During lactation, it is recommended to feed the sows 4-5
times a day. The feed dose for each sow depends on the number of piglets it nurses and their milk
intake.
Feed dose
Ideally, the feed dose should be increased concurrently with the sows’ milk producing capacity.
Consequently, the sows should be fed approx. 3.0 feed units/day at farrowing increasing to 5-6 feed
units/day in the first week of lactation. From the second week of lactation, sows should be fed
according to approximate ad lib, but the feed dose should be raised gradually. The target is an
average minimum intake of 180 feed units at four weeks’ lactation – preferably 200 as this will limit the
weight loss during lactation. The table below provides an outline of minimum feed intake during
lactation.
Minimumdaily feed intakeduring lactation.
Sows, days after farrowing
Minimumfeed intake, feed units/day
0
3.0
2
3.5
7
5.0
14
7.0
21
8.0
28
8.0
35
8.5
Total feed dose in 28 days
181
Energy concentration of lactation feed
Research shows that lactation feed should have an energy concentration of 1.05-1.10 feed units per
kg. Trial resultsshowed no significant difference in productivity in sows fed according to approximate
ad lib with diets containing 1.15 feed units per kg compared with 1.07 feed units per kg. A high
concentration of energy did not increase weaning weight; did not reduce sows’ loss of backfat; and did
not improve the subsequent reproduction. The percentage of fat added to lactation feed should not
exceed 2.5-3.0% as this will typically increase the energy concentration beyond the recommendation.
Furthermore, a high concentration of energy in lactation feed will make the feed more expensive as
more fat needs to be added.
Daily feedings
Normally, a sow’s feed intake will be sufficient to keep loss of body condition during lactation to a
minimum. However, if sows experience a large weight loss, it may be necessary to take a closer look
at the number of daily feedings during lactation:
• The number of daily feedings may be increased if some sows are developing shoulder lesions.
Research showed a significant reduction in the prevalence of shoulder lesions when sows were
fed 5-8 times a day rather than 3 times day. However, many daily feedings requires highly
accurate feeding each time, and more than 3-4 daily feedings is therefore only recommended in
farms using dry feed.
•
Research with finishers revealed that ad lib feeding increases gastric health compared with one or
two daily feedings, and it is therefore likely that 5-8 daily feedings will result in poorer gastric
health than 3 daily feedings.
Factors that may affect sows’ feed intake
Several factors may affect sows’ feed intake during lactation, and pig producers should pay
attention to all these factors when analysing on feed consumption and the correlation with
productivity:
•
•
•
•
•
•
Body condition: Fat sows typically eat less than sows in normal condition.
Age: Young sows require extra feed for development, while large sows require extra feed for
maintenance.
Composition of feed: The daily feed intake may be affected by changes in feed flavour or
significant changes in ingredients in gestation feed.
Segregation: Segregation may cause significant variations – primarily in terms of minerals and
protein - in the composition of the feed fed.
Water: Inadequate water supply may reduce feed intake among sows.A lactating sow generally
requires 4-8 l water/kg feed it eats. Sows’ performance must be expected to decrease if water
intake drops to below 25 l/day.
Temperature: The ideal temperature for sows is 17-18 °C. Feed intake drops when the
temperature in the room rises, which in turn leads to increased weight loss and loss of backfat
in the sow.For the benefit of the newborn piglets, it is generally recommended to keep a higher
temperature at the beginning of lactation.
The subsequent reproduction is affected by the feed intake during lactation. Several trials have
demonstrated that a low feed intake or a large loss of body condition during lactation adversely affect
the subsequent reproduction.
Farrowing and supervision at farrowing
To ensure an optimum farrowing course, all farrowing sows should be inspected every hour.
Supervision of farrowing
Newborn piglet observed in due time.
Sows and piglets that have trouble managing should be taken care of in due time:
During farrowing, the sow should be inspected minimum once every hour.
There must be no more than two hours between the first 4 piglets, and max. 1 hour betweenthe next.
If only dry piglets are seen at the inspection, the sow has not deliveredpiglets for the last hour. A
normal farrowing course lasts approx. 4-5 hours. This meansthat when litter size is low, a long time
passes between the piglets, while at a high littersize, little time passes between the piglets. Generally,
20 minutes pass between the piglets,but there may be pauses of up to an hour. Pauses that long are
often caused by thefarrowing having stopped, and obstetric aid should be performed as the risk of
stillbornpiglets will otherwise increase. If there are many stillborn piglets in general, night supervisionis
recommended. If farrowing stops, it is recommended to exercise the sow in the inspection alley.
It is difficult for small and weak piglets to get to the udder. They must be assured of colostrum.
If necessary, they should be warmed under the heat lamp or in an incubator. Cold and hungerdestroys
the intestinal surface of newborn piglets. Colostrum is ensured by expressingcolostrum into the mouth
of the piglet or by having a colostrum bank.
When the sow is no longer delivering piglets, assess whether farrowing is complete orwhether there
may still be foetuses inside the sow. If the sow is calm and tends to the piglets,is eating again and
there are many foetal membranes behind her (one per piglet), thesow has finished. If in doubt, provide
obstetric aid.
Colostrum
It is absolutely paramount that piglets get colostrum from the sow. Through colostrum, newborn piglets
are assured of antibodies against diseases in the herd and of the first vital energy. Piglets’ energy
reserves are extremely limited, and quick access to the udder and thereby colostrum is therefore
crucial.
Experience shows that in very large litters (>15-16 liveborn) and among newborn piglets of differing
sizes, there may be a great deal of stir by the udder. The smallest piglets lose the battle for teats,
and they can be helped to colostrum intake along by separating the 5-6 largest piglets in the creep
area for 1-2 hours while the smallest piglets get colostrum.
If farrowing is complete, it should be checked whether the sow is still letting milk down after the largest
piglets have been moved,as the smallest will otherwise then get neither warmth nor milk. Instead, all
piglets can be cut off for 45minutes, and then the 8-12 smallest can be let out when milk letdown starts.
The largest piglets are let out aftera further 30-45 minutes.
Piglets have had a sufficient colostrum intake 12 hours after birth, and then cross-fostering can begin.
As more piglets are born than the sow has teats, it is necessary to use nursing sows. It is estimated
that the need for nursing sows is approx. 20% of the sows and these should preferably be first or
second parity sows.
Conclusion
Producing 30 pigs per sow per year is not an easy task. Results from Danish pig herds clearly show
large variations in productivity, whichdemonstrates that differences in herd management are an
important factor. Since 25% of all sow herds produce more than 32 pigs per sow and the best
producers around 35 pigs, the problem is clearly not a general lack of knowledge in the pig industry.
The basis for a high-performing sow is the genetic quality and the Danish breeding system DanAvl has
a unique focus on litter size.
The quality of sow feed is also very important to fulfill the nutrient requirement during gestation and
especially lactation to ensure the high demand for nutrients for milk production. A sow weaning 14
piglets after 28 days of lactation has to produce approx. 340 kg milk, it is therefore crucial to serve the
correct amount of feed with the right composition to the sow.
Special attention has to be paid to obtain the right body condition through the reproduction cycle.
Also, the time around farrowing is very important and the demand for proper management from the
staff in this stage cannot be overestimated. The staff plays a very important role in saving newborn
piglets during farrowing and during the next 24 hours when they select the right piglets to distribute to
the right nursing sows.
LFID-10-42114 / 1. september 2014