Pig reproduction in South East Asia
A. Kunavongkrit
), T.W. Heard
Department of Obstetrics, Gynaecology and Reproduction, Faculty of Veterinary Science, Chulalongkorn UniÕersity, Bangkok 10330, Thailand
Abstract
Asia with over half the population in the world has a thriving agriculture, a large part of which is devoted to pig production. The efficiency of production varies from country to country and is largely the legacy of whether the country relies on backyard farms using native breeds or intensive commercial farms using genetically improved breeds from Europe and North America. Reproduc-tive efficiency is not as advanced as in Europe and this is the result of climatic conditions, which are hot and humid, the presence of most pig diseases, substandard management, the difficulty of obtaining quality feeds and appropriate delivery systems and the reliance on native breeds which are far less prolific than European ones. Improvements can only occur if investments are made in housing, cooling systems, disease control, management, quality feeds and better genetics.q2000 Elsevier Science B.V. All rights reserved.
Keywords: Pig; Reproductive performance; South East Asia
1. Introduction
South East Asia is one of the most interesting regions in the world by its nature, culture and history. It is comprised of eight countries, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Thailand and Vietnam. They are situated in a tropical region where the climate is hot and humid almost all the year round. The main source of income is from agriculture of which pig farming is one of the major parts. Since they are all agricultural countries, they can produce their own animal feeds and raw materials, which are converted to animal proteins such as pork.
Raw materials harvested locally and used in pig feeds include maize, rice, manioc, sweet potato, peanuts, soyabean, cotton seed, copra, coconut oil, fish meal, blood meal,
)Corresponding author. Tel.:q66-2-2196445; fax:q66-2-2553910.
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E-mail address: [email protected] A. Kunavongkrit .
0378-4320r00r$ - see front matterq2000 Elsevier Science B.V. All rights reserved.
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Table 1
The number of pigs on farm, pigs slaughteredryear and pork production in South East Asian countries
Countries Number of Number of Pork
pigs on farm pigs slaughtered production per
Ž=1000. per yearŽ=1000. yearŽ=1000 tons.
Vietnam 17,950 16,875 1104
The Philippines 9750 15,953 1037
Indonesia 7623 10,510 495
Source: Pig International June 1998, 28 6 16–18.
)
No information.
meat and bone meal, sea shells and limestone. A typical feed used for pregnant sows
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will contain crude protein 16% 18% for lactating sows , oil 6%, fibre 5%, D.E. MJ kg 13.5%, lysine 0.7%, calcium 0.8%, phosphorous 0.5%, salt 0.3% and methionine 0.25%.
This formulation can be obtained from a feed composed of the following ingredients, broken rice or corn 46%, rice bran 16%, fish meal 2%, molasses 4%, soya 11%, copra meal 15%, coconut oil 3%, limestone 1.5%, minerals and vitamins 1.5%.
The potential for producing animal protein in this region is very high. Food and
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Agriculture Organization FAO predictions foresee an increase in pork production in
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East Asia including Taiwan, China and Korea from 24.5 million tons in 1990 to 57million tonnes in 20101.
The four biggest pig producing countries in this region are Vietnam, the Philippines,
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Indonesia and Thailand Table 1 .
The pig farming systems in this region are based on sheltered accommodation with little outdoor pig keeping. Farms can be divided into two categories, intensive larger scale farming units and smaller scale farms which are present in different ratios in different countries, with an 80:20 ratio in Thailand and 20:80 in Vietnam.
Amongst the five biggest pork production countries in South East Asia, there are
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considerable differences in production efficiency Table 2 .
The reason is likely to be the number of small scale farmers using native breeds in less productive countries compared to regions which have more intensive commercial farms using genetically improved breeds.
2. The reproductive performance of breeding herds in Thailand
The reproductive performance of pure-bred sows in Thailand is not good when
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compared to the performance reported from Europe Muirhead and Alexander,1997 ,
1
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Table 2
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Pork production efficiency kgrsowryear in South East Asian countries
Countries No. of sows on farm Pork production Pork productionrsow
Ž=1000 head. Ž=1000 tons. Žkg..
Vietnam 2200 1104 502
The Philippines 1100 1037 943
Indonesia 100 495 495
Thailand 500 601 1200
Malaysia 300 239 797
Ž . Ž .
Source: Modified from Pig International June 1998, 28 6 16–18 and Pig International, January 1999, 29 1 22.
especially the number of piglets born per litter, even though the sows in Thailand come from the same breeding sources as those in Europe. The average reproductive perfor-mance of pure-bred Large White and Landrace sows in seven commercial farms is shown in Table 3.
Typically, such farms will have a high sow replacement rate approaching 50% each year. This results in a mean parity number of between 3 and 4. Farrowing rates are around 80% and sow mortality frequently averages 4% per year. The hot weather experienced in most South East Asian countries between March and May each year
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results in reduced farrowing rates and smaller litters Tantasuparuk et al., 1997 , when
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the sows served during that period farrow approximately 4 months later Table 4 . Reproductive performance can be depressed by 5–10% during this period. There is little data available on the number of abortions that occur. From time to time abortion storms are reported but accurate data is not available.
There is a wide variation in the length of the suckling period. Many big commercial farms, with access to better creep feeds are currently weaning at 22 days of age. More traditional farms using native breeds still wean at 4–5 weeks of age.
Natural mating is still the normal practice on most farms but there is a strong move towards artificial insemination which is currently practised on 20% of farms.
Normally, in Thailand farmers producing fatteners use a cross-breeding programme.
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A three-way cross is made between Landrace boars L and Large White LW dams to produce a female which is mated with a Duroc boar as the terminal sire. The typical reproductive performance of these crossbred sows is shown in Table 5.
Table 3
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The reproductive performance of Large White and Landrace sows in seven commercial breeding herds 9642
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litters, 1993–1996
Landrace Large White
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Weaning to oestrus interval days 6.46 6.11
Total bornrlitter 9.80 9.70
Born aliverlitter 8.96 8.94
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Table 4
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The effect of the hot season March–May compared to other seasons on litter size total born and weaning to
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oestrus interval WEI
Total born-10 piglets WEI-21 day a
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Hot season March–May 60.5% 88.7%
Number of litters 805 504
b
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Other seasons June–April 54.5% 90.9%
Number of litters 2153 2012
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Source: Kunavongkrit et al., 1989 . a vs. b P-0.01.
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This figure is similar to that reported earlier Kunavongkrit et al., 1989 . Such performance falls short of the sows’ potential, as reported from many temperate
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countries Nibe et al., 1995; Muirhead and Alexander, 1997 .
3. Factors affecting reproductive performance in swine breeding herds in tropical
( )
countries South East Asia
There are several factors influencing the reproductive performance of sows in the tropical conditions found in South East Asia. The following play an important role in lowering sow performance.
3.1. Climate
The climate in South East Asia can be both hot and dry and hot and wet. In the November to March period mean temperatures of 25–288C and rainfalls in the order of 0.50 cmrmonth are experienced. From April to October 27–318C is typical and the mean rainfall rises to 3 cmrmonth.
The farmer understands this problem very well, and they try many ways to solve it.
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Air conditioning or evaporative cooling systems are used in boar AI housing. Water dripping and fogging systems are used in sow houses. Both help to improve
perfor-Table 5
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Reproductive performance of crossbred LW=L sows from a commercial breeding herd 17,532 litters from
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3930 sows over a 2-year period 1997–1998
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Weaning to service interval days 6.2
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Farrowing rate % 81.6
Litterrsowryear 2.23
Total bornrlitter 9.58
Born aliverlitter 9.36
Piglets born aliversowryear 20.6
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Table 6
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Normal and abnormal oestrus of control gilts ns7 under a conventional environment and treated gilts
Žns7 in an elevated temperature control chamber during pro-oestrus at the second observed oestrus.
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Percentage number Type of abnormality Normal Abnormal
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Control 85.7 6 14.3 1 1 normal heat but no ovulation SF
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Treated 53.1 4 42.9 3 1 anoestrus 8F ,1 delayed oestrus SF , 1 follicular cyst 10 FC Fsfollicles, SFssmall follicle, FCsfollicular cyst.
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Source: Kunavongkrit and Tantasuparuk 1995
mance, however, it needs a lot of investment and redesign which some older farm cannot implement.
High temperatures and high humidity influence boar semen quality by decreasing
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semen volume and semen concentration, especially during the hot season Kunavongkrit
.
and Prateep, 1995 . Gilts when faced with high temperatures during pro-oestrus show reproductive dysfunctions, which include anoestrus, delayed anovulatory oestrus and
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cystic ovaries as shown in Table 6. Kunavongkrit and Tantasuparuk, 1995 .
The low litter size in the July–September period in Thailand might be the result of
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early embryonic death during the hot period March–May Tantasuparuk et al., 1997 .
3.2. Diseases
In South East Asian countries, there are many infectious breeding herd problems and
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most infectious diseases and reproductive diseases except African Swine fever are present. It is usual to have a preventive medicine programme in the majority of herds,
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such programmes include vaccination and antibiotic medication Table 7 . In times of economic crisis many farmers may stop using vaccination and the effect can be clearly
Table 7
Infectious diseases present in South East Asia and some preventive and treatment programs used
Diseases Preventionrtreatment
Viruses Foot and Mouth Disease Vaccinationrsupportive therapy
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Hog cholera Swine fever Vaccination
Aujeszky’s disease Vaccination
) Swine influenza
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Porcine Reproductive and Respiratory Syndrome PRRS Vaccination )
Bacteria Brucellosis No treatmentrculling
Leptospirosis Vaccinationrantibiotics
seen by the appearance of diseases which lower reproductive efficiency, such as Parvovirus and Aujeszky’s disease. Due to such diseases reproductive performance is inevitably lowered. The problems caused by these diseases present themselves as
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abortions and SMEDI syndromes stillborn, mummified, embryonic death and infertility
ŽKunavongkrit et al., 1980; Kunavongkrit and Robison 1988 . In tropical countries, the.
climate is very suitable for both bacterial multiplication and parasite survival. It also supports fungal growth, which can cause a lot of damage through such problems as mycotoxicosis. The contamination of semen with non-specific bacteria during mating or
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insemination can cause infertility return to oestrus andror early abortion Heard and
.
Kunavongkrit, 1998 . Even when antibiotics are added to semen bacterial resistance and high levels of challenge can render them ineffective.
3.3. Nutrition and management
The quality of feed in tropical countries is a major issue as fungal and bacterial contamination can easily occur. Abortion and stillborn piglets will frequently be seen if
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contaminated feed is fed to sows. Pfeifer, 1994; Etienne and Dourmed, 1994; Lemmens
.
and Krska, 1996 . Contamination with Salmonella and E. coli can considerably influence reproductive performance. Quality assurance of the raw materials being used for feed must be strictly enforced. Environment and feed management also plays an important role by affecting feed intake at critical times such as during lactation. Lactating sows in tropical conditions eat on average 4.5 kg feed per day, which is too little, they need to be taking more than 6 kg. Farmers try very hard to increase lactating sow feed intake but appetite in hot, humid conditions is depressed. Frequent feeding, wet feeding, improved feed palatability, added flavours, cooling water drips and evaporative fans are all used to help increase feed consumption but results do not always match up to the efforts employed.
The result is that the lactating sow that loses more than 15% of it’s body weight will
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become a problem sow after weaning, e.g. a longer weaning to oestrus interval Patience
.
et al., 1995; Tantasuparuk et al., 1998a . However, it is not only the environment that interferes with consumption but also the health status. Observations indicate that healthy
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sows free from mange, worms and major diseases, with good feeding and a balanced
.
energy intake can achieve a feed intake during lactation of up 7 kgrday. Such sows
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show good reproductive performance Heard, 1992 .
4. Conclusion
The reproductive performance of sows in South East Asia has not managed to achieve a level that reflects the sows’ true potential. This is due to many factors,
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including environment hot and humid , diseases, feed quality, poor genetics and
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substandard management backyard farmers vs. intensive farms . In order to improve reproductive performance and productivity it is suggested that more investment needs to
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