The potential of traditional systems of pig production in the temperate region of Xochimilco

A survey was carried out to understand the social, technological and economic aspects of backyard pig production in the region of Xochimilco, Mexico. The results showed an average number of 8 animals per producer for either breeding or fattening with Yorkshire and Landrace the main breeds used. The feeding system in the region incorporated a significative proportion of non-conventional foods such as tortilla and house garbage combined with commercial concentrates and fresh lucerne. Criteria to select animals for breeding were based on body conformation and number of teats whereas age, economic urgency and low production were utilized for the rejection. Common diseases were cholera, erysipela and pneumonia. The backyard pig production in the region has been adapted to some of the technological ways of modern pig production whilst maintaining its traditional base. The existence of this system demostrates that it is sustainable and in contrast with official plans for technification of pig development in the zone. The backyard pig production system has the characteristics of a sub-urban model with a high potential to be sustainable and presenting a realistic alternative for agricultural activities in the zone within the highly polluted city of Mexico.

Pig production in Mexico constitutes an activity of great importance as it produces meat and by-products such as fat for frying, both of which are in high demand (Chapela 1982). Though the country has highly technified pig production systems (Schwentesius and Gómez 1991), at the same time backyard pig production is distributed over the country as an inexpensive alternative to produce meat, fat and economic support for the family, becoming essential in times of financial hardship (Delgado 1984). Although backyard pig production contributes 50% of the total production in the country (Pérez 1986), to date there have been few studies of the system to enable an explanation of the sustainability factors within this model given the broad use of: (a) food rejects to feed the animals, (b) low technological inputs and (c) recycling of the manure to agriculture (Honeyman 1991). The area of Xochimilco is charaterized largely by traditional agriculture which includes pig production in backyards. The research was undertaken to provide information on the structural functioning and an evaluation of its potential as a sustainable system.

Main features of the area include 48, 526 hectares of land of which 44% is used for agriculture, 26% to forest and for the urban population 12%. Climate is classified as temperate with a range from humid to dry (García 1973). Mean annual temperature is 16 ?C varying between 33 to 7 degrees during the months of May and January respectively. The rainy season is concentrated (75%) during the period of June to October with a mean annual value of 747 mm. The dry season is focused between the months of November to May. Total human population is 418,000 inhabitants, of which 46% are occupied with activities related to agriculture and the rest to commerce, industry and tourism (DDF 1985). Predominant agricultural activities of the zone include a high scale production of cereals (mainly maize), legumes, nopal, flowers and fruits. Animal production systems are maintained at a low scale including: dairy cattle, backyard pig and poultry, sheep, draught animals and bees (INEGI 1992).

The procedure applied to the study included (a) a production evaluation to measure feed intake and liveweight gains of piglets and growing pigs and (b) a survey directed to backyard pig producers. The survey procedure included a questionnaire designed to understand the social, technological and economic aspects of backyard production and was tested succesfully in field conditions before its final application. Backyard systems were ramdomly located and the sample included 14 towns in the region of Xochimilco. In total 54 questionnaires were applied concerning 464 animals. In the second part of the research, three backyard pig production systems located in different towns were sampled daily during a 28 day period to ascertain feed intake and live weight gains. The data obtained in both procedures were analyzed using a computer program (SAS 1988) and the results expressed as percentages and means according to conventional procedures (Daniel 1994).

Backard pig production in the zone is located within the perimeter area of the producer's house. Family members of the household were in the ranges of 6-10 (65%) and 11 plus (8%). Most of the houses of the producers have services including: electricity, tap water and drainage. Predominant levels of education were primary (50%) and secondary (19%) whereas higher levels including university education were minimun (12%). A significant proportion of the producers reported as being illiterate (19%). Most of the work with pigs in backyards was carried out by women and children (52%), the women's additional activity being the care of the household. Work activities of men included: unskilled work (20%), commerce (12%), agriculture (8%) and other (8%).

Table 1: Composition of the herds in the region of Xochimilco

Type of animal	Total	%	Average per producer

Boars	51	11	1
Sows	120	26	2
Piglets	70	15	1
Fattening	223	48	4
Total	464	100	8

A high proportion of pigs were for breeding (52%) although fat- tening occupied an important place in the system (48%). The number of boars in the region was higher than expected as a direct reflection of the small size of the herds per producer and their preferences to have their own boar for breeding and hiring out.

Table 2: Main breeds of pigs used by the producers in Xochimilco

Breed	Percentage

Yorkshire	40
Landrace	20
Duroc Jersey	12
Hampshire	8
Crossbreeds	20

The prefered breed of pigs was the Yorkshire which in fact has became popular in most of the technified systems because of the low fat content in their carcass. The presence of Landrace occupied an important place in the region as a result of an official development plan in the area to introduce technified pig produc- tion. Crossbreeds were important particularly for those people carrying out fattening processes.

Housing of pigs in the zone included the traditional pig pens. Mean surface areas occupied in the households were in the ranges of: 2-3% (52%), 3-4% (24%) and >4% (24%).

Table 3: Ingredients for feeding pigs and the degree of utilization by the producers

Ingredient	Proportion of diet (%)

Tortilla*	87
Commercial feed	74
Garbage	68
Fresh lucerne	58
Wheat bran	13
Dust contaminated
wheat flour	6

Most of the producers housed the boars separated from the rest of the animals whereas in contrast, sows and growing pigs were kept together, though there were some producers who provided the sows with a maternity pen. Building materials for the pens included: concrete for the floor and walls whereas the roof was made of corrugated carboard coated with bitumen. Containers for feeding and watering were made of concrete, wood and/or metal. Cleaning of the pen was carried out daily (80%) or approximately three times per week (20%) and manure collected to be disposed of (27%) or semi-- dried before being sent to the fields to be used as a fertilizer and organic matter source (73%).

The inclusion of non-conventional foods such as tortilla and house garbage in the diet of the pigs was significant. Commercial concentrates were reported to be used mainly to support the growing of piglets whereas the feeding of lucern belongs to a general trend in the zone as a source of fresh green material. Factors concerning the decision of feeding particular ingredients in the diet were related to customs, availability and price in the market.

Table 4: Reproductive parameters of backyard pigs in the region of Xochimilco

1st service	Frequency (%)
Age (mths)
6-8	93
8-10	7

Detection of oestrous
Symptom
Nervousesness	47
Red vulva,	36
Mounting,	12
Vaginal mucous	4

Type of breeding
Natural,	96
Artificial,	4

Services per conception
One	51
Two	43
Three	6

The most important reproductive and productive related parameters are presented in Table 4.

The mean age for the first service of sows was in the range of 180 to 210 days and only a minor proportion of producers reported that they increased the age at first service claiming to get an improved reproductive response from the sow. The methods to detect oestrus in the sows included several ways, though there was a clear trend for the owners to combine some of them. As was expected, mating involved mainly the use of the boar. However, a small proportion of producers used artificial insemination as a new technique provided by local authorities originating from a technified proposal for pig development in the region.

Table 5: Production parameters of backyard pigs in the region of Xochimilco

Piglets born (1st farrowing)
Range	Frequency (%)
5-8	56
9-1	44

Piglets born (>1st farrowing)
Range	Frequency (%)
5-8	23
9-12	70
13-15	7

Range of lactation period
Days	Frequency (%)
46-60	67
65-75	5

Range of live weight of piglets at weaning
(kg)	Frequency (%)
4-6	40
7-10	50
11-13	10

The number of services per conception does not necessarily mean problems with fertility of the sows, as there is a general trend to give the female two services when mating as a process to ensure a higher number of piglets at birth.

Mean length of lactation of 46 to 60 days was stated by the producers to be an appropriate period for good development of the piglets at weaning, which in fact has became the standard method to finish lactation in contrast with the technified system often based on live weight reached by the piglets.

Criteria used to select and reject the animals for reproduction are presented in Table 6.

Table 6: Criteria for selection and rejection of the pigs for breeding

Criteria	Proportion (%)

Selection:
Body conformation	56
Number of teats	35
Past reproductivity of the sow	6
Liveweight	2

Rejection:
Age	54
Economic urgency	38
Low production	23
Illness	4

Reasons to select future pigs for breeding included mainly the conformation of the body and the number of teats. In the first case the producers claim this was related to better chances of live weight gains for the piglets whereas the second criterion (number of teats), was related to the ability of the mother to suckle more piglets. Although the main reason to reject pigs was related to age of the animals, economic urgency was considered a very important parameter which in fact has been suggested as the foundation of this system (Berdugo 1987).

Sanitary management of pig production in the studied area is presented in Table 7.

Table 7: Sanitary management of pigs in the backyards of Xochimilco

(1)Care of piglets:	(%)	(3)Main vaccinations:	(%)
Unbilical disinfection	26	Cholera	90
Iron injection	26	Erysipelas	10
Castration	17
Vaccination	16	(4)Combating parasites:
Tusk cutting	15	Yes	90
		No	10
(2)Common sickness:
Diarrhea	72	(5)Usual ways to treat sick
Erysipelas	18	animals
Cold	10	Specific animal medicines	60
		Human medicines	34
		Home remedies	7

There was a broad trend for producers to care for piglets at birth which includes mainly disinfection of the umbilical cord and iron injections. Other management techniques such as castration and tusk cutting have not become important. Most common sicknesses were reported to be diarrhea which affects mainly the new born piglets. As expected, vaccination against cholera was widespread. The same trend was present for the combating of internal parasites. Usual ways chosen by producers to treatsickness were mainly with specific medicines, though there was a clear trend for a significant proportion of them to prefer the use of human medicines and home remedies.

Main objetives of backyard pig production in the zone were oriented to self-consumption and selling during times of economic difficulty (91%). Only 9% of owners reported selling pigs as their primary goal. When the animals were sold the reasons were focussed on pigs to slaughter for meat (78%) and to a minor extent for breeding (22%). The standarized procedure for selling was by guessing the live weight of the animals (96%), only a low proportion used the actual weight of the pigs. The locations for selling the animals included: producer's house (36%), butcher (33%), slaughter house (19%) and local markets (12%).

Table 8: Herd composition of three backyard pig systems

Type of animal	----- F a m i l y -----
	S Gregorio	S Pedro	S Mateo

Sows	1	4	5
Piglets	-	8	-
Growing	3	-	5
Total	4	12	10

The number of animals presented in the families was within the mean number reported for the region. The feeding regime for the animals in the three backyards (Table 9) was composed of "tortilla", garbage, wheat bran, lucerne, contaminated wheat flour and a commercial food offered in different proportions per animal within the households. Changes in live weight during the study period were progressive as shown in Table 10 with highest increases reported for the growing pigs of Gregorio and lower for the piglets of Pedro.

Table 9: Composition and intake of feed for pigs in three households in Xochimilco (kg per animal, fresh basis)

Type of feed	H o u s e h o l d
	S Gregorio	S Pedro	S Mateo

Tortilla	0.66	0.46	0.25
Garbage	0.83	-	-
Wheat bran	0.33	-	0.50
Fresh lucerne	0.18	-	-
Commercial feed	-	0.38	1.00
Contaminated wheat flour	-	-	0.25

Table 10: Liveweight changes for pigs in the three households

Time	H o u s e h o l d s
(Days)	S Gregorio*	S Pedro*	S Mateo**

	Mean liveweight (kg per animal)
7	19.8	15.1	4.6
14	21.1	15.5	6.0
21	22.7	17.3	7.3
28	24.2	18.3	8.5

Because of the proximity of Xochimilco to Mexico City, backyard pig production has evolved with the growth of the metropolis, adapting to some of the technological ways of modern pig production whilst maintaining its traditional ways. This situation gives the system the characteristics of a sub-urban model but with high potential to be suggested as sustainable and as a real alternative, working harmoniously and beneficially within the highly polluted city of Mexico's Federal District.

The presence of backyard systems in the region of Xochimilco dates back to colonial times when the Spanish introduced their domestic animals thus, modifying production in the original family garden but to the benefit of people (Rojas 1990). This phenomenon was reinforced by the way the Spaniards distributed pigs and poultry (Woodrow 1980). Pigs were well adapted to the area because of the similar environmental conditions of their origin. The adaptation of domestic animals to the region is well documented (Romero 1990). The main components of the diet offered to backyard pigs today still include: maize, wheat and lucerne all of which constitute important agricultural products grown in the region (INEGI 1992). Thus it is clear that the link between agriculture and animal production should be taken into consideration when planning pig development in the zone.

The lack of consideration of the links between agriculture and animal production in the past lead to total failure of governmental attempts to develop technified pig production in the area. During the period between 1978 and 1982 offical authorities in charge of agricultural development of the Federal District, which includes the region of Xochimilco, carried out an ambitious plan to develop pig production by building 21 technified farms of which 16 belonged to the studied zone. The overall plan included the introduction of 2,520 sows which were supposed to produce a total of nearly 39,000 pigs per year ready to slaughter. According to the proposed values, Xochimilco was planned to have 1920 sows to produce 18,571 fattening pigs. Planning additionally included the presence of a factory to produce 90 tons per day of balanced feed and a slaughter house to process meat and byproducts (Sánchez 1982). To date only one technified farm remains in Xochimilco. A common reason for failure of the overall design was the rigidness of the technified system based on an imported model from other social, economic and cultural conditions (Pérez 1986). Support for this hypothesis is emphasized by the fact that the only farm that survives, located near the study area, had to change its original plan of production and adapt itself to the conditions of the zone. In this case most of their production switched from production of fattening pigs to slaughter, to selling of piglets for breeding or fattening, thus enabling the farm to use less feed based on cereals (Rivera et al 1993).

In contrast to the intensive systems, backyard production appears to be versatile in the use of inputs and animal management ac- cording to the needs of the people who care for them. Though the diet of animals are based on cereals and legumes that are expen- sive, the system is flexible in the use of other sources of protein and energy such as: tortilla, and flour contaminated with dust rejected for human consumption all of which are sold at low prices (Grande et al 1992). Furthermore, there is a wide spread use of garbage from the households which functions as a combined source of energy and protein supporting the low cost of the diet (Domínguez 1990; Suárez and Barkin 1990). Management of the animals is simpler for the system referred to a broad use of multipurpose pens, the use of the same containers for feeding and watering the animals, the simple and cheap construction of the pens, low use of external inputs such as commercial feed and recycling of manure to agriculture (Alonso et al 1991). Moroever, the management of pigs is largerly carried out by women and children which allows the man to seek economic resources outside the household.

Although the production of pigs has remained mainly traditional it is clear that the system behaves in a different way to other traditional models functioning in other parts of the country such as the tropics (De Dios et al 1989; Aguilar y Angeles 1991). A common characteristic of the model described in this paper is its adaptation to the sub-urban conditions of the area surrounding the city. Evidence of this suggestion is related to the presence of several technified managements such as: the broad use of specialized breeds for example: Yorkshire, Landrace, Duroc (see Table 2), a general use of vaccines against cholera as well as the use of modern medicines to combat parasites and/or illnesses, all of which are indicative of an interesting phenomena of improving traditional management without changing its original basis of production. Evidence of technified influences in productive systems in the area has been reported by us regarding other domestic species ( Cortés et al 1992). Possible reasons for this could be related to the proximity to large research and education centers located within the city. Another influence may be the grandiose plan for pig production mentioned before as there were some indications of similar production methods between the two systems, such as the use of artificial insemination, thus offering some benefits to the producers.

Although the technified model was a failure there was some adoption by traditional producers of some modern methods of management. Future pig development plans should be concerned more with backyard systems of production because of their ability to provide a large source of pig meat and by-products to family producers and the country. Thus developmens should consider improving the population of animals managed at a moderate level of intensity thus offering the producers some improved techniques suitable to ensure that the system functions efficiently within the traditional framework. That backyard systems are sustainable is born out by its longivity since the Spanish conquest even though some modifications have been made in recent times. Its adaptability is its strength and it has proved to work succesfully taking on the most appropriate aspects of high input production but able to maintain its traditional nature and appears flexible enough, should the need arise, to revert to exclusively traditional production techniques.

The authors wish to thank producers of backyard pigs in the region of Xochimilco by providing information and allowing us to measure some parameters of their system.

The authorities of Universidad Autónoma Metropolitana (Autonomous Metropolitan University) are acknowledged for the facilities given for the research.