The production of milk from dairy herds in the suburban conditions of Mexico City: II. The case of the Region of Xochimilco in the South-East of the City

A survey was carried out to study dairy systems in the region of Xochimilco. Small dairy farms are usually located next or within the owner`s house, with 66% using the labour of one family. A high percentage of the producers is literate (97%) and does not belong to any dairy association (84%) and their level of schooling is distributed as follows: primary school (47%) and secondary school (41%). Mean number of animals was eleven per owner. The majority of cows were Holstein. A significant number of the producers retain the calves for fattening (78%). The feeding system is based on 15 components including polished wheat, maize stubble, natural grasses, ground maize and a commercial concentrate. The system for milking cows is manual, with a reported mean value of 240 days per lactation and a daily milk production of 15 litres per animal. Common diseases reported were mastitis, pneumonia, bloat and rotten hoof, treated by means of specific medicines (64%) or home made treatments (26%) and human medicines (10%). Most of the milk obtained is sold at the dairy farm (57%) although there is a significative proportion (40%) which is sold in the houses of consumers. The low number of animals in these dairy farms is due to the restricted availability of forages which gives them the feature of mixed systems of agriculture-dairy farms.

Key words: Milk production, small scale, farming system.

Introduction

The earlier paper published on milk production practices in the east of Mexico city (Losada et al 1996d) enabled the understanding of the productive dynamics of a system located in the urban zones of Mexico City, based on the intensive use of fruit and vegetable residues from the large markets, the transport of manure to arable land of the periphery, and the establishment of local neighbouring markets for selling milk from the stables. In contrast with this system, the methods used for milk production from cows in the South-East of the city are different. The area is less intensely urbanised, and spaces devoted to agriculture covered with green vegetation are often used as pasture for the animals. Since there is no documented information available about this system, it seemed important to carry out a characterization and productive evaluation of the milk production system, in order to understand the factors which limit its development.

Materials and Methods

The geographical characteristics of the Xochimilco region were described in the paper by Losada et al (1995a), while the historical antecedents of milk production in the zone are similar to those described by Losada et al (1996d). The method applied in the study began with the use of a questionnaire directed at the producers of milk in the zone, in order to know the socio-economic and technological environment in which the system is embedded (Jiménez et al 1982). In the absence of information which would facilitate definition of sample size and stratification by number of producers (Kish 1972), questionnaires were randomly applied in 10 towns in the region: two in Delegation of Xochimilco, four in Milpa Alta, and four in Tlahuac. The selection of productive units was done by direct observation, and by enquiries from informants, and the questionnaire was tested in the field before being extensively used . A total of 54 questionnaires was applied, involving a sample of 731 animals during a period of 3 months. The second part of the study was a detailed evaluation of three milk producers. Milk production and food consumption were quantified. The responses obtained were analysed using an SAS package, and expressed as measures of central tendency, following conventional procedures (Daniel 1984).

Results

Socio-economic characteristics of milk producers

Similar to that observed in milk production systems in the urban part of the city, in the Xochimilco region the activity was found to be associated with the house area. 66% of producers indicated the involvement of one family in the business, and the rest two (17%), or three (17%). The mean number of inhabitants per family was over 4 (72%), compared with a lower percentage (27%) who reported 2 or 3 inhabitants. The majority of producers asked were literate (97%). Educational levels completed were: primary (47%), and secondary (41%), while only a small percentage had studied further.

In comparison with the milk production systems of Iztapalapa (Losada et al 1996d), a lesser percentage of producers (20%) obtained their income from milk production, and the main part of those questioned reported supplementing family salary with other forms of income. Over 80% of cattle men reported being independent (84%), around half mentioned being ready to receive technical assistance (47%) from specialist personnel to modify their manner of work (61%), with the aim of improving the profitability of the system.

Technological features of dairy production

Composition of herd

Mean values obtained for the composition of the regional livestock population are presented in Table 1.

Table1: Characterization of the population of cattle sampled in the Xochimilco Region

Category	No. of animals	%	Per producer

Pregnant cows	316	43	6
Non-pregnant cows	99	14	2
Stud bulls	164	22	3
Calves	152	21	3
Total	731	(100)	14

The average size of a herd in the zone was 14 animals, with a range between 2 and 20. About 80% were productive, pregnant or both, and the rest young calves and the studs. The majority of producers answered having commercial Holsteins, corresponding to the black and white offspring from crosses of American or Canadian Holsteins.

Housing of the animals

The allocation of space for animals is accounted for with two simple models of feeding and controlling the animals. Firstly, an improvised corral made of local or recycled materials (with a roof of cardboard), and secondly; a shed with floor, walls and ceiling made of concrete, brick or both, in which animals are individually tied. It was more common to find feeding, rather than drinking troughs. The former were made of concrete or brick, whereas a bucket is often used for the latter. According to the data, in 98% of cases, the unit was cleaned 6 days a week, the manure to be used for agricultural activities in the zone. Of the 43% of producers who reported dealing with rodents, the control methods used were: a cat (63%), poison (31%) and traps (6%), whilst half of these used insecticides to eliminate flies.

Feeding regime for dairy cows

Similarly to the small scale milk production system of the east of the city, in the region of Xochimilco there did not exist a defined pattern for feeding the animals, and it was carried out with a combination of components that the producers have learnt to use, by virtue of their sale price, transport, and individual preferences. The structure of the diet indicated that there exist two types of feeding regimes, in accordance with the productive stage of the animals. For cows in production, the feeding model was based on 15 products (Table 2), from which: wheat bran, sun dried alfalfa, maize stover, regional grasses, ground maize and commercial concentrate were most important. An alternate diet used to fatten the young male calves, used only 7 components, including: oat grains, maize stover and Arveja (Vicia sativa) which made up 67%. A large percentage of producers (42%) reported taking their animals to graze on natural grasslands, road sides, and canal banks.

Table 2: Dietary components, and frequency of use in the cow sheds of the Xochimilco region

Dairy cows
Ingredient	No. of Producers	% of total

Wheat bran	44	22
Sun dried alfalfa	42	21
Maize stover	39	19
Grass and forrages (1)	34	17
Maize flour	14	7
Commercial feed	12	6
Cooking waste	6	3
Oat straw	3	1
Silaged maize	3	1
Nopal- vegetable	2	1
Tortilla	1	0.5
Maize dough	1	0.5
Dough water	1	0.5
Ground Wheat	1	0.5
Malt	1	0.5
Male calves fattening:
Wheat	10	28
Maize stover	8	22
Arveja	6	17
Malt	4	11
Sun dried alfalfa	4	11
Wheat bran	2	5
Carrot	2	5

(1) Pennisetum clandestinum (kikuyu),Typha dominguensis Pers (Tule), Trifolium spp (Trébol)Brassica campestris L. (Nabo), Amaranthus hybridus L. (Quelite), Chenopodium album L. (Quelite).

Some 59% of the producers reported balancing the diet of the animals, which in practice meant a simple management of the available concentrate for the high production cows. In contrast, most reported that they do not administer mineral salts to the animals. In the same way as in the suburban production systems of the east (Losada et al 1996d), the feeding of calves was carried out using whole milk (66%), or combined with commercial concentrate (32%).

Reproductive management

Methods used to identify when females are on heat included: mounting between cows, presence of a vaginal mucus, coloration of the vulva, while the assistance for the bull was limited (4%). Some 10-20% of cows failed to mate during the first oestrus. There existed a marked preference among a majority of producers for the crossing of females with the bull (75%), and a minority (25%) who used artificial insemination. Such a situation is supported by the argument that the bull is more effective in getting the cows pregnant, and that artificial insemination requires the presence of a specialist.

Production features

The only means to carry out milking was by hand, carried out twice a day (following conventional practice), and using bucket or pitcher to collect the milk. The majority of producers (97%) washed their hands before milking and cleaning the udder (97%). According to the producers, most lactation periods lasted 240 days, with a range between 195 to 285 days. The process of drying of the cow occurs after 7 months of pregnancy, rather than waiting for a decline in milk yield as seen in technified systems. Dairy men informed us that an average quantity of milk produced per cow is 15 litres a day, although the majority (54%) maintain an average of 8 litres a day.

A significant percentage (78%) reported raising the male calves for fattening for slaughter after 18-24 months or for sale as studs. In a similar way, the yearling heifers were raised to be replacements, sold as reproducers, or both. The identification of animals was by name (46%) or ear tag (8%). The selection of heifers for replacement was based principally on body form and productivity of the mother. For males, the weight of the animal was considered as well as body form. The decision to reject was based on the age of animal and low production (Table 3).

Table 3: Criteria used by producers for selection and rejection of male and female calves (% of producers reporting for each criterion)

Selection criteria	Heifers	Males

Body conformation	44	48
Productivity of Mother	27
Conformation, productivity and LW.	21
Conformation and productivity	6
Conformation and LW	5	16
Select only females	3
Production	3
Rejection criteria:
Age	42	100
Age and low production	32
Age and reproductive disorders	16
Age, low production and disease	10
Age and disease	6
Low production	5
Economic necessity	7

Health management

The most frequently reported illnesses were mastitis, pneumonia, bloat, and rotten hoof, which were treated by the use of specific medicines (64%), traditional house remedies (26%) and medicines for human use (10%). A significant percentage of producers reported vaccinating their cows against brucellosis (53%), and carrying out TB tests (33%). Producers tended to focus activity on internal (71%) rather than external parasites (24%).

Commercial aspects of milk production

As found in the majority of milk production systems, milk has the largest commercial significance, followed by the animals themselves. The average price indicated in the zone for the sale of raw milk was 0.41 US$ per litre. Most of the milk was sold directly in the stable (57%), notwithstanding a high percentage delivered by the stable to the consumer's home (40%), while direct sale in shops represented a low proportion (3%). Most producers reported selling all of the milk they produce (82%), the rest being processed as cheese, cream and desserts for self- consumption.

Only 25% of producers reported buying animals from outside, indicating a largely closed commercialization system. The conventional form of sale of the animals was on foot, at the stable or with the butcher according to the type of animal. The proportions were: yearling calves (43%), rejected animals (27%), productive animals (18%) and pregnant cows (12%).

Case study of three herds

The herd owners in the three units studied maintained an average of 11 animals, of which 45% were currently productive, 9% were dry animals, 18% calves in growth and 27% fattening male calves.

Feeding, milk production and profits

The diet given to the productive cows was based on the use of forage (combinations of fresh alfalfa and maize stems) and concentrates mainly as wheat bran, maize grain and a commercial feed. The average production of milk pere cow varied from 13.1 to 20.4 litres/day and was directly related to the proportion of the diet in the form of concentrates (Table 4).

Table 4: Proportion of forage and concentrate and milk production in three dairy units

	Production units
	A	B	C

Forage (kg DM/day)	12.8 (71.5)*	13.8(67.6)	11.1(77.6)
Concentrate (kg/DM/day	5.1(28.5)	6.6 (32.3)	3.2(22.3)
Total DM (kg/day)	17.9(100)	20.4 (100)	13.3(100)
Milk production (kg/animal/day)	13.1	20.4	14.3
* Percentage of total dry matter consumption.

Discussion

The small scale milk production in the region of Xochimilco is an example of a system which, by virtue of the tight relation between the production process and use of natural resources for its maintenance, is suitable for future replication in accordance with the goals of sustainability. In a manner similar to that found in systems in the east of Mexico City (Blas 1990; Losada et al 1992; Losada et al 1996d), the form of production has maintained characteristics combining the house with the productive process, as well as incorporating family activity in its management. An exception to this form of production, not identified in this study, consists of the milk production in the chinampas zone of Xochimilco. Here some producers have created a system making use of abandoned agricultural areas which have become pasture, and introduced small numbers of cows, outside the context of the home producer (Canabal et al 1992). It seems the inclusion of cows in the backyard of the house, is an important characteristic of traditional systems, where the animals play an important role, and this has not been clearly understood by researchers or development agencies (Pérez 1983).

An aspect of the milk production system in the present study which contrasts with the form of production reported in the east of the city, was related to the number of animals used. Availability of natural and man-made pastures, harvest by-products, and physical space to keep animals is greater in the Xochimilco area, whilst the number of animals per producer was 14, compared with 27 in the eastern city system. The first explanation of the smaller number of cows used in Xochimilco systems, may be associated with the linkage between the production system, and agricultural activity in the zone, as well as the forage resources for feeding the livestock. Although the diet of the animals sampled showed a large variation, with 14 components, over 80% of the diet of the cows was based on feeds obtained from local agricultural production and grass resources. This suggests that variation in availability of food throughout the year may be a factor limiting the number of animals per producer. Data reported in the literature (Sánchez 1982) show that the area of Xochimilco used for crops is 47% of the total surface, while space for pasture is lower ( 7%). In addition the majority of grass species in Xochimilco are native. As a result of intensive management and environmental conditions in the winter periods, their yields of dry matter (and possibly digestibility coefficients) would be expected to be low (Salisbury and Ross 1989). Therefore the number of dairy cattle is maintained at a low level by the natural constraints of the area that the producers have accepted.

A second factor that could be associated with the low number of animals, is the lower degree of urbanisation in the area. In the urban conditions of the east of the city, a high percentage of milk is sold directly to nearby consumers. In the less urbanised Xochimilco, lower population density may present a low demand for milk in the immediate vicinity. The results obtained regarding commercialisation showed that a significant percentage of milk is delivered to the consumers, which implies a need for the producer to expend time and energy to market the product. A related issue, mentioned in the surveys, which tends to exacerbate the problems of milk marketing, is the presence of government milk factories, which sell imported milk at reduced prices. These are linked to poverty-aid programmes, which are frequently used in exchange for securing the vote of beneficiary populations in elections. The local market for milk from small producers thus limits the number of animals kept by a producer.

One of the different characteristics of the milk production system studied, compared to the other nearby systems of the city, was in the fattening of male calves for sale and use as studs in the area, or as meat for the city. The majority of milk suppliers in the country have a strategy of selling calves at 3 days of age, for slaughter and subsequent sale as veal. The system in Xochimilco may thus be characterised as dual purpose, in a similar way to those found in tropical parts of the country (Román and Aguirre1982; Ortíz 1982). The difference is that, in this study, calves were not found to be used to stimulate milk letdown, or in restricted suckling (Alvarez et al 1980), but were raised by feeding milk or milk replacer from a bucket. The determining factor in the adoption of this production system lies in the tendency of the producers to maximise profitability, to compensate for the low number of cows in production. The cows demand little attention from the producer, in contrast to technological milk production systems (Gómez 1986), in which cows are viewed as "machines" for milk production.

An interesting process to analyse in the present work is the link between the milk production system and agriculture in the zone. According to the data obtained, in 98% of cases studied, manure was collected, later to be used as fertiliser for the agricultural activities of the zone. It appears that this production system possesses another dimension to that of technological systems, which focus exclusively on animal productivity, independent of the socio-economic and physical environment in which they are situated. As reported by ourselves (Losada et al 1996c), manure is very important in local agriculture as a source of organic matter, macronutrients, heat and water. Evidence from this study shows that for some producers in the terraced zones, manure production is the principal objective of production, whilst milk and milk derived products are secondary. In a similar way, in the low chinampas zones, all the livestock producers use cow manure in chinampas cultivation of vegetables, flowers and maize. In accordance with this, it is clear that in contrast to the urban zone production systems, where milk production is the primary activity, production in the south-east of the city is an activity found to be closely linked to agriculture: a fact which must be understood by government agencies responsible for livestock development. The existing evidence in the zone confirms our suggestion that provision of a central dairy, concentrating all the cows of the chinampas zone (Losada et al 1994), would have disastrous consequences. The dislocation of the productive model from its original niche would have repercussions in the accumulation of manure around the dairy, and would provide a new locus of environmental contamination.

Acknowledgments

The authors would like to thank the students of the Licenciatura de Producción Animal for their assistance; the authorities of UAM for the facilities provided, and finally; the milk producers of the region studied, whose participation made the present work possible.