Constraints and opportunities for improved milk production and calf rearing in Sanyati communal farming area, Zimbabwe

Charlotte Pedersen and J Madsen

The Royal Veterinary and Agricultural University, 13 Bülowsvej, DK-1870 Frederiksberg C. Denmark (e-mail cvp@kvl.dk and jom@kvl.dk)

Abstract

The objectives of this study were to obtain an understanding of the Sanyati farming system, which is similar to most farming systems in the rural areas of Zimbabwe, and to investigate the constraints and opportunities for improved milk production and calf rearing in a communal farming system under tropical conditions. There are several constraints to milk production and calf rearing, most caused by poor nutrition and limited management. Gastro-intestinal nematodes are an epidemiological constraint but worsened by poor management. How these constraints affect production was in focus.

Milk yields of cows and growth rates of calves were important aspects. The average milk yield over a 150 day period was 5 litres/day and the average growth rate of calves from birth till 4-5 months old was 350 g/day. A high degree of individual variation within the herd was found. Thus, apparently, there is a good base to carry out selection for better production traits such as higher milk yields and growth rates.

Low quality roughage is the predominant feed of cattle in this farming system and supplementation is needed to increase production. It is very important to keep in mind that supplements should also promote better utilisation of the available low quality roughage. Better knowledge about which groups of cattle respond best to supplementation must be gained.

Key words: Common lands, cows, calves, milk yield, growth rate, parasites

Introduction

There are around 4.2 million heads of cattle in the communal farming areas of Zimbabwe. They constitute approximately 60% of the total cattle population in the country (FAO 1992). The remaining 40% are in the commercial farming areas and these are often exotic breeds. Communal cattle are mainly of indigenous origin and their productivity in the form of meat and milk is low. The communal pastures are of very low nutritive value most of the year and feed supplementation is often very sparse. In Sanyati communal land only dried maize stovers are traditionally given as supplementation. This poor nutrition causes low milk production for cows and depressed growth in both cows and calves.

Management in Sanyati communal farming system is limited and this, together with low nutrition and gastrointestinal nematodes, causes low production performances, especially in the calves because they are more sensitive to all of these factors. Most cattle do, by age, acquire some immunity against gastrointestinal nematodes.

There are several constraints to cattle production in the area. Nutritional constraints are predominantly caused by the climate and the fact that nothing is done to preserve and store fodder for the dry season. Limited management causes insufficient fodder supplies, low fertility, unthrifty animals and no selection for better production traits. Natural selection is the only kind of selection within the population. Deaths caused by droughts and starvation are common among cattle and thus there is a lack of animals to select from.

An improvement of the cow's nutrition, milk production and management is a possibility to increase family income and to increase the number of draught animals. There is a shortage of draught oxen and this has a negative effect on crop production.

Increased milk production through better feeding will enable farmers to sell milk and thus increase cash income. At the same time the fertility of the cattle will increase, they will grow faster and their draught abilities will increase. Also security is increased by improving cattle production. The animals are more likely to resist drought if they are in good condition. If a milk sale is created it is an extra income which will reduce the effects of any crop failure.

The Sanyati farming system

Sanyati communal land is situated in Sanyati District of the Mashonaland West Province 250 km west of Harare. The climate is sub-tropical with high temperatures (average temperatures in October and July are 30ºC and 20ºC, respectively) and a moderate to low annual rainfall (450-600 mm.). Sanyati lies within Natural Region III - IV and is thus suited for semi-intensive animal husbandry. The rain falls within the period from November - March. May - August is the dry period. The communal grazing area consists mainly of bush savanna.

In Sanyati communal farming areas cattle play an important role. The cattle are of the indigenous Mashona breed, but widely crossed with Africander and Brahman cattle. The purpose of keeping cattle is complex. Younger et al (1996) asked the farmers to rank the different uses of cattle and got the following result:

1. draught
2. transport
3. cash
4. milk and manure
5. status and lobola (bridewealth)
6. social
7. meat

Cattle are not kept for meat production, which the ranking shows, and therefore hardly any animals are slaughtered. Males are kept for draught purposes and females for reproduction. In the rainy season the animals are "kraaled" (put in pens) over-night and herded during the day. In the dry season they are left in the bush and only gathered a couple of times a week. Calving time is mainly concentrated in the first 2 months of the rainy season. This means the "kraaling" period is identical with the early and mid lactation period when the cows produce most milk. Hence in this period cows are often milked. Cow and calf are separated over-night and milking takes place in the morning. Most farmers only milk for home consumption.

No special effort is put into calf rearing in Sanyati communal area. The calves follow their mother from birth until weaning, which usually takes place at 10 - 12 months of age. The calves are fed nothing but milk and pasture grass. The calves are exposed to gastrointestinal parasites as soon as they start grazing due to the fact that they are grazing the same pastures as the rest of the herd.

The major crops grown in the area are maize and cotton. Maize is grown for home consumption. Cotton is a cash crop and the biggest source of income for most families. Sunflower (Helianthus annuus), bambara nuts (Voandzeia subterranea), groundnuts (Arachis hypogea), sorghum (Sorghum bicolor), rapoka grass (Eleusine indica) and melons (Citrullus lanatus) are also grown.

Materials and methods

The aim of the experiment was to study weight changes in cows and calves and to estimate the milk production of the individual cows in the first months of lactation with the purpose of determining any relation between milk production of cows and growth rate of their calves. The natural development of gastrointestinal nematodes in individual animals was also determined.

Animals

Thirty late-pregnant communal cows, and later 28 of their calves, were included in this study. It was not possible to get information on the age of the animals since the farmers do not keep any records of their animals. The cows were from 6-9 months pregnant at the beginning of the study in October 1996. The calves were included in the trial from birth till 3-6 months of age. The study ended in April 1997. All cows grazed the communal pastures throughout the period

Data

During the 7 months period, from October 1996 to April 1997, the weights of the cows were monitored once a month and calf weights every week. Birthweight was obtained within 24 hours of calving. Blood and faecal samples were taken every 2 weeks from both cows and calves. Estimates of daily milk production for 16 of the cows were carried out weekly. It was done after separation of cow and calf over-night, approximately a separation of 15 hours. The calf was weighed before and after sucking and the amounts of milk taken for the household were measured. The sum of these two quantities gave an estimate of daily milk yield. It was assumed that the calf had emptied the udder before the separation. Milk yield was calculated using the following formula:

Y= (M_M + M_S)* 24/H

Y= Daily milk yield (litres); M_M = Milk milked for household use (litres); M_S = Milk sucked by the calf (litres); H = Hours of separation

Blood samples were analysed in the Department of Paraclinical Veterinary studies at the University of Zimbabwe. They were analysed for albumin, haemoglobin and Packed red blood Cell Volume (PCV). Faecal samples were analysed in the same department. A McMaster flotation technique was used for gastrointestinal nematode egg counts (Henriksen and Aagaard 1976). Eggs per gram of faeces (epg) were counted. Faeces cultures were kept for 10 days at 27ºC for development of third stage larvae. Thus the different strongyle species were identified. On days of sampling, varying numbers of animals showed up and very few animals were sampled every single time. Hence data collection is not complete.

A quantitative and qualitative survey was carried out among 15 farmers in January 1997. The questionnaire concentrated on milking practices, milk production and calf management. Due to language barriers the questionnaire was done with the help of the local project technician.

Results and discussion

Weight changes of cows and calves

Figure 1: Average weight change of cows and monthly precipitation from Sept. 1996 - April 1997.

Cows were losing weight from September to December (Figure 1) as they only had access to dry areas of communal grazing. No supplements were available. The average weight loss was 40 kg. From January to March there was an average loss of 55 kg. During these months there was an abundance of food, but due to calving (causing a weight loss of around 30 kg) and early lactation, a weight loss could be observed. Most of the calvings (70%) took place in December - January. Gastrointestinal nematodes were increasing during the same period (see Figure 4) and may have contributed to the weight loss. The cow's immunity to parasites is lowered around calving (Soulsby et al 1981; Pandey et al 1993). In March the cows started gaining weight due to good nutrition, lower lactation yied and maybe regained immunity.

The monthly precipitation is also shown in Figure 1. The total precipitation (970 mm) in the 1996/97 rain season was well above average and a lack of pasture can not have been the reason for the weight loss of the cows.

Figure 2: Average weight of calves from birth till 23 weeks old

Figure 2 shows the average calf weights from birth till the age of 23 weeks. Mean birthweight was 26.5 kg (SD=3), males being a little heavier than females: 27.5 and 26.0 kg, respectively. From week 20 and onwards there are only a very few calves due to the fact that hardly any calves were more than 15 weeks old when the study ended.

The average daily growth rate per day until 2 months of age was 395 g (SD = ±185). After 2 months and until 4-5 months of age it was 305 g (SD= ±170). Growth rates varied between 150 and 705 g/day, excluding the extremes of (-60) and (925) g/day. The big variation in growth rates among calves was probably caused by environmental and genetic factors. Growth, specially in the early age, depends on the milk production of the dam which, as later shown in Figure 3, varied greatly between the cows, but it was not possible to see any relation between milk production of a cow and growth rate of her calf. There was a trend towards calf growth being dependent on the farm, meaning environment and management. This could not be verified since few of the farmers in the study owned more than one calf, but for the ones that did, growth rate of the calves from the same owner were almost the same.

The finding in this study that growth rate was higher at an early age than later is in agreement with the report of Marlowe et al (1965) who found in Hereford and Angus cattle that, in general, as calves increased in age their gains decreased. In a trial in Ethiopia with Zebu x Friesian crossbred cattle (ILCA 1994), calf growth rate was 347 g/day from 0 to 84 days old and 296 g/day from 0 to 180 days.

Milk production

Figure 3: Average milk production of cows in each of the first four months of lactation

It was not possible to monitor milk yields from all cows which made it difficult to assess the relationship between calf growth rate and the dam's milk production. Figure 3 shows the average daily milk production of cows in the first four months of lactation. The data were analysed using the General Linear Model (GLM) procedure of the Statistical Analysis Systems (SAS) software programme testing for the effect of cow and month on yield. There was a significant effect of cows (P<0.01) and of month (P<0.001). Milk sucked by the calves decreased over time. Hence in January the average daily amount of milk taken by the calf was 2.5 litres, whereas in February, March and April it was 1.5, 1.0 and 0.75 litres/calf, respectively. This is closely related to the decrease in the dam's milk production over the same period. For some calves the amount of milk sucked was too small to be monitored and it was therefore counted as zero.

Figure 4: Average milk yield (±SE) during first 4 months of lactation for individual cows

The amount of milk offtake for household consumption also decreased over time. The average daily amounts of milk taken in January, February, March and April were 2.0, 1.75, 1.5 and 0.5 litres/household, respectively. Monitoring of milk yield lasted for 5 months = 150 days. The average milk production per cow during this period was 593 litres. Data from the literature (Williamson and Payne 1978) indicate that the milk production of Mashona cows is in the range of 218 to 499 litres in a 180 - 270 day lactation period. It would thus appear that the milk production in the Sanyati communal area is higher than the milk production recorded in pure Mashona cattle.

There was no relation between milk production of the dam and growth rate of the calf. A similar finding was reported by Fernandez et al (1978a) in a dual purpose herd in the Dominican Republic, where hand milking was combined with restricted calf suckling. These authors found that the total milk production (milk offtake plus milk sucked by the calf) was closely correlated with milk offtake, and that the amount sucked by the calf (approximately 2 litres/day over the total lactation) was not related with the yield of the dam. Subtracting the milk offtake in January, February and March (2.0, 1.5 and 0.75 litres/day) from the corresponding total milk production (from Figure 3) results in estimates of calf intake of 3.6, 2.65 and 1.5 litres per day with an average of 2.6 litres. While these data are approximate estimates only for the first 3 months of lactation, they correspond roughly with the average calf intake reported by Fernandez et al (1978b) and Alvarez et al (1980) of about 2 litres/day for a 240 day. lactation.

These levels of milk consumption, on the surface, appear to be too low to secure satisfactory growth. One explanation for why the calves grew reasonably well (about 350 g/day), despite the low milk consumption and poor quality of the grazing, is that the fat content of milk sucked after hand milking of Bos indicus cows is much higher than in milk taken in the bucket. Mai van Sahn et al (1994) and Mejia et al (1998), working with Boron and Mpwapwa cattle in Tanzania, reported levels of 5.6 to 5.8% fat in suckled milk compared with 3.4 to 3.6% in that taken by hand milking before suckling.

Gastro-intestinal nematodes

Figure 5: Average epg of cows and calves from Oct. 1996 - April 1997 (end of dry season till end of rainy season)

Figure 5 shows the average gastrointestinal nematode eggs in faeces of cows and calves from the end of the dry season till the end of the rainy season.

From January to March there was, as expected, a big increase in nematode egg counts, since after the onset of the rains the humidity favours the development of nematode larvae on pasture. For the calves the parasite burden continued to increase into March and April but for the cows it seemed to stagnate. This agrees with the observations of Pandey et al (1993) that egg counts rise to a maximum in April - May. The more drastic increase in the worm burden of the calves compared to the cows is probably due to the former's lack of immunity to parasites. The individual egg counts varied widely among the cows (Figure 6). Some cows appeared to be very resistant to gastrointestinal nematodes and had a zero egg count throughout the period; whereas, others were more sensitive to infection. The very high values are an expression of the rapid increases in February-March rather than a reflection of the overall period.

Figure 6: Range of values of epg for individual cows from Oct. 1996 to April 1997.

Hardly any changes over time were found in pcv, albumin and haemoglobin in the blood of the cows. The mean values had a very low standard deviation (SD). For pcv SD was ±3.6, for albumin ±3.0 and for haemoglobin ±1.3. Gastrointestinal nematodes could therefore not be detected through blood samples. Often there is a delay in the appearance in blood of indicators of gastrointestinal nematode infections. The mean and individual pcv, albumin and haemoglobin values in this trial never fell below normal values.

Haemonchus sp. were the most predominant specie throughout the period in both cows and calves, constituting around 70% of the total helminth population. This is in agreement with the findings of Pandey (1989) and Pandey et al (1993).

Important aspects that came forward during the questionnaire

The vast majority of farmers only milk their cows during the rainy season. Thus, depending on calving time the cows are milked for 3-5 months. In this period they milk once a day in the morning at 9-10 am. The calves are allowed a minute of suckling before milking is initiated. This is done to induce milk letdown. Most farmers start milking the cows one week after calving. Two thirds of the farmers that were interviewed were aware of the importance of colostrum for the calf. On average, the farmers milk about two litres/cow per day. This is what they need for the household. Most say they could milk more, but leave some for the calf. Milk is used fresh in tea and as sour milk in a relish with sadza.

Most farmers think they could sell excessive milk to neighbours or residents at ADA (the local state farm). When asked about the price of the milk the answers were variable: from Z$1-Z$5 per 750 ml. which is the traditional measure when selling milk. The farmers were also asked if they would be interested in small scale milk production. Half answered yes. This was primarily the farmers who had enough draught animals. For most farmers milk production is secondary to draught power and therefore the cow´s ability to reproduce is more appreciated than its ability to produce milk. On average the farmers have 3 cows but they said they would like to have 6 cows. The reason they gave for wanting more animals was that they want a faster rate of reproduction.

The calves are around 12 months old when weaned. Usually farmers leave the calves to wean naturally but, if they are not weaned when 12 months old, weaner plates are used. The calves are penned either separately or with goats over-night for approximately 15 hours/day in the rainy season. There is no difference in the management of male and female calves.

According to the answers the farmers are more interested in good reproduction performances of the cows than high milk yields. The lack of draught animals is the main reason for this. From a farmer's point of view, intensification of milk production will only be interesting after securing enough oxen for cultivation of the land.

Possible opportunities to improve milk production and calf rearing

There would appear to be several opportunities for the Sanyati farmer to increase cattle production. However, most choices involve either an increase in labour or in cash outlay and therefore the suggestions will only succeed if they do not add any extra labour and costs during the months when these two factors are already limiting to production.

Feed supply and feed quality are the most important factors limiting production. They can be improved in various ways. Pasture improvement by introducing legumes is one possibility. Legumes are advantageous because they provide the rumen microbes with extra nitrogen and make these more capable of degrading the dry plants. Perennial species are to be preferred because the labour cost of cultivating these plants will be concentrated in the first couple of years. Improvement of the pasture requires that all farmers having access to a grazing area must agree on the strategy and co-operate in the establishment of legumes. The fact that no one is entitled to the grazing land is a constraint to pasture improvement. Organization of the farmers could alleviate this constraint.

Cultivation and storage of forage could become a common practice, as it is in the temperate zones. . There is a possibility to cultivate grasses and legumes for conservation and storage till the following dry season as each farmer has some fallow land that could be better utilised. Hay and silage making are practices that could be introduced to the area. Because of the wet weather during the optimum season of cutting the grass, hay making could be difficult and silage production is probably a better option. In Nharira communal area, south of Harare, ensiling of Napier grass and other species is done. Silage making here seems successful, it provides a substantial part of the dry season diet for cows owned by small scale milk producers and silage pits are built on the farm at very low costs.

Production of silage and hay does not require any kind of mechanisation, but it will require extra labour for cutting, drying, transporting, ensiling and storing. Hence labour could very well be a limiting factor for the success of silage and hay production. The time for hay and silage making will coincide with the weeding in cotton and maize. Extra labour will be needed. However, use of silage and hay could contribute to increased cattle production to the extent that the improvement could pay for hired labour. Hay and specially silage making from the communal grazing land would require improvement of pasture and animals would have to be kept out of the areas till after hay and silage making is finished. The most important factor determining the success of both hay and silage making is the attitude and acceptance of new practices by the farmers.

Since Sanyati communal pastures are bush veld, the leaves and fruits from bushes and trees are important feed resources, especially in the dry season. When trees drop their leaves cattle will pick them from the ground even when the leaves are partly decomposed. Further investigation is needed on what species are preferred and maybe these could be cultivated. Tree and bush residues are low cost supplements and they also have other advantages; they provide fuelwood, shade for people and animals and, in some cases, they provide edible fruits. They also help to control erosion and this might be very important since this semi-arid area is vulnerable to erosion.

Maize stovers are available and in the future could be utilised more efficiently. Only ruminants are capable of utilising maize stovers and their nutritive value is low. The bulky nature is a constraint to feed intake and prevent the animals from consuming sufficient amounts to meet daily energy requirement (Ulrich and Kjær 1994). However, maize stovers can be utilised more efficiently by offering them to cattle along with urea-molasses blocks. Urea-molasses blocks are relatively cheap to make and have been used elsewhere with good results (Chamberlain1989; Ghosh et al 1993).

Production traits of indigenous cattle can be improved through different methods which include selection within the existing population and cross-breeding with exotic breeds. Selection within the existing population has advantages because it ensures the development of animals which are able to adapt well to the existing feeding and management system. Hardly any selection has until now taken place within local populations in the tropics, but there should be good prospects for improving the production potentials of tropical breeds just as well as there has been for many exotic breeds (Syrstad 1991). By selecting for better production traits within the existing population the development of better performing animals will happen gradually, which means the farmers will have time to adjust to animals which will require better management, specially concerning the feeding practices. Management would have to change drastically with the introduction of exotic breeds.

Indigenous cattle are multi-purpose cattle and this should not be forgotten when carrying out breed improvement. In Sanyati communal area the draught ability of the animals is of vital importance to the crop production and if increased milk production is wanted it should not be achieved at the expense of good draught traits.

There is no doubt that improving management will have a positive effect on performance. Clean pens, detection of heat and earlier weaning are some management improvements which should be introduced. Often the rain turns the pens into pools of mud and manure. This can be the cause of many infections and spread of disease and definitely limits the welfare of the cattle. A roof, either hard or made of straw could decrease the amount of water within the pen and at the same time it would provide shade. Maize stover supplementation is often done by throwing the feed into the pen. The stover inevitably becomes contaminated with dirt and manure and hence the risk of consuming parasites increases. In Gambia, Kaufmann et al (1993) found that the nightholding area was of great importance in relation to the parasite burdens of the cattle. Cattle moved regularly had significantly fewer parasites than animals staying in the same nightholding area permanently. Pens are rarely moved in Sanyati and manure is only removed once a year. Thus the pens must be considered as constantly infected with parasites.

Lack of water for cattle limits feed intake and thus limits production. This is a problem especially during lactation. Lack of fresh water is probably also a reason for slow growth rate in calves. If milk offtake is high, access to water is very important. In the rainy season the animals drink water from puddles, but the water is often muddy and during the time they are confined in the pen, they have no access to water. This problem is very hard to solve since the distance to a permanent water source is usually quite far. More boreholes and pumps locally placed are needed. This is important not only to the health of cattle, but also to the health of people. The water problem is a major one in the area. A temporary solution could be to collect rainwater from hard roofs into big drums. This is only a solution during the rainy season and probably the roof areas for water collection are too small to obtain considerable amounts of water. However, for the calves this source of clean water during the time they are confined could be of major significance.

Calves are weaned naturally at around one year old. Earlier weaning could lower the pressure on the cow and she would regain lost weight quicker and calving interval would be shortened. It is very important that the calf is capable of ruminating and thereby able to fully utilise the available fodder at the time of weaning. The earlier that rumen activity is initiated the earlier the calf will be able to consume and utilise substantial amounts of standing hay and maize stovers. However, supplies of better quality fodder must also be secured. Early development of rumen activity can be assured by supplementing the calf with concentrates. A concentrate feed is a parasite free fodder which is of great importance to the young calf which do not yet possess any immunity against parasites. Supplementation will also have a positive effect on growth and health and calves will reach sexual maturity earlier, thus lowering the age at first calving.

To make full use of the few bulls in the area it is very important that the farmers know how to detect heat in cows. Heat detection is made difficult by the fact that the oestrus period is very short and often at night due to the high temperatures. If no bull is present in the pen, oestrus may pass without mating. Once heat is detected the cow and bull should be brought together as quickly as possible. More information to the farmers on this subject is needed and also some practical training would be useful to make the farmers more aware of the problem and to help them develop their skills.

Experiences in this trial to be considered in the future

The Danida-financed co-operation between the University of Zimbabwe, the Royal Veterinary and Agricultural University, Denmark and the Danish Institute of Agricultural Research has been conducting research in the Sanyati communal area for 6 years. The research has mainly concentrated on production of feeds, feed evaluation and feeding of cattle. The procedure has been to involve the farmers by having them respond to questionnaires, providing the land for production and testing of fodder crops and by making their animals available for the researchers.

This study was originally planned to investigate the effect of supplementing the cows and calves on weight gain, milk production and parasite load. For many reasons this supplementation was not successful. One of the major constraints was that farmers had to bring their cattle to a common feeding pen at an average distance of 4 km from the villages. Farmers did not have the time or the will to walk this far every day. Hence most cows were only brought to the feeding pen 1-2 days a week. For future trials it will be advantageous or necessary to bring the feed to the farmers and feed the cows at home. The reason for not doing this was that the farmers might misuse the experimental fodder and allot it to other animals. This is a risk but if the farmers are not in agreement that the planned research is an opportunity for them to improve production, they should not be included in the experiments. If the farmers are not able to record what needs to be recorded, then a technician must visit the farmers to assist in recording. When it comes to weight gain it may be necessary to bring the animals to a central point because it is difficult to transport a heavy weigh scale, but such measures are not needed so often.

In general, it is very important to coordinate the research work with the farmers. Good communication is of overall importance, and in this way many problems can be avoided. If an additional workload is put on the farmers during the very busy times of year, they are unable to cooperate. A situation like the one in Sanyati in late November, where no one had time to bring their animals to the feeding point because of much field work, should be foreseen and solved.

An example of the research not being in accordance with the farmers' priorities is that, although the objective was to supplement the cows, for a certain period the farmers were allowed to bring their steers for supplementation. It worked - the farmers gladly brought their steers for supplementation and in this period more steers than cows were supplemented. This indicates that the supplementation, from a farmer's point of view, was proposed for the wrong group of animals. The effects of supplementing the cows are long term whereas the effects of supplementing the steers can be seen right away. Their draught ability will improved and more land can be cultivated (Francis and Ndlovu 1995). Cropping the land gives a direct income in form of cash and this is much appreciated. It is harder to see the relation between supplementation and increased fertility and milk production because these are long term effects. Hence supplementation of steers must be considered since these animals are of great importance to the crop production.

For the present study the role of the research technicians was of indescribable value. They live in the area and are close to the farmers in their everyday life. Thus they are accepted and very trusted by the farmers. The researchers need in the same way to trust and understand the farmers to be able to carry out fruitful research from which results are going to be applied by the farmers.

Conclusions

Poor nutrition and deficient management are the major constraints to cattle production in the Sanyati farming system and must be improved if milk production and calf growth rates are to be increased. This study has shown there is a wide individual variation in production within the local cattle population. There are cows with significantly higher milk yields than average; there are cows with constantly low or zero nematode egg counts; and there are calves with very high growth rates. As these animals have not been exposed to widely different feeding and management, a significant part of this variation must be of genetic origin. Thus selection should be carried out among these animals and they should be used to build up better performing herds. Improvement of production traits such as milk yield and growth rate should be done by selecting among the indigenous cattle rather than importing exotic breeding animals or using imported semen from such breeds.

Since supplementary feeds are only available in limited amounts or are costly to buy it is very important to obtain information as to which group/groups of animals respond best to supplementation. The farmers' priority for draught animals is higher than that for dairy cows. As long as there is a shortage of draught animals in the area improved milk production will not be interesting from a farmer's point of view.

There are opportunities for several improvements in the existing feeding and management system. Cultivation of legumes would increase nitrogen content of the pasture and thus improve utilisation of the pasture. Hay and silage making could contribute to a better dry season diet of the cattle. Browsing possibilities should be extended. Utilisation of maize stovers could be increased by giving the cattle access to urea-molasses blocks. Detection of heat should be a common practice and farmers should consider whether their milk offtake for consumption in the household may be too high and therefore detrimental to calf growth. These potential improvements could all contribute to an increase of the cattle production. Animals would be in a better condition throughout the year which means that steers would provide more draught power, the fertility and milk production of cows would increase, growth rate of calves would increase, mortality would decrease and the overall result would be more animals. Hence the problem with a shortage of draught power would be eliminated.

The opportunities seen by the researchers may not be the same as the opportunities seen by the farmers, or they do not attach priorities in the same order. It is of paramount importance that the topics taken up by the researchers relate to the priorities recognised by the farmers. If this is not the case then the research may better be conducted on-station.

Acknowledgements

The authors are grateful to Mr C Mutisi and the Department of Animal Science, University of Zimbabwe (UZ) for their practical and skilled assistance. The Veterinary Department at UZ receives our thanks for their technical assistance and also many thanks to The Danish Foreign Ministry for financial support to the research co-operation.

References

Received 23 January 1998

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