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Some experiences in adapting previously free-ranging traditionally managed Matabele goats of Zimbabwe to individual stall-feeding - Essai d'adaptation à l'alimentation individuelle à l'étable de caprins Matabele du Zimbabwe précédemment élevés en plein air suivant le système traditionnel


Summary
Résumé
Introduction
Materials and methods
Results and discussion
Conclusion
Acknowledgements
References

L.M. Sibanda1, L.R. Ndlovu1 and M.J. Bryant2

1Department of Animal Science
University of Zimbabwe
P O Box MP 167, Mt. Pleasant, Harare, Zimbabwe

2 Department of Animal Production
University of Reading
Early Gate, Reading, RG6 2AT, United Kingdom

Summary

One hundred multiparous indigenous does were purchased from communal farmers for on-station trials. At the research site, the goats were confined and zero-grazed. During adaptation, six goats died, 28 aborted, 56 kidded end 10 had no reproduction records. The does lost weight and were afflicted by diseases not previously experienced under the traditional management system. After nine months of adaptation to the station regime, the goats were synchronised for oestrous and mated. Only 74% of the flock conceived and kidded while 19% did not conceive and 7% aborted. Factors considered to be associated with the poor adaptability to stall-feeding of previously freeranging goats are discussed.

Résumé

100 chèvres multipares ont été achetées auprès d'éleveurs communaux pour cette étude. Une fois arrivées sur la station expérimentale, elles ont été confinées et alimentées sans pouvoir avoir accès au pâturage. Au cours des cinq mois qu'a durée la période d'adaptation, elles ont perdu énormément de poids; six d'entre elles vent mortes, 28 ont avorté, 56 ont mis-bas tandis qu'aucun événement important sur le plan de la reproduction n'a été enregistré pour les 10 restantes. Au sixième mois, l'oestrus a été synchronisé chez les 94 chèvres encore vivantes, qui ont ensuite été mises à la lutte (1 bouc pour 10 chévres). Seules 56% d'entre elles ont conçu et mis-bas. Les chèvres précédemment élevées en plein air-c'est connusupportent mal la claustration et l'alimentation à l'étable, mais rien de concret n'a encore été fait pour remédier a ce problème. Il est recommandé que les chercheurs fassent connaître leur experience en la matière pour permettre de mieux cerner le phénomène et d'y remédier.

Introduction

Extensive goat production under the traditional communal grazing system is widely practiced in the semi-arid and arid regions of Africa which sustain 66.7% of the African goat population (FAO, 1984). This system, characterised by shortage of land, poor range management and seasonal fluctuation of feed supply favours mere survival rather than optimum production. Productivity of the goats in these areas can be improved by making more efficient use of the feed resources presently or potentially available to the farmer. To do this will require information on the nutrient quality of the feed as a function of season, the suitable physical form of the feed, the refusal rate and the physiological state and energy balance of the goats to be fed. Studies to generate such information often necessitate stallfeeding of the animals with no access to grazing. Unfortunately, when previously free-ranging goats are confined and stall-fed, they are stressed and may either eat less, lose weight, about (Wentzel, 1987) or even die (Kasowanjete et al, 1986). Many feeding trials are usually prematurely abandoned when goats fail to adapt to stall-feeding and unfortunately most of these futile efforts but nonetheless useful experiences are never reported.

This paper discusses some of the problems experienced during the adaptation to stall-feeding of 100 previously free-ranging indigenous Matabele does.

Materials and methods

Location

The reported work was carried out at the former Thuli Breeding Station which is situated in Matabeleland Province in the south-western part of Zimbabwe. The region is semi-arid. The vegetation is mainly acacia shrub and mopane woodland with species of annual grasses appearing during the rainy months of November to March. Droughts are frequent, consequently herbage quality and quantity fluctuate within and between years. The total amount of rainfall during the study year (1989) was 162 mm. The mean maximum and minimum temperatures were 28°C and 13°C, respectively.

Animals

In May 1989, one hundred multiparous indigenous Matabele goats were bought from communal farmers living within a 20-kilometre radius of the research station. The animals were driven on hoof to the research site. They were eartagged, weighed and their age was determined by counting the number of permanent incisors.

Management of the does during adaptation

On arrival the does were dewormed, dipped and vaccinated against pulpy kidney disease. Thereafter deworming and dipping were repeated on a regular basis.

The animals were housed in groups in a large animal house with concrete floors and partial roofing that allowed adequate ventilation. A forage mixture (two-thirds veld hay and one-third lucerne hay) with a mean crude protein content of 12% and neutral detergent fibre content of 60% was offered ad libitum in raised feeding troughs. Water and a salt mineral blocks were freely available to the animals. As from September 1989 (fourth month of adaptation), all the does were individually offered 100 9 maize grain daily so as to increase energy intake in preparation for breeding on-station. At the end of the fifth month of adaptation (October 1989), the goats were synchronized for oestrous using progesterone-impregnated intravaginal sheep sponges (Veramix 60 mg medroxyprogesterone, Upjohn, UK). The sponges were withdrawn after 14 days and 2 days thereafter, 10 large Matabele bucks, with a mean liveweight of 65 kg, brought in from Matopos Research Station, were introduced to the flock. The bucks continuously ran with the does during the day but were confined separately overnight so that mating records could be kept.

In order to determine pregnancy, blood was collected through the jugular vein 21 days after mating and twice weekly thereafter. The blood was kept at 2°C overnight and allowed to clot. After 24 hours, serum was decanted and stored at -20°C until assayed for progesterone levels using a radio-immunoassay technique developed for goat serum.

All goats were weighed weekly and kept under close observation during the adaptation period. All incidences of diseases and reproduction were recorded.

Results and discussion

The adaptation period was intended to take three weeks but had to be extended to six months due to problems associated with feeding, disease incidences and reproduction.

Feeding

In the first four weeks of adaptation, feed refusals were approximately 60% of the feed offered as goats selected mainly lucerne hay which constituted only 24% of the total dry matter offered. When the forages were ground in an effort to reduce selection, feed refusal rates doubled because the feed was dusty. Low dry-matter intake (below 40% of the expected intake) during the first few months of adaptation is not uncommon in stall-feeding trials involving goats fed forage-based diets (Ademosun et al, 1985). The low feed intake has largely been attributed to the ability of goats to select and ingest the higher quality of diets on offer (Owen and Aboud, 1988). Owen and Aboud (1988) have shown that intake will improve when goats are permitted to reject at least 50% of the feed offered rather than the conventional 10 to 20%.

The reduced feed intake experienced in the first few weeks of adaptation may be the root cause of the observed liveweight losses, diseases and abortions.

Diseases

The most prevalent diseases during adaptation were off (contagious ecthyma), gaseous lymphadenitis, kerato-conjunctivitis (pink eye) and swollen knee joints. In cases of orf, daily swabbing of the lesions with salt solution and gentian violet led to rapid recovery.

In the second month of adaptation (July 1989) there was an outbreak of pink eye disease which spread rapidly amongst the whole herd; treatment with oxytetracycline led to quick recovery. Swollen knee joints were observed in 20 does and all 100 breeding bucks in the second month of adaptation. These swellings were diagnosed as none pathogenic (no antibodies to caprine Arthritis encephalitis virus) and were attributed to lack of exercise due to confinement. The affected goats spontaneously recovered within four weeks.

Diseases encountered during adaptation may have led to the liveweight losses, abortions and acyclicity. In our study, incidences of orf and gaseous lymphadenitis were a lot higher than in normally experienced under the traditional system.

Six does died during the first month on station. Autopsies carried out were test negative for bacteriological and virological pathogens.

Doe liveweight changes

There were (P) differences in mean doe liveweights at buying between the different age groups (Table 1). Mature 8-tooth does were 18% and 35% heavier than the 6- and 4-tooth age groups, respectively. In the first 6 weeks on station all does lost an average 56 g/day. After six months adaptation (November 1989) when the does were mated, doe liveweight differences were smaller although the younger 4-tooth does were still significantly (P) lighter than the 6- and 8-tooth groups which were about equal in weight. As from November (sixth month of adaptation) all does gained weight. The highest gains were in the 4-tooth age group (90 g/day) compared to 53 g/d and 80 g/day for the 6- and 8-tooth groups. These weight gains could be attributed to replenishment of lost body tissue and genuine growth in the immature 4- and 6- teeth groups.

Table 1. Doe liveweights during adaptation to on-station conditions.

Date

Variable record

Age

Number of teeth

Total/Mean

4

6

8

94

May 1989

No. of goats

18

46

30


May 1989

Mean weight at buying (SD)

29.4a

33.7b

39.8b


(397)

(4.83)

(5.22)

34.8

Nov. 1989

Mean weight at mating (SD)

(2.97)

(5.64)

(4.19)


All row values with different superscripts are significantly (P < 0.05) different.
(SD) = standard deviation.

Reproduction

Not withstanding the concerted efforts to avoid buying pregnant females, about 90% of the goats purchased turned out to be pregnant (Figure 1), mostly in the second month of gestation. None of these goats had shown overt pregnancy symptoms when purchased.

During the first three months of adaptation, 30% of the does aborted. The highest number of aborters was in the young 4-tooth age group where almost 1.5 and 8 times more does aborted than in the 6- and 8-tooth age groups, respectively (Figure 1). Specimens from the aborted foetuses and placentae were tested for leptospirosis, contagious abortion, Rift Valley fever and blue tongue. All test results were negative and it was postulated that stress factors (such as a sudden change of environment, rather than disease could have caused the abortions. Based on information available in other ruminants and observations made in goat flocks, Morand-Fehr (1987) has concluded that pregnant goats are very sensitive to various kinds of stress such as rapid variations of environmental conditions, excessive animal density in the goat house, struggles between animals, psychic shock etc.

Figure 1. Reproductive response to breeding on station (April-July 1990).

Hypersensitivity to stress of pregnant goats has been explained by the theory that, unlike other domestic ruminants where both the corpus luteum and the placenta secrete progesterone, pregnancy in goats is sustained by progesterone secretion from the corpus luteum only (Sheldrick et al, 1980).

Intravaginal sponges that were used for oestrus synchronization could not be withdrawn from 10 does. The sponges were eventually pulled out after surgical manipulation of the vagina. Five of the does resumed normal oestrus after three months but the others remained acyclic.

Mating was expected to commence two days after sponge withdrawal but was delayed by 20 days. Reasons for this delay cannot be readily explained. It is possible that the sheep intravaginal sponges used were unsuitable for goats, though other workers have reported successes with progesterone impregnated sheep sponges used on goats (Cameron et al, 1988). Environmental effects such as ambient temperatures could have contributed to the delay of oestrus onset or lack of libido after sponge withdrawal. It has often been stated that goats in the tropics will kid all year round (Wilson et al, 1984; Hale, 1986). However, there are indications of definite peak kidding periods, usually two per year, availability as influenced by rainfall patterns (Hale, 1986). It is possible that the rains also have a cooling effect on cyclic goats which enhances libido. In sheep, it has been shown that a high proportion of mating occurs in the early morning and activity subsides to a low point at midday and increases again in the evening (Blockey and Cummings, 1970). In this study the mean daily temperature was above average (34°C) when the goats were exposed to the bucks and mating only commenced a day after the first rains of the season.

Mating (November 1989) lasted about four weeks and only 50°% (48 goats) of the flock conceived as confirmed by consistently high blood progesterone levels (1 ng/ml). The rest of the flock which did not conceive in November continued to run with the bucks. Twenty eight of the remaining 46 goats were mated in February after which there were no further matings (Figure 2).

Combining the reproductive outcome for matings in November and February (after 6-9 months adaptation to on-station regime), 74% of the original flock purchased managed to conceive and kid, 7% aborted while 19% remained acyclic recording basal blood progesterone levels (<0.3 ng/ml). The number of goats that aborted was far less after nine months (7%) on-station (Figure 2), as compared to 28% (Figure 1) in the second month on-station. Mature 8-teeth does had the best performance with the highest number of goats kidding (96%), the least number of does remaining empty (4%) and no aborters (Figure 2). The abortion rate was higher in the younger 4-tooth does (11%) than in the 6-tooth does (8%) which were 7.6 and 4.2 kg, respectively, does lighter than the mature 8-tooth does at mating. The presence of habitual aborters (does with a long standing poor reproductive history) in the flock cannot be ruled out. It is quite likely some farmers took advantage of the sale to rid themselves of their nonproductive stock. This could also explain barrenness of 10 goats at buying and the failure of the same goats to conceive at mating in November and in February.

The fact that more does conceived when mated in February (increasing the total kidding rate in response to breeding on-station from 46% to 74%) means that given time to adjust a larger proportion of the goats will conceive and kid. Unfortunately this prolonged adaptation greatly inflates the cost of goat research projects as compared to cattle and sheep which usually adapt to stall-feeding in 3 weeks. Unlike cattle and sheep, goats seem to have a lower stress threshold demonstrated by being very sensitive and reacting adversely in an exaggerated manner to stress caused by change of routine.

Figure 2. Reproductive response during adaptation (May-July 1989).

Poor adaptability to stall-feeding of goats previously managed under the traditional system presents serious problems to researchers wishing to carry out feeding trials and to entrepreneurs wishing to rear goats under an intensive feeding system. Kasowanjete et al (1986) lost 428 breeding does within the first 3 years of setting up a goat breeding station in Malawi and attributed the deaths to general adaptation problems. Peters (1989) has reported on-station performance below levels measured on-farm and attributed this poor on-station performance of goats to differences in management systems, reduced feed selection possibilities and higher disease risks.

Conclusion

In our experience, adaptation to on-station regime by indigenous Matabele goats previously managed under the traditional extensive system took more than 6 months. In the first few months, the goats ate very little forage and consequently lost weight. Diseases not previously experienced in the traditional system became a problem on station. Reproductive performance was poor, especially among the younger groups of females, suggesting that adult females have a better chance of adapting to complete confinement.

It seems that numerous environmental factors acting either individually or collectively will impose some degree of stress but our knowledge of the ability of these previously freeranging goats to adapt or adjust to stall-feeding needs to be improved by further long-term research.

Acknowledgements

This work was jointly funded by the University of Zimbabwe Research Board and the International Development Research Centre (IDRC).

References

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