- Productive and reproductive performance of Namaqua Afrikaner sheep
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PRODUCTIVE AND REPRODUCTIVE PERFORMANCE OF NAMAQUA AFRIKANER SHEEP
Margaretha A. Snyman, J.J. Olivier
Grootfontein Agricultural Development Institute, Middelburg CP, 5900
Carnarvon Experimental Station, P.O. Box 98, Carnarvon, 7060
The Namaqua Afrikaner and the Ronderib Afrikaner are the two oldest indigenous sheep breeds in South Africa. It is believed that the Namaqua Afrikaner has descended from the fat-tailed sheep kept by the Hottentots in the extensive areas of the northwestern part of the Republic of South Africa. These areas are characterised by extremes in temperatures and a low and erratic rainfall of less than 125 mm annually (Epstein, 1971). The breed is renowned for its hardiness under extreme environmental conditions and its ability to travel long distances in search of food (Van Rensburg, 1937).
The Namaqua is a lanky, high-standing sheep with a relatively narrow body, long, lean legs and a fat-tail in which up to 38 % of its body fat can be stored. Owing to their lanky body build, Namaqua lambs lack the conformation of other mutton breeds. This, as well as the fact that most of the subcutaneous fat is stored in the fat-tail, with a comparatively thin layer of fat spread over the rest of the body, is the reason why the Namaqua is not favoured for slaughter lamb production.
There is a dearth of published information on the productive and reproductive performance of Namaqua Afrikaner sheep. The data that were collected on two Namaqua Afrikaner flocks kept by the Department of Agriculture were analysed to provide such information.
A Namaqua Afrikaner carcass showing the fat tail
The fat tails of the Namaqua Afrikaner clearly seen here
Namaqua Afrikaner rams
MATERIALS AND METHODS
Location of the study
The largest flock of Namaqua Afrikaners found in the Republic of South Africa is kept by the Department of Agriculture at the Carnarvon Experimental Station in the northwestern Karoo. Carnarvon receives an annual rainfall of 211 mm, which occurs mainly during the autumn months. The veld type is described by Acocks (1988) as Arid Karoo. The official grazing capacity norm for Carnarvon is 32 ha/LSU. Average minimum and maximum temperatures recorded are 8,2 and 24,0 °C respectively.
The second flock of Namaqua Afrikaners is kept at the Tarka Conservation Area near Hofmeyr in the north- eastern Karoo. The average rainfall of 360 mm per annum occurs mainly during autumn. The spring rainfall at Tarka is much more reliable than at Carnarvon. The veld type at Tarka is a mixture of grass- and shrubveld. The total available fodder production, as well as the distribution thereof during the year, is better than that of Carnarvon, which contributes to the higher grazing capacity of 12 ha/LSU. Average recorded minimum and maximum temperatures are 8,4 and 24,1 °C respectively.
The Namaqua Afrikaner flock at Carnarvon consists of 100 ewes and it is kept for the purposes of (i) the preservation of this unique genetic pool and (ii) the collection of production and reproduction data on this ancient breed.
The flock runs on the veld continuously and no supplementary feed is given at any time. A system of one breeding season per year is followed, with a 34 day mating period during April. The lambs are weaned at 4 months of age. All the lambs are retained till the age of 18 months, when replacement ewes and rams are picked at random. Ewes are replaced at a rate of 20 %, while all the rams are replaced each year. No selection of any kind is carried out. The ewes in the flock are divided into three group~ and they are replaced within each of these groups. The rams are used on a rotational basis between the groups, in an effort to keep the inbreeding level as low as possible.
The Namaqua Afrikaner flock at Tarka consists of 80 ewes. A free mating system, where the rams are run with the ewes throughout the year, is followed. No supplementary feeding is given or any drenching and inoculation programme followed. Once a year replacement rams and ewes are picked at random and the surplus culled. Old ewes are culled when they have virtually no teeth left and start losing condition as a result.
Data collected from the Namaqua Afrikaner flock at Carnarvon were used for the calculation of growth parameters. Data of 1 113 lambs, born from 1982 until 1991, were used. The following traits were analysed: birth mass, 100 day weaning mass, average daily gain from birth to 100 days (ADG: birth-l00 days), 8 and 12 month body mass, average daily gain from 100 days to 12 months (ADG: 100 days-12 months) and 18 month body mass.
The data were analysed by means of Least-squares mean methods (Harvey, 1990) and the following fixed effects were included in the linear model fitted to the data, namely year of birth, sex and birth status of the lamb, age of dam, group, and all significant two-factor interactions.
The data used for the calculation of the reproductive performance of the Carnarvon Namaqua flock consist of 11113 ewe records, which were collected over an 11-year period (1982-1992).
Available data, which were collected on the Tarka Namaqua flock over a 7-year period (1986-1992), were used to calculate the following:
- Age at first and subsequent lambings
- Mating mass at first and subsequent lambings
- Lambing interval between successive lambings
RESULTS AND DISCUSSION
The average growth traits for the Namaqua rams and ewes at Carnarvon are presented in Table 1.
From Table 1 it is clear that Namaqua lambs have the ability of maintaining a high preweaning growth rate under extensive farming conditions. In addition, these results emphasise the excellent ability of Namaqua ewes to rear their lambs under harsh environmental conditions.
The averages recorded for the various preweaning traits of the Namaqua compare favourably with data recorded on Carnarvon for other sheep breeds, namely the Afrino (Badenhorst, 1989; Snyman et al., 1993), Dorper (Badenhorst et al., 1992) and Merino (Snyman, 1993). The relatively low body mass recorded at 12 and 18 months of age, suggests that the ewes have a low maintenance requirement. They should therefore be better able to produce and survive under adverse conditions than other large-framed breeds.
From Table 1 it is also clear that ram lambs are heavier than ewe lambs at birth, and that they remain heavier throughout their lives. Because the ram lambs also have a higher pre- and postweaning growth rate, this difference becomes greater with age. The difference in body mass between ram and ewe lambs at various ages was 0,28 kg at birth, 1,35 kg at 100 days, 2,51 kg at 8 months, 7,95 kg at 12 months and 8,31 kg at 18 months of age.
Reproductive performance of the Namaqua ewes at Carnarvon over a period of 11 years (198~-1992) is presented in Table 2.
The results given for the Namaqua in Table 2 compare favourably with those recorded for Merinos (Snyman et al., 1993) and Dorpers (Badenhorst et al., 1992) kept under similar conditions at Carnarvon.
Results on the average age of first and subsequent lambings, mating mass and lambing intervals, which were recorded on the Tarka Namaqua flock, are presented in Table 3.
The ewes in this flock appeared to have settled into a 8 to 9 month lambing cycle, regardless of season. From these results it is apparent that Namaqua ewes can be mated successfully throughout the year, and because of their average lambing interval of approximately 9 months, they are ideally suited for multiple lambing systems, especially in the less extensive areas of Southern Africa. Furthermore, Namaqua ewes can be mated successfully at an early age, as is evident from the fact that they produce their first lambs at the age of 16,5 months (Table 3), which suggests that they had conceived at 11,5 months.
In respect of production parameters the Namaqua compares favourably with other South African sheep breeds. The Namaqua is a very hardy and prolific breed, as is evident from the relatively high reproductive performance recorded under extensive conditions. From these results it is clear that Namaqua ewes can be mated successfully at an early age, as well as throughout the year.
The authors appreciate the assistance of Mr B.R. King in the recording of data on the Tarka Namaqua Afrikaner flock.
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Karoo Agric 5(2) : 21-24