- Focus on research at the Jansenville experimental farm
|Last update: September 2, 2011 02:24:44 PM|
Focus on research at the Jansenville experimental farm
PD Grobbelaar & FC Hayward
SEVERAL research projects in which further investigation is being undertaken into, among others, production and fleece characteristics, supplementary feeding, stocking rates as well as internal and external parasites in Angora goats under extensive farming conditions in the Noorsveld, are at present in progress on the experimental farm at Jansenville. Preliminary research findings in respect of three of these studies are not only interesting, but also of importance to producers. For this reason a short report on the most significant findings is being published, even at this early stage.
The effect of age on the production and fleece characteristics of Angora goats.
In a study in which ewes, wethers and rams have been kept continuously for 93 months on succulent mountain shrub pasture, it has been found that production and fleece characteristics were influenced by age as follows:
Body mass: In contrast to wethers in which mass continued to increase slowly, the body mass of ewes and rams stabilized at the age of approximately 60 months.
Hair production: In agreement with previous research findings it appears that hair production gradually increases with age, reaching maximum production at the age of 3 to 4 years, after which it begins to decline.
Fibre diameter: Surprisingly, and contrary to the general belief that fibre diameter increases progressively with increasing age, it appears that maximum fibre diameter was reached by all three groups between the ages of 48 to 60 months, after which it gradually declined. This tendency can possibly be ascribed to changing conditions at this stage, but continued research should provide greater clarity.
Kemp: The occurrence of kemp was slight in all three groups (table 1) and only in the case of rams did it show a fractional increase with age.
The effect of strategic supplementation with chocolate mealies on production and fleece characteristics in Angora goats.
The effect of 3 levels of energy supplementation (0, 300 and 600 g chocolate mealies per ewe per day), strategically provided for a period of from two weeks before mating until the end of a mating period of 6 weeks and again during the last four weeks of pregnancy to the end of a 12-week lactation period, on the production, reproduction and hair characteristics of Angora ewes and their kids on Noorsveld grazing was determined. For this purpose 150 ewes were divided into three equal groups of 50 and a grazing intensity of 1,7 ha per goat was maintained.
The body mass and hair production data of the ewes in the three groups at various shearing times is shown in table 2 while that of kids is given in table 3.
It appears that strategic energy supplementation with chocolate mealies only has a slight, insignificant effect on the production and hair characteristics of Angora goat ewes. Pregnancy and lactation on the other hand each had a substantial effect on both clean yield and fibre diameter in all three groups. For example the ewes produced 0,4 and 0,2 kg less hair respectively during pregnancy and lactation, while the average fibre diameter measurement declined by approximately 1 micron during lactation.
In contrast with this, energy supplementation of ewes had a significant and extremely beneficial effect on their kids. The kids belonging to ewes on the high level of chocolate mealies (600 g per ewe/day) were on average 3,2 kg heavier than those in the control group and they produced almost 20 per cent more hair on a clean basis at first shearing.
Pregnant Angora ewes apparently benefit very little from supplementation with chocolate mealies, but the kids they produce draw the benefits.
Optimal energy supplementation of chopped noors for Angora goats.
Chopped noors was supplemented with five levels of chocolate mealies (0, 200, 300, 400 and 500 g per goat per day) in order to determine the energy supplementation level required to provide for an animal's maintenance requirement for survival in drought conditions, for example.
Noors has a moisture content of about 90 per cent and is very bulky. The intake of dry material is consequently very low and varied between 170 and 340 g per goat per day. By first drying and then milling the noors before feeding it to animals at the rate of 450 to 890 g per goat per day, it is possible to increase the dry material intake almost threefold. Nevertheless animals that only received milled noors lost weight very quickly, up to as much as 43 per cent of their original mass over a 4-month period. Hair production declined at the same time from approximately 2 kg for the preceding 4-month period to 0,69 kg for the 4 months on noors.
Preliminary results indicate that by supplementing noors with 200 g of chocolate mealies, body mass is maintained and this diet will probably be capable of providing the maintenance requirements of a 35 kg Angora goat.
Angora goat and mohair journal 29 (1)