Environmental Engineering Reference
In-Depth Information
Breeding stock
The two main sources of breeding stocks in Ghana are:
•
animals caught in the wild, using various traps such as metal cages, and con-
cealed dugout holes in grass-covered areas with or without ammonia (urine)
fumes as an attractant
•
the progeny of already domesticated animals from the few approved
grasscutter-raising farms in Ghana, and some breeding animals imported
from Benin, where grasscutter production is well developed (Annan and
Weidinger, 2001).
The use of breeding animals caught in the wild has proved less efficient
because the catches as well as the quality of animal(s) are not guaranteed. The
captured animals are traumatized, thereby increasing the mortality rate during
the first few days after capture. Again, farmers experience a lot of difficulty in
trapping the animals with metal cages because the grasscutters recognize the
cages as traps and avoid them. The animals will only venture into very old
worn-out cages, which appear abandoned. Furthermore, in the first few days of
captivity the animals caught from the wild tend to throw themselves against
the restraining walls of their pens in a bid to bolt, which leads to injuries and
a high initial mortality rate.
Where breeding animals are obtained from grasscutter farms, there is the added
advantage of the opportunity to select the breeding stock.
Guidelines used for selecting breeding stock include characteristics like tem-
perament, fertility, litter size, growth rate, and vitality. Selected breeding stock
must be free of any abnormalities and deformities.
Sexing and sex ratio
Grasscutter producers recommend a breeding male:female ratio of 1:4-9. To
distinguish between the male and female the following characteristics are used:
•
head shape and size: the mature male has a bigger head than the female
•
ano-genital distance: the distance from the anus to the clitoris in the female is
considerably shorter (7 mm) than the distance from the anus to the penis in the
male (20-30 mm)
•
red/yellow patch occurs around the genital area of the male.
Handling
For sexing or other purposes, grasscutters are handled with a great deal of caution
to avoid attack with their powerful incisors, or with the claws on their hind legs.
The recommended methods of handling are holding the tail, the neck (scruff), the
rump (waist), and the backbone.
