Page 260 - Agriculture_Form_Three

Agriculture for Secondary Schools

neighbours. This will enable you to continue improving your herd by getting quality
kids/lambs that can be reared for the next stock. When a doe/ewe on heat is exposed
to a fertile buck/ram, mating will occur and the doe/ewe may conceive. Pregnancy
in goats/sheep (gestation period) lasts for about 147 - 153 days (about 5 months)
after which the doe/ewe will give birth. For goats, kidding may produce a single kid
or twins, but lambing normally produces a single lamb.

Pigs: Management of breeding sow/gilt will depend on which method you want to
use. In this part, we shall focus on the oestrus cycle of the pig to allow successful
mating. The oestrus cycle of a pig is normally 21 days. The standing heat period
lasts for 40 - 60 hours, during which the sow/gilt should be mated. There are three
methods used for mating:
(a) Pen mating involves a boar and females penned together and mating occurs
randomly.
(b) Hand mating involves bringing a female animal to a male animal for breeding.
In this system of mating, the female is normally mated two to three times during
oestrus.
(c) Artificial Insemination (AI) means depositing semen from male animal to a
vagina of a female animal for fertilisation by using artificial means.
The process of mating may be repeated after 21 days in case the sow/gilt did not
get pregnant. The gestation period for a sow is 112 - 116 days. During farrowing,
the sow is normally restless. A sow should be moved to a farrowing crate one week
before the time for farrowing. If the sow is raised on a concrete floor, it is important
to administer iron to the piglets to prevent piglet anaemia. Iron is supplied either by
using clean soil or oral supplementation of iron to each piglet. It can also be done by
smearing the sow teats with ferrous sulphate or by intramuscular injection of iron
dextran.

Rabbits: The acceptable practice in breeding of rabbits is to move the doe to the
hutch/cage of the buck for mating. Mating is done once and the doe is taken back to
its hutch/cage. In rabbits, the release of eggs in female rabbits is triggered by sexual
stimulation. It does not have regular oestrus cycle as other mammals. The rabbit
has a cycle of mating receptivity. They are receptive to mating about every 14 - 16
days. A doe is most receptive when the vagina is red and moist. Pregnancy lasts
for about 31 - 33 days. Does with a small litter (usually four or fewer kits/kittens)
seem to have longer pregnancies than those that produce larger litters. Occasionally,
pregnant does abort or reabsorb the foetuses because of nutritional deficiencies or
diseases. Nest boxes should be provided to the cage at 21 days after mating to allow
the female rabbit to prepare the nest before kindling. A day or so before giving birth,

Student’s Book Form Twos Book Form Three
Student’
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