Page 106 - Agriculture Form Two

Agriculture for Secondary Schools

Growth and maturity in farm animal

A newly born animal grows, increases in size, and develops various body
organs and systems to an age when it is said to be sexually mature. At this age,
it is said to have reached puberty, and under normal health conditions, it starts
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producing ova (for females) or sperms (for males). The reproductive cycle is a
natural mechanism by which a mature animal undergoes the reproductive and
non-reproductive phases. In mammals, the reproductive phase is also termed the
oestrus cycle. It is divided into four stages: proestrus, oestrus, metestrus, and
dioestrus, Tables 6.1 and 6.2 provide some details on the reproductive cycles,
heat duration, ovulation, and gestation periods for various classes of livestock.

Table 6.1: Age at puberty for some farm animals

Animal species Age at The gestation Name of Act of
puberty period (average offspring giving
(months) days)
birth
Cattle 10-18 281 Calf Calving
Sheep 5-7 150 Lamb Lambing

Goat 5-7 151 Kid Kidding
Rabbit 4-6 30 Kitten Kindling

Chicken 5-6 (varies Brooding time 21 Chick Hatching
with breed) days

Table 6.2: Lengths and duration of oestrus and time of ovulation in livestock

Animal species Length of cycle Duration of oestrus Time of
(average days) (average hours) ovulation
(hours)
Cattle (cows) 20 16-24 10-14 after the
onset of oestrus
Sheep (ewes) 16 30 1 before the end
of the heat
Goat (does) 20 36-48 Near the end of
the heat

98 Student’s Book Form Two

04/10/2024 18:07
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Agriculture form 2.indd 98