 |  | Better Farming Series 11- Cattle Breeding (FAO - INADES, 1977, 63 p.) | |||
 |  | How cattle reproduce | |||
|  | (introduction...) | |||
| | The reproductive systems | |||
| | Pregnancy and birth | |||
| | Age of breeding animals | |||
| | Castrating bulls | |||
| | Choosing breeding animals | |||
| | How to know your herd | |||
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· We shall now study how cattle reproduce.
It is very important to study this, in order to improve cattle breeding.
When you have a good knowledge of how cattle reproduce, you can make a good choice of breeding animals, and of the right time for breeding. Then you will get bigger animals, animals that grow faster and are stronger, that produce more milk, meat and work.
· To understand how animals reproduce, the reproductive organs of the females and males must be studied.
We have already studied the digestive system, in order to understand digestion and to know how to feed animals.
We shall now study the reproductive system of the cow and bull, in order to understand reproduction and to know how to improve the herd.
· The reproductive system of the cow
The reproductive organs of the cow are all inside the animal.
You can see only the entry to the system which is called the vulva.
Genital organs of the cow; genital
organs removed from the cow
Flowers have ovaries which contain ovules (see Booklet No. 3, pages 7 and 11).
When the ovules are fertilized by pollen, the ovules become seeds.
The cow has two ovaries. Every three weeks the ovaries produce an ovum. {In animals, the female reproductive cell is called ovum, plural ova).
If the cow is served by the bull at this time, the ovum is fertilized. It develops and becomes a calf.
· The reproductive system of the bull
This system consists of:
· two testicles which hang
between the hind legs;
· the penis;
· two ducts which connect the testicles with the penis.
Reproductive organs of the bull
Stamens give the pollen that fertilizes the ovule in a flower (see Booklet No. 3, page 10).
Testicles give the semen that fertilizes the ovum.
The fertilized ovum becomes a calf.
· When a cow carries a calf in its womb, we say she is pregnant. Pregnancy begins with fertilization and ends with the birth of the calf. It lasts about 9 months.
When a cow gives birth to a calf, it is called calving.
· If the cow has already had a calf, she must not feed this calf more than 5 or 6 months after the new fertilization. The calf she is carrying needs more food. The cow cannot feed the calf in the womb and give milk at the same time.
· Some days before the birth, the cow's udder swells.
At the time of birth, part of the membranes which cover the calf in the womb comes out. These membranes contain water. Next you see the legs of the calf come out, either the two forelegs or the two hind legs.
Sometimes it is necessary to pull downward a little on the calf's legs, to help the birth.
After the calf has come out, if the umbilical cord still joins the calf to the cow, cut it and clean it well. You can use a little iodized alcohol.
After the birth, the rest of the membranes come out. All the membranes must come out. Otherwise they may rot inside the cow and cause her to die.
At birth the calf may come out in
two ways
When the calf is born, the cow rubs it with her tongue. She licks it. Let the cow lick her calf.
At this time the cow is often thirsty. Give her water to drink. During the first few days after the birth, the mother's milk is thick and yellow. The calf must drink this milk which will clean its digestive tract.
Take great care of calves. They are delicate. They easily catch parasites. To protect them, give them a medicine to get rid of internal worms at the age of 3 weeks and of 10 weeks. They easily catch diseases. To protect them, have them vaccinated.
At 3 weeks, the calf begins to eat grass with a little cooked cassava.
Look after young calves well. Feed them well, give them good housing. If you do not, they may die and you will lose a lot of money.
Heifers
The ovaries begin to produce ova (see page 42) when a heifer is 9 or 10 months old. From that time, heifers can be fertilized.
But do not have a heifer served by a bull when she is too young. The heifer cannot go on growing herself and feed the calf she is carrying. In fact you may have accidents when the calf is born, at calving.
So wait until the heifer is big and strong enough, until she is about 2 years (24 months) old, before having her served.
The bull
The testicles of young bulls begin to produce semen when the bulls are about 8 months old.
But do not have cows served by too young a bull. The bull will get tired, will not grow well, will not eat well and will become a poor breeding animal. Do not have the bull serve cows before it is 18 months old.
To make sure that heifers are not fertilized too young, and that bulls do not serve cows before the age of 18 months, do not put heifers that are too young together with bulls, or bulls that are too young with cows.
A herd of 25 cows needs only one good bull, a good breeding animal. The other males in the herd must be castrated.
A castrated male is called an ox or bullock.
· How to castrate a bull
Either remove the testicles (see page 43) or crush the ducts which connect the testicles to the penis. The animal husbandry service and the livestock assistants have instruments for castrating bulls.
· Why castrate bulls?
After castration bulls are quieter, they are not vicious, and it is easier to harness them. They put on weight more quickly, the meat is better. They cannot fertilize the cows; in this way you prevent poor breeding animals from reproducing, and can leave them in the herd.
· At what age should bulls be castrated?
At about 10 months if you want to sell them to the butcher.
At about 18 months if you want to make working oxen.
If you wait until 18 months, the ox is stronger for work, but in that case it must be kept away from the herd, so that it cannot cover the cows.
Bulls and cows must be carefully chosen because the calves take after their parents.
· Cows that give a lot of milk usually produce females that will also give a lot of milk. This quality is passed on from mother to daughter.
Cows that grow and put on weight quickly usually produce males and females that will grow and gain weight quickly. This good quality is passed on from the mother to her calves.
· Bulls that grow and gain weight quickly, that have well developed bones and muscles, that are not vicious, usually produce calves that grow and gain weight quickly, that hew well developed bones and muscles, and are not vicious. Calves often have the good qualities of the bulls.
Bulls born from a cow that gave a lot of milk often produce females that will also have a lot of milk. The good qualities of the bull's mother are often passed on to the bull's daughter.
Choose breeding animals
· that are well formed.
Sell all poorly developed animals.
Keep animals with plenty of muscle, especially of the back and rump, because they give the best meat. This quality will be passed on to the calf.
· that gain weight
quickly.
· that are resistant to disease.
If a cow has little resistance to sleeping sickness (see page 36) her calf will also have little resistance.
· that give plenty of milk.
Such cows can easily feed their calves.
You can also milk the cow and drink the milk or sell it.
The good qualities of the bull and the cow are often passed on to their calves.
The bad qualities of the bull and the cow are also passed on to their calves. So it is very important to make a good choice of bull and cows.
It is easier to improve the herd by a good choice of bull. A cow passes on her good qualities to only one calf each year. A bull passes on his qualities to all the calves of the herd,
We have seen how important it is to make a good choice of breeding animals.
In modern animal husbandry we look for breeding animals of good quality.
But we also look for animals from parents and grandparents that were of good quality.
The family qualities are passed on to the young. This is what we mean by selection.
Modern farmers keep a herd book.
Give a number to each animal in the herd.
This number is the animal's name.
Mark the number on the animal's rump, for instance, by branding.
Use a double page of the book for each animal.
Write in the book everything you need to know about your animals (see Booklet No. 9, pages 22- 24).
RECORD OF A FEMALE
No. of animal Year of birth
No. of sire No. of dam
SERVICE
1st
No. of sire
........................................................
Date of service
.................................................................
No. of
offspring ...............................................................
No.
of deaths before weaning ..........................................
2nd
No. of sire
.............................................................................
Date
of service .................................................................
3rd
4th
5th
Feed
Production (milk, weight)
Vaccinations and
disease
Remarks
Two pages of the herd book which records each female in the herd.
RECORD OF A MALE
No. of animal Year of birth
No. of sire No. of dam
SERVICE
No. of female Date
1st
............................................
2nd
............................................
3rd
............................................
4th
............................................
5th
............................................
6th
............................................
7th
............................................
First of two pages of herd book in which each male is recorded. The second page is the same as for females (see preceding page).
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