(I) This is the fusion of the male sex cell or gamete (sperm) and the female sex cell or gamete (ovum or egg).
(Ii) It occurs in the oviduct or fallopian tube.
(iii) It finally leads to the formation of zygote.
(iv) It may occur when an animal is on heat period.
This is the period during which the female animal releases milk from its udder immediately after parturition and thereafter.
The milk is used to feed the young ones.
It is under the control of hormones, i.e., bdecrease in progesterone and an increase in oestrogen and oxytocin.
Lactation or milk let-down can be increased, or if the female animal refuses to produce milk, the animal can be injected with oxytocin injection. This injection will make the animal to secrete milk.
Lactation can also be stimulated by the presence of the young ones, presence of the milker, the use of hand to rub the udder and use of machine (milking machine) to milk the cow. Of all the farm animals, milk from goat is the richest and the best.
Structure of Mammary Gland (Udder): The mammary gland or udder is a large and succulent organ surrounded by the skin. It is attached to the body of the animal by strong ligament. It is made up of large ducts which empty their content into a large gland cistern. It terminates with an alveoli from where milk is secreted. The contraction of the alveoli leads to the letting down of milk.
Structure of mammary gland
The mammary gland is made up of smooth muscles, sympathetic and sensory nerves. The number of glands varies with farm animals. For example:
The major equipment or instrument used in extracting milk from the mammary glands of farm animals is the milking machine.
Function/Use: Milking machines are used for milking or extracting fresh milk mechanically from the udder of cattle (cow) and other milk producing animals like sheep (ewe) and goat doe).
Description: The milking machine is made up of an electric motor, vacuum pump, source of power, trap pail, vacuum controller, guage, gap, milk tank and four teat cups.
How the machine works: The milk is removed from the teat when the vacuum is applied to the outside of the teat cup liner. When the teat cup liner collapses, the teat is massaged and this action helps to prevent congestion in the teat walls and ensures regular flow of milk from the udder into the teat cups.
Milking machines are more efficient. They save labour, stop the cow from becoming strippers and reduce the danger of contamination. The quality of milk obtained depends on the care taken in cleaning and operating the machine.
Substance extracted by milking machine: The main substance that is extracted by the milking machine from farm animals like cow, ewe and goat is milk. The process by which the substance (milk) collected with the milking machine is made fit for human consumption is called pasteurisation.
Economic Importance of Milk
It is a source of protein in food.
It can be used in raising foster calves, lambs or children.
It is used in the preparation of baby food.
It supplies minerals to livlivestock
It is used as an extender in artificial insemination practices.
It is also used in the preparation of dairy products such as butter, cheese and yoghurt.
(i) Colostrum is the first milk produced for immediately after the parturition/delivery of the new born animal.
(ii) In the first five days of milk production what is essentially produced is colostrum which all young ones must have access to.
(iii) It is the yellowish white milk, produced immediately after giving birth to young ones. (iv) It is very important for the new born animal to take colostrum because:
(a) It contains some antibodies against diseases to which the mother has been exposed.
(b) It enables the new born to get immunity to diseases.
(c) It is rich in protein, especially albumin and globulins.
(d) It also contains vitamins A, E and B2 moves (riboflavin).
e) It is highly digestible and has a laxatic effect which helps the young ones to expel the foetal dung (an indication of functioning of the digestive system).
Flushing in animal production refers to the condition in which extra feeds that are rich in nutrients are increased and given to female animals called breeders, especially some days before mating. The aim of flushing is to enable the female animals to produce more eggs or ova and consequently more number of fertilised eggs or ova or large litters or young offspring.
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