Hormones and Artificial Insemination

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Hormones and Artificial Insemination
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Homework

• Make a poster summarising the key points of
  reproduction in farm mammals.

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Hormones

• The reproductive cycle is controlled by hormones.
• The female hormone is called oestrogen and
  triggers the release of eggs from the ovary.
• Sheep produce more oestrogen when the days get
  shorter so the lambs are born in spring.
• Cattle and pigs come into heat when a male is
  nearby and they can smell his pheromones.
• Hens release eggs as the days get longer in the
  spring.

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Male Hormones

• The male hormone is called testosterone.
• Testosterone is produced by the testes and gives
  the male characteristics.
• Males being kept for meat are sometimes
  castrated. This helps the male grow better and be
  less aggressive.
• Sheep farmers can put a sponge containing
  testosterone in the ewes vulva. This stops them
  coming into heat. When the sponges are removed
  all the flock comes into season at the same time.
  Why is this a good thing for the farmer?

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Problems With Keeping Bulls

• Dangerous
• Expensive to buy and keep
• Can lead to inbreeding
• Does not allow other breeds to be sired eg.dairy
  cows producing beef calves

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Artificial insemination

• This is the process where the males sperm is put
  into the females body with out the act of
  mating. It has a number of advantages and
  disadvantages.

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• AI means the farmer can select ________ that he
  wants from the bull in the catalogue. It enables
  sperm to be used more economically since the
  _________ of one bull could father 250 calves.
  Sperm is also easier to freeze, _____ and
  ________ than a bull and the farmer doesnt have
  the danger and _________ of a bull on the farm.
  The farmer can also use a number of different
  ______ of cattle.
• Words to use breeds, transport, ejaculate,
  characteristics, store, workload.

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• The disadvantages are that the farmer must know
  when the cow is on _____ and it is not suitable
  for animals that are not inspected regularly to
  check if they are in ______ e.g. _________.
• Words to use oestrus, heat, sheep.