Dairy Cattle Breeding & Selection (1)

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Dairy Cattle Breeding Selection
A cow is a very good animal in the field,
but we turn her out of a garden
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Reproduction Endocrinology

• The inter-relationship between
• the Endocrine system
• and the Nervous system.
• The origin and function
• of the major hormones involved with
• reproduction.

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Look at the Two systems

• Endocrine System
• It Causes slower and longer lasting changes
  within the body.
• Examples
• 1) Growth
• 2) Reproduction
• 3) Lactation
• 4) Secondary Sex Characteristics

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Look at the Two systems

• Nervous System
• It Causes rapid changes and/or adjustments
  within the body.
• Examples
• 1) Immediate reaction to any kind of stress such
  as
• a) Pain
• b) Fear
• c) Heat
• d) Exertion

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Two systems work together as one system

• 1. Called the Neuroendocrine System.
• a. Referred to this way
• because of the overlapping
• effect each system has on the other.
• b. Example Adrenaline will
• cover up the effects of oxytocin.

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Look at the Two systems

• 1. Hormone Chemicals synthesized from the
  endocrine glands that influence activities of
  other organs within the body.
• Example The ovary produces estrogen,
  progesterone, and relaxin, all of which affect
  the body in different ways.
• 2. Neurohormone Chemicals synthesized in the
  central nervous system (or in the neuron nerve
  cell) that influence activities of other organs
  within the body.
• Example FSH, LH (both produced in the anterior
  pituitary gland) and Oxytocin (produced in the
  posterior pituitary gland)

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Hormone Secretions in the Female are
brought about in two ways.

• A. External effects (Conditions occurring
  outside the body i.e. Environment)
• 1. Temperature changes Extreme heat for
  example will cause the blood to circulate faster.
• 2. Improper handling of cattle causes the system
  to speed up due to adrenaline secretions.
• B. Internal Affect (Conditions occurring inside
  the body i.e. Estrous Cycle)

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Subgroups In Cattles

• Bos Indicus (American by way of India)
• Heat tolerant
• Increased parasite disease tolerance
• Improved production in subtropical climates
• American Influenced
• 2) Bos Taurus (European and British)
• Maternal and(or) terminal breeds
• Positive carcass traits marbling,tenderness,
  yield
• Excellent production in temperate climates

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British Breeds

• Angus
• Hereford
• Polled Hereford
• Shorthorn
• Red Angus

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