As part of last week’s study guide, author Joe Corroon asked students three questions in relation to the topic covered, please find answers below:


Q1. Give three reasons why pendulous udders are undesirable?

Answer: Pendulous udders are more prone to mastitis (being closer to the ground) and injuries. There can be difficulties putting on the clusters at milking.

Q2. Why are teats sprayed with iodine? When/ where else is iodine used on the farm?


  • The teat canal can remain open for 30 mins or more after milking. Iodine is sprayed on the teats to prevent infection entering during this time.
  • Iodine is used to disinfect the naval of newly born animals. This prevents them from getting infected, which may cause naval ill or joint ill.
  • Iodine can also be used as a disinfectant on cuts or wounds. Vets use it to disinfect an area before surgery, eg, caesarean section.
  • Q3. What is the physiology of milk let-down?

    Answer: The cow receives an external physical stimulus (sight, sound, smell of her calf). This sends a signal to the brain via nerves. The Pituitary gland in the brain releases Oxytocin into the blood. This reaches the udder and squeezes the milk out of the ducts into the gland cistern. When the calf suckles or the clusters put on, the cow relaxes the muscle at the end of the teat canal and allows milk let-down.

    If you have any questions in relation to the content covered in the agricultural science study guides, feel free to email your questions to