Considering Friday is the end of the week, it is one of my busiest action packed days, I am going to try and cover as much as I can from today however. This morning started with the Genetics lecture which today was on genetic disorders, which was pretty cool.
Basically a disease can be a mutation, hereditary (comes from the parents via genes) or environmental where external influences cause it. Now looking at the genetics for a disease to be a mutation something has to go wrong in the transcription or translation stages in the cell cycle. For a disease to be hereditary it must be genetically coded and passed on from the parents, and finaly environmental is where it is caused by outside influences such as heavy metals.
Milk Hygiene today was looking at cream and butter, we did titration tests to calculate the fat percentage in cream which is one of the most basic quality control checks. Then with the butter we attempted to measure the water content in the butter. This test basically involves using the weight and then melting the butter over a flame to evaporate the water before measuring it again. Now this was going fine until the butter caught fire, after putting this out it did leave a rather pleasant smell in the lab, which also spread under the door and down the corridor.
After this and a short break it was time for the genetics practical, todays practical was looking at lethal and semilethal genes. From a genetics perspective a lethal factor causes > 90% mortality, a semilethal factor causes over 50% mortality and a subvital factor is less than 50% mortality. Now these are clasified according to an international standard with each animal species having a letter code:
- A : Cattle
- B : Horse
- C : Pig
- D : Sheep
- I : Goat
The specific disease/gene is then assigned a number, for example A24 is hydrocephalus where there is excessive accumulation of fluid within the brain causing an enlarged head and the animal being stillborn or dying within a couple of days.
Understanding how these diseases are linked to genetics is especially crucial when it comes to breeding males. This is because with the use of artifical insemination a single male may father 100’s of animals, ensuring that only genetically healthy males are used for semen it prevents the suffering of other animals. Today has been pretty gruesome with some of the images seen, and looking at genetic disorders. It has however been extremely useful as this knowledge is essential when it comes to breeding.