Applied Genetics in Cattle breeding

Question 1

Why is genetics important in cattle breeding?

Answer 1

• Prevention
• Economics
• Cumulative long lasting effects

Question 2

What are quantitative traits we measure and breed for?

Answer 2

• Milk yield
• Muscle growth rate
• most traits of economic interest

Question 3

What affects quantitative traits?

Answer 3

• Genes / genetics
• Environment

Question 4

What does high heritability mean?

Answer 4

• Can more easily improve trait through genetic selection
• Genes play more of a role than environmental factors

Question 5

What is pleiotropy?

Answer 5

• Genes affecting more than one trait

Question 6

What are other traits of interest?

Answer 6

• Feed efficiency/ dry matter intakes
• Greenhouse gas emissions!
• Immune response
• bovine tuberculosis (bTB) resistance
• Lameness

Question 7

What is bovine leucocyte adhesion deficiency?

Answer 7

• Single point mutation = fewer neutrophils get into tissue to fight infection
• CS = Ulcers on oral mucosa, gingivitis/periodontitis, chronic pneumonia + diarrhoea
• Death <1y/o

Question 8

What are genetic diseases?

Answer 8

• BLAD - bovine leucocyte adhesion deficiency
• CVM - complex vertebral malformation
• Bulldog calves / telemark lethal
• Holstein Haplotype for cholesterol deficiency (NEW)

Question 9

What is a PLI?

Answer 9

• Profitable life index - what to improve for a productive herd
• production, efficiency, survival, fertility, calving ability…

Question 10

Regarding conformation traits what is looked at with the legs/stance?

Answer 10

• Foot angle
• Rear legs rear view
• Rear legs side view

Question 11

Regarding conformation traits what is looked at with the udder?

Answer 11

• Udder depth
• Teat placement
• Rear udder width + depth
• Udder support
• Fore udder attachment
• Teat length

Question 12

Regarding conformation traits what is looked at with the rump + body?

Answer 12

• Rump angle
• Rump width
• Dairy form / angularity
• Strength

Question 13

What is the down side of having strong udder support?

Answer 13

• Udder cleft dermatitis can form

Question 14

What’s the downside of having weak fore udder attachment?

Answer 14

• Harder to milk
• Predisposed for udder cleft dermatitis