Introduction

Question 1

When do farm animals get fed at maintenance?

Answer 1

Trick question- this is very rare as we are always wanting to do something to produce for us, whether it be, growing, lactating, or gestating

Question 2

What is an easy way to determine the total nutrient requirements needed for a farm animal?

Answer 2

Factorial method- determine maintenance then add the estimated requirements for production and environmental factors as well as activity

Question 3

What factors are involved in determining maintenance requirements?

Answer 3

Weight, Sex, Breed type (beef vs dairy)

Question 4

Which group of cattle have the highest maintenance requirements?
A. Dairy
B. Beef Breeds
C. Bos Indicus

Answer 4

A- they have a 20% higher maintenance requirement than beef. Bos indicus require 10% less

Question 5

Why do bulls have a 15% greater maintenance requirement compared to heifers and steers?

Answer 5

Due to differences in body composition and hormones

Question 6

To what percent does lactation increase the nutrient requirements over maintenance?

Answer 6

200-400%

Question 7

To what percent does gestation increase the nutrient requirements over maintenance?

Answer 7

30-35%

Question 8

To what percent does growth increase the nutrient requirements over maintenance?

Answer 8

0-150%

Question 9

T/F: Grazing cows have a 20-30% higher energy requirement than penned cows

Answer 9

False, it is 20-50% higher

Question 10

How does feed restriction affect energy requirements?

Answer 10

It may actually decrease the requirements by 10-50% as gut and liver size adjust to intake

Question 11

How do fat animals’ requirements compare to heavily muscled animals?

Answer 11

They are lower as less energy is needed to maintain a pound of fat compared to a pound of muscle

Question 12

How does being outside of an animals thermoneutral zone affect energy requirements?

Answer 12

At both extremes energy requirements increase

Question 13

How is energy produced in ruminants?

Answer 13

Energy requirements are met by several rumen metabolites including amino acids, glycerol, ketones, lactate, and propionate

Question 14

What is the main rumen metabolite used to create energy?

Answer 14

Propionate

Question 15

How is glucose created in the ruminant?

Answer 15

Through gluconeogenesis in almost all cases. Ingested glucose is broken down by rumen microbes into glucose precursors which then are converted back into glucose in the liver

Question 16

What are the substrates for gluconeogenesis in the ruminant?

Answer 16

Propionate, Lactate, Glycerol, Amino acids

Question 17

What are acetate and butyrate used for in the cow after being created by rumen microbes?

Answer 17

Acetate: used as a fat precursor

Butyrate: used as fuel for rumen and LI epithelia

Question 18

What is the source of energy used more by ruminants than any other species?

Answer 18

KETONES- meet 10% of daily energy requirements. Ruminants live in a ketotic state compared to other animals

Question 19

What is the role of insulin in the ruminant?

Answer 19

Doesn’t have a huge rule, there is relatively low insulin activity in the blood compared to mono-gastric animals –> flatter glucose and insulin curves

Question 20

Which two tissue types in the cow are insulin independent?

Answer 20

The mammary gland and the fetus

Question 21

What is the role of corticosteroids in ruminant metabolism?

Answer 21

They stimulate release of amino acids from the muscle to aid in gluconeogenesis

Question 22

What tissue type changes the most with BCS?

Answer 22

Body Fat