Lecture 10

Question 1

What is the main thing that occurs in the pre-ruminant phase?

Answer 1

Reticular or Esophageal groove closure

Question 2

What causes for the esophageal groove to close?

Answer 2

Suckling promotes salivation

As milk passes pharynx, stimulates chemoreceptors with afferent patheways in glossopharyngeal nerve. Receptors react to Na in calves and Cu in lambs

Efferent vagal output leads to groove closure

Question 3

What does saliva contain to help with milk digestion

Answer 3

Esterase, begins digestion of milk lipids

Question 4

When does abomasal secretion occur?

Answer 4

Pre-ruminant phase

Question 5

What do abomasal secretion contain?

Answer 5

Rennin and HCl

Question 6

What do Rennin and HCl promote?

Answer 6

Hard curd formation by ppt Ca and caseinate

Question 7

What does the hard curd formation allow to enter duodenum?

Answer 7

Remaining fractions, whey proteins (albumins and globulins) enter duodenum rapidly

Question 8

What occurs to hard curd?

Answer 8

SLow digestion - 12-18hrs

Butterfat hydrolyzed by lipase from mammary and esterase from saliva

Ppt caseinate undergoes proteolysis by rennin

Question 9

What is ruminal drinking

Answer 9

Milk goes to rumen

Lactose fermented to lactic acid

Gas formation

Poor milk clot formation

Diarrhea

Question 10

What occurs to salivary gland during transitional phase?

Answer 10

increase in size and amount secreted

Question 11

What does proper rumen development during transitional phase require?

Answer 11

Dry feed

Question 12

What does metabolism become based on during transitional phase?

Answer 12

VFA production, not glucose

Question 13

What is used instead of rennin in weaning/post weaning phase?

Answer 13

Pepsinogen

Question 14

4 benefits of inophores

Answer 14

1. Increase feed efficiency
2. Helps prevent acute lactic acidosis
3. Helps prevent frothy/grain bloat
4. Helps prevent ketosis in lactating dairy cows

Question 15

4 rumen manipulations

Answer 15

1. Ionophores - monensin
2. Buffers
3. Probiotics
4. Protected enzymes

Question 16

Explain probiotics

Answer 16

Addition of selected active microbes whose fermentation pathways are desirable in particular diet

Living organisms administered in dry feed

Need to be fed constantly - not permanently established

Question 17

2 examples of probiotics

Answer 17

Yeast - absorb starch molecules, increase feed efficiency

Transfaunation - useful in younger animals

Question 18

Read Carbohydrate engorgement