10 Calf/Heifer Management

Question 1

Long term objectives of calf/heifer management

Answer 1

• minimize time to first calving
• maximize milk production potential

Question 2

What is in colostrum

Answer 2

Antibodies (immunoglobulins)
Immune cells
Hormones (insulin, IGF-1)
Energy, protein, vitamin A and NaCl

Question 3

Why is colostrum important (5)

Answer 3

• passive immunity
• maternal IgG protects newborn calves from disease
• IgG not transferred via placenta in cattle
• Insulin & IGF-1 promote gut development
• condensed source of nutrients

Question 4

What are some causes of poor colostral quality

Answer 4

• leakage prior to calving
• first-calving heifers (less exposure to diff pathogens)
• high energy diet before calving (reduced IgG content)

Question 5

Two ways of detecting colostrum quality

Answer 5

• colostrometer
• refractometer

Question 6

What is the colostrometer

Answer 6

Antibody level estimated by specific gravity
Used on colostrum fresh from the cow or at room temp

Question 7

What is a refractometer

Answer 7

Measures sugar/total solid content in milk, which is related to IgG concentration

Question 8

How much bacteria can be found in colostrum

Answer 8

More than 93% of colostrum samples contained > 100,000 cfu/ml of bacteria

Poor sanitation of colostrum equipment? Handling?

Question 9

Standard for bacteria in raw milk in AB

Answer 9

Needs to be less than 120,000 cells/mL or is not shipped

Question 10

How often do bacteria counts double in colostrum left at room temp?

Answer 10

Doubles every 30 mins

Question 11

Why is early consumption of colostrum, before intake of bacteria, important?

Answer 11

Presence of bacteria inhibits IgG absorption
If bacteria enters small intestine first, loses ability to absorb IgG
First couple of hours intestine can absorb protein without breaking it down (pinocytosis)
IgG closes the window for pinocytosis so bacteria cannot enter, or vice versa if bacteria are first

Question 12

How can you decrease colostral bacterial content

Answer 12

Pasteurize at 60C for 60 mins
Does little damage to IgG

Question 13

How does absorption efficiency of IgG change with pasteurization

Answer 13

It is higher in pasteurized colostrum bc less competition with bacteria for absorption by SI
Lower in colostrum with low and high bacterial count

Question 14

How does timing of colostrum feeding affect IgG absorption

Answer 14

There is a window where intestine can absorb IgG
If fed right after birth, IgG concentration and absorption is higher

Question 15

Reasons for failures of passive transfer

Answer 15

• calf does not get any colostrum
• calf does not get good colostrum (low IgG content, high bacterial counts)
• calf does not get enough colostrum
• calf does not get colostrum in time

Question 16

How much colostrum should be fed and when

Answer 16

150 - 200 g IgG
3-4L of colostrum (50g IgG/L) as soon as possible

Question 17

What is the DRTC colostrum protocol

Answer 17

2 L of powder colostrum (replacement) within 2h after birth
Pasteurized colostrum for three more feedings (2 L/time) every 12h

Question 18

Benefits of adding powder colostrum to poor colostrum

Answer 18

Increases Fed IgG and serum IgG
But decreases IgG absorption

Question 19

What is considered ‘excellent’ serum IgG? Brix passive transfer value?

Answer 19

> 25 g/L

> 9.4 BRIX

Slide 19

Question 20

Slide 20, 21

Answer 20

Transition milk

Question 21

What are the effects of feeding transition milk?

Answer 21

Higher average daily gain before weaning
Higher body weight at weaning
Longer vilus length in GI tract = higher digestion capacity

Question 22

Why is water intake important in calves

Answer 22

Stimulates solid feed intake

Question 23

What can be the cause of diarrhea in calves?

Answer 23

• nutrition (over feeding, poor quality milk)
• infectious (bacteria, virus, etc)

Question 24

What is more important; ventilation, temperature or bedding.

Answer 24

Calves are tolerant to low temperatures if sufficient dry bedding and good ventilation are provided

Question 25

Signs of lack of ventilation

Answer 25

• ammonia smell
• humidity
• lack of air flow
• coughing

Question 26

What is traditional calf housing? Why is it used

Answer 26

Individual housing with calf hutches
Minimizes risk of infection

Question 27

What effects does pair-housing have?

Answer 27

When paired at 3 days old, there is more calf starter intake (kg/d) and higher ADG

Social faciliation

Question 28

Slides 28, 29

Answer 28

Pair housing

Question 29

Why do we not leave the calf on the cow for a few days after birth

Answer 29

• greater risk of infection
• cannot confirm colostrum intake
• break maternal bond after developed

But… animal welfare? Consumer acceptance?

Question 30

Four types of calf housing management approaches

Answer 30

1. Individual housing, 10L whole milk per day
2. Pair housing (2 calves per pen), 10L whole milk per day
3. Group housing (6 calves per pen), 10L whole milk per day
4. Group housing w/ dams (6 calves + 6 dams), milk from dams w/o limit

Question 31

Effects of group housing with dams of pre-weaned calves? Drawback of general group housing?

Answer 31

With dams, higher BW at weaning and ADG

In group housing, higher morbidity and treatment costs

slide 32

Question 32

Future behaviours of calves raised with dams

Answer 32

• aggressive behaviour in the milking parlor at the first milking x2.3
• probability of kicking off milking unit x4.3

Question 33

Benefits and drawbacks of housing with dams

Answer 33

• better growth performance
• no negative effects on health

Drawbacks:
- reduced farm income due to less milk shipping
- long-term effects on animal behaviour and personality

public acceptance validates the cost?