Dairy 6

Question 1

Replacement heifers

Answer 1

-genetic future of farm (should be highest genetics of the farm)
-contribute 22-25% cost of milk production/raising

Question 2

How much of live heifer calves do not contribute to profit?

Answer 2

20%

Question 3

Calve efficiency in converting feed to body mass

Answer 3

55%
-monogastric for first few weeks which makes them more efficient for first few weeks

Question 4

Heifer mortality in Canada

Answer 4

Preweaning mortality 6%

Weaned heifer mortality 2%

First lactation culling rate 15%

Question 5

Calf care after birth

Answer 5

-ensure calf is resuscitated
-navel dipping
-remove calf from cow to prevent disease transmission; especially Johne’s
-colostrum
-vaccinate intranasal

Question 6

Colostrum

Answer 6

Need to get more than 300g IgG into calf
-antibodies and growth factors

Question 7

What is best way to get colostrum into the calf?

Answer 7

1. Suckling and bottle feeding
   >help close the esophageal groove
   >will try bottle first then move on to tubing
2. Stomach tube calf
   -often necessary because need 3-4L at first feeding

Question 8

Colostral quality

Answer 8

-check by using refractometer, hydrometer/colostrometer, or weight of 1st milking colostrum (old method)

**Hydrometer and refractometer overestimate IgG concentrations but are better than weight

Question 9

Transfer of passive immunity

Answer 9

Methods for testing:
1. Serum total protein >5.2 g/dl in healthy calves and 5.5 g/dl in sick calves
*sick higher because dehydrated so same amount of IgG will appear higher

2. Sodium sulfite precipitation with serum

Question 10

Preweaning period

Answer 10

-first 6-8weeks of age
-housed in hutches (wind breaks, deep bedding, exposure to sun)
-hutches should be 2m apart to prevent disease spread
-feed appropriately (20% of their BW)

Question 11

Pair housing vs. single

Answer 11

Single is good to prevent transmission
But eventually need to bring them into groups which is a stressful event. So could originally start with pairing

Question 12

Procedures conducted at preweaning

Answer 12

-dehorning, debudding, supranumerary teat removal as early as possible
*need analgesia and hemostasis

Question 13

Feeding strategies

Answer 13

-feed milk, calf starter and forage
-need to feed 20% of BW in milk/day to start
-2-3 feedings
-whole milk vs milk replacer vs waste milk

Question 14

Why not best to give waste milk?

Answer 14

-exposing them to bacteria
-exposing them to low levels of antibiotics

Question 15

Milk replacer

Answer 15

-quality dependent on protein source

Question 16

Forage feeding at preweaning

Answer 16

-cannot digest at this point
-but high fibre forage buffers rumen acid production and increases gut wall health

Question 17

Weaning

Answer 17

-around 8weeks (10weeks seems ideal base don research)

-solid feed intake is critical (2kg starter/day)
-step down protocol (gradual reduction in milk, 2-3 steps down over 2-3 weeks)

Question 18

Immune suppression at weaning

Answer 18

-avoid vaccination and stressful procedures at this time
-less stressful in paired housing (pairs of 3-4 at 21 days

Question 19

Growing period

Answer 19

-group housing
-ration formulated for stage of growth
-monitor growth (weigh tape and scale)
-70kg more BW at calving= 1000kg more milk in first lactation

Question 20

Breeding strategies

Answer 20

Breeding at around 13mths of age

1. AI to maximize genetic improvement
2. Bull breeding

*synchronization is less common with dairy heifers
*beware of freemartins!

Question 21

Transition period

Answer 21

Period either side of calving
-21 days before before calving to 21 days after calving
-dry off to peak lactation

Question 22

Two group drying vs one group

Answer 22

Challenge to move to one group but currently more using two group

Two groups:
1.early dry period; low energy ration
2.close to calving; increased energy density

Question 23

Issues with two group drying off

Answer 23

-rumen microflora takes at least 3 weeks to adapt to dietary change

-pen moves= social disruption

Question 24

Benefits of single dry cow ration

Answer 24

-consistent ration
-minimize pen moves

Question 25

Vaccinations at dry off period

Answer 25

at least 30d pre partum
-colostrogenesis

Question 26

Metabolic disease control

Answer 26

->30”/75cm feedbunk space/animal
-1kg decrease DMI= 2x risk of ketosis, 3x risk of metritis

Question 27

BCS for calving

Answer 27

3-3.5

Question 28

Supplements

Answer 28

-careful of too much oral calcium precalving- because it shuts off stores
*give them oral calcium or anionic salts

-avoid high carbohydrate diets

Question 29

Different strategies for calving

Answer 29

1. individual stalls
2. Calve in pre-fresh pen

Question 30

Individual stall calving

Answer 30

-need hourly checks then move to calving stall
-easier disease control and control of colostrum intake

*need more employees

Question 31

calving in pre-fresh pens

Answer 31

-bedding packs
-less supervision
-decreased dystocia risk because not moving cows to new pen… but can lead to increase in missed dystocias because not checking them enough
-more difficult disease and colostrial intake control

Question 32

Stages of parturition

Answer 32

1.calf at pelvis
2. calf is delivered
3. placenta is passed

Question 33

Dystocia

Answer 33

Abnormal calving
-rate less than 5%
-heifers: feto-pelvic disproportion most common
-cows: malpresentation most common

Question 34

What can be done with dystocia?

Answer 34

-correct malpresentation
-pull calf?
-C- section
-Fetotomy

*Check for pairs and tears in repro tract

Question 35

Fate of cow

Answer 35

-joins milking herd
-wtihhold period for dry cow treatment
-separate fresh cow pen
-keep fresh and sick cow pens separate
-milk fresh cows before sick cows