6 – Replacement Heifers, Transition, Parturition

Question 1

Replacement heifers

Answer 1

• Genetic future of the farm
• Contribute to 22-25% cost of milk production (need 1.5-2 lactations to make a profit)
• Calves are 55% efficient in converting feed to body mass

Question 2

Canada numbers for preweaning and weaned heifer mortality and first lactation culling rates

Answer 2

• Preweaning: 6%
• Weaned: 2%
• First lactation culling: 15%
• *20% of live heifer calves do NOT contribute to profit

Question 3

What do you need to do following birth of a calf?

Answer 3

• Ensure calf is resuscitated
• Naval dipping
• Remove calf form cow (prevent disease transmission, ex. Johne’s)
• Need to get >300g IgG absorption (LINEAR absorption)
  o Stomach tube! (can try suckling/bottle feed first)
• Intranasal vaccination

Question 4

How do you assess colostral quality?

Answer 4

• Hydrometer/colostrometer
• Refractometer
• Weight of 1st milking colostrum
• Hydrometer and refractometer over overestimate IgG concentration, but are better than weight
• *need 3-4L

Question 5

How do you assess transfer of passive immunity?

Answer 5

• Serum total protein >5.2g/dl (healthy) or 5.5g/dl (sick calves)
  o Sick calves tend to be dehydrated (same IgG but seems ‘higher protein’)
• Sodium sulfite precipitation
• *Growth factors in colostrum (so they grow appropriately

Question 6

Preweaning

Answer 6

• First 6-8 weeks
• Often housed in hutches (wind break, deep bedding, exposure to sun helps warm it up)
• Feed appropriately
• Hutches should be 2m apart
  o Now pairs or groups=removes one more area of stress
• Dehorning/disbudding/supranumerary teat removal as early as possible
  o *analgesia and hemostasis (bleeding control) MUST BE USED

Question 7

What is the feed strategy of calves?

Answer 7

• Milk + calf starter + forage
• 20% body weight in milk fed/day initially
  o 2-3 feedings

Question 8

Milk replacer for feeding

Answer 8

• Quality is dependent on protein source
• *whole milk is best (except don’t want to do if Johne’s in herd)

Question 9

Calf starter

Answer 9

• Pelleted
• <22% crude protein
• 30-40% starch

Question 10

Forage for calf feeding

Answer 10

• Calves cannot digest forage
• BUT high fiber buffers rumen acid production
• Increases gut wall health
• *calves with chopped straw=grow faster

Question 11

Weaning age and protocols

Answer 11

• > 8 weeks of age (10 weeks seems ideal)
• Solid feed intake critical: 2kg starter/day
• Step down protocols: gradual reduction in milk provided and 2-3 steps down over 2-3 weeks
• *Immune suppression: AVOID vaccination and stressful procedures
• Less stressful in paired housed calves (pairs/groups of 3-4 at 21 days)

Question 12

Growing period after weaning

Answer 12

• In group housing
• Ration formulated for stage of growth
• Monitor growth: weigh tape or scale
• *70kg more bodyweight at calving=1000kg more in first lactation

Question 13

Breeding strategies in heifers

Answer 13

• AI: maximize genetic improvement (especially with genomics)
• Bull breeding
• *synchronization is LESS common
  o Since they express estrus behaviour better than calves
• Beware of free martins (usually get rid of them sooner, but doesn’t always happen)
• *13 to 15 months of age

Question 14

Transition period with calving

Answer 14

• Either side of calving
  o 21d before, 21d after?
• *major metabolic changes (low energy requirements, to very high!
• *vaccinate at least 30d pre-partum: colostrogenesis

Question 15

Grouping dry cows: options

Answer 15

• 2 groups
  o Early dry period: low energy ration
  o Close to calving: increased energy density
• *rumen microflora takes at least 3 weeks to adapt to dietary changes
• *pen moves=social distributions

Question 16

What is a benefit of a single dry cow ration?

Answer 16

• Consistent ration
• Minimize pen moves

Question 17

What can you do for metabolic disease control in dry cows?

Answer 17

• More feedbunk space (>30inches/75cm per animal)
• 1kg decrease DMI: 2x risk of ketosis, 3x risk of metritis
• Do NOT supplement calcium pre-partum
  o ‘shut off’ and then can’t access it
• Avoid high CHO diets
• Anionic salts OR oral calcium at calving

Question 18

What is the ideal BCS for calving?

Answer 18

• 3.0-3.5

Question 19

What are the different strategies for calving? (2)

Answer 19

• Individual stall at calving
• Calve in pre-fresh pen

Question 20

Individual stall at calving

Answer 20

• Hourly checks then move to calving stall
• Easier disease control (moving to a clean pen)
• Easier control of colostral intake
• More employees needed

Question 21

Calves in pre-fresh pen

Answer 21

• Bedding packs
• Less supervision
• Decreased dystocia risk as cows not moving to new pen (increased missed dystocias as not checking them as much)
• More difficult disease and colostral intake control

Question 22

Parturition

Answer 22

• 3 stages
• Intervene at appropriate times (90% should have no human help)
• Proper (GREAT CARE) use of traction
• Careful hygiene
• Simple plan of action for calving
• Keep records (track dystocias)

Question 23

What is the maximum weight a calf puller can lift?

Answer 23

• 1000kg (1 tonne): way to much for delivering a calf
• *be careful

Question 24

Dystocia

Answer 24

• Abnormal calving
• Rate should be <5%
• *CHECK FOR PAIRS AND TEARS

Question 25

What is the more common dystocia in heifers?

Answer 25

- Feto-pelvic disproportion o Too big a calf, too small a heifer

Question 26

What is the most common dystocia in cows?

Answer 26

- Malpresentation

Question 27

What can you do with a dystocia?

Answer 27

- Correct malpresentation - Pull calf? - Caesarean section - Fetotomy

Question 28

What is the fate of the cow after calving?

Answer 28

- Joins milking herd - Withhold period for dry cow treatment - Separate fresh cow pen - Keep fresh and sick cow pens separate - Milk fresh cows before sick cows