Dairy 6 Flashcards
Replacement heifers
-genetic future of farm (should be highest genetics of the farm)
-contribute 22-25% cost of milk production/raising
How much of live heifer calves do not contribute to profit?
20%
Calve efficiency in converting feed to body mass
55%
-monogastric for first few weeks which makes them more efficient for first few weeks
Heifer mortality in Canada
Preweaning mortality 6%
Weaned heifer mortality 2%
First lactation culling rate 15%
Calf care after birth
-ensure calf is resuscitated
-navel dipping
-remove calf from cow to prevent disease transmission; especially Johne’s
-colostrum
-vaccinate intranasal
Colostrum
Need to get more than 300g IgG into calf
-antibodies and growth factors
What is best way to get colostrum into the calf?
- Suckling and bottle feeding
>help close the esophageal groove
>will try bottle first then move on to tubing - Stomach tube calf
-often necessary because need 3-4L at first feeding
Colostral quality
-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
Transfer of passive immunity
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
- Sodium sulfite precipitation with serum
Preweaning period
-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)
Pair housing vs. single
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
Procedures conducted at preweaning
-dehorning, debudding, supranumerary teat removal as early as possible
*need analgesia and hemostasis
Feeding strategies
-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
Why not best to give waste milk?
-exposing them to bacteria
-exposing them to low levels of antibiotics
Milk replacer
-quality dependent on protein source
Forage feeding at preweaning
-cannot digest at this point
-but high fibre forage buffers rumen acid production and increases gut wall health
Weaning
-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)
Immune suppression at weaning
-avoid vaccination and stressful procedures at this time
-less stressful in paired housing (pairs of 3-4 at 21 days
Growing period
-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
Breeding strategies
Breeding at around 13mths of age
- AI to maximize genetic improvement
- Bull breeding
*synchronization is less common with dairy heifers
*beware of freemartins!
Transition period
Period either side of calving
-21 days before before calving to 21 days after calving
-dry off to peak lactation
Two group drying vs one group
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
Issues with two group drying off
-rumen microflora takes at least 3 weeks to adapt to dietary change
-pen moves= social disruption
Benefits of single dry cow ration
-consistent ration
-minimize pen moves
Vaccinations at dry off period
at least 30d pre partum
-colostrogenesis
Metabolic disease control
->30”/75cm feedbunk space/animal
-1kg decrease DMI= 2x risk of ketosis, 3x risk of metritis
BCS for calving
3-3.5
Supplements
-careful of too much oral calcium precalving- because it shuts off stores
*give them oral calcium or anionic salts
-avoid high carbohydrate diets
Different strategies for calving
- individual stalls
- Calve in pre-fresh pen
Individual stall calving
-need hourly checks then move to calving stall
-easier disease control and control of colostrum intake
*need more employees
calving in pre-fresh pens
-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
Stages of parturition
1.calf at pelvis
2. calf is delivered
3. placenta is passed
Dystocia
Abnormal calving
-rate less than 5%
-heifers: feto-pelvic disproportion most common
-cows: malpresentation most common
What can be done with dystocia?
-correct malpresentation
-pull calf?
-C- section
-Fetotomy
*Check for pairs and tears in repro tract
Fate of cow
-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
