Lecture 6: Dairy 2- Weaning to Calving 1

Question 1

What is perinatal mortality?

Answer 1

-A calf carried to term or at least longer then 260d and born dead or dying within 24-48h of birth
-Dystocia plays a big role in the cause and (big cause of dystocia; fetal pelvic disproportion)

Question 2

What are 3 diseases occurring after weaning?

Answer 2

-Pneumonia - MOST COMMON DISEASE!
-Emerging disease- Salmonella Dublin
-Coccidosis

Question 3

What are a calfs respiratory disease defences?

Answer 3

-Nares: to filter pathogens and dust
-Cilia: move in one direction in trachea (stress and cld slows them down so increase infection in those conditions)
-Neutrophils, macrophages and cytokines

Question 4

TRUE OR FASLE: Over reactive cells can cause bigger issues/damage from a mild infection?

Answer 4

TRUE.

Question 5

Increased risk of bovine respiratory disease occurs with that factors?

Answer 5

-Mixing of animals (big stressors)
-Transportation
-Lightweight or younger animals within a group (Can’t get enough food)
-Persistent infection with BVDV

Question 6

What is BRSV?

Answer 6

Bovine respiratory syncytial virus
-one of the 2 most important reparatory pathogens in dairy
-High morbidity (lots of calves get sick)
-Low mortality (most will recover)
-Predisposes cattle to severe bacterial pneumonia
-Mostly affects calves that are 2-6 months old

Question 7

What are clinical signs for BRSV?

Answer 7

-High morbidity within 1 week (every calf sick)
-High fever
-Depression
-Anorexia
-Serous (clear) Nasal discharge
-increased respiratory rate (bc having diffucty breathing)

Question 8

What is the secondary infection to BRSV?

Answer 8

Mannheim Haemolytica
-One of the 2 most important respiratory pathogens in dairy calves
-Normal bacterial inhabitant of upper airway (waits for BRSV or stressor and then goes down into lungs cases problems)
-Leading cause of death as a result of respiratory disease in calves
-Causes pneumonia on own but if co-infection with viral pathogen, mortality greatly increased (more likely to die infection foes into blood stream)

Question 9

What are the clinical signs of Mannheim haemolytica?

Answer 9

-Fever
-Depression
-Anorexia
-Mucoid (lot of mucus/pus white) Nasal discharge
-Rapid respiration (area of lung will become very hard no air moving through)
-Moist, painful cough

Question 10

What are the 2 most important respiratory pathogens in dairy calves?

Answer 10

-BRSV
-Mannhemia Haemolytica

Question 11

What are prevention strategies for pneumonia?

Answer 11

-Minimize failure of transfer of immunity (colostrum)
-Improve housing and ventilation
-Adequate nutrition
-Vaccination
-Minimize weaning stress

Question 12

What are key areas for housing to minimize infections/disease?

Answer 12

1.Reduce stocking density 35sqf for preened calf
2. Improve air quality (no dust, delivering fresh air continuously)
3. Prevent contact with older animals (old ones w/ pathogen can infect young ones)
-use bedding calves can nest in (stay warm)

Question 13

Why is ventilation important?

Answer 13

-Link between respiratory disease and poorly ventilated calf housing
-Many different types
1. Postive pressure
2. Natural ventilation
3. Negative pressure

Question 14

What are the 2 vaccination programs for calves?

Answer 14

-vax program is difficult due to the complex nature of the immature immune system of calves
1. Intranasal vax <60 (YOUNG CALVES)
-Prevent infection
-Provides defence where pathogens will be invading
-Develop immune proteins (IgA) on the musical surface
-Shorter duration of immunity (only last 150d) relatively short

2.Systemic modified live vax: >60d (OLD CALVES) till after weaning
-Prevent disease
-Produces systemic humoral and cell-mediated immunity
-Produce long lasting immunity

Question 15

What are the effects of pneumonia on performance?

Answer 15

If treated for pneumonia as calf:
-Increase risk of mortality prior to calving
-Decreased growth rate
-Increased age at first calving
-Increased risk of dystocia at first calving (bc decreased growth rate and increase of pelvic disproportion)
Costs:$25-81 per case due to the long term impact on growth and survival

Question 16

What is salmonella Dublin?

Answer 16

-Emerging disease in ON
-Zoonotic
-Multiple routes of transmission
-Fecal-oral spread (calf ingest fecal matter)
-Hardy bacteria (can survive for log periods of time through cold and heat)
-Transmitted herd to herd through carriers
-carriers can be older animals that look healthy but shading in milk and manure (no clinical signs)

Question 17

What are the clinical signs of Salmonella Dublin?

Answer 17

-Calves that show clinical sings are typically infected at calving (in calving area and stressed out so shading virus into bedding)
-Importance of clean maternity area
-2m usually (2w-7m)
-Wide variety of presentations
-Pneumonia (main one)
-Septicemia (main one)
-No diarrhea
-High mortality and viable morbidity (die suddenly)

Question 18

What are prevention and control strategies for salmonella Dublin?

Answer 18

1. Reduce exposure (best way): through biosecurity (can prevent carrier into herd by doing blood test to see)
2. Improve immunity: Vax of calves and cows which is not available in CA

Question 19

What is coccidiosis?

Answer 19

-caused by Eimeria Boris and zuernii (parasitic protozoa)
-Calves infected by oocysts passed from feces of cattle with parent infections
-Moisture and cool conditions are conducive to sporulation (rainy and cold perfect environment for them)

Question 20

What are clinical signs (rarely occurs)?
Prevention?

Answer 20

-diarrhea containing mucus and blood in manure
-straining
-depression and reduced appetite
Most infections are subclinical
-Lack of growth
-Loose manure
-Poor hair coat
Immunity develops over months; ADULTS NOT AFFECTED
Prevention
-Inclusion of coccidiostat (ex monensin, lasalocid) in heifer diets
-must consume enough feed to get adequate dose but most diets are formulated for “average” calf in group
-Sanitation of environment

Question 21

What are the goals of the replacement program?

Answer 21

-Produce at least enough replacements to maintain milking herd as efficiently as possible
-Calve successfully- on average better then cows they replace
-Age of first breeding 12-14month
-Age at first calving 23-24month

Question 22

What are the pre-weaning nutrition goals?

Answer 22

-Double birth weight by weaning (avg calf born 42-52kg want to double by 6w)
-800-900g/day average daily gain

Question 23

What are some feeding strategies for pre-weaning nutrition to maximize health?

Answer 23

-Offer clean, ab-lib water from day 1-2
-Offer starter/grain from 1-2 weeks of age (papilla in stomach more developed)
-Provide chopped (2cm) straw or hay (grain may build up place on rumen wall and straw will help scrape away better digestion)

Question 24

What is weaning and why is it important?

Answer 24

-It is the change from milk diet to forages and grains
-Time of greatest stress for dairy calves
Recommended weaning criterion:
-Minimum of 3 weeks on starter
-2 lbs (0.9kg) of starter per day for 3 consecutive days
-Leave in hutch or pen for 5-7 days after weaning (1 stressor at a time)
-Dehorn at 1-4w (ideally dehorn before weaning)

Question 25

What are the 2 types of weaning strategies?

Answer 25

2 Main strategies employed;
-Abrupt (calves on milk cold turkey to grain)
-Gradual (slowly decrease level of milk and slowly increase level of solid diet)

Question 26

TRUE OR FALSE: No matter what weaning strategy employed there will always be reduced gain surrounding weaning the period.

Answer 26

TRUE:

But gradual with not be as much of a decrease in growth so its better