1. Rumen Development and Feeding Management of Young Calves
Tom Wright, Dairy Nutritionist, OMAFRA

2. Importance of Rumen Development
Growth = energy + protein
To get energy and protein from the rumen into the calf, absorption capacity is needed
Calf starter helps develop rumen papillae to optimize absorption capacity
Courtesy of Dr. M. Steele

3. Phases of Development
Three aspects of rumen development from birth to weaning:
Pre-ruminant phase (lasts 2 to 3 weeks from birth)
almost exclusively reliant on nutrients in milk for growth and development
Transitional phase
gradual intake of solid feed promotes rumen development, papillae
growth, rumen musculature, development of fermentation environment
3. Ruminant phase (at weaning)
dependent on fermentation of solid feed, absorption of nutrients,
production of microbial protein and VFAs

4. Phases of Development
Pre-ruminant
Transition
Ruminant
Milk
Solid feed
Calf starter helps develop rumen papillae to optimize absorption
capacity
Source: Penn State University. Available online

5. Rumen Development
Fermentation of carbohydrates in solid feed – primarily from starter
Promotes rumen development
Key fermentation products are butyrate and propionate (Warner, 1956)
Provision of small amounts of hay ( % of intake) can aid in rumen musculature development but in young calves, fermentation of hay is limited because:
few cellulotytic bacteria are present
rumen pH is not stabilized
papillae not fully functional to absorb VFAs11

6. Promotes lower and stable pH
Rumen Development
Starter
VFA
Promotes lower and stable pH
Protein
Rumen Wall
Starter fermentation produces volatile fatty acids (VFA), which are taken up across the rumen wall for energy

7. With too low pH, fermentation bacteria can start to die off
Rumen Development
Protein
lower rumen pH
Starter
VFA
Rumen Wall
With too low pH, fermentation bacteria can start to die off

8. Feeding and Nutritional Management

9. More to Nutrition than Nutrients
Environment and Management are just as important as nutritional quality
Consider:
Air quality
Water
Lighting
Ambient temperature
Social setting
Sanitation/Disease Pressure
Good calf managers always look at the whole picture so they set calves up to meet their potential

10. Factors Affecting Eating Behaviour
Housing
Environment
Intake
Management
Health
Light
Social Factors
Nutrition

11. Interrelationships for Eating Behaviours
Environment
Housing
Intake
Management
Health
Light
Social Factors
Nutrition

12. Feeding Management
Positive attitude direct relation to disease level (Lensink et al., 2001)
Lowest mortality in neonatal calves when a female was in charge (Losinger et al., 1997)
Three vs. twice a day liquid feeding ??
1x day for replacer no effect (Stanley et al, 2002)
Weaning 6,7,8 wk of age or older – avoid post-weaning slump
Industry in NA aims for 8 wks

13. How Fast Do You Want To Grow Them?
750 – 850 g, Zanton and Heinricks, 2005

14. Greatest Growth Potential Occurs In The First 6 Months
Source Babcock

15. Importance of Water
Most essential nutrient, represents 70% of body weight
Water is lost from respiration and manure (feces and urine)
Water balance is controlled by the kidneys
Water intake is positively correlated with dry matter intake

16. Water At what age is fresh water offered to calves?
0 – 5 days  23% (215/920)
5 – 10 days  29% (268/920)
More than 10 days  30% (280/920)
Not until after weaning  17% (157/920)

17. Some Water Myths & Issues
Water causes scours
They get enough water in milk or replacer
It’s a pain to handle and it freezes in winter

18. Water Recommendations
Water should be offered from 3 days of age, it promotes starter intake
Preferably free choice access
Needs to be clean
Calves prefer to drink warm water (though no evidence this improves gain etc., but they will drink more water if it’s warm)
Ideally it should be physically separated from the calf starter-water dribbled into calf starter reduces intake of starter
Quigley et al. 2006

19. Average Daily Water Intake
Birth to 4 wks 3.5 L
4 wk to 8 wks 5.7 L

20. Water Intake by Treatment

21. Consider Effects of Housing on Calf Feeding

22. Social Environment Packs vs. corrals vs. individual housing
No clear data on feeding and intake, mostly other behaviour responses have been documented

23. Consider Effects of Lighting
Dry cows - 12 hours
Lactating cows - 16 to 18 hours
Yearlings - 12 hours ?????
Neonatal - unknown

24. Effects of Light on Starter Intake (18h vs. 10h)
Week
Osborne et al. 2007

25. Cold Weather Feeding
45kg calf requires 382g/d of dry milk replacer at thermoneutral temperature to meet her maintenance energy requirement, but the same calf needs 725 g/d at -20 °C
Calves have little body fat reserve to use as an energy source (4 - 5% of body weight)
In cold barns, it is important to increase quantity of milk (preferably via extra feeding time) and recognize that cold stress in calves happens at a fairly comfortable ambient temperature for people (below 15°C)

26. Feeding Calves in Colder Weather
The thermoneutral zone for calves lies between 15 and 25°C
Energy required by the calf increases significantly when it’s cold
Temperature (oC) 20 10
-10
-20
Body Weight
(kg)
Maintenance Energy Required
Mcal/day 40
1.59
2.02
2.45
2.96
3.31 50
1.88
2.39
2.90
3.50
3.91 60
2.16
2.74
3.32
4.01
4.48

27. Cold Weather Feeding Options
To maintain growth:
Increase volume of milk or replacer at each feeding
PREFERRED OPTION provide an additional feeding
For accelerated programs additional milk/replacer at a third feeding is
preferable to increasing quantity
Switch to higher fat milk replacer in cold weather (20% in winter months)
5. Promote starter intake – ensure freshness etc.

28. Calf Starters and Supplements

29. Grain At what age is grain/starter introduced to calves?
0 – 5 days 32% (299/940)
5 – 10 days  46% (430/940)
11 – 20 days  17% (162/940)
More than 20 days of age  5% (49/940)
Do calves have free-choice access to grain/starter?
87%  YES

30. Feeding Calf Starter Calves should be offered starter from birth
During the pre-ruminant phase, intake of starter is small, but measurable amounts are consumed by 14 days
Goals of the traditional “Calf Starter Method” of feeding when milk is restricted fed
↑ starter intake
↑ promote rumen development
↓ age at weaning

31. Calf Starter Intake Comparisons: Early vs. late weaning Low-fed vs.
high-fed milk
program
*Weaning period
highlighted*
Reduced milk availability is best promoter of calf starter intake
Reducing available milk once before weaning helps increase starter intake at weaning
De Passillé et al., 2011

32. Introduction of Hay When are calves normally introduced to hay?
Less than 2 weeks of age  155
2 – 4 weeks of age  195
4 – 6 weeks of age  190
After weaning  20

33. Forage Intake Forage intake can influence rumen health
Intake increases with age
Doesn’t appear directly related to milk feeding program (early vs. late weaning; low vs. high-fed milk)
De Passillé et al., 2011

34. Maternal Trace Mineral Influence on Calf
Inorganic vs. organic (proteinate)
Proteinate defined: a trace mineral (Zn, Cu, Mn, Fe, Se or Co) chelated to amino acids and peptides
Main effect is on immune system
Better biological activity

35. Calf Nutrient Supplements
Probiotics (good for first 2 weeks of life)
mannanoligosaccharides, yeast cell walls
Pastes (live yeasts, vitamins, bacteria) 5ml/d
Lactoferrin – natural antibiotic, immune regulator

36. Take Home Message Organic trace minerals √ Lactoferrin ?
Probiotics/Pastes √
Group/Individual Management $
Automatic feeder Management $
Extra light √
Whole milk/replacer Management $

37. Milk Replacer

38. Milk Feeding Options Whole saleable milk Waste milk Pasteurized milk
Milk replacer (various formulations)

39. Milk Feeding

40. Whole Milk vs. Replacer Economic and management decision
No difference after weaning
Acidified replacer (formic, propionic, pH )
Has to be mixed cold
Higher Protein/Fat replacers 28/20%, soy protein, plant oils

41. Managing Replacer Feeding
Assess the water source
Bacterial contamination sources include
Scoops, pails, nipples, hands
Pest Control during storage
e.g. rodents, dogs and cats

42. Milk Replacer Feeding
Smaller stomachs require frequent feedings to allow a calf MAXIMIZE nutrient uptake
Too many nutrients at once
Milk can travel back to the rumen and cause bloating
It will pass right through the calf and cause nutritional scours
Feeding schedules should consider what a calf can physically digest in one meal

43. Types Of Milk Replacer All milk protein Alternative source
Accelerated growth
All milk - 100% proteins from milk sources - whey, caseine ect.
Alternative source - milk proteins mixed with plant, plasma or egg proteins. It provides a more cost effective, but less digestible milk replacer. It is ideal only for calves OVER 3 WEES OF AGE
Accelerated growth - early weaning. Much higher levels of protein and fat, often suggested for sick or low birth weight calves for first few days. 43

44. Milk Replacer Ingredients
Protein
Whey protein concentrate, dried whey, skim milk, casein, calcium or sodium caseinate, dried whey product, soy protein isolate, soy flour, protein modified soy flour, soy protein concentrate, wheat protein, hydrolized wheat gluten, potato protein isolate, egg product, animal plasma protein
Fat
Vegetable oils, lard, tallow, coconut oil, milk fats, lecithin
Other Ingredients
Vitamin and mineral premix, prebiotics, probiotics, organic acids, flavouring, emulsifiers, selenium yeast
Protein is the most important ingredient to look at when choosing a in a milk replacer.
As I said before there are milk proteins and alternative proteins
Milk based ingredients differ based on the amount of lactose and mineral removed (changes the % protein)
Plant based proteins differ based on digestibility and amino acid profile. They can often also have anti nutritional factors (soy flour binds to proteins making them unavailable to calves and causing digestive upset)
Hydrolyzed wheat gluten is the best alternative protein source - high in protein, low in fiber and ash with no anti nutritional factors.
Plasma protein - centrifuged blood (porcine). It is fairly expensive and carries the risk of transferring blood born illness
Fat - during the first 3 weeks of age it is best to feed mainly milk fats in milk replacer because they are the most digestible. After that time other fats are introduced in greater amounts, the most common being tallow, coconut oil and lecithin
Vitamins and minerals are always also included in replacers.
Pre and probitotics are also a very popular additions used to improve gut health 44

45. Milk Replacer Composition
Conventional Restricted Milk Fed Programs
Crude Protein content of 20% to 22% maximizes lean tissue growth (Bartlett et al., 2006)
Enhanced Milk Feeding Programs
Crude Protein must be 26% to 28%, can use a lower fat (15%) except in cold weather (energy needs to be increased to %)

46. NRC Recommendations (DM basis)
Nutrient
Whole Milk
Milk Replacer
Starter
Grower
Calcium, %
0.95
1.00
0.70
0.60
Phosphorus, %
0.76
0.45
0.40
Magnesium, %
0.10
0.07
Sodium, %
0.38
0.15
0.14
Potassium, %
1.12
0.65
Chloride, %
0.92
0.25
0.20
Sulfur, %
0.32
0.29
Iron, mg/kg
3.0
100 50
Manganese, mg/kg 40
Zinc, mg/kg
15-38
Copper, mg/kg 10
Iodine, mg/kg
0.50
Cobalt, mg/kg
0.11
Selenium, mg/kg
0.30
Vitamin A, IU/kg
11,500
9,000
4,000
Vitamin D, IU/kg
307
600
Vitamin E, IU/kg 8 25
National Research Council – min recommendation for dairy calves (2007)
Milk replacers:
Protein ranges from 20-25%
Crude fat ranges from 15-20%
Vitamins and minerals are higher than NRC min. 46

47. Notes To NRC Recommendations
Generally, they reflect the calf’s needs, but they date from 2001 and new information has been developed since that time.
Vitamin E is routinely included in milk replacers at higher than NRC levels
Based on evidence that it supports calf health.
Vitamin A is routinely added at several times the NRC recommendation but while there is some data to support this, it isn’t a conclusive benefit