Lecture Notes Prepared by Dr. RAC Rabel 1

Calf Weaning

Dairy Calf Weaning

________ transition from a ______ based diet to a _______ diet

Post-weaning slump ??

Causes and consequences !!

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Ref: https://www.purinamills.com/dairy-feed/education/detail/avoid-the-post-weaning-growth-slump-when-feeding-heifers

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Ref: https://www.purinamills.com/dairy-feed/education/detail/avoid-the-post-weaning-growth-slump-when-feeding-heifers

Ref: Bovine Medicine: Diseases and Husbandry of Cattle

1. When calves are 2 months

2. When calves are 3 months

3. When body weight increases by 150-200% of body weight

4. When ADG exceeds 750g/day

5. When the rumen is ready to digest forages

6. When calves start ruminating (regurgitation)

7. When calves consume over 750-1000g of calf starter

When should you wean calves?

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What decides if a calf is ready to be weaned?

A properly developed rumen that is ready to digest forages!

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Improper weaning:

1. Rumen not sufficiently developed → nutrients not properly absorbed →

bypass Rumen → Abomasum

2. Yet they’re given grass → slow fermentation and poor absorption → pot

belly → sub-standard growth → delayed puberty, breeding, first calf

Ref: https://www.purinamills.com/dairy-feed/education/detail/rumen-development-in-dairy-calves-101

1. Calf age 2 - 3 months

2. BWG: 150-200% of birth weight

3. ADG > 750g/day

4. Health status of calves

5. When the rumen is developed and ready to digest forages

6. When calves start ruminating (regurgitation)

7. When calves consume over 750-1000g of calf starter

How do you find out whether the rumen is developed and ready for weaning?

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Early weaning vs late weaning

• Feed costs: are pre-weaning feed or post-weaning feed more expensive?

• If so, is early weaning (4 weeks) or late weaning (6 – 8 weeks) more cost effective?

• But can early weaning have detrimental effects over the life time? E.g. age at puberty, calving age, calf health, milk yield and composition?

• Studies have shown that savings from __ week weaning can save up to $55 (~Rs. 10000)/calf compared to __ week weaning!

If you’re a farm manager, your goal should be to increase/decrease weaning age. This is

NOT weaning a calf whose rumen is not ready to receive roughages, but making the calf

ready to receive roughages at an early age! Optimize feeding, housing, health care and

stress management to make them ready for early weaning!Lecture Notes Prepared by Dr. RAC Rabel 9

Weaning

• Abrupt or gradual ?• Decrease milk quantity over 7 – 10 days

• Some farms go from b.i.d. to s.i.d.

• If s.i.d., reduce quantity

• Encourages the calf to eat more concentrate → rumen preparation for roughage!!

• Management of stressful events..1. Stopping milk?

2. Changing concentrate feed?

3. Changing roughage?

4. Changing housing?

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Take home message:

Weaning is a stressful event.

Take measures to minimize this

stress.

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IMPORTANT:

The numbers (L, Kg) of feed mentioned must be used as guidelines

only!! Amounts fed should be altered based on the temperature (cold

vs hot), breed, health status of the calf etc. e.g. energy requirement at

30 Celsius and 15 Celsius is not the same. Water requirement at 30

Celsius and 15 Celsius is not the same!

Also remember:

• Certain calves will not eat the

quantities you want it to eat,

however much you try!

• You don’t HAVE to select every

calf (e.g. poor eaters) as

replacement heifers (culling!!)

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Lecture Notes Prepared by Dr. RAC Rabel 13Weaning age?

Beef?

What do you like Better ?

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Watch your diet !!

Potbellied Calf…

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Watch your diet !!

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Potbellied Calf : Pathogenesis?

Ruminant

150 – 200 liters

VFA: Acetic, Butyric, Propionic acids

Microbial proteins

Potbellied Calf : Pathogenesis?

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Distended Rumen + Slow Fermentation

Water restriction + excess straw →

Impaction

Summary

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PROPER RUMEN DEVELOPMENT IS CRITICAL

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Other calf management aspects

• Identification – ear tagging, branding/tattooing

• Removal of extra teats

• Disbudding (what’s dehorning?)

• Deworming

• Coccidiostats

• Record keeping – weight, body condition, health records, vaccinations

Buffalo calves: water sprayers/misting

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