Lecture 1 Flashcards
When is colostrum used in calf rearing?
In the first 2 to 3 months of life
What does colostrum do?
It protects the calf against all major causes of mortality and morbidity for the young calf
- disease protection
- nutritious food for calf
What is colostrum?
- It is a form of enriched milk with extra plasma proteins and vitamins
- It’s is a concentrate I’m udder pre-partum
What do the proteins in colostrum do?
They are lacyoglobulins/ antibodies - IgG1
- passive immunity transfer
When is colostrum immunity transfer best?
The protein declines over the first few days (18% to 3.5%)
- calf antibody absorption is best in the first 6 hours
- after 24 hours the calf is no longer able to absorb antibodies in colostrum
What is the vitamin status in colostrum?
- 5 times greater vitamins than in milk
- depends on the vitamin status of the cow
What are the major differences between colostrum and milk?
- higher fat content in colostrum (almost double)
- nearly 6x greater protein
- 1/3 of the casein protein in milk
- 3x the non casein protein compared to milk
- lots of antibodies in colostrum and almost none in milk
- almost half the lactose in colostrum
Is it better or worse to leave it up to the calf to suckle after birth? Why?
Leaving it up to the calf is not a good idea - 60% failure of passive transfer
- calves need to consume 3L of colostrum in the first 2 hours
- the calf however normally suckles within 3-4 hours of birth
- good idea to store colostrum in freezer for emergency use
What test can you do to determine the immunoglobulin status of the calf?
ZST = zinc surface torbidity
This tests how effective the passive transfer from the cow to the calf is
What are possible reasons for failure of passive transfer of immunity?
- poor colostrum quality
- inadequate colostrum intake
- calf born unattended
- inadequate animal husbandry on farm
- poor health of cow or calf: difficult calving; mastitis pre-calving
- poor colostrum handling (thawing at incorrect temperature, colostrum feeding too late in calf’s life)
What could cause poor colostrum quality?
- cows running milk pre-calving (if dam starts to spontaneously secrete milk before parturition then all of the valuable immunoglobulins are lost before parturition occurs)
- heifers reared in our farms
- high yields mere may have poor colostrum quality
- Feeding of four to five day “transition milk” as colostrum
Why would you not use transition milk instead of colostrum?
-
What is the order of colostrum feeding?
- Feed 3L within the first 2 hours of life
- feed a further 3L within the first 12 hours of life
- there is little absorption of IgG after 24 hours
- after IgG absorption cease it is thought that feeding of colostrum for the first 5 days of life will proved a local immunity against things like E Coli in the GI tract (disease status important)
How is colostrum stored?
- freezing - thawing temperature is important
- commercially available dried products
Why is it important for milk feeding to be done correctly?
- Proper closure of the esophageal groove - if this does not happen the milk spills into the rumen and causes bloat or scour
- helps if lots of saliva is produced
- helps if the calf is excited
- esophageal groove reflex - Clot formation with the enzyme renin and HCL also NB in the abomasum
- clot slows the passage of nutrients to small intestine
- poor clot lots of nutrient for bacteria in small intestine to live on and cause scour
- commercial acidifiers available for adding to whole milk
What are the practical aspects of milk feeding?
- routine in milk feeding is very important
- it is essential that milk is consumed warm and soon after it is offered if possible
- The quality of milk offered is important as well as the rate of milk consumption
- badly worn rubber teats on calf buckets can cause problems - as a general rule 15% of body weight of milk should be fed per day, up to 20% may be beneficial in cold conditions
- the energy requirement of calves increases in cold conditions so can feed higher % of body weight of milk
Can you feed more than the general rule of 15% body weight of milk per day in a calf?
YES - in cold conditions calf energy requirements go up so you can feed a higher % of body weight (20%)
- when feeding more you should increase the amount slowly
- feeding more will delay rumen development
When would milk replacer be used?
Normally used on farms when milk quota is not an issue
- also useful if Johne’s diseased cows in herd
What is the timeframe for feeding milk replacer? How early can you feed it?
Can be fed to young calves if needed from 3-4 days
Possibly better to feed from 14 days though
Why is the temperature of milk replacer important?
Milk replacer temperature is critical for the formation of a proper clot in the abomasum
How effective is milk replacer in contrast to whole milk?
Milk replacer usually gives around 90% of the performance of whole milk
What types of milk replacers are there?
- skim based milk replacer
- acidified milk powder
- milk additives
What are the characteristics of skim based milk replacer?
- skim milk + animal fat
- similar in composition to whole milk
- easily digested by calf, clots in abomasum
- zero skim: little of milk constituents often recommended for older calves
- crude protein should be 25%
What are the characteristics of acidified milk powder milk replacer?
- similar in composition to whole milk
- easily digested by calf, clots in abomasum
- Crude protein should be 25%
- organic acids (citric, fumaric) - to reduce pH to 5.7
Milk additives as milk replacer
Called a milkshake
- once a day - usually used to acidify whole milk so it can be fed once a day: improves abomasal clot formation; reduces susceptibility to scouring
How fast should calves grow per day from birth to weaning?
Target is for calves to grow at at least 500 g per day from birth to weaning
Calves may grow much faster than that at 700 g per day
How large should calves be at 2 months or weaning (kg)?
75 kg
When should solid feed be introduced to calves?
From 2-3 days old
What ingredients are used in calf starter to make it palatable?
Molasses and Locust bean
What ingredients are necessary in calf developer and why?
1 palatable ingredients such as molasses and locust bean
2 grains are often not processed excessively and I encourage rumination
3 important to have starch ingredients as propionate and butyrate very important for rumen development
4 crude protein is often high
How much calf starter (solid feed) should calves be eating per day at weaning?
1 kg of feed per day
