Calf Rearing Guide

Calf rearing is all about quality colostrum, hygiene and minimising stress. Colustrum needs no introduction from us, but you can find our quick guide to the 3 Q's of Colostrum below.

Hygiene is important across all aspect of the season - from birthing to the shed, bedding and feed. Stress can be reduced by providing a warm, dry environment that is not overcrowded (1.5m2 at least per calf in a pen) and ensuring food and water requirements are met. Enrichment toys, brushes scracth mats can also reduce stress.

There are many good calf rearing and colostrum guides available. You can find our Colustrum Guide below, and more helpful links at the end of this article.

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The three Q's of Colostrum

1. Quickly - within 3-6 hours
2. Quality - 22+ brix or the best you have
3. Quantity - 10% of bodyweight in 2 feeds

Why is Colostrum so important?

Cows do not transfer antibodies across the placenta like other mammals. Immunity for calves comes from colostrum and is absorbed across the gut. The gut starts closing once the calf is born, hence the first 24 hours are crucial. A newborn calf can absorb large IgG (antibody) molecules, BUT from birth that calf gut starts to close and at 12 hours old it is unable to absorb large IgG molecules and at 24 hours the gut is closed.

FPT (Failure of Passive transfer) occurs when a calf does not get enough quality colostrum and therefore transfer of antibodies. If you are not sure, calves can be tested at 7 days old via a blood test.

If a calf does not feed from its mother, it ideally gets quality colostrum within 1-3 hours for antibody transfer, to avoid FPT. Why? When a calf does not get enough antibodies, it can get sick, potentially die, and not grow or produce as well. It will also take up a lot of resource at an already busy time.

It is recommended that you test cows individually for colostrum quality (brix), using 'test buckets'. You can then separate out Gold (A+/22%+) colostrum and store in the fridge or freezer for future use.

To ensure maximum antibody protection is given to new-born calves, 2-to-4 litres of good quality colostrum should be fed in the first 12 hours of life. Colostrum quality can vary significantly between cows. A BRIX-scale refractometer (link = 215025) enables you accurately and quickly assess colostrum quality. A refractometer is easy to use - After checking calibration of the instrument with distilled water, two drops of the colostrum to be tested are placed on the glass prism. The instrument is then aimed towards the light and the colostrum level is read off the internal scale. Readings above 22% indicate high-quality colostrum gold.

Don't have 22%+ colostrum? Just use the best you have - for every 1% increase in the Brix%, the odds of FPT Decreased by 33% (Epivets)

Brix can also be used to indicate:

• Very high brix = the cow has not calved OR has milk fever or mastitis
• Very low reading = it has likely fed a calf

Hygiene is also very important as bacteria affects the absorption. Bacteria bind to the antibody molecule and are too big to absorb across the gut. They can also sit in the pores of the gut and block absorption.

Contamination can come from multiple sources, so we recommend:

Colostrum Storage and Handling

1. Scrupulously clean test buckets (hot soapy water to remove fat residue) and storage containers, and use lids, labels for date and quality.
2. Feed, refrigerate or freeze colostrum within one hour of collection. High-bacteria colostrum needs to be used sooner and very clean colostrum can be kept longer. Colostrum is best stored in the fridge or the freezer.
3. If storing in the fridge, only keep colostrum for 4-7 days. After that, quality declines. Be sure the refrigerator is cold (0-4 degree C) to reduce the onset of bacterial growth. Using a preservative, such as potassium sorbate, will stop bacterial growth and extend the length of time colostrum can be stored, up to seven days.
4. Keep frozen colostrum for six months or less. While not everyone agrees on how long frozen colostrum can be stored without damage to the antibodies, most researchers agree the six-month mark is safe. If freezing colostrum, it is a good idea to use bags with a label of date and quality, that will stack neatly, and the increased surface area of the bag will rapidly cool and thaw the colostrum. Freezing will stop bacterial growth however it will not decrease the bacterial counts that are already present when put into the freezer.
5. Thaw frozen colostrum with warm water or a microwave. The main concern regarding thawing frozen colostrum is to thaw the ice without degrading the immune proteins. Colostrum is best thawed with warm (not hot) water. Add more water to the bath as the frozen colostrum cools down the water. Alternately, colostrum can be thawed in a microwave oven with little damage to the IgG by microwaving the colostrum for short periods on a low power.
6. Cleanliness is key. Whichever way you chose to store colostrum, the basic principles of cleanliness still apply. Milk cows and store colostrum in clean buckets. Transfer to single serve containers that you can write the date and quality on. In conclusion, storing colostrum in the fridge or freezer provides you with flexibility to ensure that a newborn calf has high quality colostrum available within hours of birth. The refrigerator can store colostrum for a few days, while the freezer can effectively store colostrum up to six months. The advantages of storing colostrum in the refrigerator or freezer, or some combination of both is to ensure there is always colostrum available on your farm.

Recent recommendations from Dairy NZ

• feeding milk twice daily for two to four weeks, allows the calf to consume and digest adequate amounts of milk, and therefore energy to maintain good health and growth.
• Adlib feeding systems also provide these benefits while conserving labour. Automatic rearing systems allow calf to choose when and how often they feed, mimic natural behaviour of a calf on a cow.
• Properly managed automated system have been found to reduce nutritional scour or non-infectious scours and the need for additional labour.

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Other Useful Resources

• Farmlands Calving Checklist & Calf Rearing Guide
• Farmsource - Gear up for Calving
• PGG Wrightsons - Calf Rearing: Surviving and Thriving
• Dairy NZ - Calf Guide