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4 steps to achieve successful passive transfer in newborn calves

Amanda Fischer for Progressive Dairyman Published on 28 February 2019

Since dairy calves are born immune-deficient, successful passive transfer of immunoglobulin G (IgG) is essential to protecting calves from any disease challenges they encounter early in life.

Successful passive transfer of IgG is defined as when the blood IgG concentration of the calf is equal to or greater than 10 milligrams of IgG per millilitre from 1 to 7 days old.

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This is accomplished by feeding adequate levels of high-quality colostrum or colostrum replacer shortly after birth.

Unfortunately, the rate of failure of passive transfer (FPT) is alarmingly high (about 19 percent), and almost half of all farms have at least one calf that has experienced FPT.

Calves that are not provided with an adequate amount of IgG after birth have an increased risk of morbidity and mortality, and feeding an inadequate volume of colostrum has been linked to decreased future milk production.

As these outcomes should be avoided in order to maximize the profitability and health of your dairy herd, proper colostrum management protocols should be followed. Typically, good colostrum management encompasses four main aspects:

1. Quality

While older research has previously recommended feeding equal to or greater than 100 grams of IgG to calves within the first hours of life to ensure successful passive transfer, more recent research suggests calves must receive 150 to 200 grams of IgG during early life.

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If you are using good-quality colostrum (equal to or greater than 50 grams of IgG per litre of colostrum), this can be achieved by feeding 3 to 4 litres.

While these guidelines may seem simple to follow, the quality of colostrum can vary greatly between animals. A 2013 study that collected colostrum samples from farms across five different states demonstrated IgG concentrations ranged from 7 to 159 grams per litre and that 16 percent of samples contained less than 50 grams per litre.

In other studies, this percentage has even been reported to be as high as 29 percent. With this large variation, it is obvious accurate measurement of IgG concentrations is essential in ensuring successful passive transfer occurs.

Unfortunately, IgG measurement is uncommon on-farm, with a study conducted by NAHMS in 2007 showing IgG content is only routinely evaluated by 13 percent of producers, with over half of those doing so by visual inspection only.

In order to prevent feeding colostrum of unknown quality to calves, an optical Brix refractometer is an efficient and user-friendly way to determine the quality of colostrum.

Optical Brix refractometers are fairly inexpensive ($100 to $200) and are just as accurate as a digital Brix refractometer ($400-plus). When measuring IgG, a Brix percentage of 21 to 23 percent signifies good-quality colostrum that can be fed to calves without having to worry about FPT. You can even use a Brix refractometer to measure IgG concentrations in the blood of calves on-farm to evaluate the effectiveness of your colostrum management protocols.

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While measuring blood IgG content with a Brix, the cut-off for successful passive transfer should be a Brix percent greater than 8.4 percent. The benefits of using a Brix refractometer greatly outweigh their already low cost, and dairy producers should consider their implementation as an essential on-farm tool.

2. Quantity

As mentioned above, if you are feeding good-quality colostrum (equal to or greater than 50 grams of IgG per litre), you should feed 3 to 4 litres of colostrum in order to ensure passive transfer. While this recommendation seems easy enough to follow, it’s important to remember not all calves are the same bodyweight and therefore cannot all handle the same volume of colostrum.

For instance, Jersey calves (average birthweight 26 to 29 kilograms) or small Holsteins (e.g., twins) should not be fed the same amount of colostrum per meal as an average-size (about 40 kilograms) singlet Holstein.

Instead of feeding small calves one large 4-litre meal immediately after birth, it is important to break up this meal into two smaller feedings (e.g., 2 litres at birth and 2 litres 12 hours later) in order to optimize the efficiency of absorption of IgG.

Feeding an adequate volume of colostrum is not only important for passive transfer but also for the future productivity of your calves.

It has been shown calves fed only 2 litres of colostrum after birth had a significantly lower average daily gain (ADG), had double the veterinary costs and produced significantly less milk during the first and second lactation compared to calves fed 4 litres of colostrum.

The authors of this study concluded feeding a greater volume of colostrum translated into an additional 550 kilograms of milk produced per cow over the first two lactations, which results an economic return of $160 per cow in additional milk.

3. Timing

Timing of the first colostrum meal is just as essential as the quality and quantity of colostrum fed. It has been well-known since the 1970s the absorption of IgG is optimal during the first hours of life and decreases in a linear trend as the calf ages.

More recent research conducted at the University of Alberta in 2018 demonstrated calves fed colostrum at 45 minutes after birth had a higher concentration of IgG compared to calves not fed until six hours and 12 hours after birth (Figure 1).

The effect of delaying colostrum feeding on serum concentrations of IgG (mg/mL) relative to the time of birth

Moreover, calves fed at 45 minutes absorbed 50 percent of the available IgG from colostrum, while those fed later only absorbed 35 percent.

Although the importance of feeding colostrum as early as possible has been known for decades, a survey conducted in Quebec in 2010 demonstrated many calves are still receiving their first colostrum meal more than six hours after birth.

This is likely due to low levels of nighttime surveillance, which leads to late identification of the calf and late colostrum feeding. If this is a common occurrence on your farm, it may be worthwhile to implement video surveillance of calving pens or the use of a calving notification device.

4. Low bacterial count

In addition to feeding colostrum with an adequate concentration of IgG in a timely manner, good-quality colostrum should also have a total bacterial count less than 100,000 colony-forming units (cfu) per millilitre and a coliform count of less than 10,000 cfu per millilitre.

A 2012 study conducted in the U.S. across 12 states demonstrated 43 percent of samples did not meet these cut-off points for total bacterial count and coliform count, and 17 percent of samples had a total bacterial count greater than 1 million cfu per millilitre.

High bacterial and coliform counts have been shown to be negatively associated with IgG absorption, as well as overall calf health. This reinforces the importance of sterile and clean colostrum collection in order to reduce the chance of bacterial contamination.

When colostrum quality is poor (e.g., low IgG concentration, high bacterial count, bloody), if you do not have the means to continually measure IgG in colostrum, or if colostrum is unavailable, the use of a colostrum replacer may be considered as an effective alternative.

While calves fed a colostrum replacer or maternal colostrum in a 2018 study had similar blood IgG concentrations, colostrum replacer-fed calves have a lower probability of receiving contaminated colostrum compared to maternal-colostrum calves, as well as a lower probability of being treated for diarrhea.

Therefore, if you are having difficulty managing proper colostrum protocols on-farm, the use of a colostrum replacer may assist in eradicating any health concerns you are having with young calves as well as give you peace of mind your calves are always receiving good-quality colostrum and adequate amounts of IgG.  end mark

References omitted but are available upon request. Click here to email an editor.

Amanda Fischer
  • Amanda Fischer

  • Research Assistant
  • University of Alberta
  • Email Amanda Fischer

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