7 considerations for choosing a colostrum replacer
You never get a second chance to feed the first meal. Many calf colostrum replacers are available, and choosing the right colostrum replacer for your program can be complicated.
Many dairy producers choose to use maternal colostrum as their primary source of immunoglobulin (IgG) protection for their calves. Having a colostrum replacer on the shelf provides a good option when colostrum volume or quality are insufficient, when biosecurity concerns exist, or when timing does not allow for maternal colostrum to be harvested and fed.
Here are seven factors to consider when choosing a colostrum replacer:
Grams of IgG delivered: The most important factor to consider with colostrum replacer is if it delivers enough IgGs to the calf. Increasing the amount of IgGs fed and absorbed results in greater protection for the calf. The amount of IgGs the calf needs is influenced by the amount of immune challenge the calf is likely to experience, the size of the calf, and when the calf is fed after birth. Colostrum replacers contain between 100 and 200 grams per dose. Quality maternal colostrum contains greater than 50 grams of IgGs per liter. So, calves fed 4 liters of maternal colostrum receive approximately 200 grams of IgGs. Calves fed 6 liters of maternal colostrum in the first 12 to 14 hours receive approximately 300 grams of IgGs.
Cost: An important aspect to evaluate a colostrum replacer is cost. One method to compare colostrum replacers is to evaluate value in dollars per gram of IgG. Simply divide the cost per dose by the grams of IgG to determine the dollars per gram of IgG. For example, if a colostrum replacer is $40 per dose and delivers 150 grams of IgG, the cost per gram of IgG is $0.27. Our market analysis determined colostrum replacers range from about $0.25 to $0.35 per gram. Choose a colostrum replacer that provides the greatest return on your investment.
Mixability: For a colostrum replacer to be effective, it needs to readily go into solution. Ideally, a colostrum replacer should have similar properties to maternal colostrum, which is complex but homogenous. Colostrum replacer that does not readily go into solution might have decreased absorption efficiency. Certainly, undissolved residual colostrum replacer remaining in the mixing bucket, nipple bottle, or tube feeder doesn’t get into the calf, and that decreases the effectiveness of the colostrum replacer.
Absorption efficiency: IgGs must be absorbed to effectively protect the calf until its own immune system becomes competent. Absorption efficiency of colostrum replacer IgGs is highly variable and ranges from 8% to 60%. Many factors impact IgG absorption efficiency, such as the calf, colostrum feeding management, timing of blood collection, and hydration status at the time of blood collection. The primary factor specific to colostrum replacer is gentle manufacturing processes to retain the chemical structure and biological activity of the IgG molecules.
Based on previous research, blood volume of young calves is estimated by multiplying birth bodyweight (in kilograms) by 0.09.
Let’s do an example. A calf with a birth bodyweight of 85 pounds (38.6 kg) has an estimated blood volume of 3.5 liters (38.6 x 0.09). In this example, the calf is fed a colostrum replacer providing 150 grams of IgGs. If the blood sample collected at 24 hours of age has an IgG concentration of 15 grams per Liter, then the calculated transfer efficiency is 35%.
(15 g/L x 3.5L)/150 g IgG) x 100 = 35%.
Serum total protein is not a reliable measure of passive transfer in calves fed colostrum replacers: Measuring total protein concentration in serum of calves from 1 to 7 days of age is a reliable method to determine passive transfer in calves fed maternal colostrum. The correlation between serum total protein and serum IgGs in colostrum-fed calves is both high and consistent.
However, serum total protein is not a reliable method to determine passive transfer in calves fed colostrum replacer. The correlation between serum total protein and serum IgGs in calves fed colostrum replacer is poor. Reasons for this lack of correlation are unclear, but are likely due to both the type and amount of protein fed to calves in a colostrum replacer versus maternal colostrum. Calves fed maternal colostrum receive both greater amounts of total protein and greater amounts of casein protein.
Packaging: Many colostrum replacer packaging systems can work. Convenient, safe and consistent delivery of the colostrum replacer are key attributes of packaging. Individually measured doses of colostrum replacer deliver the correct amount of IgGs to the calf more consistently. Colostrum replacers requiring multiple bags or partial bags to achieve the desired dose can be confusing to calf feeders and result in feeding errors. Multiple-use bulk containers of colostrum replacer might increase the risk of bacterial contamination of the colostrum replacer. Additionally, mix-in-pouch packaging of colostrum replacers requires the user to attentively knead the pouch to make sure all the colostrum replacer is fully in solution.
Calf response: The most important factor to consider when choosing a colostrum replacer is calf response. Calves fed colostrum replacer should exhibit similar health and growth responses as those fed equivalent amounts of maternal colostrum.
A timely and adequate feeding of high-quality colostrum or colostrum replacer is an essential step to raise healthy calves. Choose an IgG source (maternal colostrum or colostrum replacer) that protects your investment in raising calves. If using a colostrum replacer, be sure the product you choose is the right fit for your youngstock program.
Dr. Noah Litherland is the dairy youngstock technical specialist for Vita Plus