Breeding Matters - Colostrum – The First and Most Important Feed
Date Posted: 17th February 2026
Dr Charlotte Martin, Group Veterinary Officer, Ai Services
A calf’s future performance starts long before genetics can show their full value. The very first feed a calf receives – colostrum – plays a critical role in determining its future health, growth, and resilience. Getting colostrum management right is not just good practice – it’s one of the simplest and most effective ways to protect genetic potential and shape lifetime performance.
Calves are born without a functioning immune system. Unlike adult cattle, they cannot fight infection on their own. Colostrum is essential because it contains immune cells (IgG antibodies), which pass directly from the cow to the calf. When fed correctly these antibodies are absorbed through the calf’s gut wall into the bloodstream, providing vital protection during the first weeks and months of life.
To make colostrum work properly, three basic principles must be followed: the three Qs - Quality, Quantity, and Quickly.
Quality is key. Good colostrum must contain enough antibodies (min 50g of IgG antibodies per litre of colostrum), to give effective immunity. The quality is influenced by the cow’s nutrition, health, age, and how well she was managed during pregnancy. Well-fed, healthy cows generally produce better colostrum, while first-calvers or cows under stress may not. Measuring colostrum quality on farm, using a Brix refratomoter, removes the guesswork in seconds. For cattle, a Brix reading of at least 22% is considered the minimum for adequate protection, while readings closer to 30% are associated with optimal antibody transfer and stronger immunity in the calf.
Quantity is equally important. Even high-quality colostrum will not protect a calf if too little is fed. As a rule of thumb, calves should receive around 10% of their birth weight in colostrum within the first few hours of life. Allowing a calf to suckle naturally can make it hard to judge intake, while controlled methods such as bottle or tube feeding, can help ensure the calf gets enough volume.
Quickly - speed is the final factor. A calf’s gut most effectively absorbs antibodies in the short period after its birth. Absorption is highest in the first two hours and declines rapidly after the first six hours of life. By 24 hours, the gut is effectively closed. Feeding colostrum as soon as possible after birth gives the calf the very best chance of building strong immunity.
Where there is any doubt, the use of a proven colostrum supplement or replacer such as SCCL can help bridge the gap. Made from natural bovine colostrum powder that is dense in colostral fat, it enables farmers to respond quickly in situations such as poor colostrum quality, insufficient volume, first-calvers, or difficult calvings.
The reality is good colostrum management reduces disease, lowers treatment costs, improves growth rates, and supports long-term productivity. Genetics may set the ceiling, but good colostrum determines whether calves ever reach their potential. When it comes to breeding success, quality, quantity, and quickly matter most.