Feeding the right quantity at the right time is crucial, however, quality is equally important when dealing with colostrum, explains Volac’s nutritionist Ian Watson.
Every calf is dependent on absorption of maternal immunoglobulins (IgG) from colostrum within its first six hours of life for future health.
Colostrum quality is determined by the quantity of IgGs or antibodies – proteins to fight antigens, such as bacteria, viruses and toxins.
The IgG threshold must be 50mg/ml or greater, so it is essential to test colostrum you plan to feed with a colostrometer or refractometer, according to Ian Watson, Volac nutritionist.
He says: “Strictly speaking, only the first milking is colostrum. This is when the concentration of IgGs is at its highest. Colostral IgG levels start to reduce in the period between calving and first milking and between milkings.
“It is imperative calves are fed first milking colostrum as their initial feed to give the calf the best chance of absorbing sufficient levels of IgGs.”
To make sure your management is on track, Mr Watson advises checking calves for IgG status at seven days old, which can be done by your vet taking a blood sample.
Colostrum which was fed fresh, stored at 4degC or lower over a 48-hour period, or if freshly collected and fed immediately after pasteurisation, retained acceptable IgG levels, according to Teagasc trial findings.
In comparison, IgG levels fell to unacceptable levels in colostrum stored at higher temperatures of 13degC or more, says Teagasc’s Dr Emer Kennedy.
She says: “This response was due to bacteria binding to antibodies and reducing their efficacy. Consequently, lower levels of IgG were absorbed.
“Frequently, farmers are unable to pasteurise colostrum from newly calved cows prior to feeding, or for various reasons it cannot be fed to calves when freshly collected.
“However, we concluded storage at 4degC or lower for two days sufficiently minimises bacterial growth to ensure adequate passive transfer can occur when consumed by the calf.”
Times will arise when you have to turn to a colostrum replacer, perhaps due to high risk of the dam transmitting diseases such as Johne’s, or when fresh and frozen are not available.
Colostrum alternatives are useful in an emergency, or as a ‘top-up’ when an unknown quantity of colostrum has been suckled from the dam.
Volac’s Ian Watson advises ensuring your colostrum replacer of choice is a trusted brand and has been independently tested.
Colostrum replacers should be easy to use and of consistently high quality. As the first feed, this should be a highly digestible energy source in addition to supplying IgGs for early life protection, he says.
“Remember to ensure you are feeding enough colostrum replacer. If you are trying to replace three litres of natural colostrum [about 25 per cent dry matter], you would need to feed about 750g DM.
“Therefore, select a colostrum replacer to provide a high intake of essential energy and protein.
“It is important to check the colostrum replacer is enzootic bovine leucosis-free and pasteurised against Johne’s and other bacteria.”