No easy route in choice
No easy route in choice
of colostrum substitute
Choosing a colostrum can be
more tricky than first thought.
John Burns reports
W HICH ewe colostrum substitute gives best value for money? The short answer to that question is no one knows. Independent comparison trials could be done, but as yet no one is prepared to fund them and allow the results to be published.
The issue is complicated by the fact that colostrum serves two main functions: Providing readily available energy and ready-made protection against disease in the form of immunoglobulins. Both are vital for survival of newborn lambs, while it also supplies essential minerals and vitamins.
Any idea of requiring products to carry standard analysis information has so far been quickly smothered by the companies marketing them. Understandably, each company provides only information which flatters its own product.
According to Chris Hodgson of the Moredun Research Institute in Scotland the only meaningful tests for both main functions of colostrum would involve feeding the substitutes to lambs and measuring how much of the colostrum components were taken up and how rapidly.
Disease protection
"So far as immunoglobulins, the components which protect against diseases, are concerned, both quantity and specificity are important. And in general the more immunoglobulins the merrier.
Immunoglobulins come in three categories: IGGs which are absorbed and work in the bloodstream, and IGAs and IGMs which work on the gut lining.
"In the first few days many potential problems are in the gut and it is important for colostral immunoglobulins to be present to boost protection against disease. Later the important thing is how much has moved into the bloodstream to protect against other diseases."
Similarly, the energy sources should be readily absorbed if they are to be effective substitutes for ewe colostrum.
Dr Hodgson says the institute has tested two or three colostrum substitutes. "So far we have not come across a bad one". But those tests were financed by the companies concerned and so results are confidential.
The Veterinary Medicines Directorate (VMD) is currently working towards implementing an EC directive requiring any product claiming medicinal properties to be licensed and backed up by trials data. Consultations between the VMD and the companies which make and/or market colostrums and colostrum substitutes are in progress and decisions are expected by April.
Dual role
The dual role of colostrum – providing nutrition and disease prevention – mean vigorous debate about whether colostrum substitutes should be licensed. Directive guidelines mean they should be included if they have medicinal ingredients such as immunoglobulins and so are medicinal by function. And they will also be included if they are marketed with medicinal claims.
The trials data required to obtain a VMD product licence is expensive and it is thought likely that in some cases the cost will be avoided by simply removing the medicinal claims and references to immunoglobulins from product labels and promotional literature. Any product licensed by VMD carries its licence number on the label, indicating that VMD is satisfied about its safety and efficacy. But whether we will be any nearer the information needed to work out what is best value for money is doubtful.
Ewe colostrum substitutes fall into two main categories: Those based on concentrated cow colostrum (mainly sourced from North America) and those based on products derived from cows milk whey.
Immunoglobulins from cow colostrum appear to be as effective as those from ewe colostrum, provided the cows have faced the appropriate disease challenges. That may be provided artificially by vaccinating cows.
Industrial processes can also be used to produce immunoglobulins which can be added to colostrum substitutes if necessary.
Maggie Gould, technical manager for Volac, which makes its colostrum substitute from cows milk whey, suggests asking for trials data about each product. Some do not have any.
"In terms of analysis, most products dont state an energy value but you could look at the total dry matter in a lamb dose of made-up product. Young lambs can use lactose, fats, and proteins, so look at total nutrients."
In general, 150ml of ewe colostrum would have about 45g of dry matter. So how can some of the colostrum substitute boluses which weigh no more than 10-20g be of much help as an energy source?
Ms Goulds understanding of the VMDs approach is that only immunoglobulins will be considered for licensing and a small bolus could contain enough of these to be effective in helping prevent disease. On that basis it could get a product licence even if it contained no energy source at all, she fears.n
Lack of independent trial data and standard analyses means ensuring best value for money from colostrum substitutes can be difficult.