Dog and cat owners are increasingly looking for an alternative to ready-made wet food, and many more vets are being confronted with questions about BARFing (BARF = Bones and Raw Food) and cooking.
One of the most important questions is whether the home-prepared ration really covers all nutrients, minerals and vitamins. Various laboratories, such as IDEXX Laboratories, offer a testing option to make it easier for the vet and owner to assess the home-prepared ration.
The so-called BARF profile is a blood test in which mainly calcium, phosphorus, copper, zinc, iodine and T4, vitamin A and vitamin D are analysed. BARF profiles are very popular, but the result should be interpreted with caution.
Why is a BARF profile useful despite possible misinterpretations and how can one eliminate a nutritive misuse?
A BARF profile is often a popular choice, as it provides indications of possible deficiencies and over-supply. Whether a deviation from the norm is the result of a nutritive deficiency can be clarified by means of a nutritional counselling session. It is important to know that the blood levels of calcium, phosphorus, copper, zinc and iodine in particular only change in the case of long-term or extreme deficiencies.
- Calcium: 99% of calcium is bound in the bones and teeth, only 1% is present as ionised calcium or bound to organic acids and protein in the blood and lymph. Calcium is very important for the skeletal system and bone structure as well as for blood clotting, nerve conduction, muscle contraction and pH balance. The calcium level in the blood is kept within very narrow limits by the parathyroid hormone, calcitonin and vitamin D metabolites. In the case of calcium deficiency and oversupply, the calcium level in the blood is quickly brought back into the normal range. In addition, there are many other possible causes for a change in the calcium level, which should also be taken into account and clarified.
- Phosphorus: In the blood, phosphorus is present as inorganic phosphate, organic ester and phospholipid. It is important for the formation of ATP, the formation of cell wall and cell nucleus components, and it also influences the pH balance and the function of tendons and ligaments. In the blood, phosphorus is less tightly regulated and depends on age and feeding although diseases and medication can also influence the phosphate content in the blood.
- Copper is loosely bound to albumin and certain amino acids directly after absorption from the intestine and is then present in the blood bound to ceruloplasmin. The main storage site is the liver, so a liver biopsy would be the best way to assess the copper status, as the blood status is only a snapshot and says nothing about the body's copper reserves. Copper contributes to the formation of enzymes, blood cells and pigment. The copper level can drop if there is a feeding-related deficiency. A secondary copper deficiency with an adequate supply of copper in the feed can also cause this picture if the supply of calcium and/or zinc is very high, as less copper is then absorbed through the intestine.
- Zinc is bound to globulin and albumin in the blood. It is important for the formation of enzymes, for a strong immune system and for skin health. The zinc content in the bone, the main storage site, is the most significant. An altered zinc level can be an indication of a feed-related deficiency or diseases, toxic causes or an artefact in the blood sample can also cause this.
- Iodine and T4: Iodine is present in the blood as free iodide, bound to plasma proteins or as a component of the thyroid hormones Thyroxine (T4) and Triiodothyronine (T3). Since iodine deficiency primarily affects thyroid hormone formation, iodine is measured together with T4 in 50% of cases. In addition to checking the feed ration, the iodine content in the urine also provides a good estimate of the alimentary iodine supply, because it increases linearly with increasing feed and decreases with reduced feed. According to current knowledge, excessive iodine intake, as well as insufficient iodine intake, leads to lowered T4 values and increased TSH levels. A change from a high iodine ration to a lower iodine ration can lead to a temporary undersupply. The adaptation phase can last up to one year.
- Vitamin A refers to several chemical compounds, including retiol and retinol ester. The storage organs for vitamin A are primarily the liver and kidneys. It serves to maintain and regenerate the skin, mucous membranes and retina. It is currently common to measure retinol, but the significance of the measurement is scientifically disputed.
- Vitamin D is transported in the blood bound to proteins, with the largest proportion being original cholecalciferol and the remainder divided between 25-hydroxycholecalciferol, 1,25-dihydroxycholecalciferol and other vitamin D metabolites. Vitamin D is mainly stored in the lipid reservoirs of the animal and is relatively evenly distributed in the body. Like calcium and phosphorus, 1,25-dihydroxycholecalciferol is kept almost constant in the blood via the interaction of parathyroid hormone and calcitonin. Therefore, this vitamin D metabolite does not provide sufficient information about the daily vitamin D status in the body. 25-hydroxycholecalciferol, which is reduced in the blood in the case of a nutritive vitamin D deficiency, is more suitable here.
Nutritional counselling as a useful addition to the BARF profile - how does a ration check work?
A ration calculation is based on the required figures of the dog and the cat on the basis of the NRC (National Research Council, Nutrient requirements of dogs and cats, 2006). The weight, age, sex and activity of the dog are taken into account. In order to see whether the feeds nutritional supply is sufficient, the sum of the individual nutrients, minerals and vitamins it contains is compared with the requirement. The desired result is a supply that meets the animal's needs. Neither a permanent oversupply nor a long-lasting undersupply of important minerals and vitamins is recommended. Nutritional counselling not only examines the ration but also adjusts it to meet the needs of the animals once any deficiencies have been identified.
The bottom line is: A BARF profile can be an argumentation aid for the vet to have the ration calculated by a professional in case of deviating findings. However, an inconspicuous blood result is not synonymous with a balanced diet that meets the requirements. In order to be able to quickly and reliably assess the nutrient supply in a BARF ration at a glance, a ration calculation is the method of choice.