SmartCalfFat: Fat supplements to maximize calf productivity

Project leaders:

2021: Einar Vargas-Bello-Pérez
2022: André L.A. Neves

Background

Addition of lipids to calf rations is not generally practiced in Denmark. This is because appropriate types of lipid supplements and amounts are not established nor is it known at which growth phase lipid supplements will maximize productivity: during preruminant growth, after weaning or during both phases. This project will provide recommendations on the use of lipid supplements regarding amounts and types (saturated or unsaturated fatty acid sources) and the most appropriate growth phase (during preruminant growth, after weaning or during both) of supplementation that will add value to slaughter calf production.

Description of the project

In order to determine the maximum effect of the lipid/fat supplement type, the amount, and the time of supplementation, the project is carried out in two work packages (AP1 and AP2) to be conducted over two years. In AP1, at least 5 in-vitro experiments will be carried out to determine the breakdown in the rumen, total gas production, fatty acid production and methane production from a wide range of fat supplements. The in-vitro experiments will include saturated and unsaturated fatty acids in at least 3 doses based on rumen fluid samples from calves. This work will be carried out at the University of Copenhagen in the IVGPT laboratory in the first 8 months of 2021. Then a catalog of possible dietary supplements and their relative in-vitro value for in-vivo testing will be compiled.

Next, the effects of fat supplementation in the early postnatal phase of calf life will be determined. The work in this work package (AP2) will be carried out in a beef calves herd. Based on the results from AP1, the best possible supplements from the catalog will be selected for subsequent testing in the herd. The supplements will be tested in three treatment groups and will be compared to the baseline reference group: supplementary fat in milk replacer, supplementary fat in starter feed after weaning and supplementary fat in both milk replacer and starter feed. All explanatory variables are measured over a 9-month period after all treatment groups.

Body weight, body condition score, hip height, withers height, hip width, heart girth and fecal score will be assessed at the start of the experiments and during the different periods of supplementary feeding to assess the effect of these supplementary feeding strategies. At the same time as the clinical scores, blood samples are taken for analysis of hematology, immunoglobulins, hormones, metabolites and fatty acid profiles.

At the end of the project, we will be able to recommend the best type and amount of fatty acid supplementation and the most appropriate age/growth phase to administer the supplementation that will provide maximum growth and immune status of calves.

Future perspectives

The project will contribute with knowledge about and recommendations for the optimal type, quantity and time of use of fat supplements for beef calves pre- and post-weaning. An increase of 10-15% in growth is expected, depending on the type, quantity and timing of the supplementary feeding.

Results

The on-farm trial  (MSc theses- two students) were conducted to determine the effects of feeding saturated and unsaturated lipid supplements in milk replacers on productive traits and fecal microbiome. A summary of the in vivo trials is as follows:

• Saturated and unsaturated lipid supplementation did not increase weight gains in pre-weaned calves.
• Saturated and unsaturated lipid supplementation did not increase weight gains in post-weaned calves.
• Saturated and unsaturated lipid supplementation did not improve calf health based on blood metabolites.
• Saturated and unsaturated lipid supplementation did not change the microbiome composition and diversity. 

The results were presented to the farmer and project team on the 16th of March 2023 and to the KAF board members on the 2nd of June 2023:

• Effect of Adding Lipid Supplement to Milk Replacer and Starter Feed in Bull Calves 

The results of the trial that evaluated the impact of fat supplementation on weight gain and blood metabolites in calves will be reported in a research article, which is currently being prepared for submission in 2024.

Publications

• Effects of Adding Lipid Supplements to Milk - Replacers in Young Bull Calves (Master Thesis)
• The effect of adding supplemental fat to the milk replacer on the rumen microbiome in beef calves (Master Thesis)
• Effect of different lipids sources added to milk replacers on body weight, body condition score, fecal score, and biometric measurements in bull calves (Abstract no. 1079 of the 2022 American Diary Science Association Annual Meeting; J. Diary Sci. Vol. 105, Suppl. 1, pp. 30)

Sponsor

This project is sponsored by Kvægafgiftsfonden.

The project's results are made available free of charge to all companies active in the sector or sub-sector in question.