The Combined Effect of IgG and Fe Supply and Feeding Management on Growth Rates of Calves on Eight Commercial Dairy Farms in Germany

SIMPLE SUMMARY: Well-thought-out calf rearing is essential to produce long-lived and productive cows for future dairy herds. The first days of a calf’s life are a very important period. It is known that calves that are adequately supplied with colostrum during this period have sufficient antibodies. They gain weight faster and fall ill less frequently. Identifying other management factors that have positive effects on calf growth is the subject of this study. To investigate this, 123 Holstein calves on eight conventional dairy farms were followed from birth to 50 days of life in spring 2017, and the influence on the animals’ weight gain due to management factors such as timing and supply of colostrum, iron supplementation, feeding regime and microbial load at first feeding was analyzed. The results show that, in addition to an adequate level of antibodies in the colostrum fed to the calves, the iron concentration in the calves’ blood and the feeding regimen play an important role in the calves’ weight gains and thus in calf rearing. ABSTRACT: During the first days of a calf’s life, the foundations are laid for successful growth and thus also for the later performance of the cows. The aim of the present study was to analyze the impact on the weight gain of newborn calves due to important management factors related to colostrum supply, iron supply, feeding regime and microbial load at first feeding. In spring 2017, information of 123 Holstein calves were analyzed with regard to the colostrum supply and management factors on eight commercial dairy farms located in Germany. Additionally, blood samples of newborn calves were analyzed for total immunoglobulin G (IgG) and serum iron content. Furthermore, Brix analysis and analysis of contamination by E. coli were performed on first colostrum samples from teats or buckets. Average daily weight gain of calves at days 14 and 50 was calculated. The colostrum IgG was estimated by Brix refractometer. The volume of initial colostrum supply and the time between birth and colostrum intake significantly (p < 0.05) influenced the serum IgG concentration. The serum IgG concentration, the serum iron concentration and the feeding regimen (restrictive or not restrictive feeding) had a significant effect (p < 0.05) on daily weight gains. In conclusion, this study shows that, in addition to a sufficient supply of immunoglobulins, other aspects, such as an adequate colostrum, iron and milk supply, play an essential role in calf growth rates.