Grazing enhances immune parameters and complete blood count in calves

Summary

Seventy-two calves, distributed into three genotypes (Brown Swiss [BS], Limousin × Brown Swiss [LB] and Swiss Fleckvieh [SF]), were used in an extensive fattening trial from the fourth to the sixth month of life. Each farm included six calves of each genotype. The farm in Frick AG, where calves were kept in a barn, served as the control group, while the other three sites provided grazing access (Wülflingen ZH, Früebüel on the Zugerberg and Alp Weissenstein on the Albula Pass). Grazing time was approximately 8–9 hours per day. In the barn, all calves were fed the same hay ad libitum. The grazing calves also received 0.5kg of alfalfa and 1.3kg of maize pellets per animal per day, plus an additional 0.5kg of concentrates in the last four weeks. The calves at the Frick site received 1kg of alfalfa and 2kg of corn pellets per animal per day, plus 1.3kg of concentrates per day in the last 6 weeks and 4kg of fresh grass silage per animal per day in the last month of fattening. Blood samples were taken one week before slaughter on the 180th day of life, and at slaughter. Haemoglobin, haematocrit, erythrocytes, leukocytes and other blood count parameters as well as total protein and immunoglobulins were analysed in the blood, and lactate and cortisol were analysed in the blood from the slaughter. The farm elevation positively influenced haemoglobin, haematocrit and erythrocytes. α- and γ-globulins were higher in the groups with grazing access, especially at the high-elevation extensive sites. Overall, calves of the SF breed performed better than BS; LB were in the middle of the range.