Hematological and inflammatory markers in beef-on-dairy neonatal calves: new insights into reference intervals

Colostrum early in life supports the development and function of the gastrointestinal tract while also influencing the endocrine and metabolic systems of the newborn calf. A complete blood count (CBC) analysis is a blood test that aids as a diagnostic tool and can provide insight into the overall health of the individual. While there are established reference intervals for adult cattle, there are no universally used intervals for neonatal or young calves. The objectives of this thesis research project were to evaluate the pattern of blood markers of animal health in beef-on-dairy calves challenged with Salmonella; and to evaluate the impact of colostrum feeding on the physiological and immune blood parameters in beef-on-dairy calves from birth until 21 days of age. To achieve the outlined objectives, a total of 24 newborn male and female beef-on-dairy calves were enrolled in this study. Twelve calves received colostrum at the first feeding, while the other half were given milk replacer at their first feeding (n = 12/group). Following this initial feeding, all calves were subsequently fed milk-replacer. At 8 days of age, a subset of calves from each group was orally inoculated with Salmonella Typhimurium to induce an inflammatory response. On day 11 of the trial, all calves inoculated with Salmonella were humanely euthanized for tissue collection while the remaining calves were kept until 21 days of age for further evaluation of health parameters in the blood.