From a healthy calf to a performing cow: a case-control study

A dairy herd must be considered an integrated production unit. From newborn calves to milking cows, animal health status is pivotal to get satisfactory economic results. The neonatal phase of calves is a period of life that needs extra care due to their vulnerability. Diarrhea is considered the main pathology affecting newborn calves. Conversely, respiratory disease is the main cause of losses after sixty days of life. The present study aimed at assessing the impact of neonatal diarrhea on growth, milk productivity and health status in a selected population of dairy cattle. A case-control study involving 300 calves from 5 large dairy herds located in the Po Valley (Italy) was carried out. All animals received lived-modified or inactivated, monovalent or combined vaccines for immunization to Bovine Herpesvirus 1 (BoHV-1), Bovine Viral Diarrhea Virus (BVDV) and Bovine Respiratory Syncytial Virus (BRSV). Particularly, most calves were administered with IBR marker and BRSV vaccines by intranasal route as priming immunization treatment. The enrolled animals were divided in two groups, each consisting of 150 calves. In the group A (cases) were included the animals experiencing severe neonatal diarrhea. Conversely, the group B (controls) included calves showing no clinical signs of neonatal enteritis. The animals were monitored in order to measure the body weight at birth, 6 and 15 months of age and milk production. Moreover, mortality rate and incidence of respiratory disease episodes during life were recorded. Animals of Group A showed a lower body weight at 6 and 15 months of age and a significant loss of milk production compared to those of the Group B. Moreover, incidence of respiratory disease and relapses were significantly higher in Group A. Results support the thesis that neonatal enteritis has a negative impact on weight gain during the grow period, milk production and is related to severe respiratory disease onset.