Comparison of three different colostrum feeding methods on passive transfer of immunity, growth and health in dairy calves

Sammanfattning: Transfer of passive immunity occurs in most animals across the placenta. In calves however, the maternal blood supply is separated from the calf. As a result, no in utero transmission of immunoglobulins occurs and the calves depends solely on ingestion of immunoglobulins from colostrum. In todays’ non-organic commercial dairies, allowing calves to suckle is uncommon and has largely been replaced by artificial feeding methods such as bottle or bucket feeding since it is easier to control that all calves consume enough colostrum to ensure good transfer of passive immunity. However, bottle or bucket feeding can be time consuming and difficult when calves are not motivated to drink thus increasing the risk of failure of transfer passive of immunity. For this reason, some dairy farms have recently introduced oesophageal tube feeding (OT) as a routine for feeding colostrum to new born calves since it fairly quick and it is easier to ensure that all calves receive an appropriate amount of colostrum in their first meal. Previous studies have compared these feeding methods and showed that suckling calves have lower concentration of IgG in serum than artificially fed calves. However, in these studies each feeding routine was carried out in different farms all with different management routines making it hard to distinguish the effects of the feeding method from other management practices (such as general hygiene, housing, colostrum management etc.) that may have influenced the results. Furthermore, most studies comparing the three different feeding methods do not report growth rates or health of the calves. Therefore, the aim of this study was to compare the effects of three different colostrum feeding routines on the passive transfer of immunity, growth and health of newborn dairy calves that were handled in the same way (same farm, housing, management and staff). Sixteen new-born heifer calves were included in this study and randomly allocated to one of three different colostrum feeding methods: suckling its mother (suckling), bottle or oesophageal tube (OT) feeding. The calves were monitored for 2 weeks and feed intake, growth rate and health were recorded. In addition, IgG concentrations in the mothers’ colostrum and in the calves’ blood serum at 24 and 48 h after birth were measured using an ELISA technique. Due to the fact that only 16 calves fulfilled the criterions to be included in the study, no definite conclusions could be drawn from our results. When analyzing the results however, there were no significant differences between the different feeding methods in terms of serum IgG levels at 24h and 48h of age or calf health. The suckling group had a higher mean feed intake/meal during the first week compared to the tube fed group but growth rates were not different between the groups, at least until 14 days of age. From a management point of view, the only advantage of using an oesophageal tube to feed the calves was that the first feeding took significantly less time compared to feeding with a bottle. However, when calculating the overall time it took to feed the calves during the first four days, the difference was no longer significant. Furthermore, the time taken to feed the suckling calves was less than the OT group when including the meal where the suckling group remained with the mother. When reviewing our results and compared them to previous studies however, we concluded that the use of an oesophageal tube is a good way to ensure that calves that do not voluntary drink receive sufficient amounts of colostrum to resist infection. However, for feeding healthy calves with good motivation to drink OT does not appear to offer any advantages over bottle feeding or suckling in terms of transfer of passive immunity, health and growth. Based on these preliminary results, the routine use of OT feeding is hard to justify since it is an invasive procedure and denies them the opportunity to express their natural behavior of suckling without offering any clear health advantages.