Neonatal calves must acquire passive immunity through colostrum ingestion, as they receive no maternal immunoglubulins (IgG's) prior to birth. Therefore, the immune status of pre-weaned calves directly depends on the quantity and quality of colostrum ingested during the first few hours of life.
With appropriate colostrum protocols, calves should receive colostrum as soon as possible after birth, with at least 4 to 6 litres ingested within the first 8 hours. If passive transfer of immunity fails, rates of respiratory and digestive disease may increase, as well as mortality.
Lower morbidity and mortality of calves
In terms of hygiene and timing good management of colostrum and milk feeding is vitally important in order to bolster health status. Even if hygienically preserved and fed, both colostrum and milk can contain bacteria and other pathogens which can seriously compromise calf health. Pasteurization of both liquids significantly decreases bacterial load and can still maintain their high quality and natural factors. While studies in the past have found that calves fed on-farm pasteurized colostrum and waste milk have had lower morbidity and mortality when compared to those fed non-pasteurized liquid feed. Until now no study had looked to quantify the effects of pasteurization when higher quantities of colostrum were fed to both groups.
Raw colostrum or non-pasteurized liquid feed
In their research article entitled 'Colostrum and milk pasteurization improve health status and decrease mortality in neonatal calves receiving appropriate colostrum ingestion' Armengol and Fraile do just that. In their 18-month study involving 587 neonatal Holstein calves, they set out to evaluate how on-farm pasteurization of bulk tank milk and raw colostrum could improve health status, reduce neonatal illness, and decrease mortality during the first 3 weeks of life for calves receiving appropriate colostrum protocols. The results are compared with calves receiving non-pasteurized, but high quality and quantity of liquid feed.
The results indicate that pasteurization of colostrum and milk do indeed significantly improve calf health and reduce both morbidity and mortality during the first 3 weeks of life, compared to calves receiving the same high quality and quantity of colostrum and milk feed, but without pasteurization.