THE EFFECT OF COLOSTRUM STORED DIFFERENTLY ON PASSIVE IMMUNITY TRANSFER IN CALVES

Colostrum is one of the most important sources of essential nutrients to improve the likelihood of calf survival. In particular, colostrum contains immunoglobulins, specifically IgG, which when absorbed, protects the calf from infectious disease. Passive transfer of immunoglobulins is considered as would have failed if calves do not have a sufficient concentration of IgG in their serum when sampled at 24 hours of age. Failure of passive transfer in calves is associated with a greater mortality rate, compromised pre-weaning health and weight gain, and even reduced productivity as an adult cow. To minimize failure of passive transfer in newborn calves, a successful colostrum management plan needs to be in place, which requires producers to consistently provide calves with a sufficient volume of clean, high-quality colostrum within their first hour of life. A management plan also entails storage of colostrum under different conditions and therefore the objective of a study by Dr G. Cummins and colleagues was to compare

serum IgG concentration, weight gain and health characteristics in Irish spring-born dairy calves fed colostrum stored under a range of conditions. Their study was published in the Journal of Dairy Science, Volume 100 of 2017, pages 525 to 535, the title being: The effect of colostrum storage conditions on dairy heifer calf serum immunoglobulin G concentration and preweaning health and growth rate.

In their study they immediately after birth allocated 75 heifer calves to one of five colostrum treatments: (1) fresh pasteurized colostrum, fed immediately after pasteurization; (2) fresh colostrum, fed immediately after collection but not pasteurized; (3) colostrum stored unpasteurized at 4°C in a temperature-controlled unit for two days before being fed; (4) colostrum stored unpasteurized at 13°C in a temperature-controlled unit for two days before being fed; and (5) colostrum stored unpasteurized at 22°C in a temperature-controlled unit for two days before being fed. All colostrum initially had IgG concentrations more than 50 g/L. Blood samples were obtained from calves via the jugular vein before colostrum feeding and at 24 hours of age to determine the rate of passive transfer of IgG. Calf weights were recorded to monitor weight gain (kg/d) from birth to weaning.

Colostrum stored in warmer conditions (22°C) had 42 times more bacteria present and a pH that was 0.85 units lower and resulted in a serum IgG concentration that was almost 50% lower compared with colostrum that was pasteurized, fresh, unpasteurized and stored in a temperature-controlled unit, or stored at 4°C for two days. Colostrum stored at 4°C for two days had more bacteria present than pasteurized and fresh colostrum but did not result in reduced calf serum IgG concentrations. Average daily weight gain from birth to weaning did not differ among treatments. The results suggested that even if colostrum has sufficient IgG (more than 50g/L) but cannot be fed to calves when freshly collected, storage at about 4°C for two days is advisable to ensure adequate passive transfer.