One of the major challenges for dairy producers is to produce, harvest, and store high-quality colostrum and feed it to their replacement heifer calves. Limited published data are available in Australia regarding the relationship between colostrum management, hygiene, and quality. The objectives of this study were to investigate (1) the colostrum storage and handling practices carried out on farm; (2) the immunoglobulin concentration and bacterial composition of colostrum being fed to replacement dairy heifer calves; (3) the percentage of colostrum being fed to replacement dairy heifer calves that meet industry recommendations; and (4) risk factors for bacterial contamination of colostrum. The study was carried out on 24 dairy farms located near Rochester, Victoria, Australia. Two hundred forty colostrum samples were collected (10 samples per farm). Each farm harvested and stored first-milking colostrum under normal farm conditions. A 10-mL sample of the colostrum was collected in a sterile container immediately before feeding, and a Brix refractometer reading was taken. The samples were then frozen at -4°C and submitted for bacterial concentration analysis. Fifty-eight percent of colostrum samples met the recommended industry standard of a total plate count (TPC) of <100,000cfu/mL, and 94% of colostrum samples met the recommended industry standard of total coliform count (TCC) of 10,000cfu/mL. However, when all the current industry recommendations for TPC, TCC, and Brix refractometer percentage for colostrum quality were considered, only 23% of the samples met all standards. These findings demonstrate that a large number of calves were at risk of receiving colostrum of poor quality, with high bacterial loads that may have interfered with the acquisition of transfer of passive immunity and affected calf health. Further investigation is required to identify the farm-specific factors that may influence the level of bacterial contamination of colostrum. Recommendations as a result of this study include refrigeration of excess colostrum shortly (within 1h) after collection and thorough disinfection of the calf feeding apparatus before use.

The majority of samples assessed were below industry standard. Herd, lactation number, calf suckling or cow leaking colostrum prior to harvesting and time between calving and colostrum harvesting were factors that influenced colostrum IgG concentration. The results support current industry recommendations of harvesting colostrum shortly after parturition (ideally within 12 h of calving) and testing the quality of all colostrum prior to feeding to dairy calves.

The results from this survey highlight the need for greater awareness of industry standards for colostrum management and feeding hygiene.

The results from this survey highlight the need for greater awareness of industry standards for calf husbandry and weaning.