Table 1.
Search strings used to collect studies related to colostrum characteristics and management and their relation to transfer of passive immunity in dairy calves.
Fig 1.
Flow chart of studies identified, screened, and included in the data analysis [30].
Fig 2.
The number of studies on colostrum characteristics and management practices on transfer of passive immunity in dairy calves published each year between 1972 and 2020 (n = 256).
Fig 3.
Distribution of the sample size used in studies (n = 254).
Two studies had unclear or did not report the sample size.
Fig 4.
Schematic summary of the volumes of colostrum compared in 17 controlled studies that compared different quantities of maternal colostrum fed at first feeding.
Quantity fed at a proportion of body weight was converted to liters based on the average body weight reported in 2 studies. The thickness of lines represents the number of studies conducted between the combinations of treatment groups.
Fig 5.
Schematic summary of the concentrations of IgG in colostrum in 24 controlled studies that compared colostral quality.
Studies that targeted other risk factors as the main intervention (n = 10), wider range of colostral Ig concentration (n = 4), no information on colostral Ig concentration (n = 2) and fermented compared with unfermented colostrum (n = 1) were excluded. The thickness of lines represents the number of studies conducted between the combinations of treatment groups.
Fig 6.
Schematic summary of the times compared in 21 controlled studies on the timing of first feeding of colostrum.
Three studies were excluded since the timing of feeding ranged over multiple time periods or had an unclear definition. The thickness of lines represents the number of studies conducted between the combinations of treatment groups.