Making sure calves get enough good quality colostrum is the cornerstone to all successful calf rearing enterprises.
56% of calves tested in local laboratories had received insufficient colostral antibodies and were therefore twice as likely to die as those calves receiving adequate levels of colostrum.
The calf is born without protective antibodies or immunoglobulins (Ig) and therefore depends on successful transfer of maternally derived antibodies from colostrum. Not only mortality, but also the likelihood of disease will be significantly increased as a result of failure of passive transfer in dairy and beef calves.
Data from AFBI Hillsborough reinforces this: calves with low immunity were twice as likely to experience scour as calves with adequate immunity, and beef calves with lower immunoglobulin levels received a greater number of antibiotic treatments pre-weaning, resulting in 40% higher veterinary costs, 17% lower live weight gains from birth to three months, and were on average 17 days older at slaughter. Colostrum also has a long term benefit in the dairy herd and calves that received four versus two litres of colostrum within the first hour of life produced 550 kg more milk over the first two lactations, in addition to having reduced veterinary costs.
Calves require a minimum of 120g IgG and adequate passive transfer will depend on three factors: quality of colostrum, quantity of colostrum and the calf’s ability to absorb the colostral antibodies.
The quality of colostrum is defined by the concentration of antibodies.
Quality of colostrum can vary between cows and is generally better in beef breeds than dairy breeds. Good quality colostrum should contain at least 50g IgG/L. Beef cow’s colostrum often averages > 100 g IgG/L, whereas Holstein cow’s colostrum averages 68.5 g IgG/L with one third of Holsteins producing poor quality colostrum (<50 g IgG/L).4 Colostrum quality declines rapidly after calving; therefore time of first milking is crucial.
Bacterial contamination of colostrum can transfer disease to the calf and will reduce the amount of antibodies the calf can absorb. Cows’ teats should therefore always be cleaned before harvesting colostrum and, as bacteria multiply very quickly at room temperature, colostrum should be refrigerated or frozen immediately in a plastic bag. Refrigerated colostrum should be used within one day and frozen colostrum can be stored at -18°C to -25°C for up to a year without changing its quality. Slow thawing in a water bath at temperatures below 50°C is recommended in order to preserve the temperature sensitive proteins.
Colostrum quality can be monitored using a colostrometer or a refractometer. These can be purchased through your veterinary surgeon or on the internet. Colostrometers however are fragile and temperature sensitive. The recommended temperature for testing is 22°C6. Temperature is not an issue with a refractometer.
Poor quality colostrum should not be fed to calves as the amount they would require would be too large to give them in the first few hours of life. For instance if poor quality colostrum containing 14 g IgG/L was fed the calf would require a minimum of 8.6 litres in the first two hours of life! This is clearly impossible!
The quantity of colostrum required to provide sufficient colostral antibodies will depend on the quality. Recent advice is that 95% of calves (35-45kg) will have received sufficient maternal antibodies if three litres of first milking colostrum is fed in the first two hours and ideally followed up by a further litre fed at six hours of age.
Calves allowed to nurse may not obtain this volume from the dam without intervention.
Suckler calves should suckle on their own or with assistance within two hours of birth. It takes approximately 20 minutes of continuous sucking for a calf to consume three litres of colostrum.
An American study showed that 61% of Holstein calves left to suckle received insufficient colostrum compared to 11% of stomach tubed calves. Therefore dairy calves should be hand- fed using a nipple bottle, bucket or stomach tube.
If a minimum of 3l of colostrum is fed in the first hour of life there is little difference in terms of IgG absorption between feeding from a teated bottle versus stomach tubing.
The calf’s ability to absorb the colostral antibodies decreases a few hours after birth and has gone by 24 hours. Therefore the earlier a calf is fed/ suckles after birth, the greater the level of IgG absorption.
Colostrum uptake can be monitored with the help of your veterinary surgeon. This can be done by routinely blood sampling five-ten calves between two-seven days of age and using the zinc sulphate turbidity test (ZST) or measuring serum total protein (TP). If ZST or TP are used for screening, 80% of calves should show values above 20 units or 55g/L respectively.