Benefits of Colostrum Pasteurisation

Many disease causing organisms can be transmitted to calves via colostrum feeding, such as Mycoplasma, Listeria, E.coli, Salmonella and perhaps most importantly, the bacteria that causes Johne’s disease (Mycobacterium avium paratuberculosis or MAP).

Pasteurisation is the process of heating colostrum (or milk) to a certain temperature for a specific time to reduce the bacterial load but it will not eliminate bacteria completely. There is no guarantee that pasteurisation kills all MAP bacteria so there is a small risk these bacteria can survive and infect the calf.

Pasteurisation can reduce the immunoglobulin or antibody levels (in the region of about 10%) and so only good quality colostrum should be pasteurised (ideally over 60g/L IgG). The standard recommendation is to heat colostrum for 60 minutes at 60˚C. Above 62˚C, levels of antibodies are significantly reduced and colostrum can thicken and coagulate, making it more difficult to feed. This can lead to failure of passive transfer and greater susceptibility to scours.

A Spanish study has shown that pasteurising colostrum can reduce morbidity and mortality rates in calves during the first 3 weeks of life (Armengol and Fraile 2016). One group of Holstein calves (143 males and 144 females) were fed unpasteurised frozen colostrum (6–8 L during the first 12 h of life) and then onto whole milk. The second group (150 male and 150 female Holstein calves from the same farm) were fed the same levels of pasteurised colostrum and whole milk. All calves were blood sampled within 2 to 5 days to assess serum total protein (g/dL) as a measure of passive transfer of antibodies.

Colostrum and milk were tested for bacteria levels (cfu/mL) and calves were clinically examined every 24 hours until 3 weeks of age for signs of ill health. Bacterial levels in colostrum and milk were reduced between 1 and 2 log10 with pasteurisation.

Pasteurisation of colostrum and milk significantly reduced morbidity and mortality rates in calves compared to the unpasteurised group during the first 3 weeks, even when appropriate colostrum ingestion took place (see table below):

 

Unpasteurised group

Pasteurised group

Average Serum Total Protein g/dL

(range)

7.27

(5.8 - 9.2)

7.34

(5.8 - 9.0)

Mortality %

6.5

2.8

Morbidity %

15.0

5.2

 

While serum levels of total proteins in both groups was very similar, the lower levels of bacteria in the pasteurised colostrum/milk helped improve calf health and survival. In particular, neonatal calf diarrhoea showed a reduction in incidence compared to respiratory disease.

Reference: Armengol, R. and Fraile, L. 2016. Colostrum and milk pasteurisation improve health status and decrease mortality in neonatal calves receiving appropriate colostrum ingestion. Journal of Dairy Science, 99 (6): 4718-4725.

lorna.macpherson@sac.co.uk; 07760 990901

 

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