Do not underestimate the value of proper colostrum feeding. Newborn calves have an underdeveloped immune system and rely completely on colostrum to provide immunity against common diseases such as scour.

This immunity comes from immunoglobins in the colostrum. These are most plentiful in the first milking and the maximum absorption occurs in the newborn calf within the first two hours.

Colostrum IgG concentration in milk has been shown to decrease by 3.7% per hour post-calving.

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An excellent guide is the 3-2-1 rule. The calf should be removed from the dam, all quarters of the cow milked and this should be the first milking (1). A minimum of 3l (3) should be given to the calf within two hours (2).

Calves should get a further two litres four to six hours later. Any calf that won’t suck should be fed this volume via stomach tube, but care should be taken that this is done correctly.

Factors affecting quality

In general, older cows have better-quality colostrum than younger cows and heifers.

Healthy cows produce better-quality colostrum, while concurrent disease, poor nutrition and short dry period reduces quality. Any cows running milk prior to calving will have poorer-quality colostrum.

Colostrum should be stored, as it may be needed in emergency situations. Only store colostrum from mature cows.

Do not pool colostrum, this may lead to the spread of Johne’s disease within the herd.

Take care when thawing frozen colostrum; it should be immersed in warm water and left to thaw until it reaches body temperature. Do not microwave or thaw in boiling water, as this will damage the immunoglobulins.

Passive transfer

One of the main contributing factors to calf scour is failure of passive transfer. Leaving the calf sucking the dam does not ensure passive transfer occurs.

When investigating calf scour outbreaks, we routinely measure zinc sulfate turbidity. This test is done at less than 14 days old and this tells us if poor colostrum management is a major factor contributing to calf illness and death.

Padraic Kilmartin works at Glasslyn Veterinary Clinics, Glasslyn Rd, Bandon, Co Cork. Glasslyn Veterinary Clinics is part of XLVets, a group of practices working together to achieve a better future for agriculture and veterinary in Ireland. For information, see www.xlvets.ie.