STILLBORN CALVES

If there is a high incidence of stillbirths, the first step in the investigation must be a careful examination of the records. Were the majority of cases associated with a particular sire, with twins, with heifers or with older cows? For example, if twinning is significantly higher than the normal rate of 4-5%, this could be the sole cause of the problem.

Iodine has been strongly implicated in the perinatal weak calf syndrome, which has caused stillbirth rates as high as 30% in Ireland. Investigation of iodine deficiency by means of blood samples and foetal goitre weights is discussed in Chapter 12. Selenium/ vitamin E deficiency may produce ‘slow calvings’ in heifers, but this has not been well proven. For example, some heifers seem to start calving and then proceed no further, so that by the time assistance is given, the calf is already dead. Similarly, a high inci­dence of milk fever in cows could be involved. In both cases it must be worth blood sampling a few animals to confirm that selenium, calcium and magnesium status is adequate. To get a true assessment of cal- cium/milk fever status, samples need to be taken from the cow at calving.

Potential causes of stillbirths include:

• poor sire selection, producing oversized calves

• heifers and cows which are either extremely fat or excessively thin at calving

• poor stockmanship, including excessive disturbance and assistance given too early

• twins

• physical calving problems: leg back, breech etc.

• deficiencies such as iodine, selenium/ vitamin E, vitamin A

• abortion and premature calving

• maternal problems, e.g. a high incidence of milk fever

• salmonella, summer mastitis and other toxaemias

Examine the calf to see if it died before (prepartum) or during (intra­partum) birth. The presence of meco­nium (foetal dung, see Chapter 5) on the calf’s coat or in its ears, trachea or stomach indicates that it was alive at

the start of the birth process, but because it became short of oxygen, it defaecated into the amnion (inner water bag) when struggling for breath. Intrapartum stillbirths are the most common. Prepartum deaths can be associated with salmonella, so laboratory culture of a few stillbirths can be worthwhile.

Many of the physical and management factors associated with calves born dead are described in Chapter 5, which should be read in conjunction with this section.