Diagnosing the nutritional causes of abortion

Background

Abortions are very costly for beef producers, and accurately diagnosing the cause is very difficult. They can be caused by a variety of viruses, bacteria, toxins, nutritional deficiencies, or combinations of these factors. Both vitamins A and E have important roles in maintaining a healthy fetus, and testing livers from aborted fetuses often points to vitamin A and E deficiencies in Western Canada. This is often assumed to mean the cow herd is also deficient in these vitamins. This assumption may not be safe.

The reason is that little vitamin A or E passes across the placenta from the pregnant cow to the fetal calf under ordinary conditions. This means low vitamin A and E levels in the liver of the aborted fetus could either be caused by low transfer from the dam (i.e., the cow’s vitamin status is normal, she just didn’t transfer much to the calf), or by a true deficiency in the dam (i.e., the reason the cow didn’t transfer vitamin A and E to the fetus is because she had none of her own to transfer).

This project will collect liver vitamin A and E data from both aborted fetuses and their dams. This will help clarify the biological relationship between maternal and fetal vitamin levels and assess whether we should be testing the cow rather than her aborted fetus, or both.

objectives

• To evaluate the correlation between maternal and fetal vitamin A and E levels in bovine abortion cases
• To compare maternal and fetal liver mineral profiles as supporting indicators of systemic nutritional status
• To generate data that informs diagnostic strategies and strengthens the nutritional component of abortion investigations in cattle

what they will do

They will collect paired samples from up to 50 abortion cases (i.e., from both the aborted fetus as well as its dam). They will test the fetuses for 17 different abortion-related pathogens. Both the fetus and the dam will be tested for 21 minerals, vitamin A and E levels – in the sera of the dams and livers of the fetuses.

Vitamin A and E levels in the aborted fetus liver and dam serum will be compared to determine whether vitamin status of the aborted fetus is a good predictor of vitamin status in the cow. Similar comparisons will be conducted for various minerals.

Implications

These findings will directly inform diagnostic strategies at veterinary laboratories, guide veterinarians in nutritional risk assessment and support producers in managing reproductive health. Ultimately, it will answer a fundamental question: when investigating reproductive loss in cattle, should we be looking at the fetus or the dam?